#!/usr/bin/perl

# vim: tw=160:nowrap:expandtab:tabstop=3:shiftwidth=3:softtabstop=3

# This program is copyright (c) 2006 Baron Schwartz, baron at xaprb dot com.
# Feedback and improvements are gratefully received.
#
# THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
# WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
# MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation, version 2; OR the Perl Artistic License.  On UNIX and similar
# systems, you can issue `man perlgpl' or `man perlartistic' to read these

# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc., 59 Temple
# Place, Suite 330, Boston, MA  02111-1307  USA

use strict;
use warnings FATAL => 'all';

our $VERSION = '1.7.1';

# Find the home directory; it's different on different OSes.
our $homepath = $ENV{HOME} || $ENV{HOMEPATH} || $ENV{USERPROFILE} || '.';

# Configuration files
our $default_home_conf = "$homepath/.innotop/innotop.conf";
our $default_central_conf = "/etc/innotop/innotop.conf";
our $conf_file = "";

## Begin packages ##

package DSNParser;

use DBI;
use Data::Dumper;
$Data::Dumper::Indent    = 0;
$Data::Dumper::Quotekeys = 0;
use English qw(-no_match_vars);

use constant MKDEBUG => $ENV{MKDEBUG};

# Defaults are built-in, but you can add/replace items by passing them as
# hashrefs of {key, desc, copy, dsn}.  The desc and dsn items are optional.
# You can set properties with the prop() sub.  Don't set the 'opts' property.
sub new {
   my ( $class, @opts ) = @_;
   my $self = {
      opts => {
         A => {
            desc => 'Default character set',
            dsn  => 'charset',
            copy => 1,
         },
         D => {
            desc => 'Database to use',
            dsn  => 'database',
            copy => 1,
         },
         F => {
            desc => 'Only read default options from the given file',
            dsn  => 'mysql_read_default_file',
            copy => 1,
         },
         h => {
            desc => 'Connect to host',
            dsn  => 'host',
            copy => 1,
         },
         p => {
            desc => 'Password to use when connecting',
            dsn  => 'password',
            copy => 1,
         },
         P => {
            desc => 'Port number to use for connection',
            dsn  => 'port',
            copy => 1,
         },
         S => {
            desc => 'Socket file to use for connection',
            dsn  => 'mysql_socket',
            copy => 1,
         },
         u => {
            desc => 'User for login if not current user',
            dsn  => 'user',
            copy => 1,
         },
      },
   };
   foreach my $opt ( @opts ) {
      MKDEBUG && _d('Adding extra property ' . $opt->{key});
      $self->{opts}->{$opt->{key}} = { desc => $opt->{desc}, copy => $opt->{copy} };
   }
   return bless $self, $class;
}

# Recognized properties:
# * autokey:   which key to treat a bareword as (typically h=host).
# * dbidriver: which DBI driver to use; assumes mysql, supports Pg.
# * required:  which parts are required (hashref).
# * setvars:   a list of variables to set after connecting
sub prop {
   my ( $self, $prop, $value ) = @_;
   if ( @_ > 2 ) {
      MKDEBUG && _d("Setting $prop property");
      $self->{$prop} = $value;
   }
   return $self->{$prop};
}

sub parse {
   my ( $self, $dsn, $prev, $defaults ) = @_;
   if ( !$dsn ) {
      MKDEBUG && _d('No DSN to parse');
      return;
   }
   MKDEBUG && _d("Parsing $dsn");
   $prev     ||= {};
   $defaults ||= {};
   my %given_props;
   my %final_props;
   my %opts = %{$self->{opts}};
   my $prop_autokey = $self->prop('autokey');

   # Parse given props
   foreach my $dsn_part ( split(/,/, $dsn) ) {
      if ( my ($prop_key, $prop_val) = $dsn_part =~  m/^(.)=(.*)$/ ) {
         # Handle the typical DSN parts like h=host, P=3306, etc.
         $given_props{$prop_key} = $prop_val;
      }
      elsif ( $prop_autokey ) {
         # Handle barewords
         MKDEBUG && _d("Interpreting $dsn_part as $prop_autokey=$dsn_part");
         $given_props{$prop_autokey} = $dsn_part;
      }
      else {
         MKDEBUG && _d("Bad DSN part: $dsn_part");
      }
   }

   # Fill in final props from given, previous, and/or default props
   foreach my $key ( keys %opts ) {
      MKDEBUG && _d("Finding value for $key");
      $final_props{$key} = $given_props{$key};
      if (   !defined $final_props{$key}
           && defined $prev->{$key} && $opts{$key}->{copy} )
      {
         $final_props{$key} = $prev->{$key};
         MKDEBUG && _d("Copying value for $key from previous DSN");
      }
      if ( !defined $final_props{$key} ) {
         $final_props{$key} = $defaults->{$key};
         MKDEBUG && _d("Copying value for $key from defaults");
      }
   }

   # Sanity check props
   foreach my $key ( keys %given_props ) {
      die "Unrecognized DSN part '$key' in '$dsn'\n"
         unless exists $opts{$key};
   }
   if ( (my $required = $self->prop('required')) ) {
      foreach my $key ( keys %$required ) {
         die "Missing DSN part '$key' in '$dsn'\n" unless $final_props{$key};
      }
   }

   return \%final_props;
}

sub as_string {
   my ( $self, $dsn ) = @_;
   return $dsn unless ref $dsn;
   return join(',',
      map  { "$_=" . ($_ eq 'p' ? '...' : $dsn->{$_}) }
      grep { defined $dsn->{$_} && $self->{opts}->{$_} }
      sort keys %$dsn );
}

sub usage {
   my ( $self ) = @_;
   my $usage
      = "DSN syntax is key=value[,key=value...]  Allowable DSN keys:\n"
      . "  KEY  COPY  MEANING\n"
      . "  ===  ====  =============================================\n";
   my %opts = %{$self->{opts}};
   foreach my $key ( sort keys %opts ) {
      $usage .= "  $key    "
             .  ($opts{$key}->{copy} ? 'yes   ' : 'no    ')
             .  ($opts{$key}->{desc} || '[No description]')
             . "\n";
   }
   if ( (my $key = $self->prop('autokey')) ) {
      $usage .= "  If the DSN is a bareword, the word is treated as the '$key' key.\n";
   }
   return $usage;
}

# Supports PostgreSQL via the dbidriver element of $info, but assumes MySQL by
# default.
sub get_cxn_params {
   my ( $self, $info ) = @_;
   my $dsn;
   my %opts = %{$self->{opts}};
   my $driver = $self->prop('dbidriver') || '';
   if ( $driver eq 'Pg' ) {
      $dsn = 'DBI:Pg:dbname=' . ( $info->{D} || '' ) . ';'
         . join(';', map  { "$opts{$_}->{dsn}=$info->{$_}" }
                     grep { defined $info->{$_} }
                     qw(h P));
   }
   else {
      $dsn = 'DBI:mysql:' . ( $info->{D} || '' ) . ';'
         . join(';', map  { "$opts{$_}->{dsn}=$info->{$_}" }
                     grep { defined $info->{$_} }
                     qw(F h P S A))
         . ';mysql_read_default_group=client';
   }
   MKDEBUG && _d($dsn);
   return ($dsn, $info->{u}, $info->{p});
}


# Fills in missing info from a DSN after successfully connecting to the server.
sub fill_in_dsn {
   my ( $self, $dbh, $dsn ) = @_;
   my $vars = $dbh->selectall_hashref('SHOW VARIABLES', 'Variable_name');
   my ($user, $db) = $dbh->selectrow_array('SELECT USER(), DATABASE()');
   $user =~ s/@.*//;
   $dsn->{h} ||= $vars->{hostname}->{Value};
   $dsn->{S} ||= $vars->{'socket'}->{Value};
   $dsn->{P} ||= $vars->{port}->{Value};
   $dsn->{u} ||= $user;
   $dsn->{D} ||= $db;
}

sub get_dbh {
   my ( $self, $cxn_string, $user, $pass, $opts ) = @_;
   $opts ||= {};
   my $defaults = {
      AutoCommit        => 0,
      RaiseError        => 1,
      PrintError        => 0,
      mysql_enable_utf8 => ($cxn_string =~ m/charset=utf8/ ? 1 : 0),
   };
   @{$defaults}{ keys %$opts } = values %$opts;
   my $dbh;
   my $tries = 2;
   while ( !$dbh && $tries-- ) {
      eval {
         MKDEBUG && _d($cxn_string, ' ', $user, ' ', $pass, ' {',
            join(', ', map { "$_=>$defaults->{$_}" } keys %$defaults ), '}');
         $dbh = DBI->connect($cxn_string, $user, $pass, $defaults);
         # Immediately set character set and binmode on STDOUT.
         if ( my ($charset) = $cxn_string =~ m/charset=(\w+)/ ) {
            my $sql = "/*!40101 SET NAMES $charset*/";
            MKDEBUG && _d("$dbh: $sql");
            $dbh->do($sql);
            MKDEBUG && _d('Enabling charset for STDOUT');
            if ( $charset eq 'utf8' ) {
               binmode(STDOUT, ':utf8')
                  or die "Can't binmode(STDOUT, ':utf8'): $OS_ERROR";
            }
            else {
               binmode(STDOUT) or die "Can't binmode(STDOUT): $OS_ERROR";
            }
         }
      };
      if ( !$dbh && $EVAL_ERROR ) {
         MKDEBUG && _d($EVAL_ERROR);
         if ( $EVAL_ERROR =~ m/not a compiled character set|character set utf8/ ) {
            MKDEBUG && _d("Going to try again without utf8 support");
            delete $defaults->{mysql_enable_utf8};
         }
         if ( !$tries ) {
            die $EVAL_ERROR;
         }
      }
   }
   # If setvars exists and it's MySQL connection, set them
   my $setvars = $self->prop('setvars');
   if ( $cxn_string =~ m/mysql/i && $setvars ) {
      my $sql = "SET $setvars";
      MKDEBUG && _d("$dbh: $sql");
      eval {
         $dbh->do($sql);
      };
      if ( $EVAL_ERROR ) {
         MKDEBUG && _d($EVAL_ERROR);
      }
   }
   MKDEBUG && _d('DBH info: ',
      $dbh,
      Dumper($dbh->selectrow_hashref(
         'SELECT DATABASE(), CONNECTION_ID(), VERSION()/*!50038 , @@hostname*/')),
      ' Connection info: ', ($dbh->{mysql_hostinfo} || 'undef'),
      ' Character set info: ',
      Dumper($dbh->selectall_arrayref(
         'SHOW VARIABLES LIKE "character_set%"', { Slice => {}})),
      ' $DBD::mysql::VERSION: ', $DBD::mysql::VERSION,
      ' $DBI::VERSION: ', $DBI::VERSION,
   );
   return $dbh;
}

# Tries to figure out a hostname for the connection.
sub get_hostname {
   my ( $self, $dbh ) = @_;
   if ( my ($host) = ($dbh->{mysql_hostinfo} || '') =~ m/^(\w+) via/ ) {
      return $host;
   }
   my ( $hostname, $one ) = $dbh->selectrow_array(
      'SELECT /*!50038 @@hostname, */ 1');
   return $hostname;
}

# Disconnects a database handle, but complains verbosely if there are any active
# children.  These are usually $sth handles that haven't been finish()ed.
sub disconnect {
   my ( $self, $dbh ) = @_;
   MKDEBUG && $self->print_active_handles($dbh);
   $dbh->disconnect;
}

sub print_active_handles {
   my ( $self, $thing, $level ) = @_;
   $level ||= 0;
   printf("# Active %sh: %s %s %s\n", ($thing->{Type} || 'undef'), "\t" x $level,
      $thing, (($thing->{Type} || '') eq 'st' ? $thing->{Statement} || '' : ''))
      or die "Cannot print: $OS_ERROR";
   foreach my $handle ( grep {defined} @{ $thing->{ChildHandles} } ) {
      $self->print_active_handles( $handle, $level + 1 );
   }
}

sub _d {
   my ($package, undef, $line) = caller 0;
   @_ = map { (my $temp = $_) =~ s/\n/\n# /g; $temp; }
        map { defined $_ ? $_ : 'undef' }
        @_;
   # Use $$ instead of $PID in case the package
   # does not use English.
   print "# $package:$line $$ ", @_, "\n";
}

1;

package InnoDBParser;

use Data::Dumper;
$Data::Dumper::Sortkeys = 1;
use English qw(-no_match_vars);
use List::Util qw(max);

# Some common patterns
my $d  = qr/(\d+)/;                    # Digit
my $f  = qr/(\d+\.\d+)/;               # Float
my $t  = qr/(\d+ \d+)/;                # Transaction ID
my $i  = qr/((?:\d{1,3}\.){3}\d+)/;    # IP address
my $n  = qr/([^`\s]+)/;                # MySQL object name
my $w  = qr/(\w+)/;                    # Words
my $fl = qr/([\w\.\/]+) line $d/;      # Filename and line number
my $h  = qr/((?:0x)?[0-9a-f]*)/;       # Hex
my $s  = qr/(\d{6} .\d:\d\d:\d\d)/;    # InnoDB timestamp

# If you update this variable, also update the SYNOPSIS in the pod.
my %innodb_section_headers = (
   "TRANSACTIONS"                          => "tx",
   "BUFFER POOL AND MEMORY"                => "bp",
   "SEMAPHORES"                            => "sm",
   "LOG"                                   => "lg",
   "ROW OPERATIONS"                        => "ro",
   "INSERT BUFFER AND ADAPTIVE HASH INDEX" => "ib",
   "FILE I/O"                              => "io",
   "LATEST DETECTED DEADLOCK"              => "dl",
   "LATEST FOREIGN KEY ERROR"              => "fk",
);

my %parser_for = (
   tx => \&parse_tx_section,
   bp => \&parse_bp_section,
   sm => \&parse_sm_section,
   lg => \&parse_lg_section,
   ro => \&parse_ro_section,
   ib => \&parse_ib_section,
   io => \&parse_io_section,
   dl => \&parse_dl_section,
   fk => \&parse_fk_section,
);

my %fk_parser_for = (
   Transaction => \&parse_fk_transaction_error,
   Error       => \&parse_fk_bad_constraint_error,
   Cannot      => \&parse_fk_cant_drop_parent_error,
);

# A thread's proc_info can be at least 98 different things I've found in the
# source.  Fortunately, most of them begin with a gerunded verb.  These are
# the ones that don't.
my %is_proc_info = (
   'After create'                 => 1,
   'Execution of init_command'    => 1,
   'FULLTEXT initialization'      => 1,
   'Reopen tables'                => 1,
   'Repair done'                  => 1,
   'Repair with keycache'         => 1,
   'System lock'                  => 1,
   'Table lock'                   => 1,
   'Thread initialized'           => 1,
   'User lock'                    => 1,
   'copy to tmp table'            => 1,
   'discard_or_import_tablespace' => 1,
   'end'                          => 1,
   'got handler lock'             => 1,
   'got old table'                => 1,
   'init'                         => 1,
   'key cache'                    => 1,
   'locks'                        => 1,
   'malloc'                       => 1,
   'query end'                    => 1,
   'rename result table'          => 1,
   'rename'                       => 1,
   'setup'                        => 1,
   'statistics'                   => 1,
   'status'                       => 1,
   'table cache'                  => 1,
   'update'                       => 1,
);

sub new {
   bless {}, shift;
}

# Parse the status and return it.
# See srv_printf_innodb_monitor in innobase/srv/srv0srv.c
# Pass in the text to parse, whether to be in debugging mode, which sections
# to parse (hashref; if empty, parse all), and whether to parse full info from
# locks and such (probably shouldn't unless you need to).
sub parse_status_text {
   my ( $self, $fulltext, $debug, $sections, $full ) = @_;

   die "I can't parse undef" unless defined $fulltext;
   $fulltext =~ s/[\r\n]+/\n/g;

   $sections ||= {};
   die '$sections must be a hashref' unless ref($sections) eq 'HASH';

   my %innodb_data = (
      got_all   => 0,         # Whether I was able to get the whole thing
      ts        => '',        # Timestamp the server put on it
      last_secs => 0,         # Num seconds the averages are over
      sections  => {},        # Parsed values from each section
   );

   if ( $debug ) {
      $innodb_data{'fulltext'} = $fulltext;
   }

   # Get the most basic info about the status: beginning and end, and whether
   # I got the whole thing (if there has been a big deadlock and there are
   # too many locks to print, the output might be truncated)
   my ( $time_text ) = $fulltext =~ m/^$s INNODB MONITOR OUTPUT$/m;
   $innodb_data{'ts'} = [ parse_innodb_timestamp( $time_text ) ];
   $innodb_data{'timestring'} = ts_to_string($innodb_data{'ts'});
   ( $innodb_data{'last_secs'} ) = $fulltext
      =~ m/Per second averages calculated from the last $d seconds/;

   ( my $got_all ) = $fulltext =~ m/END OF INNODB MONITOR OUTPUT/;
   $innodb_data{'got_all'} = $got_all || 0;

   # Split it into sections.  Each section begins with
   # -----
   # LABEL
   # -----
   my %innodb_sections;
   my @matches = $fulltext
      =~ m#\n(---+)\n([A-Z /]+)\n\1\n(.*?)(?=\n(---+)\n[A-Z /]+\n\4\n|$)#gs;
   while ( my ( $start, $name, $text, $end ) = splice(@matches, 0, 4) ) {
      $innodb_sections{$name} = [ $text, $end ? 1 : 0 ];
   }
   # The Row Operations section is a special case, because instead of ending
   # with the beginning of another section, it ends with the end of the file.
   # So this section is complete if the entire file is complete.
   $innodb_sections{'ROW OPERATIONS'}->[1] ||= $innodb_data{'got_all'};

   # Just for sanity's sake, make sure I understand what to do with each
   # section
   eval {
      foreach my $section ( keys %innodb_sections ) {
         my $header = $innodb_section_headers{$section};
         die "Unknown section $section in $fulltext\n"
            unless $header;
         $innodb_data{'sections'}->{ $header }
            ->{'fulltext'} = $innodb_sections{$section}->[0];
         $innodb_data{'sections'}->{ $header }
            ->{'complete'} = $innodb_sections{$section}->[1];
      }
   };
   if ( $EVAL_ERROR ) {
      _debug( $debug, $EVAL_ERROR);
   }

   # ################################################################
   # Parse the detailed data out of the sections.
   # ################################################################
   eval {
      foreach my $section ( keys %parser_for ) {
         if ( defined $innodb_data{'sections'}->{$section}
               && (!%$sections || (defined($sections->{$section} && $sections->{$section})) )) {
            $parser_for{$section}->(
                  $innodb_data{'sections'}->{$section},
                  $innodb_data{'sections'}->{$section}->{'complete'},
                  $debug,
                  $full )
               or delete $innodb_data{'sections'}->{$section};
         }
         else {
            delete $innodb_data{'sections'}->{$section};
         }
      }
   };
   if ( $EVAL_ERROR ) {
      _debug( $debug, $EVAL_ERROR);
   }

   return \%innodb_data;
}

# Parses the status text and returns it flattened out as a single hash.
sub get_status_hash {
   my ( $self, $fulltext, $debug, $sections, $full ) = @_;

   # Parse the status text...
   my $innodb_status
      = $self->parse_status_text($fulltext, $debug, $sections, $full );

   # Flatten the hierarchical structure into a single list by grabbing desired
   # sections from it.
   return
      (map { 'IB_' . $_ => $innodb_status->{$_} } qw(timestring last_secs got_all)),
      (map { 'IB_bp_' . $_ => $innodb_status->{'sections'}->{'bp'}->{$_} }
         qw( writes_pending buf_pool_hit_rate total_mem_alloc buf_pool_reads
            awe_mem_alloc pages_modified writes_pending_lru page_creates_sec
            reads_pending pages_total buf_pool_hits writes_pending_single_page
            page_writes_sec pages_read pages_written page_reads_sec
            writes_pending_flush_list buf_pool_size add_pool_alloc
            dict_mem_alloc pages_created buf_free complete )),
      (map { 'IB_tx_' . $_ => $innodb_status->{'sections'}->{'tx'}->{$_} }
         qw( num_lock_structs history_list_len purge_done_for transactions
            purge_undo_for is_truncated trx_id_counter complete )),
      (map { 'IB_ib_' . $_ => $innodb_status->{'sections'}->{'ib'}->{$_} }
         qw( hash_table_size hash_searches_s non_hash_searches_s
            bufs_in_node_heap used_cells size free_list_len seg_size inserts
            merged_recs merges complete )),
      (map { 'IB_lg_' . $_ => $innodb_status->{'sections'}->{'lg'}->{$_} }
         qw( log_ios_done pending_chkp_writes last_chkp log_ios_s
            log_flushed_to log_seq_no pending_log_writes complete )),
      (map { 'IB_sm_' . $_ => $innodb_status->{'sections'}->{'sm'}->{$_} }
         qw( wait_array_size rw_shared_spins rw_excl_os_waits mutex_os_waits
            mutex_spin_rounds mutex_spin_waits rw_excl_spins rw_shared_os_waits
            waits signal_count reservation_count complete )),
      (map { 'IB_ro_' . $_ => $innodb_status->{'sections'}->{'ro'}->{$_} }
         qw( queries_in_queue n_reserved_extents main_thread_state
         main_thread_proc_no main_thread_id read_sec del_sec upd_sec ins_sec
         read_views_open num_rows_upd num_rows_ins num_rows_read
         queries_inside num_rows_del complete )),
      (map { 'IB_fk_' . $_ => $innodb_status->{'sections'}->{'fk'}->{$_} }
         qw( trigger parent_table child_index parent_index attempted_op
         child_db timestring fk_name records col_name reason txn parent_db
         type child_table parent_col complete )),
      (map { 'IB_io_' . $_ => $innodb_status->{'sections'}->{'io'}->{$_} }
         qw( pending_buffer_pool_flushes pending_pwrites pending_preads
         pending_normal_aio_reads fsyncs_s os_file_writes pending_sync_ios
         reads_s flush_type avg_bytes_s pending_ibuf_aio_reads writes_s
         threads os_file_reads pending_aio_writes pending_log_ios os_fsyncs
         pending_log_flushes complete )),
      (map { 'IB_dl_' . $_ => $innodb_status->{'sections'}->{'dl'}->{$_} }
         qw( timestring rolled_back txns complete ));

}

sub ts_to_string {
   my $parts = shift;
   return sprintf('%02d-%02d-%02d %02d:%02d:%02d', @$parts);
}

sub parse_innodb_timestamp {
   my $text = shift;
   my ( $y, $m, $d, $h, $i, $s )
      = $text =~ m/^(\d\d)(\d\d)(\d\d) +(\d+):(\d+):(\d+)$/;
   die("Can't get timestamp from $text\n") unless $y;
   $y += 2000;
   return ( $y, $m, $d, $h, $i, $s );
}

sub parse_fk_section {
   my ( $section, $complete, $debug, $full ) = @_;
   my $fulltext = $section->{'fulltext'};

   return 0 unless $fulltext;

   my ( $ts, $type ) = $fulltext =~ m/^$s\s+(\w+)/m;
   $section->{'ts'} = [ parse_innodb_timestamp( $ts ) ];
   $section->{'timestring'} = ts_to_string($section->{'ts'});
   $section->{'type'} = $type;

   # Decide which type of FK error happened, and dispatch to the right parser.
   if ( $type && $fk_parser_for{$type} ) {
      $fk_parser_for{$type}->( $section, $complete, $debug, $fulltext, $full );
   }

   delete $section->{'fulltext'} unless $debug;

   return 1;
}

sub parse_fk_cant_drop_parent_error {
   my ( $section, $complete, $debug, $fulltext, $full ) = @_;

   # Parse the parent/child table info out
   @{$section}{ qw(attempted_op parent_db parent_table) } = $fulltext
      =~ m{Cannot $w table `(.*)/(.*)`}m;
   @{$section}{ qw(child_db child_table) } = $fulltext
      =~ m{because it is referenced by `(.*)/(.*)`}m;

   ( $section->{'reason'} ) = $fulltext =~ m/(Cannot .*)/s;
   $section->{'reason'} =~ s/\n(?:InnoDB: )?/ /gm
      if $section->{'reason'};

   # Certain data may not be present.  Make them '' if not present.
   map { $section->{$_} ||= "" }
      qw(child_index fk_name col_name parent_col);
}

# See dict/dict0dict.c, function dict_foreign_error_report
# I don't care much about these.  There are lots of different messages, and
# they come from someone trying to create a foreign key, or similar
# statements.  They aren't indicative of some transaction trying to insert,
# delete or update data.  Sometimes it is possible to parse out a lot of
# information about the tables and indexes involved, but often the message
# contains the DDL string the user entered, which is way too much for this
# module to try to handle.
sub parse_fk_bad_constraint_error {
   my ( $section, $complete, $debug, $fulltext, $full ) = @_;

   # Parse the parent/child table and index info out
   @{$section}{ qw(child_db child_table) } = $fulltext
      =~ m{Error in foreign key constraint of table (.*)/(.*):$}m;
   $section->{'attempted_op'} = 'DDL';

   # FK name, parent info... if possible.
   @{$section}{ qw(fk_name col_name parent_db parent_table parent_col) }
      = $fulltext
      =~ m/CONSTRAINT `?$n`? FOREIGN KEY \(`?$n`?\) REFERENCES (?:`?$n`?\.)?`?$n`? \(`?$n`?\)/;

   if ( !defined($section->{'fk_name'}) ) {
      # Try to parse SQL a user might have typed in a CREATE statement or such
      @{$section}{ qw(col_name parent_db parent_table parent_col) }
         = $fulltext
         =~ m/FOREIGN\s+KEY\s*\(`?$n`?\)\s+REFERENCES\s+(?:`?$n`?\.)?`?$n`?\s*\(`?$n`?\)/i;
   }
   $section->{'parent_db'} ||= $section->{'child_db'};

   # Name of the child index (index in the same table where the FK is, see
   # definition of dict_foreign_struct in include/dict0mem.h, where it is
   # called foreign_index, as opposed to referenced_index which is in the
   # parent table.  This may not be possible to find.
   @{$section}{ qw(child_index) } = $fulltext
      =~ m/^The index in the foreign key in table is $n$/m;

   @{$section}{ qw(reason) } = $fulltext =~ m/:\s*([^:]+)(?= Constraint:|$)/ms;
   $section->{'reason'} =~ s/\s+/ /g
      if $section->{'reason'};
   
   # Certain data may not be present.  Make them '' if not present.
   map { $section->{$_} ||= "" }
      qw(child_index fk_name col_name parent_table parent_col);
}

# see source file row/row0ins.c
sub parse_fk_transaction_error {
   my ( $section, $complete, $debug, $fulltext, $full ) = @_;

   # Parse the txn info out
   my ( $txn ) = $fulltext
      =~ m/Transaction:\n(TRANSACTION.*)\nForeign key constraint fails/s;
   if ( $txn ) {
      $section->{'txn'} = parse_tx_text( $txn, $complete, $debug, $full );
   }

   # Parse the parent/child table and index info out.  There are two types: an
   # update or a delete of a parent record leaves a child orphaned
   # (row_ins_foreign_report_err), and an insert or update of a child record has
   # no matching parent record (row_ins_foreign_report_add_err).

   @{$section}{ qw(reason child_db child_table) }
      = $fulltext =~ m{^(Foreign key constraint fails for table `(.*)/(.*)`:)$}m;

   @{$section}{ qw(fk_name col_name parent_db parent_table parent_col) }
      = $fulltext
      =~ m/CONSTRAINT `$n` FOREIGN KEY \(`$n`\) REFERENCES (?:`$n`\.)?`$n` \(`$n`\)/;
   $section->{'parent_db'} ||= $section->{'child_db'};

   # Special case, which I don't know how to trigger, but see
   # innobase/row/row0ins.c row_ins_check_foreign_constraint
   if ( $fulltext =~ m/ibd file does not currently exist!/ ) {
      my ( $attempted_op, $index, $records )
         = $fulltext =~ m/^Trying to (add to index) `$n` tuple:\n(.*))?/sm;
      $section->{'child_index'} = $index;
      $section->{'attempted_op'} = $attempted_op || '';
      if ( $records && $full ) {
         ( $section->{'records'} )
            = parse_innodb_record_dump( $records, $complete, $debug );
      }
      @{$section}{qw(parent_db parent_table)}
         =~ m/^But the parent table `$n`\.`$n`$/m;
   }
   else {
      my ( $attempted_op, $which, $index )
         = $fulltext =~ m/^Trying to ([\w ]*) in (child|parent) table, in index `$n` tuple:$/m;
      if ( $which ) {
         $section->{$which . '_index'} = $index;
         $section->{'attempted_op'} = $attempted_op || '';

         # Parse out the related records in the other table.
         my ( $search_index, $records );
         if ( $which eq 'child' ) {
            ( $search_index, $records ) = $fulltext
               =~ m/^But in parent table [^,]*, in index `$n`,\nthe closest match we can find is record:\n(.*)/ms;
            $section->{'parent_index'} = $search_index;
         }
         else {
            ( $search_index, $records ) = $fulltext
               =~ m/^But in child table [^,]*, in index `$n`, (?:the record is not available|there is a record:\n(.*))?/ms;
            $section->{'child_index'} = $search_index;
         }
         if ( $records && $full ) {
            $section->{'records'}
               = parse_innodb_record_dump( $records, $complete, $debug );
         }
         else {
            $section->{'records'} = '';
         }
      }
   }

   # Parse out the tuple trying to be updated, deleted or inserted.
   my ( $trigger ) = $fulltext =~ m/^(DATA TUPLE: \d+ fields;\n.*)$/m;
   if ( $trigger ) {
      $section->{'trigger'} = parse_innodb_record_dump( $trigger, $complete, $debug );
   }

   # Certain data may not be present.  Make them '' if not present.
   map { $section->{$_} ||= "" }
      qw(child_index fk_name col_name parent_table parent_col);
}

# There are new-style and old-style record formats.  See rem/rem0rec.c
# TODO: write some tests for this
sub parse_innodb_record_dump {
   my ( $dump, $complete, $debug ) = @_;
   return undef unless $dump;

   my $result = {};

   if ( $dump =~ m/PHYSICAL RECORD/ ) {
      my $style = $dump =~ m/compact format/ ? 'new' : 'old';
      $result->{'style'} = $style;

      # This is a new-style record.
      if ( $style eq 'new' ) {
         @{$result}{qw( heap_no type num_fields info_bits )}
            = $dump
            =~ m/^(?:Record lock, heap no $d )?([A-Z ]+): n_fields $d; compact format; info bits $d$/m;
      }

      # OK, it's old-style.  Unfortunately there are variations here too.
      elsif ( $dump =~ m/-byte offs / ) {
         # Older-old style.
         @{$result}{qw( heap_no type num_fields byte_offset info_bits )}
            = $dump
            =~ m/^(?:Record lock, heap no $d )?([A-Z ]+): n_fields $d; $d-byte offs [A-Z]+; info bits $d$/m;
            if ( $dump !~ m/-byte offs TRUE/ ) {
               $result->{'byte_offset'} = 0;
            }
      }
      else {
         # Newer-old style.
         @{$result}{qw( heap_no type num_fields byte_offset info_bits )}
            = $dump
            =~ m/^(?:Record lock, heap no $d )?([A-Z ]+): n_fields $d; $d-byte offsets; info bits $d$/m;
      }

   }
   else {
      $result->{'style'} = 'tuple';
      @{$result}{qw( type num_fields )}
         = $dump =~ m/^(DATA TUPLE): $d fields;$/m;
   }

   # Fill in default values for things that couldn't be parsed.
   map { $result->{$_} ||= 0 }
      qw(heap_no num_fields byte_offset info_bits);
   map { $result->{$_} ||= '' }
      qw(style type );

   my @fields = $dump =~ m/ (\d+:.*?;?);(?=$| \d+:)/gm;
   $result->{'fields'} = [ map { parse_field($_, $complete, $debug ) } @fields ];

   return $result;
}

# New/old-style applies here.  See rem/rem0rec.c
# $text should not include the leading space or the second trailing semicolon.
sub parse_field {
   my ( $text, $complete, $debug ) = @_;

   # Sample fields:
   # '4: SQL NULL, size 4 '
   # '1: len 6; hex 000000005601; asc     V ;'
   # '6: SQL NULL'
   # '5: len 30; hex 687474703a2f2f7777772e737765657477617465722e636f6d2f73746f72; asc http://www.sweetwater.com/stor;...(truncated)'
   my ( $id, $nullsize, $len, $hex, $asc, $truncated );
   ( $id, $nullsize ) = $text =~ m/^$d: SQL NULL, size $d $/;
   if ( !defined($id) ) {
      ( $id ) = $text =~ m/^$d: SQL NULL$/;
   }
   if ( !defined($id) ) {
      ( $id, $len, $hex, $asc, $truncated )
         = $text =~ m/^$d: len $d; hex $h; asc (.*);(\.\.\.\(truncated\))?$/;
   }

   die "Could not parse this field: '$text'" unless defined $id;
   return {
      id    => $id,
      len   => defined($len) ? $len : defined($nullsize) ? $nullsize : 0,
      'hex' => defined($hex) ? $hex : '',
      asc   => defined($asc) ? $asc : '',
      trunc => $truncated ? 1 : 0,
   };

}

sub parse_dl_section {
   my ( $dl, $complete, $debug, $full ) = @_;
   return unless $dl;
   my $fulltext = $dl->{'fulltext'};
   return 0 unless $fulltext;

   my ( $ts ) = $fulltext =~ m/^$s$/m;
   return 0 unless $ts;

   $dl->{'ts'} = [ parse_innodb_timestamp( $ts ) ];
   $dl->{'timestring'} = ts_to_string($dl->{'ts'});
   $dl->{'txns'} = {};

   my @sections
      = $fulltext
      =~ m{
         ^\*{3}\s([^\n]*)  # *** (1) WAITING FOR THIS...
         (.*?)             # Followed by anything, non-greedy
         (?=(?:^\*{3})|\z) # Followed by another three stars or EOF
      }gmsx;


   # Loop through each section.  There are no assumptions about how many
   # there are, who holds and wants what locks, and who gets rolled back.
   while ( my ($header, $body) = splice(@sections, 0, 2) ) {
      my ( $txn_id, $what ) = $header =~ m/^\($d\) (.*):$/;
      next unless $txn_id;
      $dl->{'txns'}->{$txn_id} ||= {};
      my $txn = $dl->{'txns'}->{$txn_id};

      if ( $what eq 'TRANSACTION' ) {
         $txn->{'tx'} = parse_tx_text( $body, $complete, $debug, $full );
      }
      else {
         push @{$txn->{'locks'}}, parse_innodb_record_locks( $body, $complete, $debug, $full );
      }
   }

   @{ $dl }{ qw(rolled_back) }
      = $fulltext =~ m/^\*\*\* WE ROLL BACK TRANSACTION \($d\)$/m;

   # Make sure certain values aren't undef
   map { $dl->{$_} ||= '' } qw(rolled_back);

   delete $dl->{'fulltext'} unless $debug;
   return 1;
}

sub parse_innodb_record_locks {
   my ( $text, $complete, $debug, $full ) = @_;
   my @result;

   foreach my $lock ( $text =~ m/(^(?:RECORD|TABLE) LOCKS?.*$)/gm ) {
      my $hash = {};
      @{$hash}{ qw(lock_type space_id page_no n_bits index db table txn_id lock_mode) }
         = $lock
         =~ m{^(RECORD|TABLE) LOCKS? (?:space id $d page no $d n bits $d index `?$n`? of )?table `$n(?:/|`\.`)$n` trx id $t lock.mode (\S+)}m;
      ( $hash->{'special'} )
         = $lock =~ m/^(?:RECORD|TABLE) .*? locks (rec but not gap|gap before rec)/m;
      $hash->{'insert_intention'}
         = $lock =~ m/^(?:RECORD|TABLE) .*? insert intention/m ? 1 : 0;
      $hash->{'waiting'}
         = $lock =~ m/^(?:RECORD|TABLE) .*? waiting/m ? 1 : 0;

      # Some things may not be in the text, so make sure they are not
      # undef.
      map { $hash->{$_} ||= 0 } qw(n_bits page_no space_id);
      map { $hash->{$_} ||= "" } qw(index special);
      push @result, $hash;
   }

   return @result;
}

sub parse_tx_text {
   my ( $txn, $complete, $debug, $full ) = @_;

   my ( $txn_id, $txn_status, $active_secs, $proc_no, $os_thread_id )
      = $txn
      =~ m/^(?:---)?TRANSACTION $t, (\D*?)(?: $d sec)?, (?:process no $d, )?OS thread id $d/m;
   my ( $thread_status, $thread_decl_inside )
      = $txn
      =~ m/OS thread id \d+(?: ([^,]+?))?(?:, thread declared inside InnoDB $d)?$/m;

   # Parsing the line that begins 'MySQL thread id' is complicated.  The only
   # thing always in the line is the thread and query id.  See function
   # innobase_mysql_print_thd in InnoDB source file sql/ha_innodb.cc.
   my ( $thread_line ) = $txn =~ m/^(MySQL thread id .*)$/m;
   my ( $mysql_thread_id, $query_id, $hostname, $ip, $user, $query_status );

   if ( $thread_line ) {
      # These parts can always be gotten.
      ( $mysql_thread_id, $query_id ) = $thread_line =~ m/^MySQL thread id $d, query id $d/m;

      # If it's a master/slave thread, "Has (read|sent) all" may be the thread's
      # proc_info.  In these cases, there won't be any host/ip/user info
      ( $query_status ) = $thread_line =~ m/(Has (?:read|sent) all .*$)/m;
      if ( defined($query_status) ) {
         $user = 'system user';
      }

      # It may be the case that the query id is the last thing in the line.
      elsif ( $thread_line =~ m/query id \d+ / ) {
         # The IP address is the only non-word thing left, so it's the most
         # useful marker for where I have to start guessing.
         ( $hostname, $ip ) = $thread_line =~ m/query id \d+(?: ([A-Za-z]\S+))? $i/m;
         if ( defined $ip ) {
            ( $user, $query_status ) = $thread_line =~ m/$ip $w(?: (.*))?$/;
         }
         else { # OK, there wasn't an IP address.
            # There might not be ANYTHING except the query status.
            ( $query_status ) = $thread_line =~ m/query id \d+ (.*)$/;
            if ( $query_status !~ m/^\w+ing/ && !exists($is_proc_info{$query_status}) ) {
               # The remaining tokens are, in order: hostname, user, query_status.
               # It's basically impossible to know which is which.
               ( $hostname, $user, $query_status ) = $thread_line
                  =~ m/query id \d+(?: ([A-Za-z]\S+))?(?: $w(?: (.*))?)?$/m;
            }
            else {
               $user = 'system user';
            }
         }
      }
   }

   my ( $lock_wait_status, $lock_structs, $heap_size, $row_locks, $undo_log_entries )
      = $txn
      =~ m/^(?:(\D*) )?$d lock struct\(s\), heap size $d(?:, $d row lock\(s\))?(?:, undo log entries $d)?$/m;
   my ( $lock_wait_time )
      = $txn
      =~ m/^------- TRX HAS BEEN WAITING $d SEC/m;

   my $locks;
   # If the transaction has locks, grab the locks.
   if ( $txn =~ m/^TABLE LOCK|RECORD LOCKS/ ) {
      $locks = [parse_innodb_record_locks($txn, $complete, $debug, $full)];
   }
   
   my ( $tables_in_use, $tables_locked )
      = $txn
      =~ m/^mysql tables in use $d, locked $d$/m;
   my ( $txn_doesnt_see_ge, $txn_sees_lt )
      = $txn
      =~ m/^Trx read view will not see trx with id >= $t, sees < $t$/m;
   my $has_read_view = defined($txn_doesnt_see_ge);
   # Only a certain number of bytes of the query text are included here, at least
   # under some circumstances.  Some versions include 300, some 600.
   my ( $query_text )
      = $txn
      =~ m{
         ^MySQL\sthread\sid\s[^\n]+\n           # This comes before the query text
         (.*?)                                  # The query text
         (?=                                    # Followed by any of...
            ^Trx\sread\sview
            |^-------\sTRX\sHAS\sBEEN\sWAITING
            |^TABLE\sLOCK
            |^RECORD\sLOCKS\sspace\sid
            |^(?:---)?TRANSACTION
            |^\*\*\*\s\(\d\)
            |\Z
         )
      }xms;
   if ( $query_text ) {
      $query_text =~ s/\s+$//;
   }
   else {
      $query_text = '';
   }

   my %stuff = (
      active_secs        => $active_secs,
      has_read_view      => $has_read_view,
      heap_size          => $heap_size,
      hostname           => $hostname,
      ip                 => $ip,
      lock_structs       => $lock_structs,
      lock_wait_status   => $lock_wait_status,
      lock_wait_time     => $lock_wait_time,
      mysql_thread_id    => $mysql_thread_id,
      os_thread_id       => $os_thread_id,
      proc_no            => $proc_no,
      query_id           => $query_id,
      query_status       => $query_status,
      query_text         => $query_text,
      row_locks          => $row_locks,
      tables_in_use      => $tables_in_use,
      tables_locked      => $tables_locked,
      thread_decl_inside => $thread_decl_inside,
      thread_status      => $thread_status,
      txn_doesnt_see_ge  => $txn_doesnt_see_ge,
      txn_id             => $txn_id,
      txn_sees_lt        => $txn_sees_lt,
      txn_status         => $txn_status,
      undo_log_entries   => $undo_log_entries,
      user               => $user,
   );
   $stuff{'fulltext'} = $txn if $debug;
   $stuff{'locks'} = $locks if $locks;

   # Some things may not be in the txn text, so make sure they are not
   # undef.
   map { $stuff{$_} ||= 0 } qw(active_secs heap_size lock_structs
         tables_in_use undo_log_entries tables_locked has_read_view
         thread_decl_inside lock_wait_time proc_no row_locks);
   map { $stuff{$_} ||= "" } qw(thread_status txn_doesnt_see_ge
         txn_sees_lt query_status ip query_text lock_wait_status user);
   $stuff{'hostname'} ||= $stuff{'ip'};

   return \%stuff;
}

sub parse_tx_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};
   $section->{'transactions'} = [];

   # Handle the individual transactions
   my @transactions = $fulltext =~ m/(---TRANSACTION \d.*?)(?=\n---TRANSACTION|$)/gs;
   foreach my $txn ( @transactions ) {
      my $stuff = parse_tx_text( $txn, $complete, $debug, $full );
      delete $stuff->{'fulltext'} unless $debug;
      push @{$section->{'transactions'}}, $stuff;
   }

   # Handle the general info
   @{$section}{ 'trx_id_counter' }
      = $fulltext =~ m/^Trx id counter $t$/m;
   @{$section}{ 'purge_done_for', 'purge_undo_for' }
      = $fulltext =~ m/^Purge done for trx's n:o < $t undo n:o < $t$/m;
   @{$section}{ 'history_list_len' } # This isn't present in some 4.x versions
      = $fulltext =~ m/^History list length $d$/m;
   @{$section}{ 'num_lock_structs' }
      = $fulltext =~ m/^Total number of lock structs in row lock hash table $d$/m;
   @{$section}{ 'is_truncated' }
      = $fulltext =~ m/^\.\.\. truncated\.\.\.$/m ? 1 : 0;

   # Fill in things that might not be present
   foreach ( qw(history_list_len) ) {
      $section->{$_} ||= 0;
   }

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

# I've read the source for this section.
sub parse_ro_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};

   # Grab the info
   @{$section}{ 'queries_inside', 'queries_in_queue' }
      = $fulltext =~ m/^$d queries inside InnoDB, $d queries in queue$/m;
   ( $section->{ 'read_views_open' } )
      = $fulltext =~ m/^$d read views open inside InnoDB$/m;
   ( $section->{ 'n_reserved_extents' } )
      = $fulltext =~ m/^$d tablespace extents now reserved for B-tree/m;
   @{$section}{ 'main_thread_proc_no', 'main_thread_id', 'main_thread_state' }
      = $fulltext =~ m/^Main thread (?:process no. $d, )?id $d, state: (.*)$/m;
   @{$section}{ 'num_rows_ins', 'num_rows_upd', 'num_rows_del', 'num_rows_read' }
      = $fulltext =~ m/^Number of rows inserted $d, updated $d, deleted $d, read $d$/m;
   @{$section}{ 'ins_sec', 'upd_sec', 'del_sec', 'read_sec' }
      = $fulltext =~ m#^$f inserts/s, $f updates/s, $f deletes/s, $f reads/s$#m;
   $section->{'main_thread_proc_no'} ||= 0;

   map { $section->{$_} ||= 0 } qw(read_views_open n_reserved_extents);
   delete $section->{'fulltext'} unless $debug;
   return 1;
}

sub parse_lg_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section;
   my $fulltext = $section->{'fulltext'};

   # Grab the info
   ( $section->{ 'log_seq_no' } )
      = $fulltext =~ m/Log sequence number \s*(\d.*)$/m;
   ( $section->{ 'log_flushed_to' } )
      = $fulltext =~ m/Log flushed up to \s*(\d.*)$/m;
   ( $section->{ 'last_chkp' } )
      = $fulltext =~ m/Last checkpoint at \s*(\d.*)$/m;
   @{$section}{ 'pending_log_writes', 'pending_chkp_writes' }
      = $fulltext =~ m/$d pending log writes, $d pending chkp writes/;
   @{$section}{ 'log_ios_done', 'log_ios_s' }
      = $fulltext =~ m#$d log i/o's done, $f log i/o's/second#;

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

sub parse_ib_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};

   # Some servers will output ibuf information for tablespace 0, as though there
   # might be many tablespaces with insert buffers.  (In practice I believe
   # the source code shows there will only ever be one).  I have to parse both
   # cases here, but I assume there will only be one.
   @{$section}{ 'size', 'free_list_len', 'seg_size' }
      = $fulltext =~ m/^Ibuf(?: for space 0)?: size $d, free list len $d, seg size $d,$/m;
   @{$section}{ 'inserts', 'merged_recs', 'merges' }
      = $fulltext =~ m/^$d inserts, $d merged recs, $d merges$/m;

   @{$section}{ 'hash_table_size', 'used_cells', 'bufs_in_node_heap' }
      = $fulltext =~ m/^Hash table size $d, used cells $d, node heap has $d buffer\(s\)$/m;
   @{$section}{ 'hash_searches_s', 'non_hash_searches_s' }
      = $fulltext =~ m{^$f hash searches/s, $f non-hash searches/s$}m;

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

sub parse_wait_array {
   my ( $text, $complete, $debug, $full ) = @_;
   my %result;

   @result{ qw(thread waited_at_filename waited_at_line waited_secs) }
      = $text =~ m/^--Thread $d has waited at $fl for $f seconds/m;

   # Depending on whether it's a SYNC_MUTEX,RW_LOCK_EX,RW_LOCK_SHARED,
   # there will be different text output
   if ( $text =~ m/^Mutex at/m ) {
      $result{'request_type'} = 'M';
      @result{ qw( lock_mem_addr lock_cfile_name lock_cline lock_var) }
         = $text =~ m/^Mutex at $h created file $fl, lock var $d$/m;
      @result{ qw( waiters_flag )}
         = $text =~ m/^waiters flag $d$/m;
   }
   else {
      @result{ qw( request_type lock_mem_addr lock_cfile_name lock_cline) }
         = $text =~ m/^(.)-lock on RW-latch at $h created in file $fl$/m;
      @result{ qw( writer_thread writer_lock_mode ) }
         = $text =~ m/^a writer \(thread id $d\) has reserved it in mode  (.*)$/m;
      @result{ qw( num_readers waiters_flag )}
         = $text =~ m/^number of readers $d, waiters flag $d$/m;
      @result{ qw(last_s_file_name last_s_line ) }
         = $text =~ m/Last time read locked in file $fl$/m;
      @result{ qw(last_x_file_name last_x_line ) }
         = $text =~ m/Last time write locked in file $fl$/m;
   }

   $result{'cell_waiting'} = $text =~ m/^wait has ended$/m ? 0 : 1;
   $result{'cell_event_set'} = $text =~ m/^wait is ending$/m ? 1 : 0;

   # Because there are two code paths, some things won't get set.
   map { $result{$_} ||= '' }
      qw(last_s_file_name last_x_file_name writer_lock_mode);
   map { $result{$_} ||= 0 }
      qw(num_readers lock_var last_s_line last_x_line writer_thread);

   return \%result;
}

sub parse_sm_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return 0 unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};

   # Grab the info
   @{$section}{ 'reservation_count', 'signal_count' }
      = $fulltext =~ m/^OS WAIT ARRAY INFO: reservation count $d, signal count $d$/m;
   @{$section}{ 'mutex_spin_waits', 'mutex_spin_rounds', 'mutex_os_waits' }
      = $fulltext =~ m/^Mutex spin waits $d, rounds $d, OS waits $d$/m;
   @{$section}{ 'rw_shared_spins', 'rw_shared_os_waits', 'rw_excl_spins', 'rw_excl_os_waits' }
      = $fulltext =~ m/^RW-shared spins $d, OS waits $d; RW-excl spins $d, OS waits $d$/m;

   # Look for info on waits.
   my @waits = $fulltext =~ m/^(--Thread.*?)^(?=Mutex spin|--Thread)/gms;
   $section->{'waits'} = [ map { parse_wait_array($_, $complete, $debug) } @waits ];
   $section->{'wait_array_size'} = scalar(@waits);

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

# I've read the source for this section.
sub parse_bp_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};

   # Grab the info
   @{$section}{ 'total_mem_alloc', 'add_pool_alloc' }
      = $fulltext =~ m/^Total memory allocated $d; in additional pool allocated $d$/m;
   @{$section}{'dict_mem_alloc'}     = $fulltext =~ m/Dictionary memory allocated $d/;
   @{$section}{'awe_mem_alloc'}      = $fulltext =~ m/$d MB of AWE memory/;
   @{$section}{'buf_pool_size'}      = $fulltext =~ m/^Buffer pool size\s*$d$/m;
   @{$section}{'buf_free'}           = $fulltext =~ m/^Free buffers\s*$d$/m;
   @{$section}{'pages_total'}        = $fulltext =~ m/^Database pages\s*$d$/m;
   @{$section}{'pages_modified'}     = $fulltext =~ m/^Modified db pages\s*$d$/m;
   @{$section}{'pages_read', 'pages_created', 'pages_written'}
      = $fulltext =~ m/^Pages read $d, created $d, written $d$/m;
   @{$section}{'page_reads_sec', 'page_creates_sec', 'page_writes_sec'}
      = $fulltext =~ m{^$f reads/s, $f creates/s, $f writes/s$}m;
   @{$section}{'buf_pool_hits', 'buf_pool_reads'}
      = $fulltext =~ m{Buffer pool hit rate $d / $d$}m;
   if ($fulltext =~ m/^No buffer pool page gets since the last printout$/m) {
      @{$section}{'buf_pool_hits', 'buf_pool_reads'} = (0, 0);
      @{$section}{'buf_pool_hit_rate'} = '--';
   }
   else {
      @{$section}{'buf_pool_hit_rate'}
         = $fulltext =~ m{Buffer pool hit rate (\d+ / \d+)$}m;
   }
   @{$section}{'reads_pending'} = $fulltext =~ m/^Pending reads $d/m;
   @{$section}{'writes_pending_lru', 'writes_pending_flush_list', 'writes_pending_single_page' }
      = $fulltext =~ m/^Pending writes: LRU $d, flush list $d, single page $d$/m;

   map { $section->{$_} ||= 0 }
      qw(writes_pending_lru writes_pending_flush_list writes_pending_single_page
      awe_mem_alloc dict_mem_alloc);
   @{$section}{'writes_pending'} = List::Util::sum(
      @{$section}{ qw(writes_pending_lru writes_pending_flush_list writes_pending_single_page) });

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

# I've read the source for this.
sub parse_io_section {
   my ( $section, $complete, $debug, $full ) = @_;
   return unless $section && $section->{'fulltext'};
   my $fulltext = $section->{'fulltext'};
   $section->{'threads'} = {};

   # Grab the I/O thread info
   my @threads = $fulltext =~ m<^(I/O thread \d+ .*)$>gm;
   foreach my $thread (@threads) {
      my ( $tid, $state, $purpose, $event_set )
         = $thread =~ m{I/O thread $d state: (.+?) \((.*)\)(?: ev set)?$}m;
      if ( defined $tid ) {
         $section->{'threads'}->{$tid} = {
            thread    => $tid,
            state     => $state,
            purpose   => $purpose,
            event_set => $event_set ? 1 : 0,
         };
      }
   }

   # Grab the reads/writes/flushes info
   @{$section}{ 'pending_normal_aio_reads', 'pending_aio_writes' }
      = $fulltext =~ m/^Pending normal aio reads: $d, aio writes: $d,$/m;
   @{$section}{ 'pending_ibuf_aio_reads', 'pending_log_ios', 'pending_sync_ios' }
      = $fulltext =~ m{^ ibuf aio reads: $d, log i/o's: $d, sync i/o's: $d$}m;
   @{$section}{ 'flush_type', 'pending_log_flushes', 'pending_buffer_pool_flushes' }
      = $fulltext =~ m/^Pending flushes \($w\) log: $d; buffer pool: $d$/m;
   @{$section}{ 'os_file_reads', 'os_file_writes', 'os_fsyncs' }
      = $fulltext =~ m/^$d OS file reads, $d OS file writes, $d OS fsyncs$/m;
   @{$section}{ 'reads_s', 'avg_bytes_s', 'writes_s', 'fsyncs_s' }
      = $fulltext =~ m{^$f reads/s, $d avg bytes/read, $f writes/s, $f fsyncs/s$}m;
   @{$section}{ 'pending_preads', 'pending_pwrites' }
      = $fulltext =~ m/$d pending preads, $d pending pwrites$/m;
   @{$section}{ 'pending_preads', 'pending_pwrites' } = (0, 0)
      unless defined($section->{'pending_preads'});

   delete $section->{'fulltext'} unless $debug;
   return 1;
}

sub _debug {
   my ( $debug, $msg ) = @_;
   if ( $debug ) {
      die $msg;
   }
   else {
      warn $msg;
   }
   return 1;
}

1;

# end_of_package InnoDBParser

package main;

use sigtrap qw(handler finish untrapped normal-signals);

use Data::Dumper;
use DBI;
use English qw(-no_match_vars);
use File::Basename qw(dirname);
use File::Temp;
use Getopt::Long;
use List::Util qw(max min maxstr sum);
use POSIX qw(ceil);
use Time::HiRes qw(time sleep);
use Term::ReadKey qw(ReadMode ReadKey);

# License and warranty information. {{{1
# ###########################################################################

my $innotop_license = <<"LICENSE";

This is innotop version $VERSION, a MySQL and InnoDB monitor.

This program is copyright (c) 2006 Baron Schwartz.
Feedback and improvements are welcome.

THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation, version 2; OR the Perl Artistic License.  On UNIX and similar
systems, you can issue `man perlgpl' or `man perlartistic' to read these
licenses.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA  02111-1307  USA.
LICENSE

# Configuration information and global setup {{{1
# ###########################################################################

# Really, really, super-global variables.
my @config_versions = (
   "000-000-000", "001-003-000", # config file was one big name-value hash.
   "001-003-000", "001-004-002", # config file contained non-user-defined stuff.
);

my $clear_screen_sub;
my $dsn_parser = new DSNParser();

# This defines expected properties and defaults for the column definitions that
# eventually end up in tbl_meta.
my %col_props = (
   hdr     => '',
   just    => '-',
   dec     => 0,     # Whether to align the column on the decimal point
   num     => 0,
   label   => '',
   user    => 0,
   src     => '',
   tbl     => '',    # Helps when writing/reading custom columns in config files
   minw    => 0,
   maxw    => 0,
   trans   => [],
   agg     => 'first',  # Aggregate function
   aggonly => 0,        # Whether to show only when tbl_meta->{aggregate} is true
);

# Actual DBI connections to MySQL servers.
my %dbhs;

# Command-line parameters {{{2
# ###########################################################################

my @opt_spec = (
   { s => 'help',       d => 'Show this help message' },
   { s => 'color|C!',   d => 'Use terminal coloring (default)',   c => 'color' },
   { s => 'config|c=s', d => 'Config file to read' },
   { s => 'nonint|n',   d => 'Non-interactive, output tab-separated fields' },
   { s => 'count=i',    d => 'Number of updates before exiting' },
   { s => 'delay|d=f',  d => 'Delay between updates in seconds',  c => 'interval' },
   { s => 'mode|m=s',   d => 'Operating mode to start in',        c => 'mode' },
   { s => 'inc|i!',     d => 'Measure incremental differences',   c => 'status_inc' },
   { s => 'write|w',    d => 'Write running configuration into home directory if no config files were loaded' },
   { s => 'skipcentral|s',     d => 'Skip reading the central configuration file' },
   { s => 'version',    d => 'Output version information and exit' },
   { s => 'user|u=s',   d => 'User for login if not current user' },
   { s => 'password|p=s',   d => 'Password to use for connection' },
   { s => 'host|h=s',   d => 'Connect to host' },
   { s => 'port|P=i',   d => 'Port number to use for connection' },
);

# This is the container for the command-line options' values to be stored in
# after processing.  Initial values are defaults.
my %opts = (
   n => !( -t STDIN && -t STDOUT ), # If in/out aren't to terminals, we're interactive
);
# Post-process...
my %opt_seen;
foreach my $spec ( @opt_spec ) {
   my ( $long, $short ) = $spec->{s} =~ m/^(\w+)(?:\|([^!+=]*))?/;
   $spec->{k} = $short || $long;
   $spec->{l} = $long;
   $spec->{t} = $short;
   $spec->{n} = $spec->{s} =~ m/!/;
   $opts{$spec->{k}} = undef unless defined $opts{$spec->{k}};
   die "Duplicate option $spec->{k}" if $opt_seen{$spec->{k}}++;
}

Getopt::Long::Configure('no_ignore_case', 'bundling');
GetOptions( map { $_->{s} => \$opts{$_->{k}} } @opt_spec) or $opts{help} = 1;

if ( $opts{version} ) {
   print "innotop  Ver $VERSION\n";
   exit(0);
}

if ( $opts{c} and ! -f $opts{c} ) {
   print $opts{c} . " doesn't exist.  Exiting.\n";
   exit(1);
}
if ( $opts{'help'} ) {
   print "Usage: innotop <options> <innodb-status-file>\n\n";
   my $maxw = max(map { length($_->{l}) + ($_->{n} ? 4 : 0)} @opt_spec);
   foreach my $spec ( sort { $a->{l} cmp $b->{l} } @opt_spec ) {
      my $long  = $spec->{n} ? "[no]$spec->{l}" : $spec->{l};
      my $short = $spec->{t} ? "-$spec->{t}" : '';
      printf("  --%-${maxw}s %-4s %s\n", $long, $short, $spec->{d});
   }
   print <<USAGE;

innotop is a MySQL and InnoDB transaction/status monitor, like 'top' for
MySQL.  It displays queries, InnoDB transactions, lock waits, deadlocks,
foreign key errors, open tables, replication status, buffer information,
row operations, logs, I/O operations, load graph, and more.  You can
monitor many servers at once with innotop. 

USAGE
   exit(1);
}

# Meta-data (table definitions etc) {{{2
# ###########################################################################

# Expressions {{{3
# Convenience so I can copy/paste these in several places...
# ###########################################################################
my %exprs = (
   Host              => q{my $host = host || hostname || ''; ($host) = $host =~ m/^((?:[\d.]+(?=:))|(?:[a-zA-Z]\w+))/; return $host || ''},
   Port              => q{my ($p) = host =~ m/:(.*)$/; return $p || 0},
   OldVersions       => q{dulint_to_int(IB_tx_trx_id_counter) - dulint_to_int(IB_tx_purge_done_for)},
   MaxTxnTime        => q/max(map{ $_->{active_secs} } @{ IB_tx_transactions }) || 0/,
   NumTxns           => q{scalar @{ IB_tx_transactions } },
   DirtyBufs         => q{ $cur->{IB_bp_pages_modified} / ($cur->{IB_bp_buf_pool_size} || 1) },
   BufPoolFill       => q{ $cur->{IB_bp_pages_total} / ($cur->{IB_bp_buf_pool_size} || 1) },
   ServerLoad        => q{ $cur->{Threads_connected}/(Questions||1)/Uptime_hires },
   TxnTimeRemain     => q{ defined undo_log_entries && defined $pre->{undo_log_entries} && undo_log_entries < $pre->{undo_log_entries} ? undo_log_entries / (($pre->{undo_log_entries} - undo_log_entries)/((active_secs-$pre->{active_secs})||1))||1 : 0},
   SlaveCatchupRate  => ' defined $cur->{seconds_behind_master} && defined $pre->{seconds_behind_master} && $cur->{seconds_behind_master} < $pre->{seconds_behind_master} ? ($pre->{seconds_behind_master}-$cur->{seconds_behind_master})/($cur->{Uptime_hires}-$pre->{Uptime_hires}) : 0',
   QcacheHitRatio    => q{(Qcache_hits||0)/(((Com_select||0)+(Qcache_hits||0))||1)},
);

# ###########################################################################
# Column definitions {{{3
# Defines every column in every table. A named column has the following
# properties:
#    * hdr    Column header/title
#    * label  Documentation for humans.
#    * num    Whether it's numeric (for sorting).
#    * just   Alignment; generated from num, user-overridable in tbl_meta
#    * minw, maxw Auto-generated, user-overridable.
# Values from this hash are just copied to tbl_meta, which is where everything
# else in the program should read from.
# ###########################################################################

my %columns = (
   active_secs                 => { hdr => 'SecsActive',          num => 1, label => 'Seconds transaction has been active', },
   add_pool_alloc              => { hdr => 'Add\'l Pool',         num => 1, label => 'Additonal pool allocated' },
   attempted_op                => { hdr => 'Action',              num => 0, label => 'The action that caused the error' },
   awe_mem_alloc               => { hdr => 'AWE Memory',          num => 1, label => '[Windows] AWE memory allocated' },
   binlog_cache_overflow       => { hdr => 'Binlog Cache',        num => 1, label => 'Transactions too big for binlog cache that went to disk' },
   binlog_do_db                => { hdr => 'Binlog Do DB',        num => 0, label => 'binlog-do-db setting' },
   binlog_ignore_db            => { hdr => 'Binlog Ignore DB',    num => 0, label => 'binlog-ignore-db setting' },
   bps_in                      => { hdr => 'BpsIn',               num => 1, label => 'Bytes per second received by the server', },
   bps_out                     => { hdr => 'BpsOut',              num => 1, label => 'Bytes per second sent by the server', },
   buf_free                    => { hdr => 'Free Bufs',           num => 1, label => 'Buffers free in the buffer pool' },
   buf_pool_hit_rate           => { hdr => 'Hit Rate',            num => 0, label => 'Buffer pool hit rate' },
   buf_pool_hits               => { hdr => 'Hits',                num => 1, label => 'Buffer pool hits' },
   buf_pool_reads              => { hdr => 'Reads',               num => 1, label => 'Buffer pool reads' },
   buf_pool_size               => { hdr => 'Size',                num => 1, label => 'Buffer pool size' },
   bufs_in_node_heap           => { hdr => 'Node Heap Bufs',      num => 1, label => 'Buffers in buffer pool node heap' },
   bytes_behind_master         => { hdr => 'ByteLag',             num => 1, label => 'Bytes the slave lags the master in binlog' },
   cell_event_set              => { hdr => 'Ending?',             num => 1, label => 'Whether the cell event is set' },
   cell_waiting                => { hdr => 'Waiting?',            num => 1, label => 'Whether the cell is waiting' },
   child_db                    => { hdr => 'Child DB',            num => 0, label => 'The database of the child table' },
   child_index                 => { hdr => 'Child Index',         num => 0, label => 'The index in the child table' },
   child_table                 => { hdr => 'Child Table',         num => 0, label => 'The child table' },
   cmd                         => { hdr => 'Cmd',                 num => 0, label => 'Type of command being executed', },
   cnt                         => { hdr => 'Cnt',                 num => 0, label => 'Count', agg => 'count', aggonly => 1 },
   connect_retry               => { hdr => 'Connect Retry',       num => 1, label => 'Slave connect-retry timeout' },
   cxn                         => { hdr => 'CXN',                 num => 0, label => 'Connection from which the data came', },
   db                          => { hdr => 'DB',                  num => 0, label => 'Current database', },
   dict_mem_alloc              => { hdr => 'Dict Mem',            num => 1, label => 'Dictionary memory allocated' },
   dirty_bufs                  => { hdr => 'Dirty Buf',           num => 1, label => 'Dirty buffer pool pages' },
   dl_txn_num                  => { hdr => 'Num',                 num => 0, label => 'Deadlocked transaction number', },
   event_set                   => { hdr => 'Evt Set?',            num => 1, label => '[Win32] if a wait event is set', },
   exec_master_log_pos         => { hdr => 'Exec Master Log Pos', num => 1, label => 'Exec Master Log Position' },
   fk_name                     => { hdr => 'Constraint',          num => 0, label => 'The name of the FK constraint' },
   free_list_len               => { hdr => 'Free List Len',       num => 1, label => 'Length of the free list' },
   has_read_view               => { hdr => 'Rd View',             num => 1, label => 'Whether the transaction has a read view' },
   hash_searches_s             => { hdr => 'Hash/Sec',            num => 1, label => 'Number of hash searches/sec' },
   hash_table_size             => { hdr => 'Size',                num => 1, label => 'Number of non-hash searches/sec' },
   heap_no                     => { hdr => 'Heap',                num => 1, label => 'Heap number' },
   heap_size                   => { hdr => 'Heap',                num => 1, label => 'Heap size' },
   history_list_len            => { hdr => 'History',             num => 1, label => 'History list length' },
   host_and_domain             => { hdr => 'Host',                num => 0, label => 'Hostname/IP and domain' },
   host_and_port               => { hdr => 'Host/IP',             num => 0, label => 'Hostname or IP address, and port number', },
   hostname                    => { hdr => 'Host',                num => 0, label => 'Hostname' },
   index                       => { hdr => 'Index',               num => 0, label => 'The index involved' },
   index_ref                   => { hdr => 'Index Ref',           num => 0, label => 'Index referenced' },
   info                        => { hdr => 'Query',               num => 0, label => 'Info or the current query', },
   insert_intention            => { hdr => 'Ins Intent',          num => 1, label => 'Whether the thread was trying to insert' },
   inserts                     => { hdr => 'Inserts',             num => 1, label => 'Inserts' },
   io_bytes_s                  => { hdr => 'Bytes/Sec',           num => 1, label => 'Average I/O bytes/sec' },
   io_flush_type               => { hdr => 'Flush Type',          num => 0, label => 'I/O Flush Type' },
   io_fsyncs_s                 => { hdr => 'fsyncs/sec',          num => 1, label => 'I/O fsyncs/sec' },
   io_reads_s                  => { hdr => 'Reads/Sec',           num => 1, label => 'Average I/O reads/sec' },
   io_writes_s                 => { hdr => 'Writes/Sec',          num => 1, label => 'Average I/O writes/sec' },
   ip                          => { hdr => 'IP',                  num => 0, label => 'IP address' },
   is_name_locked              => { hdr => 'Locked',              num => 1, label => 'Whether table is name locked', },
   key_buffer_hit              => { hdr => 'KCacheHit',           num => 1, label => 'Key cache hit ratio', },
   key_len                     => { hdr => 'Key Length',          num => 1, label => 'Number of bytes used in the key' },
   last_chkp                   => { hdr => 'Last Checkpoint',     num => 0, label => 'Last log checkpoint' },
   last_errno                  => { hdr => 'Last Errno',          num => 1, label => 'Last error number' },
   last_error                  => { hdr => 'Last Error',          num => 0, label => 'Last error' },
   last_s_file_name            => { hdr => 'S-File',              num => 0, label => 'Filename where last read locked' },
   last_s_line                 => { hdr => 'S-Line',              num => 1, label => 'Line where last read locked' },
   last_x_file_name            => { hdr => 'X-File',              num => 0, label => 'Filename where last write locked' },
   last_x_line                 => { hdr => 'X-Line',              num => 1, label => 'Line where last write locked' },
   last_pct                    => { hdr => 'Pct',                 num => 1, label => 'Last Percentage' },
   last_total                  => { hdr => 'Last Total',          num => 1, label => 'Last Total' },
   last_value                  => { hdr => 'Last Incr',           num => 1, label => 'Last Value' },
   load                        => { hdr => 'Load',                num => 1, label => 'Server load' },
   lock_cfile_name             => { hdr => 'Crtd File',           num => 0, label => 'Filename where lock created' },
   lock_cline                  => { hdr => 'Crtd Line',           num => 1, label => 'Line where lock created' },
   lock_mem_addr               => { hdr => 'Addr',                num => 0, label => 'The lock memory address' },
   lock_mode                   => { hdr => 'Mode',                num => 0, label => 'The lock mode' },
   lock_structs                => { hdr => 'LStrcts',             num => 1, label => 'Number of lock structs' },
   lock_type                   => { hdr => 'Type',                num => 0, label => 'The lock type' },
   lock_var                    => { hdr => 'Lck Var',             num => 1, label => 'The lock variable' },
   lock_wait_time              => { hdr => 'Wait',                num => 1, label => 'How long txn has waited for a lock' },
   log_flushed_to              => { hdr => 'Flushed To',          num => 0, label => 'Log position flushed to' },
   log_ios_done                => { hdr => 'IO Done',             num => 1, label => 'Log I/Os done' },
   log_ios_s                   => { hdr => 'IO/Sec',              num => 1, label => 'Average log I/Os per sec' },
   log_seq_no                  => { hdr => 'Sequence No.',        num => 0, label => 'Log sequence number' },
   main_thread_id              => { hdr => 'Main Thread ID',      num => 1, label => 'Main thread ID' },
   main_thread_proc_no         => { hdr => 'Main Thread Proc',    num => 1, label => 'Main thread process number' },
   main_thread_state           => { hdr => 'Main Thread State',   num => 0, label => 'Main thread state' },
   master_file                 => { hdr => 'File',                num => 0, label => 'Master file' },
   master_host                 => { hdr => 'Master',              num => 0, label => 'Master server hostname' },
   master_log_file             => { hdr => 'Master Log File',     num => 0, label => 'Master log file' },
   master_port                 => { hdr => 'Master Port',         num => 1, label => 'Master port' },
   master_pos                  => { hdr => 'Position',            num => 1, label => 'Master position' },
   master_ssl_allowed          => { hdr => 'Master SSL Allowed',  num => 0, label => 'Master SSL Allowed' },
   master_ssl_ca_file          => { hdr => 'Master SSL CA File',  num => 0, label => 'Master SSL Cert Auth File' },
   master_ssl_ca_path          => { hdr => 'Master SSL CA Path',  num => 0, label => 'Master SSL Cert Auth Path' },
   master_ssl_cert             => { hdr => 'Master SSL Cert',     num => 0, label => 'Master SSL Cert' },
   master_ssl_cipher           => { hdr => 'Master SSL Cipher',   num => 0, label => 'Master SSL Cipher' },
   master_ssl_key              => { hdr => 'Master SSL Key',      num => 0, label => 'Master SSL Key' },
   master_user                 => { hdr => 'Master User',         num => 0, label => 'Master username' },
   max_txn                     => { hdr => 'MaxTxnTime',          num => 1, label => 'MaxTxn' },
   merged_recs                 => { hdr => 'Merged Recs',         num => 1, label => 'Merged records' },
   merges                      => { hdr => 'Merges',              num => 1, label => 'Merges' },
   mutex_os_waits              => { hdr => 'Waits',               num => 1, label => 'Mutex OS Waits' },
   mutex_spin_rounds           => { hdr => 'Rounds',              num => 1, label => 'Mutex Spin Rounds' },
   mutex_spin_waits            => { hdr => 'Spins',               num => 1, label => 'Mutex Spin Waits' },
   mysql_thread_id             => { hdr => 'ID',                  num => 1, label => 'MySQL connection (thread) ID', },
   name                        => { hdr => 'Name',                num => 0, label => 'Variable Name' },
   n_bits                      => { hdr => '# Bits',              num => 1, label => 'Number of bits' },
   non_hash_searches_s         => { hdr => 'Non-Hash/Sec',        num => 1, label => 'Non-hash searches/sec' },
   num_deletes                 => { hdr => 'Del',                 num => 1, label => 'Number of deletes' },
   num_deletes_sec             => { hdr => 'Del/Sec',             num => 1, label => 'Number of deletes' },
   num_inserts                 => { hdr => 'Ins',                 num => 1, label => 'Number of inserts' },
   num_inserts_sec             => { hdr => 'Ins/Sec',             num => 1, label => 'Number of inserts' },
   num_readers                 => { hdr => 'Readers',             num => 1, label => 'Number of readers' },
   num_reads                   => { hdr => 'Read',                num => 1, label => 'Number of reads' },
   num_reads_sec               => { hdr => 'Read/Sec',            num => 1, label => 'Number of reads' },
   num_res_ext                 => { hdr => 'BTree Extents',       num => 1, label => 'Number of extents reserved for B-Tree' },
   num_rows                    => { hdr => 'Row Count',           num => 1, label => 'Number of rows estimated to examine' },
   num_times_open              => { hdr => 'In Use',              num => 1, label => '# times table is opened', },
   num_txns                    => { hdr => 'Txns',                num => 1, label => 'Number of transactions' },
   num_updates                 => { hdr => 'Upd',                 num => 1, label => 'Number of updates' },
   num_updates_sec             => { hdr => 'Upd/Sec',             num => 1, label => 'Number of updates' },
   os_file_reads               => { hdr => 'OS Reads',            num => 1, label => 'OS file reads' },
   os_file_writes              => { hdr => 'OS Writes',           num => 1, label => 'OS file writes' },
   os_fsyncs                   => { hdr => 'OS fsyncs',           num => 1, label => 'OS fsyncs' },
   os_thread_id                => { hdr => 'OS Thread',           num => 1, label => 'The operating system thread ID' },
   p_aio_writes                => { hdr => 'Async Wrt',           num => 1, label => 'Pending asynchronous I/O writes' },
   p_buf_pool_flushes          => { hdr => 'Buffer Pool Flushes', num => 1, label => 'Pending buffer pool flushes' },
   p_ibuf_aio_reads            => { hdr => 'IBuf Async Rds',      num => 1, label => 'Pending insert buffer asynch I/O reads' },
   p_log_flushes               => { hdr => 'Log Flushes',         num => 1, label => 'Pending log flushes' },
   p_log_ios                   => { hdr => 'Log I/Os',            num => 1, label => 'Pending log I/O operations' },
   p_normal_aio_reads          => { hdr => 'Async Rds',           num => 1, label => 'Pending asynchronous I/O reads' },
   p_preads                    => { hdr => 'preads',              num => 1, label => 'Pending p-reads' },
   p_pwrites                   => { hdr => 'pwrites',             num => 1, label => 'Pending p-writes' },
   p_sync_ios                  => { hdr => 'Sync I/Os',           num => 1, label => 'Pending synchronous I/O operations' },
   page_creates_sec            => { hdr => 'Creates/Sec',         num => 1, label => 'Page creates/sec' },
   page_no                     => { hdr => 'Page',                num => 1, label => 'Page number' },
   page_reads_sec              => { hdr => 'Reads/Sec',           num => 1, label => 'Page reads per second' },
   page_writes_sec             => { hdr => 'Writes/Sec',          num => 1, label => 'Page writes per second' },
   pages_created               => { hdr => 'Created',             num => 1, label => 'Pages created' },
   pages_modified              => { hdr => 'Dirty Pages',         num => 1, label => 'Pages modified (dirty)' },
   pages_read                  => { hdr => 'Reads',               num => 1, label => 'Pages read' },
   pages_total                 => { hdr => 'Pages',               num => 1, label => 'Pages total' },
   pages_written               => { hdr => 'Writes',              num => 1, label => 'Pages written' },
   parent_col                  => { hdr => 'Parent Column',       num => 0, label => 'The referred column in the parent table', },
   parent_db                   => { hdr => 'Parent DB',           num => 0, label => 'The database of the parent table' },
   parent_index                => { hdr => 'Parent Index',        num => 0, label => 'The referred index in the parent table' },
   parent_table                => { hdr => 'Parent Table',        num => 0, label => 'The parent table' },
   part_id                     => { hdr => 'Part ID',             num => 1, label => 'Sub-part ID of the query' },
   partitions                  => { hdr => 'Partitions',          num => 0, label => 'Query partitions used' },
   pct                         => { hdr => 'Pct',                 num => 1, label => 'Percentage' },
   pending_chkp_writes         => { hdr => 'Chkpt Writes',        num => 1, label => 'Pending log checkpoint writes' },
   pending_log_writes          => { hdr => 'Log Writes',          num => 1, label => 'Pending log writes' },
   port                        => { hdr => 'Port',                num => 1, label => 'Client port number', },
   possible_keys               => { hdr => 'Poss. Keys',          num => 0, label => 'Possible keys' },
   proc_no                     => { hdr => 'Proc',                num => 1, label => 'Process number' },
   q_cache_hit                 => { hdr => 'QCacheHit',           num => 1, label => 'Query cache hit ratio', },
   qps                         => { hdr => 'QPS',                 num => 1, label => 'How many queries/sec', },
   queries_in_queue            => { hdr => 'Queries Queued',      num => 1, label => 'Queries in queue' },
   queries_inside              => { hdr => 'Queries Inside',      num => 1, label => 'Queries inside InnoDB' },
   query_id                    => { hdr => 'Query ID',            num => 1, label => 'Query ID' },
   query_status                => { hdr => 'Query Status',        num => 0, label => 'The query status' },
   query_text                  => { hdr => 'Query Text',          num => 0, label => 'The query text' },
   questions                   => { hdr => 'Questions',           num => 1, label => 'How many queries the server has gotten', },
   read_master_log_pos         => { hdr => 'Read Master Pos',     num => 1, label => 'Read master log position' },
   read_views_open             => { hdr => 'Rd Views',            num => 1, label => 'Number of read views open' },
   reads_pending               => { hdr => 'Pending Reads',       num => 1, label => 'Reads pending' },
   relay_log_file              => { hdr => 'Relay File',          num => 0, label => 'Relay log file' },
   relay_log_pos               => { hdr => 'Relay Pos',           num => 1, label => 'Relay log position' },
   relay_log_size              => { hdr => 'Relay Size',          num => 1, label => 'Relay log size' },
   relay_master_log_file       => { hdr => 'Relay Master File',   num => 0, label => 'Relay master log file' },
   replicate_do_db             => { hdr => 'Do DB',               num => 0, label => 'Replicate-do-db setting' },
   replicate_do_table          => { hdr => 'Do Table',            num => 0, label => 'Replicate-do-table setting' },
   replicate_ignore_db         => { hdr => 'Ignore DB',           num => 0, label => 'Replicate-ignore-db setting' },
   replicate_ignore_table      => { hdr => 'Ignore Table',        num => 0, label => 'Replicate-do-table setting' },
   replicate_wild_do_table     => { hdr => 'Wild Do Table',       num => 0, label => 'Replicate-wild-do-table setting' },
   replicate_wild_ignore_table => { hdr => 'Wild Ignore Table',   num => 0, label => 'Replicate-wild-ignore-table setting' },
   request_type                => { hdr => 'Type',                num => 0, label => 'Type of lock the thread waits for' },
   reservation_count           => { hdr => 'ResCnt',              num => 1, label => 'Reservation Count' },
   row_locks                   => { hdr => 'RLocks',              num => 1, label => 'Number of row locks' },
   rw_excl_os_waits            => { hdr => 'RW Waits',            num => 1, label => 'R/W Excl. OS Waits' },
   rw_excl_spins               => { hdr => 'RW Spins',            num => 1, label => 'R/W Excl. Spins' },
   rw_shared_os_waits          => { hdr => 'Sh Waits',            num => 1, label => 'R/W Shared OS Waits' },
   rw_shared_spins             => { hdr => 'Sh Spins',            num => 1, label => 'R/W Shared Spins' },
   scan_type                   => { hdr => 'Type',                num => 0, label => 'Scan type in chosen' },
   seg_size                    => { hdr => 'Seg. Size',           num => 1, label => 'Segment size' },
   select_type                 => { hdr => 'Select Type',         num => 0, label => 'Type of select used' },
   signal_count                => { hdr => 'Signals',             num => 1, label => 'Signal Count' },
   size                        => { hdr => 'Size',                num => 1, label => 'Size of the tablespace' },
   skip_counter                => { hdr => 'Skip Counter',        num => 1, label => 'Skip counter' },
   slave_catchup_rate          => { hdr => 'Catchup',             num => 1, label => 'How fast the slave is catching up in the binlog' },
   slave_io_running            => { hdr => 'Slave-IO',            num => 0, label => 'Whether the slave I/O thread is running' },
   slave_io_state              => { hdr => 'Slave IO State',      num => 0, label => 'Slave I/O thread state' },
   slave_open_temp_tables      => { hdr => 'Temp',                num => 1, label => 'Slave open temp tables' },
   slave_sql_running           => { hdr => 'Slave-SQL',           num => 0, label => 'Whether the slave SQL thread is running' },
   slow                        => { hdr => 'Slow',                num => 1, label => 'How many slow queries', },
   space_id                    => { hdr => 'Space',               num => 1, label => 'Tablespace ID' },
   special                     => { hdr => 'Special',             num => 0, label => 'Special/Other info' },
   state                       => { hdr => 'State',               num => 0, label => 'Connection state', maxw => 18, },
   tables_in_use               => { hdr => 'Tbl Used',            num => 1, label => 'Number of tables in use' },
   tables_locked               => { hdr => 'Tbl Lck',             num => 1, label => 'Number of tables locked' },
   tbl                         => { hdr => 'Table',               num => 0, label => 'Table', },
   thread                      => { hdr => 'Thread',              num => 1, label => 'Thread number' },
   thread_decl_inside          => { hdr => 'Thread Inside',       num => 0, label => 'What the thread is declared inside' },
   thread_purpose              => { hdr => 'Purpose',             num => 0, label => "The thread's purpose" },
   thread_status               => { hdr => 'Thread Status',       num => 0, label => 'The thread status' },
   time                        => { hdr => 'Time',                num => 1, label => 'Time since the last event', },
   time_behind_master          => { hdr => 'TimeLag',             num => 1, label => 'Time slave lags master' },
   timestring                  => { hdr => 'Timestring',          num => 0, label => 'Time the event occurred' },
   total                       => { hdr => 'Total',               num => 1, label => 'Total' },
   total_mem_alloc             => { hdr => 'Memory',              num => 1, label => 'Total memory allocated' },
   truncates                   => { hdr => 'Trunc',               num => 0, label => 'Whether the deadlock is truncating InnoDB status' },
   txn_doesnt_see_ge           => { hdr => "Txn Won't See",       num => 0, label => 'Where txn read view is limited' },
   txn_id                      => { hdr => 'ID',                  num => 0, label => 'Transaction ID' },
   txn_sees_lt                 => { hdr => 'Txn Sees',            num => 1, label => 'Where txn read view is limited' },
   txn_status                  => { hdr => 'Txn Status',          num => 0, label => 'Transaction status' },
   txn_time_remain             => { hdr => 'Remaining',           num => 1, label => 'Time until txn rollback/commit completes' },
   undo_log_entries            => { hdr => 'Undo',                num => 1, label => 'Number of undo log entries' },
   undo_for                    => { hdr => 'Undo',                num => 0, label => 'Undo for' },
   until_condition             => { hdr => 'Until Condition',     num => 0, label => 'Slave until condition' },
   until_log_file              => { hdr => 'Until Log File',      num => 0, label => 'Slave until log file' },
   until_log_pos               => { hdr => 'Until Log Pos',       num => 1, label => 'Slave until log position' },
   used_cells                  => { hdr => 'Cells Used',          num => 1, label => 'Number of cells used' },
   used_bufs                   => { hdr => 'Used Bufs',           num => 1, label => 'Number of buffer pool pages used' },
   user                        => { hdr => 'User',                num => 0, label => 'Database username', },
   value                       => { hdr => 'Value',               num => 1, label => 'Value' },
   versions                    => { hdr => 'Versions',            num => 1, label => 'Number of InnoDB MVCC versions unpurged' },
   victim                      => { hdr => 'Victim',              num => 0, label => 'Whether this txn was the deadlock victim' },
   wait_array_size             => { hdr => 'Wait Array Size',     num => 1, label => 'Wait Array Size' },
   wait_status                 => { hdr => 'Lock Status',         num => 0, label => 'Status of txn locks' },
   waited_at_filename          => { hdr => 'File',                num => 0, label => 'Filename at which thread waits' },
   waited_at_line              => { hdr => 'Line',                num => 1, label => 'Line at which thread waits' },
   waiters_flag                => { hdr => 'Waiters',             num => 1, label => 'Waiters Flag' },
   waiting                     => { hdr => 'Waiting',             num => 1, label => 'Whether lock is being waited for' },
   when                        => { hdr => 'When',                num => 0, label => 'Time scale' },
   writer_lock_mode            => { hdr => 'Wrtr Lck Mode',       num => 0, label => 'Writer lock mode' },
   writer_thread               => { hdr => 'Wrtr Thread',         num => 1, label => 'Writer thread ID' },
   writes_pending              => { hdr => 'Writes',              num => 1, label => 'Number of writes pending' },
   writes_pending_flush_list   => { hdr => 'Flush List Writes',   num => 1, label => 'Number of flush list writes pending' },
   writes_pending_lru          => { hdr => 'LRU Writes',          num => 1, label => 'Number of LRU writes pending' },
   writes_pending_single_page  => { hdr => '1-Page Writes',       num => 1, label => 'Number of 1-page writes pending' },
);

# Apply a default property or three.  By default, columns are not width-constrained,
# aligned left, and sorted alphabetically, not numerically.
foreach my $col ( values %columns ) {
   map { $col->{$_} ||= 0 } qw(num minw maxw);
   $col->{just} = $col->{num} ? '' : '-';
}

# Filters {{{3
# This hash defines every filter that can be applied to a table.  These
# become part of tbl_meta as well.  Each filter is just an expression that
# returns true or false.
# Properties of each entry:
#  * func:   the subroutine
#  * name:   the name, repeated
#  * user:   whether it's a user-defined filter (saved in config)
#  * text:   text of the subroutine
#  * note:   explanation
my %filters = ();

# These are pre-processed to live in %filters above, by compiling them.
my %builtin_filters = (
   hide_self => {
      text => <<'      END',
         return ( !$set->{info} || $set->{info} ne 'SHOW FULL PROCESSLIST' )
             && ( !$set->{query_text}    || $set->{query_text} !~ m/INNODB STATUS$/ );
      END
      note => 'Removes the innotop processes from the list',
      tbls => [qw(innodb_transactions processlist)],
   },
   hide_inactive => {
      text => <<'      END',
         return ( !defined($set->{txn_status}) || $set->{txn_status} ne 'not started' )
             && ( !defined($set->{cmd})        || $set->{cmd} !~ m/Sleep|Binlog Dump/ )
             && ( !defined($set->{info})       || $set->{info} =~ m/\S/               );
      END
      note => 'Removes processes which are not doing anything',
      tbls => [qw(innodb_transactions processlist)],
   },
   hide_slave_io => {
      text => <<'      END',
         return !$set->{state} || $set->{state} !~ m/^(?:Waiting for master|Has read all relay)/;
      END
      note => 'Removes slave I/O threads from the list',
      tbls => [qw(processlist slave_io_status)],
   },
   table_is_open => {
      text => <<'      END',
         return $set->{num_times_open} + $set->{is_name_locked};
      END
      note => 'Removes tables that are not in use or locked',
      tbls => [qw(open_tables)],
   },
   cxn_is_master => {
      text => <<'      END',
         return $set->{master_file} ? 1 : 0;
      END
      note => 'Removes servers that are not masters',
      tbls => [qw(master_status)],
   },
   cxn_is_slave => {
      text => <<'      END',
         return $set->{master_host} ? 1 : 0;
      END
      note => 'Removes servers that are not slaves',
      tbls => [qw(slave_io_status slave_sql_status)],
   },
   thd_is_not_waiting => {
      text => <<'      END',
         return $set->{thread_status} !~ m#waiting for i/o request#;
      END
      note => 'Removes idle I/O threads',
      tbls => [qw(io_threads)],
   },
);
foreach my $key ( keys %builtin_filters ) {
   my ( $sub, $err ) = compile_filter($builtin_filters{$key}->{text});
   $filters{$key} = {
      func => $sub,
      text => $builtin_filters{$key}->{text},
      user => 0,
      name => $key, # useful for later
      note => $builtin_filters{$key}->{note},
      tbls => $builtin_filters{$key}->{tbls},
   }
}

# Variable sets {{{3
# Sets (arrayrefs) of variables that are used in S mode.  They are read/written to
# the config file.
my %var_sets = (
   general => {
      text => join(
         ', ',
         'set_precision(Questions/Uptime_hires) as QPS',
         'set_precision(Com_commit/Uptime_hires) as Commit_PS',
         'set_precision((Com_rollback||0)/(Com_commit||1)) as Rollback_Commit',
         'set_precision(('
            . join('+', map { "($_||0)" }
               qw(Com_delete Com_delete_multi Com_insert Com_insert_select Com_replace
                  Com_replace_select Com_select Com_update Com_update_multi))
            . ')/(Com_commit||1)) as Write_Commit',
         'set_precision((Com_select+(Qcache_hits||0))/(('
            . join('+', map { "($_||0)" }
               qw(Com_delete Com_delete_multi Com_insert Com_insert_select Com_replace
                  Com_replace_select Com_select Com_update Com_update_multi))
            . ')||1)) as R_W_Ratio',
         'set_precision(Opened_tables/Uptime_hires) as Opens_PS',
         'percent($cur->{Open_tables}/($cur->{table_cache})) as Table_Cache_Used',
         'set_precision(Threads_created/Uptime_hires) as Threads_PS',
         'percent($cur->{Threads_cached}/($cur->{thread_cache_size}||1)) as Thread_Cache_Used',
         'percent($cur->{Max_used_connections}/($cur->{max_connections}||1)) as CXN_Used_Ever',
         'percent($cur->{Threads_connected}/($cur->{max_connections}||1)) as CXN_Used_Now',
      ),
   },
   commands => {
      text => join(
         ', ',
         qw(Uptime Questions Com_delete Com_delete_multi Com_insert
         Com_insert_select Com_replace Com_replace_select Com_select Com_update
         Com_update_multi)
      ),
   },
   query_status => {
      text => join(
         ',',
         qw( Uptime Select_full_join Select_full_range_join Select_range
         Select_range_check Select_scan Slow_queries Sort_merge_passes
         Sort_range Sort_rows Sort_scan)
      ),
   },
   innodb => {
      text => join(
         ',',
         qw( Uptime Innodb_row_lock_current_waits Innodb_row_lock_time
         Innodb_row_lock_time_avg Innodb_row_lock_time_max Innodb_row_lock_waits
         Innodb_rows_deleted Innodb_rows_inserted Innodb_rows_read
         Innodb_rows_updated)
      ),
   },
   txn => {
      text => join(
         ',',
         qw( Uptime Com_begin Com_commit Com_rollback Com_savepoint
         Com_xa_commit Com_xa_end Com_xa_prepare Com_xa_recover Com_xa_rollback
         Com_xa_start)
      ),
   },
   key_cache => {
      text => join(
         ',',
         qw( Uptime Key_blocks_not_flushed Key_blocks_unused Key_blocks_used
         Key_read_requests Key_reads Key_write_requests Key_writes )
      ),
   },
   query_cache => {
      text => join(
         ',',
         "percent($exprs{QcacheHitRatio}) as Hit_Pct",
         'set_precision((Qcache_hits||0)/(Qcache_inserts||1)) as Hit_Ins',
         'set_precision((Qcache_lowmem_prunes||0)/Uptime_hires) as Lowmem_Prunes_sec',
         'percent(1-((Qcache_free_blocks||0)/(Qcache_total_blocks||1))) as Blocks_used',
         qw( Qcache_free_blocks Qcache_free_memory Qcache_not_cached Qcache_queries_in_cache)
      ),
   },
   handler => {
      text => join(
         ',',
         qw( Uptime Handler_read_key Handler_read_first Handler_read_next
         Handler_read_prev Handler_read_rnd Handler_read_rnd_next Handler_delete
         Handler_update Handler_write)
      ),
   },
   cxns_files_threads => {
      text => join(
         ',',
         qw( Uptime Aborted_clients Aborted_connects Bytes_received Bytes_sent
         Compression Connections Created_tmp_disk_tables Created_tmp_files
         Created_tmp_tables Max_used_connections Open_files Open_streams
         Open_tables Opened_tables Table_locks_immediate Table_locks_waited
         Threads_cached Threads_connected Threads_created Threads_running)
      ),
   },
   prep_stmt => {
      text => join(
         ',',
         qw( Uptime Com_dealloc_sql Com_execute_sql Com_prepare_sql Com_reset
         Com_stmt_close Com_stmt_execute Com_stmt_fetch Com_stmt_prepare
         Com_stmt_reset Com_stmt_send_long_data )
      ),
   },
   innodb_health => {
      text => join(
         ',',
         "$exprs{OldVersions} as OldVersions",
         qw(IB_sm_mutex_spin_waits IB_sm_mutex_spin_rounds IB_sm_mutex_os_waits),
         "$exprs{NumTxns} as NumTxns",
         "$exprs{MaxTxnTime} as MaxTxnTime",
         qw(IB_ro_queries_inside IB_ro_queries_in_queue),
         "set_precision($exprs{DirtyBufs} * 100) as dirty_bufs",
         "set_precision($exprs{BufPoolFill} * 100) as buf_fill",
         qw(IB_bp_pages_total IB_bp_pages_read IB_bp_pages_written IB_bp_pages_created)
      ),
   },
   innodb_health2 => {
      text => join(
         ', ',
         'percent(1-((Innodb_buffer_pool_pages_free||0)/($cur->{Innodb_buffer_pool_pages_total}||1))) as BP_page_cache_usage',
         'percent(1-((Innodb_buffer_pool_reads||0)/(Innodb_buffer_pool_read_requests||1))) as BP_cache_hit_ratio',
         'Innodb_buffer_pool_wait_free',
         'Innodb_log_waits',
      ),
   },
   slow_queries => {
      text => join(
         ', ',
         'set_precision(Slow_queries/Uptime_hires) as Slow_PS',
         'set_precision(Select_full_join/Uptime_hires) as Full_Join_PS',
         'percent(Select_full_join/(Com_select||1)) as Full_Join_Ratio',
      ),
   },
);

# Server sets {{{3
# Defines sets of servers between which the user can quickly switch.
my %server_groups;

# Connections {{{3
# This hash defines server connections.  Each connection is a string that can be passed to
# the DBI connection.  These are saved in the connections section in the config file.
my %connections;
# Defines the parts of connections.
my @conn_parts = qw(user have_user pass have_pass dsn savepass dl_table);

# Graph widths {{{3
# This hash defines the max values seen for various status/variable values, for graphing.
# These are stored in their own section in the config file.  These are just initial values:
my %mvs = (
   Com_select   => 50,
   Com_insert   => 50,
   Com_update   => 50,
   Com_delete   => 50,
   Questions    => 100,
);

# ###########################################################################
# Valid Term::ANSIColor color strings.
# ###########################################################################
my %ansicolors = map { $_ => 1 }
   qw( black blink blue bold clear concealed cyan dark green magenta on_black
       on_blue on_cyan on_green on_magenta on_red on_white on_yellow red reset
       reverse underline underscore white yellow);

# ###########################################################################
# Valid comparison operators for color rules
# ###########################################################################
my %comp_ops = (
   '==' => 'Numeric equality',
   '>'  => 'Numeric greater-than',
   '<'  => 'Numeric less-than',
   '>=' => 'Numeric greater-than/equal',
   '<=' => 'Numeric less-than/equal',
   '!=' => 'Numeric not-equal',
   'eq' => 'String equality',
   'gt' => 'String greater-than',
   'lt' => 'String less-than',
   'ge' => 'String greater-than/equal',
   'le' => 'String less-than/equal',
   'ne' => 'String not-equal',
   '=~' => 'Pattern match',
   '!~' => 'Negated pattern match',
);

# ###########################################################################
# Valid aggregate functions.
# ###########################################################################
my %agg_funcs = (
   first => sub {
      return $_[0]
   },
   count => sub {
      return 0 + @_;
   },
   avg   => sub {
      my @args = grep { defined $_ } @_;
      return (sum(map { m/([\d\.-]+)/g } @args) || 0) / (scalar(@args) || 1);
   },
   sum   => sub {
      my @args = grep { defined $_ } @_;
      return sum(@args);
   }
);

# ###########################################################################
# Valid functions for transformations.
# ###########################################################################
my %trans_funcs = (
   shorten      => \&shorten,
   secs_to_time => \&secs_to_time,
   no_ctrl_char => \&no_ctrl_char,
   percent      => \&percent,
   commify      => \&commify,
   dulint_to_int => \&dulint_to_int,
   set_precision => \&set_precision,
);

# Table definitions {{{3
# This hash defines every table that can get displayed in every mode.  Each
# table specifies columns and column data sources.  The column is
# defined by the %columns hash.
#
# Example: foo => { src => 'bar' } means the foo column (look at
# $columns{foo} for its definition) gets its data from the 'bar' element of
# the current data set, whatever that is.
#
# These columns are post-processed after being defined, because they get stuff
# from %columns.  After all the config is loaded for columns, there's more
# post-processing too; the subroutines compiled from src get added to
# the hash elements for extract_values to use.
# ###########################################################################

my %tbl_meta = (
   adaptive_hash_index => {
      capt => 'Adaptive Hash Index',
      cust => {},
      cols => {
         cxn                 => { src => 'cxn' },
         hash_table_size     => { src => 'IB_ib_hash_table_size', trans => [qw(shorten)], },
         used_cells          => { src => 'IB_ib_used_cells' },
         bufs_in_node_heap   => { src => 'IB_ib_bufs_in_node_heap' },
         hash_searches_s     => { src => 'IB_ib_hash_searches_s' },
         non_hash_searches_s => { src => 'IB_ib_non_hash_searches_s' },
      },
      visible => [ qw(cxn hash_table_size used_cells bufs_in_node_heap hash_searches_s non_hash_searches_s) ],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'ib',
      group_by => [],
      aggregate => 0,
   },
   buffer_pool => {
      capt => 'Buffer Pool',
      cust => {},
      cols => {
         cxn                        => { src => 'cxn' },
         total_mem_alloc            => { src => 'IB_bp_total_mem_alloc', trans => [qw(shorten)], },
         awe_mem_alloc              => { src => 'IB_bp_awe_mem_alloc', trans => [qw(shorten)], },
         add_pool_alloc             => { src => 'IB_bp_add_pool_alloc', trans => [qw(shorten)], },
         buf_pool_size              => { src => 'IB_bp_buf_pool_size', trans => [qw(shorten)], },
         buf_free                   => { src => 'IB_bp_buf_free' },
         buf_pool_hit_rate          => { src => 'IB_bp_buf_pool_hit_rate' },
         buf_pool_reads             => { src => 'IB_bp_buf_pool_reads' },
         buf_pool_hits              => { src => 'IB_bp_buf_pool_hits' },
         dict_mem_alloc             => { src => 'IB_bp_dict_mem_alloc' },
         pages_total                => { src => 'IB_bp_pages_total' },
         pages_modified             => { src => 'IB_bp_pages_modified' },
         reads_pending              => { src => 'IB_bp_reads_pending' },
         writes_pending             => { src => 'IB_bp_writes_pending' },
         writes_pending_lru         => { src => 'IB_bp_writes_pending_lru' },
         writes_pending_flush_list  => { src => 'IB_bp_writes_pending_flush_list' },
         writes_pending_single_page => { src => 'IB_bp_writes_pending_single_page' },
         page_creates_sec           => { src => 'IB_bp_page_creates_sec' },
         page_reads_sec             => { src => 'IB_bp_page_reads_sec' },
         page_writes_sec            => { src => 'IB_bp_page_writes_sec' },
         pages_created              => { src => 'IB_bp_pages_created' },
         pages_read                 => { src => 'IB_bp_pages_read' },
         pages_written              => { src => 'IB_bp_pages_written' },
      },
      visible => [ qw(cxn buf_pool_size buf_free pages_total pages_modified buf_pool_hit_rate total_mem_alloc add_pool_alloc)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'bp',
      group_by => [],
      aggregate => 0,
   },
   # TODO: a new step in set_to_tbl: join result to itself, grouped?
   # TODO: this would also enable pulling Q and T data together.
   # TODO: using a SQL-ish language would also allow pivots to be easier -- treat the pivoted data as a view and SELECT from it.
   cmd_summary => {
      capt => 'Command Summary',
      cust => {},
      cols => {
         name       => { src => 'name' },
         total      => { src => 'total' },
         value      => { src => 'value',                     agg   => 'sum'},
         pct        => { src => 'value/total',               trans => [qw(percent)] },
         last_total => { src => 'last_total' },
         last_value => { src => 'last_value',                agg   => 'sum'},
         last_pct   => { src => 'last_value/last_total',     trans => [qw(percent)] },
      },
      visible   => [qw(name value pct last_value last_pct)],
      filters   => [qw()],
      sort_cols => '-value',
      sort_dir  => '1',
      innodb    => '',
      group_by  => [qw(name)],
      aggregate => 1,
   },
   deadlock_locks => {
      capt => 'Deadlock Locks',
      cust => {},
      cols => {
         cxn              => { src => 'cxn' },
         mysql_thread_id  => { src => 'mysql_thread_id' },
         dl_txn_num       => { src => 'dl_txn_num' },
         lock_type        => { src => 'lock_type' },
         space_id         => { src => 'space_id' },
         page_no          => { src => 'page_no' },
         heap_no          => { src => 'heap_no' },
         n_bits           => { src => 'n_bits' },
         index            => { src => 'index' },
         db               => { src => 'db' },
         tbl              => { src => 'table' },
         lock_mode        => { src => 'lock_mode' },
         special          => { src => 'special' },
         insert_intention => { src => 'insert_intention' },
         waiting          => { src => 'waiting' },
      },
      visible => [ qw(cxn mysql_thread_id waiting lock_mode db tbl index special insert_intention)],
      filters => [],
      sort_cols => 'cxn mysql_thread_id',
      sort_dir => '1',
      innodb   => 'dl',
      group_by => [],
      aggregate => 0,
   },
   deadlock_transactions => {
      capt => 'Deadlock Transactions',
      cust => {},
      cols => {
         cxn                => { src => 'cxn' },
         active_secs        => { src => 'active_secs' },
         dl_txn_num         => { src => 'dl_txn_num' },
         has_read_view      => { src => 'has_read_view' },
         heap_size          => { src => 'heap_size' },
         host_and_domain    => { src => 'hostname' },
         hostname           => { src => $exprs{Host} },
         ip                 => { src => 'ip' },
         lock_structs       => { src => 'lock_structs' },
         lock_wait_time     => { src => 'lock_wait_time', trans => [ qw(secs_to_time) ] },
         mysql_thread_id    => { src => 'mysql_thread_id' },
         os_thread_id       => { src => 'os_thread_id' },
         proc_no            => { src => 'proc_no' },
         query_id           => { src => 'query_id' },
         query_status       => { src => 'query_status' },
         query_text         => { src => 'query_text', trans => [ qw(no_ctrl_char) ] },
         row_locks          => { src => 'row_locks' },
         tables_in_use      => { src => 'tables_in_use' },
         tables_locked      => { src => 'tables_locked' },
         thread_decl_inside => { src => 'thread_decl_inside' },
         thread_status      => { src => 'thread_status' },
         'time'             => { src => 'active_secs', trans => [ qw(secs_to_time) ] },
         timestring         => { src => 'timestring' },
         txn_doesnt_see_ge  => { src => 'txn_doesnt_see_ge' },
         txn_id             => { src => 'txn_id' },
         txn_sees_lt        => { src => 'txn_sees_lt' },
         txn_status         => { src => 'txn_status' },
         truncates          => { src => 'truncates' },
         undo_log_entries   => { src => 'undo_log_entries' },
         user               => { src => 'user' },
         victim             => { src => 'victim' },
         wait_status        => { src => 'lock_wait_status' },
      },
      visible => [ qw(cxn mysql_thread_id timestring user hostname victim time undo_log_entries lock_structs query_text)],
      filters => [],
      sort_cols => 'cxn mysql_thread_id',
      sort_dir => '1',
      innodb   => 'dl',
      group_by => [],
      aggregate => 0,
   },
   explain => {
      capt => 'EXPLAIN Results',
      cust => {},
      cols => {
         part_id       => { src => 'id' },
         select_type   => { src => 'select_type' },
         tbl           => { src => 'table' },
         partitions    => { src => 'partitions' },
         scan_type     => { src => 'type' },
         possible_keys => { src => 'possible_keys' },
         index         => { src => 'key' },
         key_len       => { src => 'key_len' },
         index_ref     => { src => 'ref' },
         num_rows      => { src => 'rows' },
         special       => { src => 'extra' },
      },
      visible => [ qw(select_type tbl partitions scan_type possible_keys index key_len index_ref num_rows special)],
      filters => [],
      sort_cols => '',
      sort_dir => '1',
      innodb   => '',
      group_by => [],
      aggregate => 0,
   },
   file_io_misc => {
      capt => 'File I/O Misc',
      cust => {},
      cols => {
         cxn            => { src => 'cxn' },
         io_bytes_s     => { src => 'IB_io_avg_bytes_s' },
         io_flush_type  => { src => 'IB_io_flush_type' },
         io_fsyncs_s    => { src => 'IB_io_fsyncs_s' },
         io_reads_s     => { src => 'IB_io_reads_s' },
         io_writes_s    => { src => 'IB_io_writes_s' },
         os_file_reads  => { src => 'IB_io_os_file_reads' },
         os_file_writes => { src => 'IB_io_os_file_writes' },
         os_fsyncs      => { src => 'IB_io_os_fsyncs' },
      },
      visible => [ qw(cxn os_file_reads os_file_writes os_fsyncs io_reads_s io_writes_s io_bytes_s)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'io',
      group_by => [],
      aggregate => 0,
   },
   fk_error => {
      capt => 'Foreign Key Error Info',
      cust => {},
      cols => {
         timestring   => { src => 'IB_fk_timestring' },
         child_db     => { src => 'IB_fk_child_db' },
         child_table  => { src => 'IB_fk_child_table' },
         child_index  => { src => 'IB_fk_child_index' },
         fk_name      => { src => 'IB_fk_fk_name' },
         parent_db    => { src => 'IB_fk_parent_db' },
         parent_table => { src => 'IB_fk_parent_table' },
         parent_col   => { src => 'IB_fk_parent_col' },
         parent_index => { src => 'IB_fk_parent_index' },
         attempted_op => { src => 'IB_fk_attempted_op' },
      },
      visible => [ qw(timestring child_db child_table child_index parent_db parent_table parent_col parent_index fk_name attempted_op)],
      filters => [],
      sort_cols => '',
      sort_dir => '1',
      innodb   => 'fk',
      group_by => [],
      aggregate => 0,
   },
   insert_buffers => {
      capt => 'Insert Buffers',
      cust => {},
      cols => {
         cxn           => { src => 'cxn' },
         inserts       => { src => 'IB_ib_inserts' },
         merged_recs   => { src => 'IB_ib_merged_recs' },
         merges        => { src => 'IB_ib_merges' },
         size          => { src => 'IB_ib_size' },
         free_list_len => { src => 'IB_ib_free_list_len' },
         seg_size      => { src => 'IB_ib_seg_size' },
      },
      visible => [ qw(cxn inserts merged_recs merges size free_list_len seg_size)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'ib',
      group_by => [],
      aggregate => 0,
   },
   innodb_locks  => {
      capt => 'InnoDB Locks',
      cust => {},
      cols => {
         cxn              => { src => 'cxn' },
         db               => { src => 'db' },
         index            => { src => 'index' },
         insert_intention => { src => 'insert_intention' },
         lock_mode        => { src => 'lock_mode' },
         lock_type        => { src => 'lock_type' },
         lock_wait_time   => { src => 'lock_wait_time', trans => [ qw(secs_to_time) ] },
         mysql_thread_id  => { src => 'mysql_thread_id' },
         n_bits           => { src => 'n_bits' },
         page_no          => { src => 'page_no' },
         space_id         => { src => 'space_id' },
         special          => { src => 'special' },
         tbl              => { src => 'table' },
         'time'           => { src => 'active_secs', hdr => 'Active', trans => [ qw(secs_to_time) ] },
         txn_id           => { src => 'txn_id' },
         waiting          => { src => 'waiting' },
      },
      visible => [ qw(cxn mysql_thread_id lock_type waiting lock_wait_time time lock_mode db tbl index insert_intention special)],
      filters => [],
      sort_cols => 'cxn -lock_wait_time',
      sort_dir => '1',
      innodb   => 'tx',
      colors   => [
         { col => 'lock_wait_time', op => '>',  arg => 60, color => 'red' },
         { col => 'lock_wait_time', op => '>',  arg => 30, color => 'yellow' },
         { col => 'lock_wait_time', op => '>',  arg => 10, color => 'green' },
      ],
      group_by => [],
      aggregate => 0,
   },
   innodb_transactions => {
      capt => 'InnoDB Transactions',
      cust => {},
      cols => {
         cxn                => { src => 'cxn' },
         active_secs        => { src => 'active_secs' },
         has_read_view      => { src => 'has_read_view' },
         heap_size          => { src => 'heap_size' },
         hostname           => { src => $exprs{Host} },
         ip                 => { src => 'ip' },
         wait_status        => { src => 'lock_wait_status' },
         lock_wait_time     => { src => 'lock_wait_time',      trans => [ qw(secs_to_time) ] },
         lock_structs       => { src => 'lock_structs' },
         mysql_thread_id    => { src => 'mysql_thread_id' },
         os_thread_id       => { src => 'os_thread_id' },
         proc_no            => { src => 'proc_no' },
         query_id           => { src => 'query_id' },
         query_status       => { src => 'query_status' },
         query_text         => { src => 'query_text',          trans => [ qw(no_ctrl_char) ] },
         txn_time_remain    => { src => $exprs{TxnTimeRemain}, trans => [ qw(secs_to_time) ] },
         row_locks          => { src => 'row_locks' },
         tables_in_use      => { src => 'tables_in_use' },
         tables_locked      => { src => 'tables_locked' },
         thread_decl_inside => { src => 'thread_decl_inside' },
         thread_status      => { src => 'thread_status' },
         'time'             => { src => 'active_secs',         trans => [ qw(secs_to_time) ], agg => 'sum' },
         txn_doesnt_see_ge  => { src => 'txn_doesnt_see_ge' },
         txn_id             => { src => 'txn_id' },
         txn_sees_lt        => { src => 'txn_sees_lt' },
         txn_status         => { src => 'txn_status',          minw => 10, maxw => 10 },
         undo_log_entries   => { src => 'undo_log_entries' },
         user               => { src => 'user',                maxw => 10 },
         cnt                => { src => 'mysql_thread_id',     minw => 0 },
      },
      visible => [ qw(cxn cnt mysql_thread_id user hostname txn_status time undo_log_entries query_text)],
      filters => [ qw( hide_self hide_inactive ) ],
      sort_cols => '-active_secs txn_status cxn mysql_thread_id',
      sort_dir => '1',
      innodb   => 'tx',
      hide_caption => 1,
      colors   => [
         { col => 'wait_status', op => 'eq', arg => 'LOCK WAIT',   color => 'black on_red' },
         { col => 'time',        op => '>',  arg => 600,           color => 'red' },
         { col => 'time',        op => '>',  arg => 300,           color => 'yellow' },
         { col => 'time',        op => '>',  arg => 60,            color => 'green' },
         { col => 'time',        op => '>',  arg => 30,            color => 'cyan' },
         { col => 'txn_status',  op => 'eq', arg => 'not started', color => 'white' },
      ],
      group_by => [ qw(cxn txn_status) ],
      aggregate => 0,
   },
   io_threads => {
      capt => 'I/O Threads',
      cust => {},
      cols => {
         cxn            => { src => 'cxn' },
         thread         => { src => 'thread' },
         thread_purpose => { src => 'purpose' },
         event_set      => { src => 'event_set' },
         thread_status  => { src => 'state' },
      },
      visible => [ qw(cxn thread thread_purpose thread_status)],
      filters => [ qw() ],
      sort_cols => 'cxn thread',
      sort_dir => '1',
      innodb   => 'io',
      group_by => [],
      aggregate => 0,
   },
   log_statistics => {
      capt => 'Log Statistics',
      cust => {},
      cols => {
         cxn                 => { src => 'cxn' },
         last_chkp           => { src => 'IB_lg_last_chkp' },
         log_flushed_to      => { src => 'IB_lg_log_flushed_to' },
         log_ios_done        => { src => 'IB_lg_log_ios_done' },
         log_ios_s           => { src => 'IB_lg_log_ios_s' },
         log_seq_no          => { src => 'IB_lg_log_seq_no' },
         pending_chkp_writes => { src => 'IB_lg_pending_chkp_writes' },
         pending_log_writes  => { src => 'IB_lg_pending_log_writes' },
      },
      visible => [ qw(cxn log_seq_no log_flushed_to last_chkp log_ios_done log_ios_s)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'lg',
      group_by => [],
      aggregate => 0,
   },
   master_status => {
      capt => 'Master Status',
      cust => {},
      cols => {
         cxn                         => { src => 'cxn' },
         binlog_do_db                => { src => 'binlog_do_db' },
         binlog_ignore_db            => { src => 'binlog_ignore_db' },
         master_file                 => { src => 'file' },
         master_pos                  => { src => 'position' },
         binlog_cache_overflow       => { src => '(Binlog_cache_disk_use||0)/(Binlog_cache_use||1)', trans => [ qw(percent) ] },
      },
      visible => [ qw(cxn master_file master_pos binlog_cache_overflow)],
      filters => [ qw(cxn_is_master) ],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => '',
      group_by => [],
      aggregate => 0,
   },
   pending_io => {
      capt => 'Pending I/O',
      cust => {},
      cols => {
         cxn                => { src => 'cxn' },
         p_normal_aio_reads => { src => 'IB_io_pending_normal_aio_reads' },
         p_aio_writes       => { src => 'IB_io_pending_aio_writes' },
         p_ibuf_aio_reads   => { src => 'IB_io_pending_ibuf_aio_reads' },
         p_sync_ios         => { src => 'IB_io_pending_sync_ios' },
         p_buf_pool_flushes => { src => 'IB_io_pending_buffer_pool_flushes' },
         p_log_flushes      => { src => 'IB_io_pending_log_flushes' },
         p_log_ios          => { src => 'IB_io_pending_log_ios' },
         p_preads           => { src => 'IB_io_pending_preads' },
         p_pwrites          => { src => 'IB_io_pending_pwrites' },
      },
      visible => [ qw(cxn p_normal_aio_reads p_aio_writes p_ibuf_aio_reads p_sync_ios p_log_flushes p_log_ios)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'io',
      group_by => [],
      aggregate => 0,
   },
   open_tables => {
      capt => 'Open Tables',
      cust => {},
      cols => {
         cxn            => { src => 'cxn' },
         db             => { src => 'database' },
         tbl            => { src => 'table' },
         num_times_open => { src => 'in_use' },
         is_name_locked => { src => 'name_locked' },
      },
      visible => [ qw(cxn db tbl num_times_open is_name_locked)],
      filters => [ qw(table_is_open) ],
      sort_cols => '-num_times_open cxn db tbl',
      sort_dir => '1',
      innodb   => '',
      group_by => [],
      aggregate => 0,
   },
   page_statistics => {
      capt => 'Page Statistics',
      cust => {},
      cols => {
         cxn              => { src => 'cxn' },
         pages_read       => { src => 'IB_bp_pages_read' },
         pages_written    => { src => 'IB_bp_pages_written' },
         pages_created    => { src => 'IB_bp_pages_created' },
         page_reads_sec   => { src => 'IB_bp_page_reads_sec' },
         page_writes_sec  => { src => 'IB_bp_page_writes_sec' },
         page_creates_sec => { src => 'IB_bp_page_creates_sec' },
      },
      visible => [ qw(cxn pages_read pages_written pages_created page_reads_sec page_writes_sec page_creates_sec)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'bp',
      group_by => [],
      aggregate => 0,
   },
   processlist => {
      capt => 'MySQL Process List',
      cust => {},
      cols => {
         cxn             => { src => 'cxn',        minw => 6,  maxw => 10 },
         mysql_thread_id => { src => 'id',         minw => 6,  maxw => 0 },
         user            => { src => 'user',       minw => 5,  maxw => 8 },
         hostname        => { src => $exprs{Host}, minw => 13, maxw => 8, },
         port            => { src => $exprs{Port}, minw => 0,  maxw => 0, },
         host_and_port   => { src => 'host',       minw => 0,  maxw => 0 },
         db              => { src => 'db',         minw => 6,  maxw => 12 },
         cmd             => { src => 'command',    minw => 5,  maxw => 0 },
         time            => { src => 'time',       minw => 5,  maxw => 0, trans => [ qw(secs_to_time) ], agg => 'sum' },
         state           => { src => 'state',      minw => 0,  maxw => 0 },
         info            => { src => 'info',       minw => 0,  maxw => 0, trans => [ qw(no_ctrl_char) ] },
         cnt             => { src => 'id',         minw => 0,  maxw => 0 },
      },
      visible => [ qw(cxn cmd cnt mysql_thread_id state user hostname db time info)],
      filters => [ qw(hide_self hide_inactive hide_slave_io) ],
      sort_cols => '-time cxn hostname mysql_thread_id',
      sort_dir => '1',
      innodb   => '',
      hide_caption => 1,
      colors   => [
         { col => 'state',       op => 'eq', arg => 'Locked',      color => 'black on_red' },
         { col => 'cmd',         op => 'eq', arg => 'Sleep',       color => 'white' },
         { col => 'user',        op => 'eq', arg => 'system user', color => 'white' },
         { col => 'cmd',         op => 'eq', arg => 'Connect',     color => 'white' },
         { col => 'cmd',         op => 'eq', arg => 'Binlog Dump', color => 'white' },
         { col => 'time',        op => '>',  arg => 600,           color => 'red' },
         { col => 'time',        op => '>',  arg => 120,           color => 'yellow' },
         { col => 'time',        op => '>',  arg => 60,            color => 'green' },
         { col => 'time',        op => '>',  arg => 30,            color => 'cyan' },
      ],
      group_by => [qw(cxn cmd)],
      aggregate => 0,
   },

   # TODO: some more columns:
   # kb_used=hdr='BufUsed' minw='0' num='0' src='percent(1 - ((Key_blocks_unused * key_cache_block_size) / (key_buffer_size||1)))' dec='0' trans='' tbl='q_header' just='-' user='1' maxw='0' label='User-defined'
   # retries=hdr='Retries' minw='0' num='0' src='Slave_retried_transactions' dec='0' trans='' tbl='slave_sql_status' just='-' user='1' maxw='0' label='User-defined'
   # thd=hdr='Thd' minw='0' num='0' src='Threads_connected' dec='0' trans='' tbl='slave_sql_status' just='-' user='1' maxw='0' label='User-defined'

   q_header => {
      capt => 'Q-mode Header',
      cust => {},
      cols => {
         cxn            => { src => 'cxn' },
         questions      => { src => 'Questions' },
         qps            => { src => 'Questions/Uptime_hires',               dec => 1, trans => [qw(shorten)] },
         load           => { src => $exprs{ServerLoad},                     dec => 1, trans => [qw(shorten)] },
         slow           => { src => 'Slow_queries',                         dec => 1, trans => [qw(shorten)] },
         q_cache_hit    => { src => $exprs{QcacheHitRatio},                 dec => 1, trans => [qw(percent)] },
         key_buffer_hit => { src => '1-(Key_reads/(Key_read_requests||1))', dec => 1, trans => [qw(percent)] },
         bps_in         => { src => 'Bytes_received/Uptime_hires',          dec => 1, trans => [qw(shorten)] },
         bps_out        => { src => 'Bytes_sent/Uptime_hires',              dec => 1, trans => [qw(shorten)] },
         when           => { src => 'when' },
      },
      visible => [ qw(cxn when load qps slow q_cache_hit key_buffer_hit bps_in bps_out)],
      filters => [],
      sort_cols => 'when cxn',
      sort_dir => '1',
      innodb   => '',
      hide_caption => 1,
      group_by => [],
      aggregate => 0,
   },
   row_operations => {
      capt => 'InnoDB Row Operations',
      cust => {},
      cols => {
         cxn         => { src => 'cxn' },
         num_inserts => { src => 'IB_ro_num_rows_ins' },
         num_updates => { src => 'IB_ro_num_rows_upd' },
         num_reads   => { src => 'IB_ro_num_rows_read' },
         num_deletes => { src => 'IB_ro_num_rows_del' },
         num_inserts_sec => { src => 'IB_ro_ins_sec' },
         num_updates_sec => { src => 'IB_ro_upd_sec' },
         num_reads_sec   => { src => 'IB_ro_read_sec' },
         num_deletes_sec => { src => 'IB_ro_del_sec' },
      },
      visible => [ qw(cxn num_inserts num_updates num_reads num_deletes num_inserts_sec
                       num_updates_sec num_reads_sec num_deletes_sec)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'ro',
      group_by => [],
      aggregate => 0,
   },
   row_operation_misc => {
      capt => 'Row Operation Misc',
      cust => {},
      cols => {
         cxn                 => { src => 'cxn' },
         queries_in_queue    => { src => 'IB_ro_queries_in_queue' },
         queries_inside      => { src => 'IB_ro_queries_inside' },
         read_views_open     => { src => 'IB_ro_read_views_open' },
         main_thread_id      => { src => 'IB_ro_main_thread_id' },
         main_thread_proc_no => { src => 'IB_ro_main_thread_proc_no' },
         main_thread_state   => { src => 'IB_ro_main_thread_state' },
         num_res_ext         => { src => 'IB_ro_n_reserved_extents' },
      },
      visible => [ qw(cxn queries_in_queue queries_inside read_views_open main_thread_state)],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'ro',
      group_by => [],
      aggregate => 0,
   },
   semaphores => {
      capt => 'InnoDB Semaphores',
      cust => {},
      cols => {
         cxn                => { src => 'cxn' },
         mutex_os_waits     => { src => 'IB_sm_mutex_os_waits' },
         mutex_spin_rounds  => { src => 'IB_sm_mutex_spin_rounds' },
         mutex_spin_waits   => { src => 'IB_sm_mutex_spin_waits' },
         reservation_count  => { src => 'IB_sm_reservation_count' },
         rw_excl_os_waits   => { src => 'IB_sm_rw_excl_os_waits' },
         rw_excl_spins      => { src => 'IB_sm_rw_excl_spins' },
         rw_shared_os_waits => { src => 'IB_sm_rw_shared_os_waits' },
         rw_shared_spins    => { src => 'IB_sm_rw_shared_spins' },
         signal_count       => { src => 'IB_sm_signal_count' },
         wait_array_size    => { src => 'IB_sm_wait_array_size' },
      },
      visible => [ qw(cxn mutex_os_waits mutex_spin_waits mutex_spin_rounds
         rw_excl_os_waits rw_excl_spins rw_shared_os_waits rw_shared_spins
         signal_count reservation_count )],
      filters => [],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => 'sm',
      group_by => [],
      aggregate => 0,
   },
   slave_io_status => {
      capt => 'Slave I/O Status',
      cust => {},
      cols => {
         cxn                         => { src => 'cxn' },
         connect_retry               => { src => 'connect_retry' },
         master_host                 => { src => 'master_host', hdr => 'Master'},
         master_log_file             => { src => 'master_log_file', hdr => 'File' },
         master_port                 => { src => 'master_port' },
         master_ssl_allowed          => { src => 'master_ssl_allowed' },
         master_ssl_ca_file          => { src => 'master_ssl_ca_file' },
         master_ssl_ca_path          => { src => 'master_ssl_ca_path' },
         master_ssl_cert             => { src => 'master_ssl_cert' },
         master_ssl_cipher           => { src => 'master_ssl_cipher' },
         master_ssl_key              => { src => 'master_ssl_key' },
         master_user                 => { src => 'master_user' },
         read_master_log_pos         => { src => 'read_master_log_pos', hdr => 'Pos' },
         relay_log_size              => { src => 'relay_log_space', trans => [qw(shorten)] },
         slave_io_running            => { src => 'slave_io_running', hdr => 'On?' },
         slave_io_state              => { src => 'slave_io_state', hdr => 'State' },
      },
      visible => [ qw(cxn master_host slave_io_running master_log_file relay_log_size read_master_log_pos slave_io_state)],
      filters => [ qw( cxn_is_slave ) ],
      sort_cols => 'slave_io_running cxn',
      colors   => [
         { col => 'slave_io_running',  op => 'ne', arg => 'Yes', color => 'black on_red' },
      ],
      sort_dir => '1',
      innodb   => '',
      group_by => [],
      aggregate => 0,
   },
   slave_sql_status => {
      capt => 'Slave SQL Status',
      cust => {},
      cols => {
         cxn                         => { src => 'cxn' },
         exec_master_log_pos         => { src => 'exec_master_log_pos', hdr => 'Master Pos' },
         last_errno                  => { src => 'last_errno' },
         last_error                  => { src => 'last_error' },
         master_host                 => { src => 'master_host', hdr => 'Master' },
         relay_log_file              => { src => 'relay_log_file' },
         relay_log_pos               => { src => 'relay_log_pos' },
         relay_log_size              => { src => 'relay_log_space', trans => [qw(shorten)] },
         relay_master_log_file       => { src => 'relay_master_log_file', hdr => 'Master File' },
         replicate_do_db             => { src => 'replicate_do_db' },
         replicate_do_table          => { src => 'replicate_do_table' },
         replicate_ignore_db         => { src => 'replicate_ignore_db' },
         replicate_ignore_table      => { src => 'replicate_ignore_table' },
         replicate_wild_do_table     => { src => 'replicate_wild_do_table' },
         replicate_wild_ignore_table => { src => 'replicate_wild_ignore_table' },
         skip_counter                => { src => 'skip_counter' },
         slave_sql_running           => { src => 'slave_sql_running', hdr => 'On?' },
         until_condition             => { src => 'until_condition' },
         until_log_file              => { src => 'until_log_file' },
         until_log_pos               => { src => 'until_log_pos' },
         time_behind_master          => { src => 'seconds_behind_master', trans => [ qw(secs_to_time) ] },
         bytes_behind_master         => { src => 'master_log_file && master_log_file eq relay_master_log_file ? read_master_log_pos - exec_master_log_pos : 0', trans => [qw(shorten)] },
         slave_catchup_rate          => { src => $exprs{SlaveCatchupRate}, trans => [ qw(set_precision) ] },
         slave_open_temp_tables      => { src => 'Slave_open_temp_tables' },
      },
      visible => [ qw(cxn master_host slave_sql_running time_behind_master slave_catchup_rate slave_open_temp_tables relay_log_pos last_error)],
      filters => [ qw( cxn_is_slave ) ],
      sort_cols => 'slave_sql_running cxn',
      sort_dir => '1',
      innodb   => '',
      colors   => [
         { col => 'slave_sql_running',  op => 'ne', arg => 'Yes', color => 'black on_red' },
         { col => 'time_behind_master', op => '>',  arg => 600,   color => 'red' },
         { col => 'time_behind_master', op => '>',  arg => 60,    color => 'yellow' },
         { col => 'time_behind_master', op => '==', arg => 0,     color => 'white' },
      ],
      group_by => [],
      aggregate => 0,
   },
   t_header => {
      capt => 'T-Mode Header',
      cust => {},
      cols => {
         cxn                         => { src => 'cxn' },
         dirty_bufs                  => { src => $exprs{DirtyBufs},           trans => [qw(percent)] },
         history_list_len            => { src => 'IB_tx_history_list_len' },
         lock_structs                => { src => 'IB_tx_num_lock_structs' },
         num_txns                    => { src => $exprs{NumTxns} },
         max_txn                     => { src => $exprs{MaxTxnTime},          trans => [qw(secs_to_time)] },
         undo_for                    => { src => 'IB_tx_purge_undo_for' },
         used_bufs                   => { src => $exprs{BufPoolFill},         trans => [qw(percent)]},
         versions                    => { src => $exprs{OldVersions} },
      },
      visible => [ qw(cxn history_list_len versions undo_for dirty_bufs used_bufs num_txns max_txn lock_structs)],
      filters => [ ],
      sort_cols => 'cxn',
      sort_dir => '1',
      innodb   => '',
      colors   => [],
      hide_caption => 1,
      group_by => [],
      aggregate => 0,
   },
   var_status => {
      capt      => 'Variables & Status',
      cust      => {},
      cols      => {}, # Generated from current varset
      visible   => [], # Generated from current varset
      filters   => [],
      sort_cols => '',
      sort_dir  => 1,
      innodb    => '',
      temp      => 1, # Do not persist to config file.
      hide_caption  => 1,
      pivot     => 0,
      group_by => [],
      aggregate => 0,
   },
   wait_array => {
      capt => 'InnoDB Wait Array',
      cust => {},
      cols => {
         cxn                => { src => 'cxn' },
         thread             => { src => 'thread' },
         waited_at_filename => { src => 'waited_at_filename' },
         waited_at_line     => { src => 'waited_at_line' },
         'time'             => { src => 'waited_secs', trans => [ qw(secs_to_time) ] },
         request_type       => { src => 'request_type' },
         lock_mem_addr      => { src => 'lock_mem_addr' },
         lock_cfile_name    => { src => 'lock_cfile_name' },
         lock_cline         => { src => 'lock_cline' },
         writer_thread      => { src => 'writer_thread' },
         writer_lock_mode   => { src => 'writer_lock_mode' },
         num_readers        => { src => 'num_readers' },
         lock_var           => { src => 'lock_var' },
         waiters_flag       => { src => 'waiters_flag' },
         last_s_file_name   => { src => 'last_s_file_name' },
         last_s_line        => { src => 'last_s_line' },
         last_x_file_name   => { src => 'last_x_file_name' },
         last_x_line        => { src => 'last_x_line' },
         cell_waiting       => { src => 'cell_waiting' },
         cell_event_set     => { src => 'cell_event_set' },
      },
      visible => [ qw(cxn thread time waited_at_filename waited_at_line request_type num_readers lock_var waiters_flag cell_waiting cell_event_set)],
      filters => [],
      sort_cols => 'cxn -time',
      sort_dir => '1',
      innodb   => 'sm',
      group_by => [],
      aggregate => 0,
   },
);

# Initialize %tbl_meta from %columns and do some checks.
foreach my $table_name ( keys %tbl_meta ) {
   my $table = $tbl_meta{$table_name};
   my $cols  = $table->{cols};

   foreach my $col_name ( keys %$cols ) {
      my $col_def = $table->{cols}->{$col_name};
      die "I can't find a column named '$col_name' for '$table_name'" unless $columns{$col_name};
      $columns{$col_name}->{referenced} = 1;

      foreach my $prop ( keys %col_props ) {
         # Each column gets non-existing values set from %columns or defaults from %col_props.
         if ( !$col_def->{$prop} ) {
            $col_def->{$prop}
               = defined($columns{$col_name}->{$prop})
               ? $columns{$col_name}->{$prop}
               : $col_props{$prop};
         }
      }

      # Ensure transformations and aggregate functions are valid
      die "Unknown aggregate function '$col_def->{agg}' "
         . "for column '$col_name' in table '$table_name'"
         unless exists $agg_funcs{$col_def->{agg}};
      foreach my $trans ( @{$col_def->{trans}} ) {
         die "Unknown transformation '$trans' "
            . "for column '$col_name' in table '$table_name'"
            unless exists $trans_funcs{$trans};
      }
   }

   # Ensure each column in visible and group_by exists in cols
   foreach my $place ( qw(visible group_by) ) {
      foreach my $col_name ( @{$table->{$place}} ) {
         if ( !exists $cols->{$col_name} ) {
            die "Column '$col_name' is listed in '$place' for '$table_name', but doesn't exist";
         }
      }
   }

   # Compile sort and color subroutines
   $table->{sort_func}  = make_sort_func($table);
   $table->{color_func} = make_color_func($table);
}

# This is for code cleanup:
{
   my @unused_cols = grep { !$columns{$_}->{referenced} } sort keys %columns;
   if ( @unused_cols ) {
      die "The following columns are not used: "
         . join(' ', @unused_cols);
   }
}

# ###########################################################################
# Operating modes {{{3
# ###########################################################################
my %modes = (
   B => {
      hdr               => 'InnoDB Buffers',
      cust              => {},
      note              => 'Shows buffer info from InnoDB',
      action_for        => {
         i => {
            action => sub { toggle_config('status_inc') },
            label  => 'Toggle incremental status display',
         },
      },
      display_sub       => \&display_B,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(buffer_pool page_statistics insert_buffers adaptive_hash_index)],
      visible_tables    => [qw(buffer_pool page_statistics insert_buffers adaptive_hash_index)],
   },
   C => {
      hdr               => 'Command Summary',
      cust              => {},
      note              => 'Shows relative magnitude of variables',
      action_for        => {
         s => {
            action => sub { get_config_interactive('cmd_filter') },
            label  => 'Choose variable prefix',
         },
      },
      display_sub       => \&display_C,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(cmd_summary)],
      visible_tables    => [qw(cmd_summary)],
   },
   D => {
      hdr               => 'InnoDB Deadlocks',
      cust              => {},
      note              => 'View InnoDB deadlock information',
      action_for        => {
         c => {
            action => sub { edit_table('deadlock_transactions') },
            label  => 'Choose visible columns',
         },
         w => {
            action => \&create_deadlock,
            label  => 'Wipe deadlock status info by creating a deadlock',
         },
      },
      display_sub       => \&display_D,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(deadlock_transactions deadlock_locks)],
      visible_tables    => [qw(deadlock_transactions deadlock_locks)],
   },
   F => {
      hdr               => 'InnoDB FK Err',
      cust              => {},
      note              => 'View the latest InnoDB foreign key error',
      action_for        => {},
      display_sub       => \&display_F,
      connections       => [],
      server_group      => '',
      one_connection    => 1,
      tables            => [qw(fk_error)],
      visible_tables    => [qw(fk_error)],
   },
   I => {
      hdr               => 'InnoDB I/O Info',
      cust              => {},
      note              => 'Shows I/O info (i/o, log...) from InnoDB',
      action_for        => {
         i => {
            action => sub { toggle_config('status_inc') },
            label  => 'Toggle incremental status display',
         },
      },
      display_sub       => \&display_I,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(io_threads pending_io file_io_misc log_statistics)],
      visible_tables    => [qw(io_threads pending_io file_io_misc log_statistics)],
   },
   L => {
      hdr             => 'Locks',
      cust            => {},
      note            => 'Shows transaction locks',
      action_for      => {
         a => {
            action => sub { send_cmd_to_servers('CREATE TABLE IF NOT EXISTS test.innodb_lock_monitor(a int) ENGINE=InnoDB', 0, '', []); },
            label  => 'Start the InnoDB Lock Monitor',
         },
         o => {
            action => sub { send_cmd_to_servers('DROP TABLE IF EXISTS test.innodb_lock_monitor', 0, '', []); },
            label  => 'Stop the InnoDB Lock Monitor',
         },
      },
      display_sub     => \&display_L,
      connections     => [],
      server_group    => '',
      one_connection  => 0,
      tables            => [qw(innodb_locks)],
      visible_tables    => [qw(innodb_locks)],
   },
   M => {
      hdr               => 'Replication Status',
      cust              => {},
      note              => 'Shows replication (master and slave) status',
      action_for        => {
         a => {
            action => sub { send_cmd_to_servers('START SLAVE', 0, 'START SLAVE SQL_THREAD UNTIL MASTER_LOG_FILE = ?, MASTER_LOG_POS = ?', []); },
            label  => 'Start slave(s)',
         },
         i => {
            action => sub { toggle_config('status_inc') },
            label  => 'Toggle incremental status display',
         },
         o => {
            action => sub { send_cmd_to_servers('STOP SLAVE', 0, '', []); },
            label  => 'Stop slave(s)',
         },
         b => {
            action => sub { purge_master_logs() },
            label  => 'Purge unused master logs',
         },
      },
      display_sub       => \&display_M,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(slave_sql_status slave_io_status master_status)],
      visible_tables    => [qw(slave_sql_status slave_io_status master_status)],
   },
   O => {
      hdr               => 'Open Tables',
      cust              => {},
      note              => 'Shows open tables in MySQL',
      action_for        => {
         r => {
            action => sub { reverse_sort('open_tables'); },
            label  => 'Reverse sort order',
         },
         s => {
            action => sub { choose_sort_cols('open_tables'); },
            label => "Choose sort column",
         },
      },
      display_sub       => \&display_O,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(open_tables)],
      visible_tables    => [qw(open_tables)],
   },
   Q => {
      hdr        => 'Query List',
      cust       => {},
      note       => 'Shows queries from SHOW FULL PROCESSLIST',
      action_for => {
         a => {
            action => sub { toggle_filter('processlist', 'hide_self') },
            label  => 'Toggle the innotop process',
         },
         c => {
            action => sub { edit_table('processlist') },
            label  => 'Choose visible columns',
         },
         e => {
            action => sub { analyze_query('e'); },
            label  => "Explain a thread's query",
         },
         f => {
            action => sub { analyze_query('f'); },
            label  => "Show a thread's full query",
         },
         h => {
            action => sub { toggle_visible_table('Q', 'q_header') },
            label  => 'Toggle the header on and off',
         },
         i => {
            action => sub { toggle_filter('processlist', 'hide_inactive') },
            label  => 'Toggle idle processes',
         },
         k => {
            action => sub { kill_query('CONNECTION') },
            label => "Kill a query's connection",
         },
         r => {
            action => sub { reverse_sort('processlist'); },
            label  => 'Reverse sort order',
         },
         s => {
            action => sub { choose_sort_cols('processlist'); },
            label => "Change the display's sort column",
         },
         x => {
            action => sub { kill_query('QUERY') },
            label => "Kill a query",
         },
      },
      display_sub       => \&display_Q,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(q_header processlist)],
      visible_tables    => [qw(q_header processlist)],
   },
   R => {
      hdr               => 'InnoDB Row Ops',
      cust              => {},
      note              => 'Shows InnoDB row operation and semaphore info',
      action_for        => {
         i => {
            action => sub { toggle_config('status_inc') },
            label  => 'Toggle incremental status display',
         },
      },
      display_sub       => \&display_R,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(row_operations row_operation_misc semaphores wait_array)],
      visible_tables    => [qw(row_operations row_operation_misc semaphores wait_array)],
   },
   S => {
      hdr               => 'Variables & Status',
      cust              => {},
      note              => 'Shows query load statistics a la vmstat',
      action_for        => {
         '>' => {
            action => sub { switch_var_set('S_set', 1) },
            label  => 'Switch to next variable set',
         },
         '<' => {
            action => sub { switch_var_set('S_set', -1) },
            label  => 'Switch to prev variable set',
         },
         c => {
            action => sub {
               choose_var_set('S_set');
               start_S_mode();
            },
            label => "Choose which set to display",
         },
         e => {
            action => \&edit_current_var_set,
            label  => 'Edit the current set of variables',
         },
         i => {
            action => sub { $clear_screen_sub->(); toggle_config('status_inc') },
            label  => 'Toggle incremental status display',
         },
         '-' => {
            action => sub { set_display_precision(-1) },
            label  => 'Decrease fractional display precision',
         },
         '+' => {
            action => sub { set_display_precision(1) },
            label  => 'Increase fractional display precision',
         },
         g => {
            action => sub { set_s_mode('g') },
            label  => 'Switch to graph (tload) view',
         },
         s => {
            action => sub { set_s_mode('s') },
            label  => 'Switch to standard (vmstat) view',
         },
         v => {
            action => sub { set_s_mode('v') },
            label  => 'Switch to pivoted view',
         },
      },
      display_sub       => \&display_S,
      no_clear_screen   => 1,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(var_status)],
      visible_tables    => [qw(var_status)],
   },
   T => {
      hdr        => 'InnoDB Txns',
      cust       => {},
      note       => 'Shows InnoDB transactions in top-like format',
      action_for => {
         a => {
            action => sub { toggle_filter('innodb_transactions', 'hide_self') },
            label  => 'Toggle the innotop process',
         },
         c => {
            action => sub { edit_table('innodb_transactions') },
            label  => 'Choose visible columns',
         },
         e => {
            action => sub { analyze_query('e'); },
            label  => "Explain a thread's query",
         },
         f => {
            action => sub { analyze_query('f'); },
            label  => "Show a thread's full query",
         },
         h => {
            action => sub { toggle_visible_table('T', 't_header') },
            label  => 'Toggle the header on and off',
         },
         i => {
            action => sub { toggle_filter('innodb_transactions', 'hide_inactive') },
            label  => 'Toggle inactive transactions',
         },
         k => {
            action => sub { kill_query('CONNECTION') },
            label  => "Kill a transaction's connection",
         },
         r => {
            action => sub { reverse_sort('innodb_transactions'); },
            label  => 'Reverse sort order',
         },
         s => {
            action => sub { choose_sort_cols('innodb_transactions'); },
            label  => "Change the display's sort column",
         },
         x => {
            action => sub { kill_query('QUERY') },
            label  => "Kill a query",
         },
      },
      display_sub       => \&display_T,
      connections       => [],
      server_group      => '',
      one_connection    => 0,
      tables            => [qw(t_header innodb_transactions)],
      visible_tables    => [qw(t_header innodb_transactions)],
   },
);

# ###########################################################################
# Global key mappings {{{3
# Keyed on a single character, which is read from the keyboard.  Uppercase
# letters switch modes.  Lowercase letters access commands when in a mode.
# These can be overridden by action_for in %modes.
# ###########################################################################
my %action_for = (
   '$' => {
      action => \&edit_configuration,
      label  => 'Edit configuration settings',
   },
   '?' => {
      action => \&display_help,
      label  => 'Show help',
   },
   '!' => {
      action => \&display_license,
      label  => 'Show license and warranty',
   },
   '^' => {
      action => \&edit_table,
      label  => "Edit the displayed table(s)",
   },
   '#' => {
      action => \&choose_server_groups,
      label  => 'Select/create server groups',
   },
   '@' => {
      action => \&choose_servers,
      label  => 'Select/create server connections',
   },
   '/' => {
      action => \&add_quick_filter,
      label  => 'Quickly filter what you see',
   },
   '\\' => {
      action => \&clear_quick_filters,
      label  => 'Clear quick-filters',
   },
   '%' => {
      action => \&choose_filters,
      label  => 'Choose and edit table filters',
   },
   "\t" => {
      action => \&next_server_group,
      label  => 'Switch to the next server group',
      key    => 'TAB',
   },
   '=' => {
      action => \&toggle_aggregate,
      label  => 'Toggle aggregation',
   },
   # TODO: can these be auto-generated from %modes?
   B => {
      action => sub { switch_mode('B') },
      label  => '',
   },
   C => {
      action => sub { switch_mode('C') },
      label  => '',
   },
   D => {
      action => sub { switch_mode('D') },
      label  => '',
   },
   F => {
      action => sub { switch_mode('F') },
      label  => '',
   },
   I => {
      action => sub { switch_mode('I') },
      label  => '',
   },
   L => {
      action => sub { switch_mode('L') },
      label  => '',
   },
   M => {
      action => sub { switch_mode('M') },
      label  => '',
   },
   O => {
      action => sub { switch_mode('O') },
      label  => '',
   },
   Q => {
      action => sub { switch_mode('Q') },
      label  => '',
   },
   R => {
      action => sub { switch_mode('R') },
      label  => '',
   },
   S => {
      action => \&start_S_mode,
      label  => '',
   },
   T => {
      action => sub { switch_mode('T') },
      label  => '',
   },
   d => {
      action => sub { get_config_interactive('interval') },
      label  => 'Change refresh interval',
   },
   n => { action => \&next_server,       label => 'Switch to the next connection' },
   p => { action => \&pause,             label => 'Pause innotop', },
   q => { action => \&finish,            label => 'Quit innotop', },
);

# ###########################################################################
# Sleep times after certain statements {{{3
# ###########################################################################
my %stmt_sleep_time_for = ();

# ###########################################################################
# Config editor key mappings {{{3
# ###########################################################################
my %cfg_editor_action = (
   c => {
      note => 'Edit columns, etc in the displayed table(s)',
      func => \&edit_table,
   },
   g => {
      note => 'Edit general configuration',
      func => \&edit_configuration_variables,
   },
   k => {
      note => 'Edit row-coloring rules',
      func => \&edit_color_rules,
   },
   p => {
      note => 'Manage plugins',
      func => \&edit_plugins,
   },
   s => {
      note => 'Edit server groups',
      func => \&edit_server_groups,
   },
   S => {
      note => 'Edit SQL statement sleep delays',
      func => \&edit_stmt_sleep_times,
   },
   t => {
      note => 'Choose which table(s) to display in this mode',
      func => \&choose_mode_tables,
   },
);

# ###########################################################################
# Color editor key mappings {{{3
# ###########################################################################
my %color_editor_action = (
   n => {
      note => 'Create a new color rule',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my $meta = $tbl_meta{$tbl};

         $clear_screen_sub->();
         my $col;
         do {
            $col = prompt_list(
               'Choose the target column for the rule',
               '',
               sub { return keys %{$meta->{cols}} },
               { map { $_ => $meta->{cols}->{$_}->{label} } keys %{$meta->{cols}} });
         } while ( !$col );
         ( $col ) = grep { $_ } split(/\W+/, $col);
         return $idx unless $col && exists $meta->{cols}->{$col};

         $clear_screen_sub->();
         my $op;
         do {
            $op = prompt_list(
               'Choose the comparison operator for the rule',
               '',
               sub { return keys %comp_ops },
               { map { $_ => $comp_ops{$_} } keys %comp_ops } );
         } until ( $op );
         $op =~ s/\s+//g;
         return $idx unless $op && exists $comp_ops{$op};

         my $arg;
         do {
            $arg = prompt('Specify an argument for the comparison');
         } until defined $arg;

         my $color;
         do {
            $color = prompt_list(
               'Choose the color(s) the row should be when the rule matches',
               '',
               sub { return keys %ansicolors },
               { map { $_ => $_ } keys %ansicolors } );
         } until defined $color;
         $color = join(' ', unique(grep { exists $ansicolors{$_} } split(/\W+/, $color)));
         return $idx unless $color;

         push @{$tbl_meta{$tbl}->{colors}}, {
            col   => $col,
            op    => $op,
            arg   => $arg,
            color => $color
         };
         $tbl_meta{$tbl}->{cust}->{colors} = 1;

         return $idx;
      },
   },
   d => {
      note => 'Remove the selected rule',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my @rules = @{ $tbl_meta{$tbl}->{colors} };
         return 0 unless @rules > 0 && $idx < @rules && $idx >= 0;
         splice(@{$tbl_meta{$tbl}->{colors}}, $idx, 1);
         $tbl_meta{$tbl}->{cust}->{colors} = 1;
         return $idx == @rules ? $#rules : $idx;
      },
   },
   j => {
      note => 'Move highlight down one',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my $num_rules = scalar @{$tbl_meta{$tbl}->{colors}};
         return ($idx + 1) % $num_rules;
      },
   },
   k => {
      note => 'Move highlight up one',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my $num_rules = scalar @{$tbl_meta{$tbl}->{colors}};
         return ($idx - 1) % $num_rules;
      },
   },
   '+' => {
      note => 'Move selected rule up one',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my $meta = $tbl_meta{$tbl};
         my $dest = $idx == 0 ? scalar(@{$meta->{colors}} - 1) : $idx - 1;
         my $temp = $meta->{colors}->[$idx];
         $meta->{colors}->[$idx]  = $meta->{colors}->[$dest];
         $meta->{colors}->[$dest] = $temp;
         $meta->{cust}->{colors} = 1;
         return $dest;
      },
   },
   '-' => {
      note => 'Move selected rule down one',
      func => sub {
         my ( $tbl, $idx ) = @_;
         my $meta = $tbl_meta{$tbl};
         my $dest = $idx == scalar(@{$meta->{colors}} - 1) ? 0 : $idx + 1;
         my $temp = $meta->{colors}->[$idx];
         $meta->{colors}->[$idx]  = $meta->{colors}->[$dest];
         $meta->{colors}->[$dest] = $temp;
         $meta->{cust}->{colors} = 1;
         return $dest;
      },
   },
);

# ###########################################################################
# Plugin editor key mappings {{{3
# ###########################################################################
my %plugin_editor_action = (
   '*' => {
      note => 'Toggle selected plugin active/inactive',
      func => sub {
         my ( $plugins, $idx ) = @_;
         my $plugin = $plugins->[$idx];
         $plugin->{active} = $plugin->{active} ? 0 : 1;
         return $idx;
      },
   },
   j => {
      note => 'Move highlight down one',
      func => sub {
         my ( $plugins, $idx ) = @_;
         return ($idx + 1) % scalar(@$plugins);
      },
   },
   k => {
      note => 'Move highlight up one',
      func => sub {
         my ( $plugins, $idx ) = @_;
         return $idx == 0 ? @$plugins - 1 : $idx - 1;
      },
   },
);

# ###########################################################################
# Table editor key mappings {{{3
# ###########################################################################
my %tbl_editor_action = (
   a => {
      note => 'Add a column to the table',
      func => sub {
         my ( $tbl, $col ) = @_;
         my @visible_cols = @{ $tbl_meta{$tbl}->{visible} };
         my %all_cols     = %{ $tbl_meta{$tbl}->{cols} };
         delete @all_cols{@visible_cols};
         my $choice = prompt_list(
            'Choose a column',
            '',
            sub { return keys %all_cols; },
            { map { $_ => $all_cols{$_}->{label} || $all_cols{$_}->{hdr} } keys %all_cols });
         if ( $all_cols{$choice} ) {
            push @{$tbl_meta{$tbl}->{visible}}, $choice;
            $tbl_meta{$tbl}->{cust}->{visible} = 1;
            return $choice;
         }
         return $col;
      },
   },
   n => {
      note => 'Create a new column and add it to the table',
      func => sub {
         my ( $tbl, $col ) = @_;

         $clear_screen_sub->();
         print word_wrap("Choose a name for the column.  This name is not displayed, and is used only "
               . "for internal reference.  It can contain only lowercase letters, numbers, "
               . "and underscores.");
         print "\n\n";
         do {
            $col = prompt("Enter column name");
            $col = '' if $col =~ m/[^a-z0-9_]/;
         } while ( !$col );

         $clear_screen_sub->();
         my $hdr;
         do {
            $hdr = prompt("Enter column header");
         } while ( !$hdr );

         $clear_screen_sub->();
         print "Choose a source for the column's data\n\n";
         my ( $src, $sub, $err );
         do {
            if ( $err ) {
               print "Error: $err\n\n";
            }
            $src = prompt("Enter column source");
            if ( $src ) {
               ( $sub, $err ) = compile_expr($src);
            }
         } until ( !$err);

         # TODO: this duplicates %col_props.
         $tbl_meta{$tbl}->{cols}->{$col} = {
            hdr   => $hdr,
            src   => $src,
            just  => '-',
            num   => 0,
            label => 'User-defined',
            user  => 1,
            tbl   => $tbl,
            minw  => 0,
            maxw  => 0,
            trans => [],
            func  => $sub,
            dec   => 0,
            agg   => 0,
            aggonly => 0,
         };

         $tbl_meta{$tbl}->{visible} = [ unique(@{$tbl_meta{$tbl}->{visible}}, $col) ];
         $tbl_meta{$tbl}->{cust}->{visible} = 1;
         return $col;
      },
   },
   d => {
      note => 'Remove selected column',
      func => sub {
         my ( $tbl, $col ) = @_;
         my @visible_cols = @{ $tbl_meta{$tbl}->{visible} };
         my $idx          = 0;
         return $col unless @visible_cols > 1;
         while ( $visible_cols[$idx] ne $col ) {
            $idx++;
         }
         $tbl_meta{$tbl}->{visible} = [ grep { $_ ne $col } @visible_cols ];
         $tbl_meta{$tbl}->{cust}->{visible} = 1;
         return $idx == $#visible_cols ? $visible_cols[$idx - 1] : $visible_cols[$idx + 1];
      },
   },
   e => {
      note => 'Edit selected column',
      func => sub {
         # TODO: make this editor hotkey-driven and give readline support.
         my ( $tbl, $col ) = @_;
         $clear_screen_sub->();
         my $meta = $tbl_meta{$tbl}->{cols}->{$col};
         my @prop = qw(hdr label src just num minw maxw trans agg); # TODO redundant

         my $answer;
         do {
            # Do what the user asked...
            if ( $answer && grep { $_ eq $answer } @prop ) {
               # Some properties are arrays, others scalars.
               my $ini = ref $col_props{$answer} ? join(' ', @{$meta->{$answer}}) : $meta->{$answer};
               my $val = prompt("New value for $answer", undef, $ini);
               $val = [ split(' ', $val) ] if ref($col_props{$answer});
               if ( $answer eq 'trans' ) {
                  $val = [ unique(grep{ exists $trans_funcs{$_} } @$val) ];
               }
               @{$meta}{$answer, 'user', 'tbl' } = ( $val, 1, $tbl );
            }

            my @display_lines = (
               '',
               "You are editing column $tbl.$col.\n",
            );

            push @display_lines, create_table2(
               \@prop,
               { map { $_ => $_ } @prop },
               { map { $_ => ref $meta->{$_} eq 'ARRAY' ? join(' ', @{$meta->{$_}})
                           : ref $meta->{$_}            ? '[expression code]'
                           :                              $meta->{$_}
                     } @prop
               },
               { sep => '  ' });
            draw_screen(\@display_lines, { raw => 1 });
            print "\n\n"; # One to add space, one to clear readline artifacts
            $answer = prompt('Edit what? (q to quit)');
         } while ( $answer ne 'q' );

         return $col;
      },
   },
   j => {
      note => 'Move highlight down one',
      func => sub {
         my ( $tbl, $col ) = @_;
         my @visible_cols = @{ $tbl_meta{$tbl}->{visible} };
         my $idx          = 0;
         while ( $visible_cols[$idx] ne $col ) {
            $idx++;
         }
         return $visible_cols[ ($idx + 1) % @visible_cols ];
      },
   },
   k => {
      note => 'Move highlight up one',
      func => sub {
         my ( $tbl, $col ) = @_;
         my @visible_cols = @{ $tbl_meta{$tbl}->{visible} };
         my $idx          = 0;
         while ( $visible_cols[$idx] ne $col ) {
            $idx++;
         }
         return $visible_cols[ $idx - 1 ];
      },
   },
   '+' => {
      note => 'Move selected column up one',
      func => sub {
         my ( $tbl, $col ) = @_;
         my $meta         = $tbl_meta{$tbl};
         my @visible_cols = @{$meta->{visible}};
         my $idx          = 0;
         while ( $visible_cols[$idx] ne $col ) {
            $idx++;
         }
         if ( $idx ) {
            $visible_cols[$idx]     = $visible_cols[$idx - 1];
            $visible_cols[$idx - 1] = $col;
            $meta->{visible}        = \@visible_cols;
         }
         else {
            shift @{$meta->{visible}};
            push @{$meta->{visible}}, $col;
         }
         $meta->{cust}->{visible} = 1;
         return $col;
      },
   },
   '-' => {
      note => 'Move selected column down one',
      func => sub {
         my ( $tbl, $col ) = @_;
         my $meta         = $tbl_meta{$tbl};
         my @visible_cols = @{$meta->{visible}};
         my $idx          = 0;
         while ( $visible_cols[$idx] ne $col ) {
            $idx++;
         }
         if ( $idx == $#visible_cols ) {
            unshift @{$meta->{visible}}, $col;
            pop @{$meta->{visible}};
         }
         else {
            $visible_cols[$idx]     = $visible_cols[$idx + 1];
            $visible_cols[$idx + 1] = $col;
            $meta->{visible}        = \@visible_cols;
         }
         $meta->{cust}->{visible} = 1;
         return $col;
      },
   },
   f => {
      note => 'Choose filters',
      func => sub {
         my ( $tbl, $col ) = @_;
         choose_filters($tbl);
         return $col;
      },
   },
   o => {
      note => 'Edit color rules',
      func => sub {
         my ( $tbl, $col ) = @_;
         edit_color_rules($tbl);
         return $col;
      },
   },
   s => {
      note => 'Choose sort columns',
      func => sub {
         my ( $tbl, $col ) = @_;
         choose_sort_cols($tbl);
         return $col;
      },
   },
   g => {
      note => 'Choose group-by (aggregate) columns',
      func => sub {
         my ( $tbl, $col ) = @_;
         choose_group_cols($tbl);
         return $col;
      },
   },
);

# ###########################################################################
# Global variables and environment {{{2
# ###########################################################################

my @this_term_size; # w_chars, h_chars, w_pix, h_pix
my @last_term_size; # w_chars, h_chars, w_pix, h_pix
my $char;
my $windows       = $OSNAME =~ m/MSWin/;
my $have_color    = 0;
my $MAX_ULONG     = 4294967295; # 2^32-1
my $num_regex     = qr/^[+-]?(?=\d|\.)\d*(?:\.\d+)?(?:E[+-]?\d+|)$/i;
my $int_regex     = qr/^\d+$/;
my $bool_regex    = qr/^[01]$/;
my $term          = undef;
my $file          = undef; # File to watch for InnoDB monitor output
my $file_mtime    = undef; # Status of watched file
my $file_data     = undef; # Last chunk of text read from file
my $innodb_parser = InnoDBParser->new;

my $nonfatal_errs = join('|',
   'Access denied for user',
   'Unknown MySQL server host',
   'Unknown database',
   'Can\'t connect to local MySQL server through socket',
   'Can\'t connect to MySQL server on',
   'MySQL server has gone away',
   'Cannot call SHOW INNODB STATUS',
   'Access denied',
   'AutoCommit',
);

if ( !$opts{n} ) {
   require Term::ReadLine;
   $term = Term::ReadLine->new('innotop');
}

# Stores status, variables, innodb status, master/slave status etc.
# Keyed on connection name.  Each entry is a hashref of current and past data sets,
# keyed on clock tick.
my %vars;
my %info_gotten = (); # Which things have been retrieved for the current clock tick.

# Stores info on currently displayed queries: cxn, connection ID, query text.
my @current_queries;

my $lines_printed       = 0;
my $clock               = 0;   # Incremented with every wake-sleep cycle
my $clearing_deadlocks  = 0;

# If terminal coloring is available, use it.  The only function I want from
# the module is the colored() function.
eval {
   if ( !$opts{n} ) {
      if ( $windows ) {
         require Win32::Console::ANSI;
      }
      require Term::ANSIColor;
      import Term::ANSIColor qw(colored);
      $have_color = 1;
   }
};
if ( $EVAL_ERROR || $opts{n} ) {
   # If there was an error, manufacture my own colored() function that does no
   # coloring.
   *colored = sub { pop @_; @_; };
}

if ( $opts{n} ) {
   $clear_screen_sub = sub {};
}
elsif ( $windows ) {
   $clear_screen_sub = sub { $lines_printed = 0; system("cls") };
}
else {
   my $clear = `clear`;
   $clear_screen_sub = sub { $lines_printed = 0; print $clear };
}

# ###########################################################################
# Config storage. {{{2
# ###########################################################################
my %config = (
   color => {
      val  => $have_color,
      note => 'Whether to use terminal coloring',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   cmd_filter => {
      val  => 'Com_',
      note => 'Prefix for values in C mode',
      conf => [qw(C)],
   },
   plugin_dir => {
      val  => "$homepath/.innotop/plugins",
      note => 'Directory where plugins can be found',
      conf => 'ALL',
   },
   show_percent => {
      val  => 1,
      note => 'Show the % symbol after percentages',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   skip_innodb => {
      val  => 0,
      note => 'Disable SHOW INNODB STATUS',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   S_func => {
      val  => 's',
      note => 'What to display in S mode: graph, status, pivoted status',
      conf => [qw(S)],
      pat  => qr/^[gsv]$/,
   },
   cxn_timeout => {
      val  => 28800,
      note => 'Connection timeout for keeping unused connections alive',
      conf => 'ALL',
      pat  => $int_regex,
   },
   graph_char => {
      val  => '*',
      note => 'Character for drawing graphs',
      conf => [ qw(S) ],
      pat  => qr/^.$/,
   },
   show_cxn_errors_in_tbl => {
      val  => 1,
      note => 'Whether to display connection errors as rows in the table',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   hide_hdr => {
      val  => 0,
      note => 'Whether to show column headers',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   show_cxn_errors => {
      val  => 1,
      note => 'Whether to print connection errors to STDOUT',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   readonly => {
      val  => 1,
      note => 'Whether the config file is read-only',
      conf => [ qw() ],
      pat  => $bool_regex,
   },
   global => {
      val  => 1,
      note => 'Whether to show GLOBAL variables and status',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   header_highlight => {
      val  => 'bold',
      note => 'How to highlight table column headers',
      conf => 'ALL',
      pat  => qr/^(?:bold|underline)$/,
   },
   display_table_captions => {
      val  => 1,
      note => 'Whether to put captions on tables',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   charset => {
      val  => 'ascii',
      note => 'What type of characters should be displayed in queries (ascii, unicode, none)',
      conf => 'ALL',
      pat  => qr/^(?:ascii|unicode|none)$/,
   },
   auto_wipe_dl => {
      val  => 0,
      note => 'Whether to auto-wipe InnoDB deadlocks',
      conf => 'ALL',
      pat  => $bool_regex,
   },
   max_height => {
      val  => 30,
      note => '[Win32] Max window height',
      conf => 'ALL',
   },
   debug => {
      val  => 0,
      pat  => $bool_regex,
      note => 'Debug mode (more verbose errors, uses more memory)',
      conf => 'ALL',
   },
   num_digits => {
      val  => 2,
      pat  => $int_regex,
      note => 'How many digits to show in fractional numbers and percents',
      conf => 'ALL',
   },
   debugfile => {
      val  => "$homepath/.innotop/core_dump",
      note => 'A debug file in case you are interested in error output',
   },
   show_statusbar => {
      val  => 1,
      pat  => $bool_regex,
      note => 'Whether to show the status bar in the display',
      conf => 'ALL',
   },
   mode => {
      val  => "Q",
      note => "Which mode to start in",
      cmdline => 1,
   },
   status_inc => {
      val  => 0,
      note => 'Whether to show raw or incremental values for status variables',
      pat  => $bool_regex,
   },
   interval => {
      val  => 10,
      pat  => qr/^(?:(?:\d*?[1-9]\d*(?:\.\d*)?)|(?:\d*\.\d*?[1-9]\d*))$/,
      note => "The interval at which the display will be refreshed.  Fractional values allowed.",
   },
   num_status_sets => {
      val  => 9,
      pat  => $int_regex,
      note => 'How many sets of STATUS and VARIABLES values to show',
      conf => [ qw(S) ],
   },
   S_set => {
      val  => 'general',
      pat  => qr/^\w+$/,
      note => 'Which set of variables to display in S (Variables & Status) mode',
      conf => [ qw(S) ],
   },
);

# ###########################################################################
# Config file sections {{{2
# The configuration file is broken up into sections like a .ini file.  This
# variable defines those sections and the subroutines responsible for reading
# and writing them.
# ###########################################################################
my %config_file_sections = (
   plugins => {
      reader => \&load_config_plugins,
      writer => \&save_config_plugins,
   },
   group_by => {
      reader => \&load_config_group_by,
      writer => \&save_config_group_by,
   },
   filters => {
      reader => \&load_config_filters,
      writer => \&save_config_filters,
   },
   active_filters => {
      reader => \&load_config_active_filters,
      writer => \&save_config_active_filters,
   },
   visible_tables => {
      reader => \&load_config_visible_tables,
      writer => \&save_config_visible_tables,
   },
   sort_cols => {
      reader => \&load_config_sort_cols,
      writer => \&save_config_sort_cols,
   },
   active_columns => {
      reader => \&load_config_active_columns,
      writer => \&save_config_active_columns,
   },
   tbl_meta => {
      reader => \&load_config_tbl_meta,
      writer => \&save_config_tbl_meta,
   },
   general => {
      reader => \&load_config_config,
      writer => \&save_config_config,
   },
   connections => {
      reader => \&load_config_connections,
      writer => \&save_config_connections,
   },
   active_connections => {
      reader => \&load_config_active_connections,
      writer => \&save_config_active_connections,
   },
   server_groups => {
      reader => \&load_config_server_groups,
      writer => \&save_config_server_groups,
   },
   active_server_groups => {
      reader => \&load_config_active_server_groups,
      writer => \&save_config_active_server_groups,
   },
   max_values_seen => {
      reader => \&load_config_mvs,
      writer => \&save_config_mvs,
   },
   varsets => {
      reader => \&load_config_varsets,
      writer => \&save_config_varsets,
   },
   colors => {
      reader => \&load_config_colors,
      writer => \&save_config_colors,
   },
   stmt_sleep_times => {
      reader => \&load_config_stmt_sleep_times,
      writer => \&save_config_stmt_sleep_times,
   },
);

# Config file sections have some dependencies, so they have to be read/written in order.
my @ordered_config_file_sections = qw(general plugins filters active_filters tbl_meta
   connections active_connections server_groups active_server_groups max_values_seen
   active_columns sort_cols visible_tables varsets colors stmt_sleep_times
   group_by);

# All events for which plugins may register themselves.  Entries are arrayrefs.
my %event_listener_for = map { $_ => [] }
   qw(
      extract_values
      set_to_tbl_pre_filter set_to_tbl_pre_sort set_to_tbl_pre_group
      set_to_tbl_pre_colorize set_to_tbl_pre_transform set_to_tbl_pre_pivot
      set_to_tbl_pre_create set_to_tbl_post_create
      draw_screen
   );

# All variables to which plugins have access.
my %pluggable_vars = (
   action_for    => \%action_for,
   agg_funcs     => \%agg_funcs,
   config        => \%config,
   connections   => \%connections,
   dbhs          => \%dbhs,
   filters       => \%filters,
   modes         => \%modes,
   server_groups => \%server_groups,
   tbl_meta      => \%tbl_meta,
   trans_funcs   => \%trans_funcs,
   var_sets      => \%var_sets,
);

# ###########################################################################
# Contains logic to generate prepared statements for a given function for a
# given DB connection.  Returns a $sth.
# ###########################################################################
my %stmt_maker_for = (
   INNODB_STATUS => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare(version_ge( $dbh, '5.0.0' )
             ? 'SHOW ENGINE INNODB STATUS'
             : 'SHOW INNODB STATUS');
   },
   SHOW_VARIABLES => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare($config{global}->{val} && version_ge( $dbh, '4.0.3' )
             ? 'SHOW GLOBAL VARIABLES'
             : 'SHOW VARIABLES');
   },
   SHOW_STATUS => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare($config{global}->{val} && version_ge( $dbh, '5.0.2' )
             ? 'SHOW GLOBAL STATUS'
             : 'SHOW STATUS');
   },
   KILL_QUERY => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare(version_ge( $dbh, '5.0.0' )
             ? 'KILL QUERY ?'
             : 'KILL ?');
   },
   SHOW_MASTER_LOGS => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare('SHOW MASTER LOGS');
   },
   SHOW_MASTER_STATUS => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare('SHOW MASTER STATUS');
   },
   SHOW_SLAVE_STATUS => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare('SHOW SLAVE STATUS');
   },
   KILL_CONNECTION => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare(version_ge( $dbh, '5.0.0' )
             ? 'KILL CONNECTION ?'
             : 'KILL ?');
   },
   OPEN_TABLES => sub {
      my ( $dbh ) = @_;
      return version_ge($dbh, '4.0.0')
         ? $dbh->prepare('SHOW OPEN TABLES')
         : undef;
   },
   PROCESSLIST => sub {
      my ( $dbh ) = @_;
      return $dbh->prepare('SHOW FULL PROCESSLIST');
   },
);

# Plugins!
my %plugins = (
);

# ###########################################################################
# Run the program {{{1
# ###########################################################################

# This config variable is only useful for MS Windows because its terminal
# can't tell how tall it is.
if ( !$windows ) {
   delete $config{max_height};
}

# Try to lower my priority.
eval { setpriority(0, 0, getpriority(0, 0) + 10); };

# Print stuff to the screen immediately, don't wait for a newline.
$OUTPUT_AUTOFLUSH = 1;

# Clear the screen and load the configuration.
$clear_screen_sub->();
load_config();

# Override config variables with command-line options
my %cmdline =
   map  { $_->{c} => $opts{$_->{k}} }
   grep { exists $_->{c} && exists $opts{$_->{k}} }
   @opt_spec;

foreach my $name (keys %cmdline) {
   next if not defined $cmdline{$name};
   my $val = $cmdline{$name};
   if ( exists($config{$name}) and (!$config{$name}->{pat} or $val =~ m/$config{$name}->{pat}/ )) {
      $config{$name}->{val} = $val;
   }
}

post_process_tbl_meta();

# Make sure no changes are written to config file in non-interactive mode.
if ( $opts{n} ) {
   $config{readonly}->{val} = 1;
}

eval {

   # Open the file for InnoDB status
   if ( @ARGV ) {
      my $filename = shift @ARGV;
      open $file, "<", $filename
         or die "Cannot open '$filename': $OS_ERROR";
   }

   # In certain modes we might have to collect data for two cycles
   # before printing anything out, so we need to bump up the count one.
   if ( $opts{n} && $opts{count} && $config{status_inc}->{val}
      && $config{mode}->{val} =~ m/[S]/ )
   {
      $opts{count}++;
   }

   while (++$clock) {

      my $mode = $config{mode}->{val} || 'Q';
      if ( !$modes{$mode} ) {
         die "Mode '$mode' doesn't exist; try one of these:\n"
            . join("\n", map { "  $_ $modes{$_}->{hdr}" }  sort keys %modes)
            . "\n";
      }

      if ( !$opts{n} ) {
         @last_term_size = @this_term_size;
         @this_term_size = Term::ReadKey::GetTerminalSize(\*STDOUT);
         if ( $windows ) {
            $this_term_size[0]--;
            $this_term_size[1]
               = min($this_term_size[1], $config{max_height}->{val});
         }
         die("Can't read terminal size") unless @this_term_size;
      }

      # If there's no connection to a database server, we need to fix that...
      if ( !%connections ) {
         print "You have not defined any database connections.\n\n";
         add_new_dsn();
      }

      # See whether there are any connections defined for this mode.  If there's only one
      # connection total, assume the user wants to just use innotop for a single server
      # and don't ask which server to connect to.  Also, if we're monitoring from a file,
      # we just use the first connection.
      if ( !get_connections() ) {
         if ( $file || 1 == scalar keys %connections ) {
            $modes{$config{mode}->{val}}->{connections} = [ keys %connections ];
         }
         else {
            choose_connections();
         }
      }

      # Term::ReadLine might have re-set $OUTPUT_AUTOFLUSH.
      $OUTPUT_AUTOFLUSH = 1;

      # Prune old data
      my $sets = $config{num_status_sets}->{val};
      foreach my $store ( values %vars ) {
         delete @{$store}{ grep { $_ < $clock - $sets } keys %$store };
      }
      %info_gotten = ();

      # Call the subroutine to display this mode.
      $modes{$mode}->{display_sub}->();

      # It may be time to quit now.
      if ( $opts{count} && $clock >= $opts{count} ) {
         finish();
      }

      # Wait for a bit.
      if ( $opts{n} ) {
         sleep($config{interval}->{val});
      }
      else {
         ReadMode('cbreak');
         $char = ReadKey($config{interval}->{val});
         ReadMode('normal');
      }

      # Handle whatever action the key indicates.
      do_key_action();

   }
};
if ( $EVAL_ERROR ) {
   core_dump( $EVAL_ERROR );
}
finish();

# Subroutines {{{1
# Mode functions{{{2
# switch_mode {{{3
sub switch_mode {
   my $mode = shift;
   $config{mode}->{val} = $mode;
}

# Prompting functions {{{2
# prompt_list {{{3
# Prompts the user for a value, given a question, initial value,
# a completion function and a hashref of hints.
sub prompt_list {
   die "Can't call in non-interactive mode" if $opts{n};
   my ( $question, $init, $completion, $hints ) = @_;
   if ( $hints ) {
      # Figure out how wide the table will be
      my $max_name = max(map { length($_) } keys %$hints );
      $max_name ||= 0;
      $max_name +=  3;
      my @meta_rows = create_table2(
               [ sort keys %$hints ],
               { map { $_ => $_ } keys %$hints },
               { map { $_ => trunc($hints->{$_}, $this_term_size[0] - $max_name) } keys %$hints },
               { sep => '  ' });
      if (@meta_rows > 10) {
         # Try to split and stack the meta rows next to each other
         my $split = int(@meta_rows / 2);
         @meta_rows = stack_next(
            [@meta_rows[0..$split - 1]],
            [@meta_rows[$split..$#meta_rows]],
            { pad => ' | '},
         );
      }
      print join( "\n",
         '',
         map { ref $_ ? colored(@$_) : $_ } create_caption('Choose from', @meta_rows), ''),
         "\n";
   }
   $term->Attribs->{completion_function} = $completion;
   my $answer = $term->readline("$question: ", $init);
   $OUTPUT_AUTOFLUSH = 1;
   $answer = '' if !defined($answer);
   $answer =~ s/\s+$//;
   return $answer;
}

# prompt {{{3
# Prints out a prompt and reads from the keyboard, then validates with the
# validation regex until the input is correct.
sub prompt {
   die "Can't call in non-interactive mode" if $opts{n};
   my ( $prompt, $regex, $init, $completion ) = @_;
   my $response;
   my $success = 0;
   do {
      if ( $completion ) {
         $term->Attribs->{completion_function} = $completion;
      }
      $response = $term->readline("$prompt: ", $init);
      if ( $regex && $response !~ m/$regex/ ) {
         print "Invalid response.\n\n";
      }
      else {
         $success = 1;
      }
   } while ( !$success );
   $OUTPUT_AUTOFLUSH = 1;
   $response =~ s/\s+$//;
   return $response;
}

# prompt_noecho {{{3
# Unfortunately, suppressing echo with Term::ReadLine isn't reliable; the user might not
# have that library, or it might not support that feature.
sub prompt_noecho {
   my ( $prompt ) = @_;
   print colored("$prompt: ", 'underline');
   my $response;
   ReadMode('noecho');
   $response = <STDIN>;
   chomp($response);
   ReadMode('normal');
   return $response;
}

# do_key_action {{{3
# Depending on whether a key was read, do something.  Keys have certain
# actions defined in lookup tables.  Each mode may have its own lookup table,
# which trumps the global table -- so keys can be context-sensitive.  The key
# may be read and written in a subroutine, so it's a global.
sub do_key_action {
   if ( defined $char ) {
      my $mode = $config{mode}->{val};
      my $action
         = defined($modes{$mode}->{action_for}->{$char})
         ? $modes{$mode}->{action_for}->{$char}->{action}
         : defined($action_for{$char})
         ? $action_for{$char}->{action}
         : sub{};
      $action->();
   }
}

# pause {{{3
sub pause {
   die "Can't call in non-interactive mode" if $opts{n};
   my $msg = shift;
   print defined($msg) ? "\n$msg" : "\nPress any key to continue";
   ReadMode('cbreak');
   my $char = ReadKey(0);
   ReadMode('normal');
   return $char;
}

# reverse_sort {{{3
sub reverse_sort {
   my $tbl = shift;
   $tbl_meta{$tbl}->{sort_dir} *= -1;
}

# select_cxn {{{3
# Selects connection(s).  If the mode (or argument list) has only one, returns
# it without prompt.
sub select_cxn {
   my ( $prompt, @cxns ) = @_;
   if ( !@cxns ) {
      @cxns = get_connections();
   }
   if ( @cxns == 1 ) {
      return $cxns[0];
   }
   my $choices = prompt_list(
         $prompt,
         $cxns[0],
         sub{ return @cxns },
         { map { $_ => $connections{$_}->{dsn} } @cxns });
   my @result = unique(grep { my $a = $_; grep { $_ eq $a } @cxns } split(/\s+/, $choices));
   return @result;
}

# kill_query {{{3
# Kills a connection, or on new versions, optionally a query but not connection.
sub kill_query {
   my ( $q_or_c ) = @_;

   my $info = choose_thread(
      sub { 1 },
      'Select a thread to kill the ' . $q_or_c,
   );
   return unless $info;
   return unless pause("Kill $info->{id}?") =~ m/y/i;

   eval {
      do_stmt($info->{cxn}, $q_or_c eq 'QUERY' ? 'KILL_QUERY' : 'KILL_CONNECTION', $info->{id} );
   };

   if ( $EVAL_ERROR ) {
      print "\nError: $EVAL_ERROR";
      pause();
   }
}

# set_display_precision {{{3
sub set_display_precision {
   my $dir = shift;
   $config{num_digits}->{val} = min(9, max(0, $config{num_digits}->{val} + $dir));
}

sub toggle_visible_table {
   my ( $mode, $table ) = @_;
   my $visible = $modes{$mode}->{visible_tables};
   if ( grep { $_ eq $table } @$visible ) {
      $modes{$mode}->{visible_tables} = [ grep { $_ ne $table } @$visible ];
   }
   else {
      unshift @$visible, $table;
   }
   $modes{$mode}->{cust}->{visible_tables} = 1;
}

# toggle_filter{{{3
sub toggle_filter {
   my ( $tbl, $filter ) = @_;
   my $filters = $tbl_meta{$tbl}->{filters};
   if ( grep { $_ eq $filter } @$filters ) {
      $tbl_meta{$tbl}->{filters} = [ grep { $_ ne $filter } @$filters ];
   }
   else {
      push @$filters, $filter;
   }
   $tbl_meta{$tbl}->{cust}->{filters} = 1;
}

# toggle_config {{{3
sub toggle_config {
   my ( $key ) = @_;
   $config{$key}->{val} ^= 1;
}

# create_deadlock {{{3
sub create_deadlock {
   $clear_screen_sub->();

   print "This function will deliberately cause a small deadlock, "
      . "clearing deadlock information from the InnoDB monitor.\n\n";

   my $answer = prompt("Are you sure you want to proceed?  Say 'y' if you do");
   return 0 unless $answer eq 'y';

   my ( $cxn ) = select_cxn('Clear on which server? ');
   return unless $cxn && exists($connections{$cxn});

   clear_deadlock($cxn);
}

# deadlock_thread {{{3
sub deadlock_thread {
   my ( $id, $tbl, $cxn ) = @_;

   eval {
      my $dbh = get_new_db_connection($cxn, 1);
      my @stmts = (
         "set transaction isolation level serializable",
         (version_ge($dbh, '4.0.11') ? "start transaction" : 'begin'),
         "select * from $tbl where a = $id",
         "update $tbl set a = $id where a <> $id",
      );

      foreach my $stmt (@stmts[0..2]) {
         $dbh->do($stmt);
      }
      sleep(1 + $id);
      $dbh->do($stmts[-1]);
   };
   if ( $EVAL_ERROR ) {
      if ( $EVAL_ERROR !~ m/Deadlock found/ ) {
         die $EVAL_ERROR;
      }
   }
   exit(0);
}

# Purges unused binlogs on the master, up to but not including the latest log.
# TODO: guess which connections are slaves of a given master.
sub purge_master_logs {
   my @cxns = get_connections();

   get_master_slave_status(@cxns);

   # Toss out the rows that don't have master/slave status...
   my @vars =
      grep { $_ && ($_->{file} || $_->{master_host}) }
      map  { $vars{$_}->{$clock} } @cxns;
   @cxns = map { $_->{cxn} } @vars;

   # Figure out which master to purge ons.
   my @masters = map { $_->{cxn} } grep { $_->{file} } @vars;
   my ( $master ) = select_cxn('Which master?', @masters );
   return unless $master;
   my ($master_status) = grep { $_->{cxn} eq $master } @vars;

   # Figure out the result order (not lexical order) of master logs.
   my @master_logs = get_master_logs($master);
   my $i = 0;
   my %master_logs = map { $_->{log_name} => $i++ } @master_logs;

   # Ask which slave(s) are reading from this master.
   my @slave_status = grep { $_->{master_host} } @vars;
   my @slaves = map { $_->{cxn} } @slave_status;
   @slaves = select_cxn("Which slaves are reading from $master?", @slaves);
   @slave_status = grep { my $item = $_; grep { $item->{cxn} eq $_ } @slaves } @slave_status;
   return unless @slave_status;

   # Find the minimum binary log in use.
   my $min_log = min(map { $master_logs{$_->{master_log_file}} } @slave_status);
   my $log_name = $master_logs[$min_log]->{log_name};

   my $stmt = "PURGE MASTER LOGS TO '$log_name'";
   send_cmd_to_servers($stmt, 0, 'PURGE {MASTER | BINARY} LOGS {TO "log_name" | BEFORE "date"}', [$master]);
}

sub send_cmd_to_servers {
   my ( $cmd, $all, $hint, $cxns ) = @_;
   if ( $all ) {
      @$cxns = get_connections();
   }
   elsif ( !@$cxns ) {
      @$cxns = select_cxn('Which servers?', @$cxns);
   }
   if ( $hint ) {
      print "\nHint: $hint\n";
   }
   $cmd = prompt('Command to send', undef, $cmd);
   foreach my $cxn ( @$cxns ) {
      eval {
         my $sth = do_query($cxn, $cmd);
      };
      if ( $EVAL_ERROR ) {
         print "Error from $cxn: $EVAL_ERROR\n";
      }
      else {
         print "Success on $cxn\n";
      }
   }
   pause();
}

# Display functions {{{2

sub set_s_mode {
   my ( $func ) = @_;
   $clear_screen_sub->();
   $config{S_func}->{val} = $func;
}

# start_S_mode {{{3
sub start_S_mode {
   $clear_screen_sub->();
   switch_mode('S');
}

# display_B {{{3
sub display_B {
   my @display_lines;
   my @cxns = get_connections();
   get_innodb_status(\@cxns);

   my @buffer_pool;
   my @page_statistics;
   my @insert_buffers;
   my @adaptive_hash_index;
   my %rows_for = (
      buffer_pool         => \@buffer_pool,
      page_statistics     => \@page_statistics,
      insert_buffers      => \@insert_buffers,
      adaptive_hash_index => \@adaptive_hash_index,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   foreach my $cxn ( @cxns ) {
      my $set = $vars{$cxn}->{$clock};
      my $pre = $vars{$cxn}->{$clock-1} || $set;

      if ( $set->{IB_bp_complete} ) {
         if ( $wanted{buffer_pool} ) {
            push @buffer_pool, extract_values($set, $set, $pre, 'buffer_pool');
         }
         if ( $wanted{page_statistics} ) {
            push @page_statistics, extract_values($set, $set, $pre, 'page_statistics');
         }
      }
      if ( $set->{IB_ib_complete} ) {
         if ( $wanted{insert_buffers} ) {
            push @insert_buffers, extract_values(
               $config{status_inc}->{val} ? inc(0, $cxn) : $set, $set, $pre,
               'insert_buffers');
         }
         if ( $wanted{adaptive_hash_index} ) {
            push @adaptive_hash_index, extract_values($set, $set, $pre, 'adaptive_hash_index');
         }
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_C {{{3
sub display_C {
   my @display_lines;
   my @cxns = get_connections();
   get_status_info(@cxns);

   my @cmd_summary;
   my %rows_for = (
      cmd_summary => \@cmd_summary,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   # For now, I'm manually pulling these variables out and pivoting.  Eventually a SQL-ish
   # dialect should let me join a table to a grouped and pivoted table and do this more easily.
   # TODO: make it so.
   my $prefix = qr/^$config{cmd_filter}->{val}/; # TODO: this is a total hack
   my @values;
   my ($total, $last_total) = (0, 0);
   foreach my $cxn ( @cxns ) {
      my $set = $vars{$cxn}->{$clock};
      my $pre = $vars{$cxn}->{$clock-1} || $set;
      foreach my $key ( keys %$set ) {
         next unless $key =~ m/$prefix/i;
         my $val = $set->{$key};
         next unless defined $val && $val =~ m/^\d+$/;
         my $last_val = $val - ($pre->{$key} || 0);
         $total      += $val;
         $last_total += $last_val;
         push @values, {
            name       => $key,
            value      => $val,
            last_value => $last_val,
         };
      }
   }

   # Add aggregation and turn into a real set TODO: total hack
   if ( $wanted{cmd_summary} ) {
      foreach my $value ( @values ) {
         @{$value}{qw(total last_total)} = ($total, $last_total);
         push @cmd_summary, extract_values($value, $value, $value, 'cmd_summary');
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_D {{{3
sub display_D {
   my @display_lines;
   my @cxns = get_connections();
   get_innodb_status(\@cxns);

   my @deadlock_transactions;
   my @deadlock_locks;
   my %rows_for = (
      deadlock_transactions => \@deadlock_transactions,
      deadlock_locks        => \@deadlock_locks,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   foreach my $cxn ( @cxns ) {
      my $innodb_status = $vars{$cxn}->{$clock};
      my $prev_status   = $vars{$cxn}->{$clock-1} || $innodb_status;

      if ( $innodb_status->{IB_dl_timestring} ) {

         my $victim = $innodb_status->{IB_dl_rolled_back} || 0;

         if ( %wanted ) {
            foreach my $txn_id ( keys %{$innodb_status->{IB_dl_txns}} ) {
               my $txn = $innodb_status->{IB_dl_txns}->{$txn_id};
               my $pre = $prev_status->{IB_dl_txns}->{$txn_id} || $txn;

               if ( $wanted{deadlock_transactions} ) {
                  my $hash = extract_values($txn->{tx}, $txn->{tx}, $pre->{tx}, 'deadlock_transactions');
                  $hash->{cxn}        = $cxn;
                  $hash->{dl_txn_num} = $txn_id;
                  $hash->{victim}     = $txn_id == $victim ? 'Yes' : 'No';
                  $hash->{timestring} = $innodb_status->{IB_dl_timestring};
                  $hash->{truncates}  = $innodb_status->{IB_dl_complete} ? 'No' : 'Yes';
                  push @deadlock_transactions, $hash;
               }

               if ( $wanted{deadlock_locks} ) {
                  foreach my $lock ( @{$txn->{locks}} ) {
                     my $hash = extract_values($lock, $lock, $lock, 'deadlock_locks');
                     $hash->{dl_txn_num}      = $txn_id;
                     $hash->{cxn}             = $cxn;
                     $hash->{mysql_thread_id} = $txn->{tx}->{mysql_thread_id};
                     push @deadlock_locks, $hash;
                  }
               }

            }
         }
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_F {{{3
sub display_F {
   my @display_lines;
   my ( $cxn ) = get_connections();
   get_innodb_status([$cxn]);
   my $innodb_status = $vars{$cxn}->{$clock};

   if ( $innodb_status->{IB_fk_timestring} ) {

      push @display_lines, 'Reason: ' . $innodb_status->{IB_fk_reason};

      # Display FK errors caused by invalid DML.
      if ( $innodb_status->{IB_fk_txn} ) {
         my $txn = $innodb_status->{IB_fk_txn};
         push @display_lines,
            '',
            "User $txn->{user} from $txn->{hostname}, thread $txn->{mysql_thread_id} was executing:",
            '', no_ctrl_char($txn->{query_text});
      }

      my @fk_table = create_table2(
         $tbl_meta{fk_error}->{visible},
         meta_to_hdr('fk_error'),
         extract_values($innodb_status, $innodb_status, $innodb_status, 'fk_error'),
         { just => '-', sep => '  '});
      push @display_lines, '', @fk_table;

   }
   else {
      push @display_lines, '', 'No foreign key error data.';
   }
   draw_screen(\@display_lines, { raw => 1 } );
}

# display_I {{{3
sub display_I {
   my @display_lines;
   my @cxns = get_connections();
   get_innodb_status(\@cxns);

   my @io_threads;
   my @pending_io;
   my @file_io_misc;
   my @log_statistics;
   my %rows_for = (
      io_threads     => \@io_threads,
      pending_io     => \@pending_io,
      file_io_misc   => \@file_io_misc,
      log_statistics => \@log_statistics,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   foreach my $cxn ( @cxns ) {
      my $set = $vars{$cxn}->{$clock};
      my $pre = $vars{$cxn}->{$clock-1} || $set;

      if ( $set->{IB_io_complete} ) {
         if ( $wanted{io_threads} ) {
            my $cur_threads = $set->{IB_io_threads};
            my $pre_threads = $pre->{IB_io_threads} || $cur_threads;
            foreach my $key ( sort keys %$cur_threads ) {
               my $cur_thd = $cur_threads->{$key};
               my $pre_thd = $pre_threads->{$key} || $cur_thd;
               my $hash = extract_values($cur_thd, $cur_thd, $pre_thd, 'io_threads');
               $hash->{cxn} = $cxn;
               push @io_threads, $hash;
            }
         }
         if ( $wanted{pending_io} ) {
            push @pending_io, extract_values($set, $set, $pre, 'pending_io');
         }
         if ( $wanted{file_io_misc} ) {
            push @file_io_misc, extract_values(
               $config{status_inc}->{val} ? inc(0, $cxn) : $set,
               $set, $pre, 'file_io_misc');
         }
      }
      if ( $set->{IB_lg_complete} && $wanted{log_statistics} ) {
         push @log_statistics, extract_values($set, $set, $pre, 'log_statistics');
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_L {{{3
sub display_L {
   my @display_lines;
   my @cxns = get_connections();
   get_innodb_status(\@cxns);

   my @innodb_locks;
   my %rows_for = (
      innodb_locks => \@innodb_locks,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   # Get info on locks
   foreach my $cxn ( @cxns ) {
      my $set = $vars{$cxn}->{$clock} or next;
      my $pre = $vars{$cxn}->{$clock-1} || $set;

      if ( $wanted{innodb_locks} && defined $set->{IB_tx_transactions} && @{$set->{IB_tx_transactions}} ) {

         my $cur_txns = $set->{IB_tx_transactions};
         my $pre_txns = $pre->{IB_tx_transactions} || $cur_txns;
         my %cur_txns = map { $_->{mysql_thread_id} => $_ } @$cur_txns;
         my %pre_txns = map { $_->{mysql_thread_id} => $_ } @$pre_txns;
         foreach my $txn ( @$cur_txns ) {
            foreach my $lock ( @{$txn->{locks}} ) {
               my %hash = map { $_ => $txn->{$_} } qw(txn_id mysql_thread_id lock_wait_time active_secs);
               map { $hash{$_} = $lock->{$_} } qw(lock_type space_id page_no n_bits index db table txn_id lock_mode special insert_intention waiting);
               $hash{cxn} = $cxn;
               push @innodb_locks, extract_values(\%hash, \%hash, \%hash, 'innodb_locks');
            }
         }
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_M {{{3
sub display_M {
   my @display_lines;
   my @cxns = get_connections();
   get_master_slave_status(@cxns);
   get_status_info(@cxns);

   my @slave_sql_status;
   my @slave_io_status;
   my @master_status;
   my %rows_for = (
      slave_sql_status => \@slave_sql_status,
      slave_io_status  => \@slave_io_status,
      master_status    => \@master_status,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   foreach my $cxn ( @cxns ) {
      my $set  = $config{status_inc}->{val} ? inc(0, $cxn) : $vars{$cxn}->{$clock};
      my $pre  = $vars{$cxn}->{$clock - 1} || $set;
      if ( $wanted{slave_sql_status} ) {
         push @slave_sql_status, extract_values($set, $set, $pre, 'slave_sql_status');
      }
      if ( $wanted{slave_io_status} ) {
         push @slave_io_status, extract_values($set, $set, $pre, 'slave_io_status');
      }
      if ( $wanted{master_status} ) {
         push @master_status, extract_values($set, $set, $pre, 'master_status');
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_O {{{3
sub display_O {
   my @display_lines = ('');
   my @cxns          = get_connections();
   my @open_tables   = get_open_tables(@cxns);
   my @tables = map { extract_values($_, $_, $_, 'open_tables') } @open_tables;
   push @display_lines, set_to_tbl(\@tables, 'open_tables'), get_cxn_errors(@cxns);
   draw_screen(\@display_lines);
}

# display_Q {{{3
sub display_Q {
   my @display_lines;

   my @q_header;
   my @processlist;
   my %rows_for = (
      q_header    => \@q_header,
      processlist => \@processlist,
   );

   my @visible = $opts{n} ? 'processlist' : get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   # Get the data
   my @cxns             = get_connections();
   my @full_processlist = get_full_processlist(@cxns);

   # Create header
   if ( $wanted{q_header} ) {
      get_status_info(@cxns);
      foreach my $cxn ( @cxns ) {
         my $set = $vars{$cxn}->{$clock};
         my $pre = $vars{$cxn}->{$clock-1} || $set;
         my $hash = extract_values($set, $set, $pre, 'q_header');
         $hash->{cxn} = $cxn;
         $hash->{when} = 'Total';
         push @q_header, $hash;

         if ( exists $vars{$cxn}->{$clock - 1} ) {
            my $inc = inc(0, $cxn);
            my $hash = extract_values($inc, $set, $pre, 'q_header');
            $hash->{cxn} = $cxn;
            $hash->{when} = 'Now';
            push @q_header, $hash;
         }
      }
   }

   if ( $wanted{processlist} ) {
      # TODO: save prev values
      push @processlist, map { extract_values($_, $_, $_, 'processlist') } @full_processlist;
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      next unless $wanted{$tbl};
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   # Save queries in global variable for analysis.  The rows in %rows_for have been
   # filtered, etc as a side effect of set_to_tbl(), so they are the same as the rows
   # that get pushed to the screen.
   @current_queries = map {
      my %hash;
      @hash{ qw(cxn id db query secs) } = @{$_}{ qw(cxn mysql_thread_id db info secs) };
      \%hash;
   } @{$rows_for{processlist}};

   draw_screen(\@display_lines);
}

# display_R {{{3
sub display_R {
   my @display_lines;
   my @cxns = get_connections();
   get_innodb_status(\@cxns);

   my @row_operations;
   my @row_operation_misc;
   my @semaphores;
   my @wait_array;
   my %rows_for = (
      row_operations     => \@row_operations,
      row_operation_misc => \@row_operation_misc,
      semaphores         => \@semaphores,
      wait_array         => \@wait_array,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;
   my $incvar  = $config{status_inc}->{val};

   foreach my $cxn ( @cxns ) {
      my $set = $vars{$cxn}->{$clock};
      my $pre = $vars{$cxn}->{$clock-1} || $set;
      my $inc; # Only assigned to if wanted

      if ( $set->{IB_ro_complete} ) {
         if ( $wanted{row_operations} ) {
            $inc ||= $incvar ? inc(0, $cxn) : $set;
            push @row_operations, extract_values($inc, $set, $pre, 'row_operations');
         }
         if ( $wanted{row_operation_misc} ) {
            push @row_operation_misc, extract_values($set, $set, $pre, 'row_operation_misc'),
         }
      }

      if ( $set->{IB_sm_complete} && $wanted{semaphores} ) {
         $inc ||= $incvar ? inc(0, $cxn) : $set;
         push @semaphores, extract_values($inc, $set, $pre, 'semaphores');
      }

      if ( $set->{IB_sm_wait_array_size} && $wanted{wait_array} ) {
         foreach my $wait ( @{$set->{IB_sm_waits}} ) {
            my $hash = extract_values($wait, $wait, $wait, 'wait_array');
            $hash->{cxn} = $cxn;
            push @wait_array, $hash;
         }
      }
   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   draw_screen(\@display_lines);
}

# display_T {{{3
sub display_T {
   my @display_lines;

   my @t_header;
   my @innodb_transactions;
   my %rows_for = (
      t_header            => \@t_header,
      innodb_transactions => \@innodb_transactions,
   );

   my @visible = $opts{n} ? 'innodb_transactions' : get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;

   my @cxns = get_connections();

   # If the header is to be shown, buffer pool data is required.
   get_innodb_status( \@cxns, [ $wanted{t_header} ? qw(bp) : () ] );

   foreach my $cxn ( get_connections() ) {
      my $set = $vars{$cxn}->{$clock};
      my $pre = $vars{$cxn}->{$clock-1} || $set;

      next unless $set->{IB_tx_transactions};

      if ( $wanted{t_header} ) {
         my $hash = extract_values($set, $set, $pre, 't_header');
         push @t_header, $hash;
      }

      if ( $wanted{innodb_transactions} ) {
         my $cur_txns = $set->{IB_tx_transactions};
         my $pre_txns = $pre->{IB_tx_transactions} || $cur_txns;
         my %cur_txns = map { $_->{mysql_thread_id} => $_ } @$cur_txns;
         my %pre_txns = map { $_->{mysql_thread_id} => $_ } @$pre_txns;
         foreach my $thd_id ( sort keys %cur_txns ) {
            my $cur_txn = $cur_txns{$thd_id};
            my $pre_txn = $pre_txns{$thd_id} || $cur_txn;
            my $hash    = extract_values($cur_txn, $cur_txn, $pre_txn, 'innodb_transactions');
            $hash->{cxn} = $cxn;
            push @innodb_transactions, $hash;
         }
      }

   }

   my $first_table = 0;
   foreach my $tbl ( @visible ) {
      push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
      push @display_lines, get_cxn_errors(@cxns)
         if ( $config{debug}->{val} || !$first_table++ );
   }

   # Save queries in global variable for analysis.  The rows in %rows_for have been
   # filtered, etc as a side effect of set_to_tbl(), so they are the same as the rows
   # that get pushed to the screen.
   @current_queries = map {
      my %hash;
      @hash{ qw(cxn id db query secs) } = @{$_}{ qw(cxn mysql_thread_id db query_text active_secs) };
      \%hash;
   } @{$rows_for{innodb_transactions}};

   draw_screen(\@display_lines);
}

# display_S {{{3
sub display_S {
   my $fmt  = get_var_set('S_set');
   my $func = $config{S_func}->{val};
   my $inc  = $func eq 'g' || $config{status_inc}->{val};

   # The table's meta-data is generated from the compiled var_set.
   my ( $cols, $visible );
   if ( $tbl_meta{var_status}->{fmt} && $fmt eq $tbl_meta{var_status}->{fmt} ) {
      ( $cols, $visible ) = @{$tbl_meta{var_status}}{qw(cols visible)};
   }
   else {
      ( $cols, $visible ) = compile_select_stmt($fmt);

      # Apply missing values to columns.  Always apply averages across all connections.
      map {
         $_->{agg}   = 'avg';
         $_->{label} = $_->{hdr};
      } values %$cols;

      $tbl_meta{var_status}->{cols}    = $cols;
      $tbl_meta{var_status}->{visible} = $visible;
      $tbl_meta{var_status}->{fmt}     = $fmt;
      map { $tbl_meta{var_status}->{cols}->{$_}->{just} = ''} @$visible;
   }

   my @var_status;
   my %rows_for = (
      var_status => \@var_status,
   );

   my @visible = get_visible_tables();
   my %wanted  = map { $_ => 1 } @visible;
   my @cxns    = get_connections();

   get_status_info(@cxns);
   get_innodb_status(\@cxns);

   # Set up whether to pivot and how many sets to extract.
   $tbl_meta{var_status}->{pivot} = $func eq 'v';

   my $num_sets
      = $func eq 'v'
      ? $config{num_status_sets}->{val}
      : 0;
   foreach my $set ( 0 .. $num_sets ) {
      my @rows;
      foreach my $cxn ( @cxns ) {
         my $vars = $inc ? inc($set, $cxn) : $vars{$cxn}->{$clock - $set};
         my $cur  = $vars{$cxn}->{$clock-$set};
         my $pre  = $vars{$cxn}->{$clock-$set-1} || $cur;
         next unless $vars && %$vars;
         my $hash = extract_values($vars, $cur, $pre, 'var_status');
         push @rows, $hash;
      }
      @rows = apply_group_by('var_status', [], @rows);
      push @var_status, @rows;
   }

   # Recompile the sort func. TODO: avoid recompiling at every refresh.
   # Figure out whether the data is all numeric and decide on a sort type.
   # my $cmp
   #   = scalar(
   #      grep { !defined $_ || $_ !~ m/^\d+$/ }
   #      map  { my $col = $_; map { $_->{$col} } @var_status }
   #           $tbl_meta{var_status}->{sort_cols} =~ m/(\w+)/g)
   #   ? 'cmp'
   #   : '<=>';
   $tbl_meta{var_status}->{sort_func} = make_sort_func($tbl_meta{var_status});

   # ################################################################
   # Now there is specific display code based on $config{S_func}
   # ################################################################
   if ( $func =~ m/s|g/ ) {
      my $min_width = 4;

      # Clear the screen if the display width changed.
      if ( @last_term_size && $this_term_size[0] != $last_term_size[0] ) {
         $lines_printed = 0;
         $clear_screen_sub->();
      }

      if ( $func eq 's' ) {
         # Decide how wide columns should be.
         my $num_cols = scalar(@$visible);
         my $width    = $opts{n} ? 0 : max($min_width, int(($this_term_size[0] - $num_cols + 1) / $num_cols));
         my $g_format = $opts{n} ? ( "%s\t" x $num_cols ) : ( "%-${width}s " x $num_cols );

         # Print headers every now and then.  Headers can get really long, so compact them.
         my @hdr = @$visible;
         if ( $opts{n} ) {
            if ( $lines_printed == 0 ) {
               print join("\t", @hdr), "\n";
               $lines_printed++;
            }
         }
         elsif ( $lines_printed == 0 || $lines_printed > $this_term_size[1] - 2 ) {
            @hdr = map { donut(crunch($_, $width), $width) } @hdr;
            print join(' ', map { sprintf( "%${width}s", donut($_, $width)) } @hdr) . "\n";
            $lines_printed = 1;
         }

         # Design a column format for the values.
         my $format
            = $opts{n}
            ? join("\t", map { '%s' } @$visible) . "\n"
            : join(' ',  map { "%${width}s" } @hdr) . "\n";

         foreach my $row ( @var_status ) {
            printf($format, map { defined $_ ? $_ : '' } @{$row}{ @$visible });
            $lines_printed++;
         }
      }
      else { # 'g' mode
         # Design a column format for the values.
         my $num_cols = scalar(@$visible);
         my $width    = $opts{n} ? 0 : int(($this_term_size[0] - $num_cols + 1) / $num_cols);
         my $format   = $opts{n} ? ( "%s\t" x $num_cols ) : ( "%-${width}s " x $num_cols );
         $format      =~ s/\s$/\n/;

         # Print headers every now and then.
         if ( $opts{n} ) {
            if ( $lines_printed == 0 ) {
               print join("\t", @$visible), "\n";
               print join("\t", map { shorten($mvs{$_}) } @$visible), "\n";
            }
         }
         elsif ( $lines_printed == 0 || $lines_printed > $this_term_size[1] - 2 ) {
            printf($format, map { donut(crunch($_, $width), $width) } @$visible);
            printf($format, map { shorten($mvs{$_} || 0) } @$visible);
            $lines_printed = 2;
         }

         # Update the max ever seen, and scale by the max ever seen.
         my $set = $var_status[0];
         foreach my $col ( @$visible ) {
            $set->{$col}  = 1 unless defined $set->{$col} && $set->{$col} =~ m/$num_regex/;
            $set->{$col}  = ($set->{$col} || 1) / ($set->{Uptime_hires} || 1);
            $mvs{$col}    = max($mvs{$col} || 1, $set->{$col});
            $set->{$col} /= $mvs{$col};
         }
         printf($format, map { ( $config{graph_char}->{val} x int( $width * $set->{$_} )) || '.' } @$visible );
         $lines_printed++;

      }
   }
   else { # 'v'
      my $first_table = 0;
      my @display_lines;
      foreach my $tbl ( @visible ) {
         push @display_lines, '', set_to_tbl($rows_for{$tbl}, $tbl);
         push @display_lines, get_cxn_errors(@cxns)
            if ( $config{debug}->{val} || !$first_table++ );
      }
      $clear_screen_sub->();
      draw_screen( \@display_lines );
   }
}

# display_explain {{{3
sub display_explain {
   my $info = shift;
   my $cxn   = $info->{cxn};
   my $db    = $info->{db};

   my ( $mods, $query ) = rewrite_for_explain($info->{query});

   my @display_lines;

   if ( $query ) {

      my $part = version_ge($dbhs{$cxn}->{dbh}, '5.1.5') ? 'PARTITIONS' : '';
      $query = "EXPLAIN $part\n" . $query;

      eval {
         if ( $db ) {
            do_query($cxn, "use $db");
         }
         my $sth = do_query($cxn, $query);

         my $res;
         while ( $res = $sth->fetchrow_hashref() ) {
            map { $res->{$_} ||= '' } ( 'partitions', keys %$res);
            my @this_table = create_caption("Sub-Part $res->{id}",
               create_table2(
                  $tbl_meta{explain}->{visible},
                  meta_to_hdr('explain'),
                  extract_values($res, $res, $res, 'explain')));
            @display_lines = stack_next(\@display_lines, \@this_table, { pad => '  ', vsep => 2 });
         }
      };

      if ( $EVAL_ERROR ) {
         push @display_lines,
            '',
            "The query could not be explained.  Only SELECT queries can be "
            . "explained; innotop tries to rewrite certain REPLACE and INSERT queries "
            . "into SELECT, but this doesn't always succeed.";
      }

   }
   else {
      push @display_lines, '', 'The query could not be explained.';
   }

   if ( $mods ) {
      push @display_lines, '', '[This query has been re-written to be explainable]';
   }

   unshift @display_lines, no_ctrl_char($query);
   draw_screen(\@display_lines, { raw => 1 } );
}

# rewrite_for_explain {{{3
sub rewrite_for_explain {
   my $query = shift;

   my $mods = 0;
   my $orig = $query;
   $mods += $query =~ s/^\s*(?:replace|insert).*?select/select/is;
   $mods += $query =~ s/^
      \s*create\s+(?:temporary\s+)?table
      \s+(?:\S+\s+)as\s+select/select/xis;
   $mods += $query =~ s/\s+on\s+duplicate\s+key\s+update.*$//is;
   return ( $mods, $query );
}

# show_optimized_query {{{3
sub show_optimized_query {
   my $info = shift;
   my $cxn   = $info->{cxn};
   my $db    = $info->{db};
   my $meta  = $dbhs{$cxn};

   my @display_lines;

   my ( $mods, $query ) = rewrite_for_explain($info->{query});

   if ( $mods ) {
      push @display_lines, '[This query has been re-written to be explainable]';
   }

   if ( $query ) {
      push @display_lines, no_ctrl_char($info->{query});

      eval {
         if ( $db ) {
            do_query($cxn, "use $db");
         }
         do_query( $cxn, 'EXPLAIN EXTENDED ' . $query ) or die "Can't explain query";
         my $sth = do_query($cxn, 'SHOW WARNINGS');
         my $res = $sth->fetchall_arrayref({});

         if ( $res ) {
            foreach my $result ( @$res ) {
               push @display_lines, 'Note:', no_ctrl_char($result->{message});
            }
         }
         else {
            push @display_lines, '', 'The query optimization could not be generated.';
         }
      };

      if ( $EVAL_ERROR ) {
         push @display_lines, '', "The optimization could not be generated: $EVAL_ERROR";
      }

   }
   else {
      push @display_lines, '', 'The query optimization could not be generated.';
   }

   draw_screen(\@display_lines, { raw => 1 } );
}

# display_help {{{3
sub display_help {
   my $mode = $config{mode}->{val};

   # Get globally mapped keys, then overwrite them with mode-specific ones.
   my %keys = map {
         $_ => $action_for{$_}->{label}
      } keys %action_for;
   foreach my $key ( keys %{$modes{$mode}->{action_for}} ) {
      $keys{$key} = $modes{$mode}->{action_for}->{$key}->{label};
   }
   delete $keys{'?'};

   # Split them into three kinds of keys: MODE keys, action keys, and
   # magic (special character) keys.
   my @modes   = sort grep { m/[A-Z]/   } keys %keys;
   my @actions = sort grep { m/[a-z]/   } keys %keys;
   my @magic   = sort grep { m/[^A-Z]/i } keys %keys;

   my @display_lines = ( '', 'Switch to a different mode:' );

   # Mode keys
   my @all_modes = map { "$_  $modes{$_}->{hdr}" } @modes;
   my @col1 = splice(@all_modes, 0, ceil(@all_modes/3));
   my @col2 = splice(@all_modes, 0, ceil(@all_modes/2));
   my $max1 = max(map {length($_)} @col1);
   my $max2 = max(map {length($_)} @col2);
   while ( @col1 ) {
      push @display_lines, sprintf("   %-${max1}s  %-${max2}s  %s",
         (shift @col1      || ''),
         (shift @col2      || ''),
         (shift @all_modes || ''));
   }

   # Action keys
   my @all_actions = map { "$_  $keys{$_}" } @actions;
   @col1 = splice(@all_actions, 0, ceil(@all_actions/2));
   $max1 = max(map {length($_)} @col1);
   push @display_lines, '', 'Actions:';
   while ( @col1 ) {
      push @display_lines, sprintf("   %-${max1}s  %s",
         (shift @col1        || ''),
         (shift @all_actions || ''));
   }

   # Magic keys
   my @all_magic = map { sprintf('%4s', $action_for{$_}->{key} || $_) . "  $keys{$_}" } @magic;
   @col1 = splice(@all_magic, 0, ceil(@all_magic/2));
   $max1 = max(map {length($_)} @col1);
   push @display_lines, '', 'Other:';
   while ( @col1 ) {
      push @display_lines, sprintf("%-${max1}s%s",
         (shift @col1      || ''),
         (shift @all_magic || ''));
   }

   $clear_screen_sub->();
   draw_screen(\@display_lines, { show_all => 1 } );
   pause();
   $clear_screen_sub->();
}

# show_full_query {{{3
sub show_full_query {
   my $info = shift;
   my @display_lines = no_ctrl_char($info->{query});
   draw_screen(\@display_lines, { raw => 1 });
}

# Formatting functions {{{2

# create_table2 {{{3
# Makes a two-column table, labels on left, data on right.
# Takes refs of @cols, %labels and %data, %user_prefs
sub create_table2 {
   my ( $cols, $labels, $data, $user_prefs ) = @_;
   my @rows;

   if ( @$cols && %$data ) {

      # Override defaults
      my $p = {
         just  => '',
         sep   => ':',
         just1 => '-',
      };
      if ( $user_prefs ) {
         map { $p->{$_} = $user_prefs->{$_} } keys %$user_prefs;
      }

      # Fix undef values
      map { $data->{$_} = '' unless defined $data->{$_} } @$cols;

      # Format the table
      my $max_l = max(map{ length($labels->{$_}) } @$cols);
      my $max_v = max(map{ length($data->{$_}) } @$cols);
      my $format    = "%$p->{just}${max_l}s$p->{sep} %$p->{just1}${max_v}s";
      foreach my $col ( @$cols ) {
         push @rows, sprintf($format, $labels->{$col}, $data->{$col});
      }
   }
   return @rows;
}

# stack_next {{{3
# Stacks one display section next to the other.  Accepts left-hand arrayref,
# right-hand arrayref, and options hashref.  Tries to stack as high as
# possible, so
# aaaaaa
# bbb
# can stack ccc next to the bbb.
# NOTE: this DOES modify its arguments, even though it returns a new array.
sub stack_next {
   my ( $left, $right, $user_prefs ) = @_;
   my @result;

   my $p = {
      pad   => ' ',
      vsep  => 0,
   };
   if ( $user_prefs ) {
      map { $p->{$_} = $user_prefs->{$_} } keys %$user_prefs;
   }

   # Find out how wide the LHS can be and still let the RHS fit next to it.
   my $pad   = $p->{pad};
   my $max_r = max( map { length($_) } @$right) || 0;
   my $max_l = $this_term_size[0] - $max_r - length($pad);

   # Find the minimum row on the LHS that the RHS will fit next to.
   my $i = scalar(@$left) - 1;
   while ( $i >= 0 && length($left->[$i]) <= $max_l ) {
      $i--;
   }
   $i++;
   my $offset = $i;

   if ( $i < scalar(@$left) ) {
      # Find the max width of the section of the LHS against which the RHS
      # will sit.
      my $max_i_in_common = min($i + scalar(@$right) - 1, scalar(@$left) - 1);
      my $max_width = max( map { length($_) } @{$left}[$i..$max_i_in_common]);

      # Append the RHS onto the LHS until one runs out.
      while ( $i < @$left && $i - $offset < @$right ) {
         my $format = "%-${max_width}s$pad%${max_r}s";
         $left->[$i] = sprintf($format, $left->[$i], $right->[$i - $offset]);
         $i++;
      }
      while ( $i - $offset < @$right ) {
         # There is more RHS to push on the end of the array
         push @$left,
            sprintf("%${max_width}s$pad%${max_r}s", ' ', $right->[$i - $offset]);
         $i++;
      }
      push @result, @$left;
   }
   else {
      # There is no room to put them side by side.  Add them below, with
      # a blank line above them if specified.
      push @result, @$left;
      push @result, (' ' x $this_term_size[0]) if $p->{vsep} && @$left;
      push @result, @$right;
   }
   return @result;
}

# create_caption {{{3
sub create_caption {
   my ( $caption, @rows ) = @_;
   if ( @rows ) {

      # Calculate the width of what will be displayed, so it can be centered
      # in that space.  When the thing is wider than the display, center the
      # caption in the display.
      my $width = min($this_term_size[0], max(map { length(ref($_) ? $_->[0] : $_) } @rows));

      my $cap_len = length($caption);

      # It may be narrow enough to pad the sides with underscores and save a
      # line on the screen.
      if ( $cap_len <= $width - 6 ) {
         my $left = int(($width - 2 - $cap_len) / 2);
         unshift @rows,
            ("_" x $left) . " $caption " . ("_" x ($width - $left - $cap_len - 2));
      }

      # The caption is too wide to add underscores on each side.
      else {

         # Color is supported, so we can use terminal underlining.
         if ( $config{color}->{val} ) {
            my $left = int(($width - $cap_len) / 2);
            unshift @rows, [
               (" " x $left) . $caption . (" " x ($width - $left - $cap_len)),
               'underline',
            ];
         }

         # Color is not supported, so we have to add a line underneath to separate the
         # caption from whatever it's captioning.
         else {
            my $left = int(($width - $cap_len) / 2);
            unshift @rows, ('-' x $width);
            unshift @rows, (" " x $left) . $caption . (" " x ($width - $left - $cap_len));
         }

         # The caption is wider than the thing it labels, so we have to pad the
         # thing it labels to a consistent width.
         if ( $cap_len > $width ) {
            @rows = map {
               ref($_)
                  ? [ sprintf('%-' . $cap_len . 's', $_->[0]), $_->[1] ]
                  : sprintf('%-' . $cap_len . 's', $_);
            } @rows;
         }

      }
   }
   return @rows;
}

# create_table {{{3
# Input: an arrayref of columns, hashref of col info, and an arrayref of hashes
# Example: [ 'a', 'b' ]
#          { a => spec, b => spec }
#          [ { a => 1, b => 2}, { a => 3, b => 4 } ]
# The 'spec' is a hashref of hdr => label, just => ('-' or '').  It also supports min and max-widths
# vi the minw and maxw params.
# Output: an array of strings, one per row.
# Example:
# Column One Column Two
# ---------- ----------
# 1          2
# 3          4
sub create_table {
   my ( $cols, $info, $data, $prefs ) = @_;
   $prefs ||= {};
   $prefs->{no_hdr} ||= ($opts{n} && $clock != 1);

   # Truncate rows that will surely be off screen even if this is the only table.
   if ( !$opts{n} && !$prefs->{raw} && !$prefs->{show_all} && $this_term_size[1] < @$data-1 ) {
      $data = [ @$data[0..$this_term_size[1] - 1] ];
   }

   my @rows = ();

   if ( @$cols && %$info ) {

      # Fix undef values, collapse whitespace.
      foreach my $row ( @$data ) {
         map { $row->{$_} = collapse_ws($row->{$_}) } @$cols;
      }

      my $col_sep = $opts{n} ? "\t" : '  ';

      # Find each column's max width.
      my %width_for;
      if ( !$opts{n} ) {
         %width_for = map {
            my $col_name  = $_;
            if ( $info->{$_}->{dec} ) {
               # Align along the decimal point
               my $max_rodp = max(0, map { $_->{$col_name} =~ m/([^\s\d-].*)$/ ? length($1) : 0 } @$data);
               foreach my $row ( @$data ) {
                  my $col = $row->{$col_name};
                  my ( $l, $r ) = $col =~ m/^([\s\d]*)(.*)$/;
                  $row->{$col_name} = sprintf("%s%-${max_rodp}s", $l, $r);
               }
            }
            my $max_width = max( length($info->{$_}->{hdr}), map { length($_->{$col_name}) } @$data);
            if ( $info->{$col_name}->{maxw} ) {
               $max_width = min( $max_width, $info->{$col_name}->{maxw} );
            }
            if ( $info->{$col_name}->{minw} ) {
               $max_width = max( $max_width, $info->{$col_name}->{minw} );
            }
            $col_name => $max_width;
         } @$cols;
      }

      # The table header.
      if ( !$config{hide_hdr}->{val} && !$prefs->{no_hdr} ) {
         push @rows, $opts{n}
            ? join( $col_sep, @$cols )
            : join( $col_sep, map { sprintf( "%-$width_for{$_}s", trunc($info->{$_}->{hdr}, $width_for{$_}) ) } @$cols );
         if ( $config{color}->{val} && $config{header_highlight}->{val} ) {
            push @rows, [ pop @rows, $config{header_highlight}->{val} ];
         }
         elsif ( !$opts{n} ) {
            push @rows, join( $col_sep, map { "-" x $width_for{$_} } @$cols );
         }
      }

      # The table data.
      if ( $opts{n} ) {
         foreach my $item ( @$data ) {
            push @rows, join($col_sep, map { $item->{$_} } @$cols );
         }
      }
      else {
         my $format = join( $col_sep,
            map { "%$info->{$_}->{just}$width_for{$_}s" } @$cols );
         foreach my $item ( @$data ) {
            my $row = sprintf($format, map { trunc($item->{$_}, $width_for{$_}) } @$cols );
            if ( $config{color}->{val} && $item->{_color} ) {
               push @rows, [ $row, $item->{_color} ];
            }
            else {
               push @rows, $row;
            }
         }
      }
   }

   return @rows;
}

# Aggregates a table.  If $group_by is an arrayref of columns, the grouping key
# is the specified columns; otherwise it's just the empty string (e.g.
# everything is grouped as one group).
sub apply_group_by {
   my ( $tbl, $group_by, @rows ) = @_;
   my $meta = $tbl_meta{$tbl};
   my %is_group = map { $_ => 1 } @$group_by;
   my @non_grp  = grep { !$is_group{$_} } keys %{$meta->{cols}};

   my %temp_table;
   foreach my $row ( @rows ) {
      my $group_key
         = @$group_by
         ? '{' . join('}{', map { defined $_ ? $_ : '' } @{$row}{@$group_by}) . '}'
         : '';
      $temp_table{$group_key} ||= [];
      push @{$temp_table{$group_key}}, $row;
   }

   # Crush the rows together...
   my @new_rows;
   foreach my $key ( sort keys %temp_table ) {
      my $group = $temp_table{$key};
      my %new_row;
      @new_row{@$group_by} = @{$group->[0]}{@$group_by};
      foreach my $col ( @non_grp ) {
         my $agg = $meta->{cols}->{$col}->{agg} || 'first';
         $new_row{$col} = $agg_funcs{$agg}->( map { $_->{$col} } @$group );
      }
      push @new_rows, \%new_row;
   }
   return @new_rows;
}

# set_to_tbl {{{3
# Unifies all the work of filtering, sorting etc.  Alters the input.
# TODO: pull all the little pieces out into subroutines and stick events in each of them.
sub set_to_tbl {
   my ( $rows, $tbl ) = @_;
   my $meta = $tbl_meta{$tbl} or die "No such table $tbl in tbl_meta";

   # don't show cxn if there's only one connection being displayed
   my @visible;
   if (scalar @{$modes{$config{mode}->{val}}->{connections}} == 1) {
      map { push @visible, $_ if $_ !~ /^cxn$/ } @{$meta->{visible}};
      delete $$rows[0]{cxn} if defined $$rows[0]{cxn};
   }
   else {
      @visible = @{$meta->{visible}};
   }

   if ( !$meta->{pivot} ) {

      # Hook in event listeners
      foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_filter}} ) {
         $listener->set_to_tbl_pre_filter($rows, $tbl);
      }

      # Apply filters.  Note that if the table is pivoted, filtering and sorting
      # are applied later.
      foreach my $filter ( @{$meta->{filters}} ) {
         eval {
            @$rows = grep { $filters{$filter}->{func}->($_) } @$rows;
         };
         if ( $EVAL_ERROR && $config{debug}->{val} ) {
            die $EVAL_ERROR;
         }
      }

      foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_sort}} ) {
         $listener->set_to_tbl_pre_sort($rows, $tbl);
      }

      # Sort.  Note that if the table is pivoted, sorting might have the wrong
      # columns and it could crash.  This will only be an issue if it's possible
      # to toggle pivoting on and off, which it's not at the moment.
      if ( @$rows && $meta->{sort_func} && !$meta->{aggregate} ) {
         if ( $meta->{sort_dir} > 0 ) {
            @$rows = $meta->{sort_func}->( @$rows );
         }
         else {
            @$rows = reverse $meta->{sort_func}->( @$rows );
         }
      }

   }

   # Stop altering arguments now.
   my @rows = @$rows;

   foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_group}} ) {
      $listener->set_to_tbl_pre_group(\@rows, $tbl);
   }

   # Apply group-by.
   if ( $meta->{aggregate} ) {
      @rows = apply_group_by($tbl, $meta->{group_by}, @rows);

      # Sort.  Note that if the table is pivoted, sorting might have the wrong
      # columns and it could crash.  This will only be an issue if it's possible
      # to toggle pivoting on and off, which it's not at the moment.
      if ( @rows && $meta->{sort_func} ) {
         if ( $meta->{sort_dir} > 0 ) {
            @rows = $meta->{sort_func}->( @rows );
         }
         else {
            @rows = reverse $meta->{sort_func}->( @rows );
         }
      }

   }

   foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_colorize}} ) {
      $listener->set_to_tbl_pre_colorize(\@rows, $tbl);
   }

   if ( !$meta->{pivot} ) {
      # Colorize.  Adds a _color column to rows.
      if ( @rows && $meta->{color_func} ) {
         eval {
            foreach my $row ( @rows ) {
               $row->{_color} = $meta->{color_func}->($row);
            }
         };
         if ( $EVAL_ERROR ) {
            pause($EVAL_ERROR);
         }
      }
   }

   foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_transform}} ) {
      $listener->set_to_tbl_pre_transform(\@rows, $tbl);
   }

   # Apply_transformations.
   if ( @rows ) {
      my $cols = $meta->{cols};
      foreach my $col ( keys %{$rows->[0]} ) {
         # Don't auto-vivify $tbl_meta{tbl}-{cols}->{_color}->{trans}
         next if $col eq '_color';
         foreach my $trans ( @{$cols->{$col}->{trans}} ) {
            map { $_->{$col} = $trans_funcs{$trans}->($_->{$col}) } @rows;
         }
      }
   }

   my ($fmt_cols, $fmt_meta);

   # Pivot.
   if ( $meta->{pivot} ) {

      foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_pivot}} ) {
         $listener->set_to_tbl_pre_pivot(\@rows, $tbl);
      }

      my @vars = @{$meta->{visible}};
      my @tmp  = map { { name => $_ } } @vars;
      my @cols = 'name';
      foreach my $i ( 0..@$rows-1 ) {
         my $col = "set_$i";
         push @cols, $col;
         foreach my $j ( 0..@vars-1 ) {
            $tmp[$j]->{$col} = $rows[$i]->{$vars[$j]};
         }
      }
      $fmt_meta = { map { $_ => { hdr => $_, just => '-' } } @cols };
      $fmt_cols = \@cols;
      @rows = @tmp;

      # Hook in event listeners
      foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_filter}} ) {
         $listener->set_to_tbl_pre_filter($rows, $tbl);
      }

      # Apply filters.
      foreach my $filter ( @{$meta->{filters}} ) {
         eval {
            @rows = grep { $filters{$filter}->{func}->($_) } @rows;
         };
         if ( $EVAL_ERROR && $config{debug}->{val} ) {
            die $EVAL_ERROR;
         }
      }

      foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_sort}} ) {
         $listener->set_to_tbl_pre_sort($rows, $tbl);
      }

      # Sort.
      if ( @rows && $meta->{sort_func} ) {
         if ( $meta->{sort_dir} > 0 ) {
            @rows = $meta->{sort_func}->( @rows );
         }
         else {
            @rows = reverse $meta->{sort_func}->( @rows );
         }
      }

   }
   else {
      # If the table isn't pivoted, just show all columns that are supposed to
      # be shown; but eliminate aggonly columns if the table isn't aggregated.
      my $aggregated = $meta->{aggregate};
      $fmt_cols = [ grep { $aggregated || !$meta->{cols}->{$_}->{aggonly} } @visible ];
      $fmt_meta = { map  { $_ => $meta->{cols}->{$_}                      } @$fmt_cols };

      # If the table is aggregated, re-order the group_by columns to the left of
      # the display.
      if ( $aggregated ) {
         my %is_group = map { $_ => 1 } @{$meta->{group_by}};
         $fmt_cols = [ @{$meta->{group_by}}, grep { !$is_group{$_} } @$fmt_cols ];
      }
   }

   foreach my $listener ( @{$event_listener_for{set_to_tbl_pre_create}} ) {
      $listener->set_to_tbl_pre_create(\@rows, $tbl);
   }

   @rows = create_table( $fmt_cols, $fmt_meta, \@rows);
   if ( !$meta->{hide_caption} && !$opts{n} && $config{display_table_captions}->{val} ) {
      @rows = create_caption($meta->{capt}, @rows)
   }

   foreach my $listener ( @{$event_listener_for{set_to_tbl_post_create}} ) {
      $listener->set_to_tbl_post_create(\@rows, $tbl);
   }

   return @rows;
}

# meta_to_hdr {{{3
sub meta_to_hdr {
   my $tbl = shift;
   my $meta = $tbl_meta{$tbl};
   my %labels = map { $_ => $meta->{cols}->{$_}->{hdr} } @{$meta->{visible}};
   return \%labels;
}

# commify {{{3
# From perlfaq5: add commas.
sub commify {
   my ( $num ) = @_;
   $num = 0 unless defined $num;
   $num =~ s/(^[-+]?\d+?(?=(?>(?:\d{3})+)(?!\d))|\G\d{3}(?=\d))/$1,/g;
   return $num;
}

# set_precision {{{3
# Trim to desired precision.
sub set_precision {
   my ( $num, $precision ) = @_;
   $precision = $config{num_digits}->{val} if !defined $precision;
   sprintf("%.${precision}f", $num);
}

# percent {{{3
# Convert to percent
sub percent {
   my ( $num ) = @_;
   $num = 0 unless defined $num;
   my $digits = $config{num_digits}->{val};
   return sprintf("%.${digits}f", $num * 100)
      . ($config{show_percent}->{val} ? '%' : '');
}

# shorten {{{3
sub shorten {
   my ( $num, $opts ) = @_;

   return $num if !defined($num) || $opts{n} || $num !~ m/$num_regex/;

   $opts ||= {};
   my $pad = defined $opts->{pad} ? $opts->{pad} : '';
   my $num_digits = defined $opts->{num_digits}
      ? $opts->{num_digits}
      : $config{num_digits}->{val};
   my $force = defined $opts->{force};

   my $n = 0;
   while ( $num >= 1_024 ) {
      $num /= 1_024;
      ++$n;
   }
   return sprintf(
      $num =~ m/\./ || $n || $force
         ? "%.${num_digits}f%s"
         : '%d',
      $num, ($pad,'k','M','G', 'T')[$n]);

}

# Utility functions {{{2
# unique {{{3
sub unique {
   my %seen;
   return grep { !$seen{$_}++ } @_;
}

# make_color_func {{{3
sub make_color_func {
   my ( $tbl ) = @_;
   my @criteria;
   foreach my $spec ( @{$tbl->{colors}} ) {
      next unless exists $comp_ops{$spec->{op}};
      my $val = $spec->{op} =~ m/^(?:eq|ne|le|ge|lt|gt)$/ ? "'$spec->{arg}'"
              : $spec->{op} =~ m/^(?:=~|!~)$/             ? "m/" . quotemeta($spec->{arg}) . "/"
              :                                             $spec->{arg};
      push @criteria,
         "( defined \$set->{$spec->{col}} && \$set->{$spec->{col}} $spec->{op} $val ) { return '$spec->{color}'; }";
   }
   return undef unless @criteria;
   my $sub = eval 'sub { my ( $set ) = @_; if ' . join(" elsif ", @criteria) . '}';
   die if $EVAL_ERROR;
   return $sub;
}

# make_sort_func {{{3
# Gets a list of sort columns from the table, like "+cxn -time" and returns a
# subroutine that will sort that way.
sub make_sort_func {
   my ( $tbl ) = @_;
   my @criteria;

   # Pivoted tables can be sorted by 'name' and set_x columns; others must be
   # sorted by existing columns.  TODO: this will crash if you toggle between
   # pivoted and nonpivoted.  I have several other 'crash' notes about this if
   # this ever becomes possible.

   if ( $tbl->{pivot} ) {
      # Sort type is not really possible on pivoted columns, because a 'column'
      # contains data from an entire non-pivoted row, so there could be a mix of
      # numeric and non-numeric data.  Thus everything has to be 'cmp' type.
      foreach my $col ( split(/\s+/, $tbl->{sort_cols} ) ) {
         next unless $col;
         my ( $dir, $name ) = $col =~ m/([+-])?(\w+)$/;
         next unless $name && $name =~ m/^(?:name|set_\d+)$/;
         $dir ||= '+';
         my $op = 'cmp';
         my $df = "''";
         push @criteria,
            $dir eq '+'
            ? "(\$a->{$name} || $df) $op (\$b->{$name} || $df)"
            : "(\$b->{$name} || $df) $op (\$a->{$name} || $df)";
      }
   }
   else {
      foreach my $col ( split(/\s+/, $tbl->{sort_cols} ) ) {
         next unless $col;
         my ( $dir, $name ) = $col =~ m/([+-])?(\w+)$/;
         next unless $name && $tbl->{cols}->{$name};
         $dir ||= '+';
         my $op = $tbl->{cols}->{$name}->{num} ? "<=>" : "cmp";
         my $df = $tbl->{cols}->{$name}->{num} ? "0"   : "''";
         push @criteria,
            $dir eq '+'
            ? "(\$a->{$name} || $df) $op (\$b->{$name} || $df)"
            : "(\$b->{$name} || $df) $op (\$a->{$name} || $df)";
      }
   }
   return sub { return @_ } unless @criteria;
   my $sub = eval 'sub { sort {' . join("||", @criteria) . '} @_; }';
   die if $EVAL_ERROR;
   return $sub;
}

# trunc {{{3
# Shortens text to specified length.
sub trunc {
   my ( $text, $len ) = @_;
   if ( length($text) <= $len ) {
      return $text;
   }
   return substr($text, 0, $len);
}

# donut {{{3
# Takes out the middle of text to shorten it.
sub donut {
   my ( $text, $len ) = @_;
   return $text if length($text) <= $len;
   my $max = length($text) - $len;
   my $min = $max - 1;

   # Try to remove a single "word" from somewhere in the center
   if ( $text =~ s/_[^_]{$min,$max}_/_/ ) {
      return $text;
   }

   # Prefer removing the end of a "word"
   if ( $text =~ s/([^_]+)[^_]{$max}_/$1_/ ) {
      return $text;
   }

   $text = substr($text, 0, int($len/2))
         . "_"
         . substr($text, int($len/2) + $max + 1);
   return $text;
}

# crunch {{{3
# Removes vowels and compacts repeated letters to shorten text.
sub crunch {
   my ( $text, $len ) = @_;
   return $text if $len && length($text) <= $len;
   $text =~ s/^IB_\w\w_//;
   $text =~ s/(?<![_ ])[aeiou]//g;
   $text =~ s/(.)\1+/$1/g;
   return $text;
}

# collapse_ws {{{3
# Collapses all whitespace to a single space.
sub collapse_ws {
   my ( $text ) = @_;
   return '' unless defined $text;
   $text =~ s/\s+/ /g;
   return $text;
}

# Strips out non-printable characters within fields, which freak terminals out.
sub no_ctrl_char {
   my ( $text ) = @_;
   return '' unless defined $text;
   my $charset = $config{charset}->{val};
   if ( $charset && $charset eq 'unicode' ) {
      $text =~ s/
         ("(?:(?!(?<!\\)").)*"  # Double-quoted string
         |'(?:(?!(?<!\\)').)*') # Or single-quoted string
         /$1 =~ m#\p{IsC}# ? "[BINARY]" : $1/egx;
   }
   elsif ( $charset && $charset eq 'none' ) {
      $text =~ s/
         ("(?:(?!(?<!\\)").)*"
         |'(?:(?!(?<!\\)').)*')
         /[TEXT]/gx;
   }
   else { # The default is 'ascii'
      $text =~ s/
         ("(?:(?!(?<!\\)").)*"
         |'(?:(?!(?<!\\)').)*')
         /$1 =~ m#[^\040-\176]# ? "[BINARY]" : $1/egx;
   }
   return $text;
}

# word_wrap {{{3
# Wraps text at word boundaries so it fits the screen.
sub word_wrap {
   my ( $text, $width) = @_;
   $width ||= $this_term_size[0];
   $text =~ s/(.{0,$width})(?:\s+|$)/$1\n/g;
   $text =~ s/ +$//mg;
   return $text;
}

# draw_screen {{{3
# Prints lines to the screen.  The first argument is an arrayref.  Each
# element of the array is either a string or an arrayref.  If it's a string it
# just gets printed.  If it's an arrayref, the first element is the string to
# print, and the second is args to colored().
sub draw_screen {
   my ( $display_lines, $prefs ) = @_;
   if ( !$opts{n} && $config{show_statusbar}->{val} ) {
      unshift @$display_lines, create_statusbar();
   }

   foreach my $listener ( @{$event_listener_for{draw_screen}} ) {
      $listener->draw_screen($display_lines);
   }

   $clear_screen_sub->()
      if $prefs->{clear} || !$modes{$config{mode}->{val}}->{no_clear_screen};
   if ( $opts{n} || $prefs->{raw} ) {
      my $num_lines = 0;
      print join("\n",
         map {
            $num_lines++;
            ref $_
               ? colored($_->[0], $_->[1])
               : $_;
         }
         grep { !$opts{n} || $_ } # Suppress empty lines
         @$display_lines);
      if ( $opts{n} && $num_lines ) {
         print "\n";
      }
   }
   else {
      my $max_lines = $prefs->{show_all}
         ? scalar(@$display_lines)- 1
         : min(scalar(@$display_lines), $this_term_size[1]);
      print join("\n",
         map {
            ref $_
               ? colored(substr($_->[0], 0, $this_term_size[0]), $_->[1])
               : substr($_, 0, $this_term_size[0]);
         } @$display_lines[0..$max_lines - 1]);
   }
}

# secs_to_time {{{3
sub secs_to_time {
   my ( $secs, $fmt ) = @_;
   $secs ||= 0;
   return '00:00' unless $secs;

   # Decide what format to use, if not given
   $fmt ||= $secs >= 86_400 ? 'd'
          : $secs >= 3_600  ? 'h'
          :                   'm';

   return
      $fmt eq 'd' ? sprintf(
         "%d+%02d:%02d:%02d",
         int($secs / 86_400),
         int(($secs % 86_400) / 3_600),
         int(($secs % 3_600) / 60),
         $secs % 60)
      : $fmt eq 'h' ? sprintf(
         "%02d:%02d:%02d",
         int(($secs % 86_400) / 3_600),
         int(($secs % 3_600) / 60),
         $secs % 60)
      : sprintf(
         "%02d:%02d",
         int(($secs % 3_600) / 60),
         $secs % 60);
}

# dulint_to_int {{{3
# Takes a number that InnoDB formats as two ulint integers, like transaction IDs
# and such, and turns it into a single integer
sub dulint_to_int {
   my $num = shift;
   return 0 unless $num;
   my ( $high, $low ) = $num =~ m/^(\d+) (\d+)$/;
   return $low unless $high;
   return $low + ( $high * $MAX_ULONG );
}

# create_statusbar {{{3
sub create_statusbar {
   my $mode = $config{mode}->{val};
   my @cxns = sort { $a cmp $b } get_connections();

   my $modeline        = ( $config{readonly}->{val} ? '[RO] ' : '' )
                         . $modes{$mode}->{hdr} . " (? for help)";
   my $mode_width      = length($modeline);
   my $remaining_width = $this_term_size[0] - $mode_width - 1;
   my $result;

   # The thingie in top-right that says what we're monitoring.
   my $cxn = '';

   if ( 1 == @cxns && $dbhs{$cxns[0]} && $dbhs{$cxns[0]}->{dbh} ) {
      $cxn = $dbhs{$cxns[0]}->{dbh}->{mysql_serverinfo} || '';
   }
   else {
      if ( $modes{$mode}->{server_group} ) {
         $cxn = "Servers: " . $modes{$mode}->{server_group};
         my $err_count = grep { $dbhs{$_} && $dbhs{$_}->{err_count} } @cxns;
         if ( $err_count ) {
            $cxn .= "(" . ( scalar(@cxns) - $err_count ) . "/" . scalar(@cxns) . ")";
         }
      }
      else {
         $cxn = join(' ', map { ($dbhs{$_}->{err_count} ? '!' : '') . $_ }
            grep { $dbhs{$_} } @cxns);
      }
   }

   if ( 1 == @cxns ) {
      get_driver_status(@cxns);
      my $vars = $vars{$cxns[0]}->{$clock};
      my $inc  = inc(0, $cxns[0]);

      # Format server uptime human-readably, calculate QPS...
      my $uptime = secs_to_time( $vars->{Uptime_hires} );
      my $qps    = ($inc->{Questions}||0) / ($inc->{Uptime_hires}||1);
      my $ibinfo = '';

      if ( exists $vars->{IB_last_secs} ) {
         $ibinfo .= "InnoDB $vars->{IB_last_secs}s ";
         if ( $vars->{IB_got_all} ) {
            if ( ($mode eq 'T' || $mode eq 'W')
                  && $vars->{IB_tx_is_truncated} ) {
               $ibinfo .= ':^|';
            }
            else {
               $ibinfo .= ':-)';
            }
         }
         else {
            $ibinfo .= ':-(';
         }
      }
      $result = sprintf(
         "%-${mode_width}s %${remaining_width}s",
         $modeline,
         join(', ', grep { $_ } (
            $cxns[0],
            $uptime,
            $ibinfo,
            shorten($qps) . " QPS",
            ($vars->{Threads} || 0) . "/" . ($vars->{Threads_running} || 0) . "/" . ($vars->{Threads_cached} || 0) . " con/run/cac thds",
            $cxn)));
   }
   else {
      $result = sprintf(
         "%-${mode_width}s %${remaining_width}s",
         $modeline,
         $cxn);
   }

   return $config{color}->{val} ? [ $result, 'bold reverse' ] : $result;
}

# Database connections {{{3
sub add_new_dsn {
   my ( $name, $dsn, $dl_table, $have_user, $user, $have_pass, $pass, $savepass ) = @_;

   if ( defined $name ) {
      $name =~ s/[\s:;]//g;
   }

   if ( !$name ) {
      print word_wrap("Choose a name for the connection.  It cannot contain "
         . "whitespace, colons or semicolons."), "\n\n";
      do {
         $name = prompt("Enter a name");
         $name =~ s/[\s:;]//g;
      } until ( $name );
   }

   if ( !$dsn ) {
      do {
         $clear_screen_sub->();
         print "Typical DSN strings look like\n   DBI:mysql:;host=hostname;port=port\n"
            . "The db and port are optional and can usually be omitted.\n"
            . "If you specify 'mysql_read_default_group=mysql' many options can be read\n"
            . "from your mysql options files (~/.my.cnf, /etc/my.cnf).\n\n";
         $dsn = prompt("Enter a DSN string", undef, "DBI:mysql:;mysql_read_default_group=mysql;host=$name");
      } until ( $dsn );
   }
   if ( !$dl_table ) {
      $clear_screen_sub->();
      my $dl_table = prompt("Optional: enter a table (must not exist) to use when resetting InnoDB deadlock information",
         undef, 'test.innotop_dl');
   }

   $connections{$name} = {
      dsn       => $dsn,
      dl_table  => $dl_table,
      have_user => $have_user,
      user      => $user,
      have_pass => $have_pass,
      pass      => $pass,
      savepass  => $savepass
   };
}

sub add_new_server_group {
   my ( $name ) = @_;

   if ( defined $name ) {
      $name =~ s/[\s:;]//g;
   }

   if ( !$name ) {
      print word_wrap("Choose a name for the group.  It cannot contain "
         . "whitespace, colons or semicolons."), "\n\n";
      do {
         $name = prompt("Enter a name");
         $name =~ s/[\s:;]//g;
      } until ( $name );
   }

   my @cxns;
   do {
      $clear_screen_sub->();
      @cxns = select_cxn("Choose servers for $name", keys %connections);
   } until ( @cxns );

   $server_groups{$name} = \@cxns;
   return $name;
}

sub get_var_set {
   my ( $name ) = @_;
   while ( !$name || !exists($var_sets{$config{$name}->{val}}) ) {
      $name = choose_var_set($name);
   }
   return $var_sets{$config{$name}->{val}}->{text};
}

sub add_new_var_set {
   my ( $name ) = @_;

   if ( defined $name ) {
      $name =~ s/\W//g;
   }

   if ( !$name ) {
      do {
         $name = prompt("Enter a name");
         $name =~ s/\W//g;
      } until ( $name );
   }

   my $variables;
   do {
      $clear_screen_sub->();
      $variables = prompt("Enter variables for $name", undef );
   } until ( $variables );

   $var_sets{$name} = { text => $variables, user => 1 };
}

sub next_server {
   my $mode     = $config{mode}->{val};
   my @cxns     = sort keys %connections;
   my ($cur)    = get_connections($mode);
   $cur         ||= $cxns[0];
   my $pos      = grep { $_ lt $cur } @cxns;
   my $newpos   = ($pos + 1) % @cxns;
   $modes{$mode}->{server_group} = '';
   $modes{$mode}->{connections} = [ $cxns[$newpos] ];
   $clear_screen_sub->();
}

sub next_server_group {
   my $mode = shift || $config{mode}->{val};
   my @grps = sort keys %server_groups;
   my $curr = $modes{$mode}->{server_group};

   return unless @grps;

   if ( $curr ) {
      # Find the current group's position.
      my $pos = 0;
      while ( $curr ne $grps[$pos] ) {
         $pos++;
      }
      $modes{$mode}->{server_group} = $grps[ ($pos + 1) % @grps ];
   }
   else {
      $modes{$mode}->{server_group} = $grps[0];
   }
}

# Get a list of connection names used in this mode.
sub get_connections {
   if ( $file ) {
      return qw(file);
   }
   my $mode = shift || $config{mode}->{val};
   my @connections = $modes{$mode}->{server_group}
      ? @{$server_groups{$modes{$mode}->{server_group}}}
      : @{$modes{$mode}->{connections}};
   if ( $modes{$mode}->{one_connection} ) {
      @connections = @connections ? $connections[0] : ();
   }
   return unique(@connections);
}

# Get a list of tables used in this mode.  If innotop is running non-interactively, just use the first.
sub get_visible_tables {
   my $mode = shift || $config{mode}->{val};
   my @tbls = @{$modes{$mode}->{visible_tables}};
   if ( $opts{n} ) {
      return $tbls[0];
   }
   else {
      return @tbls;
   }
}

# Choose from among available connections or server groups.
# If the mode has a server set in use, prefers that instead.
sub choose_connections {
   $clear_screen_sub->();
   my $mode    = $config{mode}->{val};
   my $meta    =  { map { $_ => $connections{$_}->{dsn} } keys %connections };
   foreach my $group ( keys %server_groups ) {
      $meta->{"#$group"} = join(' ', @{$server_groups{$group}});
   }

   my $choices = prompt_list("Choose connections or a group for $mode mode",
      undef, sub { return keys %$meta }, $meta);

   my @choices = unique(grep { $_ } split(/\s+/, $choices));
   if ( @choices ) {
      if ( $choices[0] =~ s/^#// && exists $server_groups{$choices[0]} ) {
         $modes{$mode}->{server_group} = $choices[0];
      }
      else {
         $modes{$mode}->{connections} = [ grep { exists $connections{$_} } @choices ];
      }
   }
}

# Accepts a DB connection name and the name of a prepared query (e.g. status, kill).
# Also a list of params for the prepared query.  This allows not storing prepared
# statements globally.  Returns a $sth that's been executed.
# ERROR-HANDLING SEMANTICS: if the statement throws an error, propagate, but if the
# connection has gone away or can't connect, DO NOT.  Just return undef.
sub do_stmt {
   my ( $cxn, $stmt_name, @args ) = @_;

   return undef if $file;

   # Test if the cxn should not even be tried
   return undef if $dbhs{$cxn}
      && $dbhs{$cxn}->{err_count} 
      && ( !$dbhs{$cxn}->{dbh} || !$dbhs{$cxn}->{dbh}->{Active} || $dbhs{$cxn}->{mode} eq $config{mode}->{val} )
      && $dbhs{$cxn}->{wake_up} > $clock;

   my $sth;
   my $retries = 1;
   my $success = 0;
   TRY:
   while ( $retries-- >= 0 && !$success ) {

      eval {
         my $dbh = connect_to_db($cxn);

         # If the prepared query doesn't exist, make it.
         if ( !exists $dbhs{$cxn}->{stmts}->{$stmt_name} ) {
            $dbhs{$cxn}->{stmts}->{$stmt_name} = $stmt_maker_for{$stmt_name}->($dbh);
         }

         $sth = $dbhs{$cxn}->{stmts}->{$stmt_name};
         if ( $sth ) {
            $sth->execute(@args);
         }
         $success = 1;
      };
      if ( $EVAL_ERROR ) {
         if ( $EVAL_ERROR =~ m/$nonfatal_errs/ ) {
            handle_cxn_error($cxn, $EVAL_ERROR);
         }
         else {
            die "$cxn $stmt_name: $EVAL_ERROR";
         }
         if ( $retries < 0 ) {
            $sth = undef;
         }
      }
   }

   if ( $sth && $sth->{NUM_OF_FIELDS} ) {
      sleep($stmt_sleep_time_for{$stmt_name}) if $stmt_sleep_time_for{$stmt_name};
      return $sth;
   }
}

# Keeps track of error count, sleep times till retries, etc etc.
# When there's an error we retry the connection every so often, increasing in
# Fibonacci series to prevent too much banging on the server.
sub handle_cxn_error {
   my ( $cxn, $err ) = @_;
   my $meta = $dbhs{$cxn};
   $meta->{err_count}++;

   # This is used so errors that have to do with permissions needed by the current
   # mode will get displayed as long as we're in this mode, but get ignored if the
   # mode changes.
   $meta->{mode} = $config{mode}->{val};

   # Strip garbage from the error text if possible.
   $err =~ s/\s+/ /g;
   if ( $err =~ m/failed: (.*?) at \S*innotop line/ ) {
      $err = $1;
   }

   $meta->{last_err}   = $err;
   my $sleep_time      = $meta->{this_sleep} + $meta->{prev_sleep};
   $meta->{prev_sleep} = $meta->{this_sleep};
   $meta->{this_sleep} = $sleep_time;
   $meta->{wake_up}    = $clock + $sleep_time;
   if ( $config{show_cxn_errors}->{val} ) {
      print STDERR "Error at tick $clock $cxn $err" if $config{debug}->{val};
   }
}

# Accepts a DB connection name and a (string) query.  Returns a $sth that's been
# executed.
sub do_query {
   my ( $cxn, $query ) = @_;

   return undef if $file;

   # Test if the cxn should not even be tried
   return undef if $dbhs{$cxn}
      && $dbhs{$cxn}->{err_count} 
      && ( !$dbhs{$cxn}->{dbh} || !$dbhs{$cxn}->{dbh}->{Active} || $dbhs{$cxn}->{mode} eq $config{mode}->{val} )
      && $dbhs{$cxn}->{wake_up} > $clock;

   my $sth;
   my $retries = 1;
   my $success = 0;
   TRY:
   while ( $retries-- >= 0 && !$success ) {

      eval {
         my $dbh = connect_to_db($cxn);

         $sth = $dbh->prepare($query);
         $sth->execute();
         $success = 1;
      };
      if ( $EVAL_ERROR ) {
         if ( $EVAL_ERROR =~ m/$nonfatal_errs/ ) {
            handle_cxn_error($cxn, $EVAL_ERROR);
         }
         else {
            die $EVAL_ERROR;
         }
         if ( $retries < 0 ) {
            $sth = undef;
         }
      }
   }
 
   return $sth;
}

sub get_uptime {
   my ( $cxn ) = @_;
   $dbhs{$cxn}->{start_time} ||= time();
   # Avoid dividing by zero
   return (time() - $dbhs{$cxn}->{start_time}) || .001;
}

sub connect_to_db {
   my ( $cxn ) = @_;

   $dbhs{$cxn} ||= {
      stmts      => {},  # bucket for prepared statements.
      prev_sleep => 0,
      this_sleep => 1,
      wake_up    => 0,
      start_time => 0,
      dbh        => undef,
   };
   my $href = $dbhs{$cxn};

   if ( !$href->{dbh} || ref($href->{dbh}) !~ m/DBI/ || !$href->{dbh}->ping ) {
      my $dbh = get_new_db_connection($cxn);
      @{$href}{qw(dbh err_count wake_up this_sleep start_time prev_sleep)}
               = ($dbh, 0, 0, 1, 0, 0);

      # Derive and store the server's start time in hi-res
      my $uptime = $dbh->selectrow_hashref("show status like 'Uptime'")->{value};
      $href->{start_time} = time() - $uptime;

      # Set timeouts so an unused connection stays alive.
      # For example, a connection might be used in Q mode but idle in T mode.
      if ( version_ge($dbh, '4.0.3')) {
         my $timeout = $config{cxn_timeout}->{val};
         $dbh->do("set session wait_timeout=$timeout, interactive_timeout=$timeout");
      }
   }
   return $href->{dbh};
}

# Compares versions like 5.0.27 and 4.1.15-standard-log
sub version_ge {
   my ( $dbh, $target ) = @_;
   my $version = sprintf('%03d%03d%03d', $dbh->{mysql_serverinfo} =~ m/(\d+)/g);
   return $version ge sprintf('%03d%03d%03d', $target =~ m/(\d+)/g);
}

# Extracts status values that can be gleaned from the DBD driver without doing a whole query.
sub get_driver_status {
   my @cxns = @_;
   if ( !$info_gotten{driver_status}++ ) {
      foreach my $cxn ( @cxns ) {
         next unless $dbhs{$cxn} && $dbhs{$cxn}->{dbh} && $dbhs{$cxn}->{dbh}->{Active};
         $vars{$cxn}->{$clock} ||= {};
         my $vars = $vars{$cxn}->{$clock};
         my %res = map {  $_ =~ s/ +/_/g; $_ } $dbhs{$cxn}->{dbh}->{mysql_stat} =~ m/(\w[^:]+): ([\d\.]+)/g;
         map { $vars->{$_} ||= $res{$_} } keys %res;
         $vars->{Uptime_hires} ||= get_uptime($cxn);
         $vars->{cxn} = $cxn;
      }
   }
}

sub get_new_db_connection {
   my ( $connection, $destroy ) = @_;
   if ( $file ) {
      die "You can't connect to a MySQL server while monitoring a file.  This is probably a bug.";
   }

   my $dsn = $connections{$connection}
      or die "No connection named '$connection' is defined in your configuration";

   # don't ask for a username if mysql_read_default_group=client is in the DSN
   if ( !defined $dsn->{have_user} and $dsn->{dsn} !~ /mysql_read_default_group=client/ ) {
      my $answer = prompt("Do you want to specify a username for $connection?", undef, 'n');
      $dsn->{have_user} = $answer && $answer =~ m/1|y/i;
   }

   # don't ask for a password if mysql_read_default_group=client is in the DSN
   if ( !defined $dsn->{have_pass} and $dsn->{dsn} !~ /mysql_read_default_group=client/ ) {
      my $answer = prompt("Do you want to specify a password for $connection?", undef, 'n');
      $dsn->{have_pass} = $answer && $answer =~ m/1|y/i;
   }

   if ( !$dsn->{user} && $dsn->{have_user} ) {
      my $user = $ENV{USERNAME} || $ENV{USER} || getlogin() || getpwuid($REAL_USER_ID) || undef;
      $dsn->{user} = prompt("Enter username for $connection", undef, $user);
   }

   if ( !defined $dsn->{user} ) {
      $dsn->{user} = '';
   }

   if ( !$dsn->{pass} && !$dsn->{savepass} && $dsn->{have_pass} ) {
      $dsn->{pass} = prompt_noecho("Enter password for '$dsn->{user}' on $connection");
      print "\n";
      if ( !defined($dsn->{savepass}) ) {
         my $answer = prompt("Save password in plain text in the config file?", undef, 'y');
         $dsn->{savepass} = $answer && $answer =~ m/1|y/i;
      }
   }

   my $dbh = DBI->connect(
      $dsn->{dsn}, $dsn->{user}, $dsn->{pass},
      { RaiseError => 1, PrintError => 0, AutoCommit => 1 });
   $dbh->{InactiveDestroy} = 1 unless $destroy; # Can't be set in $db_options
   $dbh->{FetchHashKeyName} = 'NAME_lc'; # Lowercases all column names for fetchrow_hashref
   return $dbh;
}

sub get_cxn_errors {
   my @cxns = @_;
   return () unless $config{show_cxn_errors_in_tbl}->{val};
   return
      map  { [ $_ . ': ' . $dbhs{$_}->{last_err}, 'red' ] }
      grep { $dbhs{$_} && $dbhs{$_}->{err_count} && $dbhs{$_}->{mode} eq $config{mode}->{val} }
      @cxns;
}

# Setup and tear-down functions {{{2

# Takes a string and turns it into a hashref you can apply to %tbl_meta tables.  The string
# can be in the form 'foo, bar, foo/bar, foo as bar' much like a SQL SELECT statement.
sub compile_select_stmt {
   my ($str) = @_;
   my @exps = $str =~ m/\s*([^,]+(?i:\s+as\s+[^,\s]+)?)\s*(?=,|$)/g;
   my %cols;
   my @visible;
   foreach my $exp ( @exps ) {
      my ( $text, $colname );
      if ( $exp =~ m/as\s+(\w+)\s*/ ) {
         $colname = $1;
         $exp =~ s/as\s+(\w+)\s*//;
         $text    = $exp;
      }
      else {
         $text = $colname = $exp;
      }
      my ($func, $err) = compile_expr($text);
      $cols{$colname} = {
         src  => $text,
         hdr  => $colname,
         num  => 0,
         func => $func,
      };
      push @visible, $colname;
   }
   return (\%cols, \@visible);
}

# compile_filter {{{3
sub compile_filter {
   my ( $text ) = @_;
   my ( $sub, $err );
   eval "\$sub = sub { my \$set = shift; $text }";
   if ( $EVAL_ERROR ) {
      $EVAL_ERROR =~ s/at \(eval.*$//;
      $sub = sub { return $EVAL_ERROR };
      $err = $EVAL_ERROR;
   }
   return ( $sub, $err );
}

# compile_expr {{{3
sub compile_expr {
   my ( $expr ) = @_;
   # Leave built-in functions alone so they get called as Perl functions, unless
   # they are the only word in $expr, in which case treat them as hash keys.
   if ( $expr =~ m/\W/ ) {
      $expr =~ s/(?<!\{|\$)\b([A-Za-z]\w{2,})\b/is_func($1) ? $1 : "\$set->{$1}"/eg;
   }
   else {
      $expr = "\$set->{$expr}";
   }
   my ( $sub, $err );
   my $quoted = quotemeta($expr);
   eval qq{
      \$sub = sub {
         my (\$set, \$cur, \$pre) = \@_;
         my \$val = eval { $expr };
         if ( \$EVAL_ERROR && \$config{debug}->{val} ) {
            \$EVAL_ERROR =~ s/ at \\(eval.*//s;
            die "\$EVAL_ERROR in expression $quoted";
         }
         return \$val;
      }
   };
   if ( $EVAL_ERROR ) {
      if ( $config{debug}->{val} ) {
         die $EVAL_ERROR;
      }
      $EVAL_ERROR =~ s/ at \(eval.*$//;
      $sub = sub { return $EVAL_ERROR };
      $err = $EVAL_ERROR;
   }
   return ( $sub, $err );
}

# finish {{{3
# This is a subroutine because it's called from a key to quit the program.
sub finish {
   save_config();
   ReadMode('normal') unless $opts{n};
   print "\n";
   exit(0);
}

# core_dump {{{3
sub core_dump {
   my $msg = shift;
   if ($config{debugfile}->{val} && $config{debug}->{val}) {
      eval {
         open my $file, '>>', $config{debugfile}->{val};
         if ( %vars ) {
            print $file "Current variables:\n" . Dumper(\%vars);
         }
         close $file;
      };
   }
   print $msg;
}

# migrate_config {{{3
sub migrate_config {

   my ($old_filename, $new_filename) = @_;

   # don't proceed if old file doesn't exist
   if ( ! -f $old_filename ) {
      die "Error migrating '$old_filename': file doesn't exist.\n";
   }
   # don't migrate files if new file exists
   elsif ( -f $new_filename ) {
      die "Error migrating '$old_filename' to '$new_filename': new file already exists.\n";
   }
   # if migrating from one file to another in the same directory, just rename them
   if (dirname($old_filename) eq dirname($new_filename)) {
      rename($old_filename, $new_filename)
         or die "Can't rename '$old_filename' to '$new_filename': $OS_ERROR";
   }
   # otherwise, move the existing conf file to a temp file, make the necessary directory structure,
   # and move the temp conf file to its new home
   else {
      my $tmp = File::Temp->new( TEMPLATE => 'innotopXXXXX', DIR => $homepath, SUFFIX => '.conf');
      my $tmp_filename = $tmp->filename;
      my $dirname = dirname($new_filename);
      rename($old_filename, $tmp_filename)
         or die "Can't rename '$old_filename' to '$tmp_filename': $OS_ERROR";
      mkdir($dirname) or die "Can't create directory '$dirname': $OS_ERROR";
      mkdir("$dirname/plugins") or die "Can't create directory '$dirname/plugins': $OS_ERROR";
      rename($tmp_filename, $new_filename)
         or die "Can't rename '$tmp_filename' to '$new_filename': $OS_ERROR";
   }
}

# load_config {{{3
sub load_config {
    
   my ($old_filename, $answer);

   if ( $opts{u} or $opts{p} or $opts{h} or $opts{P} ) {
     my @params = $dsn_parser->get_cxn_params(\%opts); # dsn=$params[0]
     add_new_dsn($opts{h} || 'localhost', $params[0], 'test.innotop_dl', 
                 $opts{u} ? 1 : 0, $opts{u}, $opts{p} ? 1 : 0, $opts{p});
   }
   if ($opts{c}) {
      $conf_file = $opts{c};
   }  
   # innotop got upgraded and this is an old config file.
   elsif ( -f "$homepath/.innotop" or -f "$homepath/.innotop/innotop.ini" ) {
      $conf_file = $default_home_conf;
      if ( -f  "$homepath/.innotop") {
         $old_filename = "$homepath/.innotop";
      }
      elsif ( -f "$homepath/.innotop/innotop.ini" ) {
         $old_filename = "$homepath/.innotop/innotop.ini";
      }
      $answer = pause("Innotop's default config location has moved to '$conf_file'.  Move old config file '$old_filename' there now? y/n");
      if ( lc $answer eq 'y' ) {
         migrate_config($old_filename, $conf_file);
      }
      else {
         print "\nInnotop will now exit so you can fix the config file.\n";
         exit(0);
      }
   }
   elsif ( -f $default_home_conf ) {
      $conf_file = $default_home_conf;
   }
   elsif ( -f $default_central_conf and not $opts{s} ) {
      $conf_file = $default_central_conf;
   }
   else {
      # If no config file was loaded, set readonly to 0 if the user wants to 
      # write a config
      $config{readonly}->{val} = 0 if $opts{w};
      # If no connections have been defined, connect to a MySQL database 
      # on localhost using mysql_read_default_group=client
      if (!%connections) {
         add_new_dsn('localhost', 
                     'DBI:mysql:;host=localhost;mysql_read_default_group=client', 
                     'test.innotop_dl');
      }
   }

   if ( -f "$conf_file" ) {
      open my $file, "<", $conf_file or die("Can't open '$conf_file': $OS_ERROR");

      # Check config file version.  Just ignore if either innotop or the file has
      # garbage in the version number.
      if ( defined(my $line = <$file>) && $VERSION =~ m/\d/ ) {
         chomp $line;
         if ( my ($maj, $min, $rev) = $line =~ m/^version=(\d+)\.(\d+)(?:\.(\d+))?$/ ) {
            $rev ||= 0;
            my $cfg_ver          = sprintf('%03d-%03d-%03d', $maj, $min, $rev);
            ( $maj, $min, $rev ) = $VERSION =~ m/^(\d+)\.(\d+)(?:\.(\d+))?$/;
            $rev ||= 0;
            my $innotop_ver      = sprintf('%03d-%03d-%03d', $maj, $min, $rev);

            if ( $cfg_ver gt $innotop_ver ) {
               pause("The config file is for a newer version of innotop and may not be read correctly.");
            }
            else {
               my @ver_history = @config_versions;
               while ( my ($start, $end) = splice(@ver_history, 0, 2) ) {
                  # If the config file is between the endpoints and innotop is greater than
                  # the endpoint, innotop has a newer config file format than the file.
                  if ( $cfg_ver ge $start && $cfg_ver lt $end && $innotop_ver ge $end ) {
                     my $msg = "innotop's config file format has changed.  Overwrite $conf_file?  y or n";
                     if ( pause($msg) eq 'n' ) {
                        $config{readonly}->{val} = 1;
                        print "\ninnotop will not save any configuration changes you make.";
                        pause();
                        print "\n";
                     }
                     close $file;
                     return;
                  }
               }
            }
         }
      }

      while ( my $line = <$file> ) {
         chomp $line;
         next unless $line =~ m/^\[([a-z_]+)\]$/;
         if ( exists $config_file_sections{$1} ) {
            $config_file_sections{$1}->{reader}->($file);
         }
         else {
            warn "Unknown config file section '$1'";
         }
      }
      close $file or die("Can't close $conf_file: $OS_ERROR");
   }

}

# Do some post-processing on %tbl_meta: compile src properties into func etc.
sub post_process_tbl_meta {
   foreach my $table ( values %tbl_meta ) {
      foreach my $col_name ( keys %{$table->{cols}} ) {
         my $col_def = $table->{cols}->{$col_name};
         my ( $sub, $err ) = compile_expr($col_def->{src});
         $col_def->{func} = $sub;
      }
   }
}

# load_config_plugins {{{3
sub load_config_plugins {
   my ( $file ) = @_;

   # First, find a list of all plugins that exist on disk, and get information about them.
   my $dir = $config{plugin_dir}->{val};
   foreach my $p_file ( <$dir/*.pm> ) {
      my ($package, $desc);
      eval {
         open my $p_in, "<", $p_file or die $OS_ERROR;
         while ( my $line = <$p_in> ) {
            chomp $line;
            if ( $line =~ m/^package\s+(.*?);/ ) {
               $package = $1;
            }
            elsif ( $line =~ m/^# description: (.*)/ ) {
               $desc = $1;
            }
            last if $package && $desc;
         }
         close $p_in;
      };
      if ( $package ) {
         $plugins{$package} = {
            file   => $p_file,
            desc   => $desc,
            class  => $package,
            active => 0,
         };
         if ( $config{debug}->{val} && $EVAL_ERROR ) {
            die $EVAL_ERROR;
         }
      }
   }

   # Now read which ones the user has activated.  Each line simply represents an active plugin.
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;
      next unless $line && $plugins{$line};

      my $obj;
      eval {
         require $plugins{$line}->{file};
         $obj = $line->new(%pluggable_vars);
         foreach my $event ( $obj->register_for_events() ) {
            my $queue = $event_listener_for{$event};
            if ( $queue ) {
               push @$queue, $obj;
            }
         }
      };
      if ( $config{debug}->{val} && $EVAL_ERROR ) {
         die $EVAL_ERROR;
      }
      if ( $obj ) {
         $plugins{$line}->{active} = 1;
         $plugins{$line}->{object} = $obj;
      }
   }
}

# save_config_plugins {{{3
sub save_config_plugins {
   my $file = shift;
   foreach my $class ( sort keys %plugins ) {
      next unless $plugins{$class}->{active};
      print $file "$class\n";
   }
}

# load_config_active_server_groups {{{3
sub load_config_active_server_groups {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $mode, $group ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $mode && $group
         && exists $modes{$mode} && exists $server_groups{$group};
      $modes{$mode}->{server_group} = $group;
   }
}

# save_config_active_server_groups {{{3
sub save_config_active_server_groups {
   my $file = shift;
   foreach my $mode ( sort keys %modes ) {
      print $file "$mode=$modes{$mode}->{server_group}\n";
   }
}

# load_config_server_groups {{{3
sub load_config_server_groups {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $name, $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $name && $rest;
      my @vars = unique(grep { $_ && exists $connections{$_} } split(/\s+/, $rest));
      next unless @vars;
      $server_groups{$name} = \@vars;
   }
}

# save_config_server_groups {{{3
sub save_config_server_groups {
   my $file = shift;
   foreach my $set ( sort keys %server_groups ) {
      print $file "$set=", join(' ', @{$server_groups{$set}}), "\n";
   }
}

# load_config_varsets {{{3
sub load_config_varsets {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $name, $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $name && $rest;
      $var_sets{$name} = {
         text => $rest,
         user => 1,
      };
   }
}

# save_config_varsets {{{3
sub save_config_varsets {
   my $file = shift;
   foreach my $varset ( sort keys %var_sets ) {
      next unless $var_sets{$varset}->{user};
      print $file "$varset=$var_sets{$varset}->{text}\n";
   }
}

# load_config_group_by {{{3
sub load_config_group_by {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $tbl , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $tbl && exists $tbl_meta{$tbl};
      my @parts = unique(grep { exists($tbl_meta{$tbl}->{cols}->{$_}) } split(/\s+/, $rest));
      $tbl_meta{$tbl}->{group_by} = [ @parts ];
      $tbl_meta{$tbl}->{cust}->{group_by} = 1;
   }
}

# save_config_group_by {{{3
sub save_config_group_by {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      next if $tbl_meta{$tbl}->{temp};
      next unless $tbl_meta{$tbl}->{cust}->{group_by};
      my $aref = $tbl_meta{$tbl}->{group_by};
      print $file "$tbl=", join(' ', @$aref), "\n";
   }
}

# load_config_filters {{{3
sub load_config_filters {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key, $rest ) = $line =~ m/^(.+?)=(.*)$/;
      next unless $key && $rest;

      my %parts = $rest =~ m/(\w+)='((?:(?!(?<!\\)').)*)'/g; # Properties are single-quoted
      next unless $parts{text} && $parts{tbls};

      foreach my $prop ( keys %parts ) {
         # Un-escape escaping
         $parts{$prop} =~ s/\\\\/\\/g;
         $parts{$prop} =~ s/\\'/'/g;
      }

      my ( $sub, $err ) = compile_filter($parts{text});
      my @tbls = unique(split(/\s+/, $parts{tbls}));
      @tbls = grep { exists $tbl_meta{$_} } @tbls;
      $filters{$key} = {
         func => $sub,
         text => $parts{text},
         user => 1,
         name => $key,
         note => 'User-defined filter',
         tbls => \@tbls,
      }
   }
}

# save_config_filters {{{3
sub save_config_filters {
   my $file = shift;
   foreach my $key ( sort keys %filters ) {
      next if !$filters{$key}->{user} || $filters{$key}->{quick};
      my $text = $filters{$key}->{text};
      $text =~ s/([\\'])/\\$1/g;
      my $tbls = join(" ", @{$filters{$key}->{tbls}});
      print $file "$key=text='$text' tbls='$tbls'\n";
   }
}

# load_config_visible_tables {{{3
sub load_config_visible_tables {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $mode, $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $mode && exists $modes{$mode};
      $modes{$mode}->{visible_tables} =
         [ unique(grep { $_ && exists $tbl_meta{$_} } split(/\s+/, $rest)) ];
      $modes{$mode}->{cust}->{visible_tables} = 1;
   }
}

# save_config_visible_tables {{{3
sub save_config_visible_tables {
   my $file = shift;
   foreach my $mode ( sort keys %modes ) {
      next unless $modes{$mode}->{cust}->{visible_tables};
      my $tables = $modes{$mode}->{visible_tables};
      print $file "$mode=", join(' ', @$tables), "\n";
   }
}

# load_config_sort_cols {{{3
sub load_config_sort_cols {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $key && exists $tbl_meta{$key};
      $tbl_meta{$key}->{sort_cols} = $rest;
      $tbl_meta{$key}->{cust}->{sort_cols} = 1;
      $tbl_meta{$key}->{sort_func} = make_sort_func($tbl_meta{$key});
   }
}

# save_config_sort_cols {{{3
sub save_config_sort_cols {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      next unless $tbl_meta{$tbl}->{cust}->{sort_cols};
      my $col = $tbl_meta{$tbl}->{sort_cols};
      print $file "$tbl=$col\n";
   }
}

# load_config_active_filters {{{3
sub load_config_active_filters {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $tbl , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $tbl && exists $tbl_meta{$tbl};
      my @parts = unique(grep { exists($filters{$_}) } split(/\s+/, $rest));
      @parts = grep { grep { $tbl eq $_ } @{$filters{$_}->{tbls}} } @parts;
      $tbl_meta{$tbl}->{filters} = [ @parts ];
      $tbl_meta{$tbl}->{cust}->{filters} = 1;
   }
}

# save_config_active_filters {{{3
sub save_config_active_filters {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      next if $tbl_meta{$tbl}->{temp};
      next unless $tbl_meta{$tbl}->{cust}->{filters};
      my $aref = $tbl_meta{$tbl}->{filters};
      print $file "$tbl=", join(' ', @$aref), "\n";
   }
}

# load_config_active_columns {{{3
sub load_config_active_columns {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $key && exists $tbl_meta{$key};
      my @parts = grep { exists($tbl_meta{$key}->{cols}->{$_}) } unique split(/ /, $rest);
      $tbl_meta{$key}->{visible} = [ @parts ];
      $tbl_meta{$key}->{cust}->{visible} = 1;
   }
}

# save_config_active_columns {{{3
sub save_config_active_columns {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      next unless $tbl_meta{$tbl}->{cust}->{visible};
      my $aref = $tbl_meta{$tbl}->{visible};
      print $file "$tbl=", join(' ', @$aref), "\n";
   }
}

# save_config_tbl_meta {{{3
sub save_config_tbl_meta {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      foreach my $col ( keys %{$tbl_meta{$tbl}->{cols}} ) {
         my $meta = $tbl_meta{$tbl}->{cols}->{$col};
         next unless $meta->{user};
         print $file "$col=", join(
            " ",
            map {
               # Some properties (trans) are arrays, others scalars
               my $val = ref($meta->{$_}) ? join(',', @{$meta->{$_}}) : $meta->{$_};
               $val =~ s/([\\'])/\\$1/g;  # Escape backslashes and single quotes
               "$_='$val'";               # Enclose in single quotes
            }
            grep { $_ ne 'func' }
            keys %$meta
         ), "\n";
      }
   }
}

# save_config_config {{{3
sub save_config_config {
   my $file = shift;
   foreach my $key ( sort keys %config ) {
      eval {
      if ( $key ne 'password' || $config{savepass}->{val} ) {
         print $file "# $config{$key}->{note}\n"
            or die "Cannot print to file: $OS_ERROR";
         my $val = $config{$key}->{val};
         $val = '' unless defined($val);
         if ( ref( $val ) eq 'ARRAY' ) {
            print $file "$key="
               . join( " ", @$val ) . "\n"
               or die "Cannot print to file: $OS_ERROR";
         }
         elsif ( ref( $val ) eq 'HASH' ) {
            print $file "$key="
               . join( " ",
                  map { "$_:$val->{$_}" } keys %$val
               ) . "\n";
         }
         else {
            print $file "$key=$val\n";
         }
      }
      };
      if ( $EVAL_ERROR ) { print "$EVAL_ERROR in $key"; };
   }

}

# load_config_config {{{3
sub load_config_config {
   my ( $file ) = @_;

   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $name, $val ) = $line =~ m/^(.+?)=(.*)$/;
      next unless defined $name && defined $val;

      # Validate the incoming values...
      if ( $name && exists( $config{$name} ) ) {
         if ( !$config{$name}->{pat} || $val =~ m/$config{$name}->{pat}/ ) {
            $config{$name}->{val} = $val;
            $config{$name}->{read} = 1;
         }
      }
   }
}

# load_config_tbl_meta {{{3
sub load_config_tbl_meta {
   my ( $file ) = @_;

   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      # Each tbl_meta section has all the properties defined in %col_props.
      my ( $col , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $col;
      my %parts = $rest =~ m/(\w+)='((?:(?!(?<!\\)').)*)'/g; # Properties are single-quoted

      # Each section read from the config file has one extra property: which table it
      # goes in.
      my $tbl  = $parts{tbl}     or die "There's no table for tbl_meta $col";
      my $meta = $tbl_meta{$tbl} or die "There's no table in tbl_meta named $tbl";

      # The section is user-defined by definition (if that makes sense).
      $parts{user} = 1;

      # The column may already exist in the table, in which case this is just a
      # customization.
      $meta->{cols}->{$col} ||= {};

      foreach my $prop ( keys %col_props ) {
         if ( !defined($parts{$prop}) ) {
            die "Undefined property $prop for column $col in table $tbl";
         }

         # Un-escape escaping
         $parts{$prop} =~ s/\\\\/\\/g;
         $parts{$prop} =~ s/\\'/'/g;

         if ( ref $col_props{$prop} ) {
            if ( $prop eq 'trans' ) {
               $meta->{cols}->{$col}->{trans}
                  = [ unique(grep { exists $trans_funcs{$_} } split(',', $parts{$prop})) ];
            }
            else {
               $meta->{cols}->{$col}->{$prop} = [ split(',', $parts{$prop}) ];
            }
         }
         else {
            $meta->{cols}->{$col}->{$prop} = $parts{$prop};
         }
      }

   }
}

# save_config {{{3
sub save_config {
   print "\n";
   return if $config{readonly}->{val};
   # return if no config file was loaded and -w wasn't specified
   if (not $conf_file) {
      if (not $opts{w}) {
         return;
      }
      else {
         # if no config was loaded but -w was specified,
         # write to $default_home_conf
         $conf_file = $default_home_conf;
      }
   }
   elsif ($conf_file and $opts{w}) {
     print "Loaded config file on start-up, so ignoring -w (see --help)\n"
   }
   
   my $dirname  = dirname($conf_file);

   # if directories don't exist, create them.  This could cause errors
   # or warnings if a central config doesn't have readonly=1, but being
   # flexible requires giving the user enough rope to hang themselves with.
   if ( ! -d $dirname ) {
      mkdir $dirname
         or die "Can't create directory '$dirname': $OS_ERROR";
   }
   if ( ! -d "$dirname/plugins" ) {
      mkdir "$dirname/plugins"
         or warn "Can't create directory '$dirname/plugins': $OS_ERROR\n";
   }

   # Save to a temp file first, so a crash doesn't destroy the main config file
   my $tmpfile = File::Temp->new( TEMPLATE => 'innotopXXXXX', DIR => $dirname, SUFFIX => '.conf.tmp');
   open my $file, "+>", $tmpfile
      or die("Can't write to $tmpfile: $OS_ERROR");
   print $file "version=$VERSION\n";

   foreach my $section ( @ordered_config_file_sections ) {
      die "No such config file section $section" unless $config_file_sections{$section};
      print $file "\n[$section]\n\n";
      $config_file_sections{$section}->{writer}->($file);
      print $file "\n[/$section]\n";
   }

   # Now clobber the main config file with the temp.
   close $file or die("Can't close $tmpfile: $OS_ERROR");
   rename($tmpfile, $conf_file) or die("Can't rename $tmpfile to $conf_file: $OS_ERROR");
}

# load_config_connections {{{3
sub load_config_connections {
   return if $opts{u} or $opts{p} or $opts{h} or $opts{P}; # don't load connections if DSN or user/pass options used
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $key;
      my %parts = $rest =~ m/(\S+?)=(\S*)/g;
      my %conn  = map { $_ => $parts{$_} || '' } @conn_parts;
      $connections{$key} = \%conn;
   }
}

# save_config_connections {{{3
sub save_config_connections {
   my $file = shift;
   foreach my $conn ( sort keys %connections ) {
      my $href = $connections{$conn};
      my @keys = $href->{savepass} ? @conn_parts : grep { $_ ne 'pass' } @conn_parts;
      print $file "$conn=", join(' ', map { "$_=$href->{$_}" } grep { defined $href->{$_} } @keys), "\n";
   }
}

sub load_config_colors {
   my ( $file ) = @_;
   my %rule_set_for;

   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $tbl, $rule ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $tbl && $rule;
      next unless exists $tbl_meta{$tbl};
      my %parts = $rule =~ m/(\w+)='((?:(?!(?<!\\)').)*)'/g; # Properties are single-quoted
      next unless $parts{col} && exists $tbl_meta{$tbl}->{cols}->{$parts{col}};
      next unless $parts{op}  && exists $comp_ops{$parts{op}};
      next unless defined $parts{arg};
      next unless defined $parts{color};
      my @colors = unique(grep { exists $ansicolors{$_} } split(/\W+/, $parts{color}));
      next unless @colors;

      # Finally!  Enough validation...
      $rule_set_for{$tbl} ||= [];
      push @{$rule_set_for{$tbl}}, \%parts;
   }

   foreach my $tbl ( keys %rule_set_for ) {
      $tbl_meta{$tbl}->{colors} = $rule_set_for{$tbl};
      $tbl_meta{$tbl}->{color_func} = make_color_func($tbl_meta{$tbl});
      $tbl_meta{$tbl}->{cust}->{colors} = 1;
   }
}

# save_config_colors {{{3
sub save_config_colors {
   my $file = shift;
   foreach my $tbl ( sort keys %tbl_meta ) {
      my $meta = $tbl_meta{$tbl};
      next unless $meta->{cust}->{colors};
      foreach my $rule ( @{$meta->{colors}} ) {
         print $file "$tbl=", join(
            ' ',
            map {
               my $val = $rule->{$_};
               $val =~ s/([\\'])/\\$1/g;  # Escape backslashes and single quotes
               "$_='$val'";               # Enclose in single quotes
            }
            qw(col op arg color)
         ), "\n";
      }
   }
}

# load_config_active_connections {{{3
sub load_config_active_connections {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $rest ) = $line =~ m/^(.*?)=(.*)$/;
      next unless $key && exists $modes{$key};
      my @parts = grep { exists $connections{$_} } split(/ /, $rest);
      $modes{$key}->{connections} = [ @parts ] if exists $modes{$key};
   }
}

# save_config_active_connections {{{3
sub save_config_active_connections {
   my $file = shift;
   foreach my $mode ( sort keys %modes ) {
      my @connections = get_connections($mode);
      print $file "$mode=", join(' ', @connections), "\n";
   }
}

# load_config_stmt_sleep_times {{{3
sub load_config_stmt_sleep_times {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $val ) = split('=', $line);
      next unless $key && defined $val && $val =~ m/$num_regex/;
      $stmt_sleep_time_for{$key} = $val;
   }
}

# save_config_stmt_sleep_times {{{3
sub save_config_stmt_sleep_times {
   my $file = shift;
   foreach my $key ( sort keys %stmt_sleep_time_for ) {
      print $file "$key=$stmt_sleep_time_for{$key}\n";
   }
}

# load_config_mvs {{{3
sub load_config_mvs {
   my ( $file ) = @_;
   while ( my $line = <$file> ) {
      chomp $line;
      next if $line =~ m/^#/;
      last if $line =~ m/^\[/;

      my ( $key , $val ) = split('=', $line);
      next unless $key && defined $val && $val =~ m/$num_regex/;
      $mvs{$key} = $val;
   }
}

# save_config_mvs {{{3
sub save_config_mvs {
   my $file = shift;
   foreach my $key ( sort keys %mvs ) {
      print $file "$key=$mvs{$key}\n";
   }
}

# edit_configuration {{{3
sub edit_configuration {
   my $key = '';
   while ( $key ne 'q' ) {
      $clear_screen_sub->();
      my @display_lines = '';

      if ( $key && $cfg_editor_action{$key} ) {
         $cfg_editor_action{$key}->{func}->();
      }

      # Show help
      push @display_lines, create_caption('What configuration do you want to edit?',
      create_table2(
         [ sort keys %cfg_editor_action ],
         { map { $_ => $_ } keys %cfg_editor_action },
         { map { $_ => $cfg_editor_action{$_}->{note} } keys %cfg_editor_action },
         { sep => '  ' }));

      draw_screen(\@display_lines);
      $key = pause('');
   }
}

# edit_configuration_variables {{{3
sub edit_configuration_variables {
   $clear_screen_sub->();
   my $mode = $config{mode}->{val};

   my %config_choices
      = map  { $_ => $config{$_}->{note} || '' }
        # Only config values that are marked as applying to this mode.
        grep {
           my $key = $_;
           $config{$key}->{conf} &&
              ( $config{$key}->{conf} eq 'ALL'
              || grep { $mode eq $_ } @{$config{$key}->{conf}} )
        } keys %config;

   my $key = prompt_list(
      "Enter the name of the variable you wish to configure",
      '',
      sub{ return keys %config_choices },
      \%config_choices);

   if ( exists($config_choices{$key}) ) {
      get_config_interactive($key);
   }
}

# edit_color_rules {{{3
sub edit_color_rules {
   my ( $tbl ) = @_;
   $clear_screen_sub->();
   $tbl ||= choose_visible_table();
   if ( $tbl && exists($tbl_meta{$tbl}) ) {
      my $meta = $tbl_meta{$tbl};
      my @cols = ('', qw(col op arg color));
      my $info = { map { $_ => { hdr => $_, just => '-', } }  @cols };
      $info->{label}->{maxw} = 30;
      my $key;
      my $selected_rule;

      # This loop builds a tabular view of the rules.
      do {

         # Show help
         if ( $key && $key eq '?' ) {
            my @display_lines = '';
            push @display_lines, create_caption('Editor key mappings',
            create_table2(
               [ sort keys %color_editor_action ],
               { map { $_ => $_ } keys %color_editor_action },
               { map { $_ => $color_editor_action{$_}->{note} } keys %color_editor_action },
               { sep => '  ' }));
            draw_screen(\@display_lines);
            pause();
            $key = '';
         }
         else {

            # Do the action specified
            $selected_rule ||= 0;
            if ( $key && $color_editor_action{$key} ) {
               $selected_rule = $color_editor_action{$key}->{func}->($tbl, $selected_rule);
               $selected_rule ||= 0;
            }

            # Build the table of rules.  If the terminal has color, the selected rule
            # will be highlighted; otherwise a > at the left will indicate.
            my $data = $meta->{colors} || [];
            foreach my $i ( 0..@$data - 1  ) {
               $data->[$i]->{''} = $i == $selected_rule ? '>' : '';
            }
            my @display_lines = create_table(\@cols, $info, $data);

            # Highlight selected entry
            for my $i ( 0 .. $#display_lines ) {
               if ( $display_lines[$i] =~ m/^>/ ) {
                  $display_lines[$i] = [ $display_lines[$i], 'reverse' ];
               }
            }

            # Draw the screen and wait for a command.
            unshift @display_lines, '',
               "Editing color rules for $meta->{capt}.  Press ? for help, q to "
               . "quit.", '';
            draw_screen(\@display_lines);
            print "\n\n", word_wrap('Rules are applied in order from top to '
               . 'bottom.  The first matching rule wins and prevents the '
               . 'rest of the rules from being applied.');
            $key = pause('');
         }
      } while ( $key ne 'q' );
      $meta->{color_func} = make_color_func($meta);
   }
}

# add_quick_filter {{{3
sub add_quick_filter {
   my $tbl = choose_visible_table();
   if ( $tbl && exists($tbl_meta{$tbl}) ) {
      print "\n";
      my $response = prompt_list(
         "Enter column name and filter text",
         '',
         sub { return keys %{$tbl_meta{$tbl}->{cols}} },
         ()
      );
      my ( $col, $text ) = split(/\s+/, $response, 2);

      # You can't filter on a nonexistent column.  But if you filter on a pivoted
      # table, the columns are different, so on a pivoted table, allow filtering
      # on the 'name' column.
      # NOTE: if a table is pivoted and un-pivoted, this will likely cause crashes.
      # Currently not an issue since there's no way to toggle pivot/nopivot.
      return unless $col && $text &&
         (exists($tbl_meta{$tbl}->{cols}->{$col})
            || ($tbl_meta{$tbl}->{pivot} && $col eq 'name'));

      my ( $sub, $err ) = compile_filter( "defined \$set->{$col} && \$set->{$col} =~ m/$text/" );
      return if !$sub || $err;
      my $name = "quick_$tbl.$col";
      $filters{$name} = {
         func  => $sub,
         text  => $text,
         user  => 1,
         quick => 1,
         name  => $name,
         note  => 'Quick-filter',
         tbls  => [$tbl],
      };
      push @{$tbl_meta{$tbl}->{filters}}, $name;
   }
}

# clear_quick_filters {{{3
sub clear_quick_filters {
   my $tbl = choose_visible_table(
      # Only tables that have quick-filters
      sub {
         my ( $tbl ) = @_;
         return scalar grep { $filters{$_}->{quick} } @{ $tbl_meta{$tbl}->{filters} };
      }
   );
   if ( $tbl && exists($tbl_meta{$tbl}) ) {
      my @current = @{$tbl_meta{$tbl}->{filters}};
      @current = grep { !$filters{$_}->{quick} } @current;
      $tbl_meta{$tbl}->{filters} = \@current;
   }
}

sub edit_plugins {
   $clear_screen_sub->();

   my @cols = ('', qw(class desc active));
   my $info = { map { $_ => { hdr => $_, just => '-', } }  @cols };
   my @rows = map { $plugins{$_} } sort keys %plugins;
   my $key;
   my $selected;

   # This loop builds a tabular view of the plugins.
   do {

      # Show help
      if ( $key && $key eq '?' ) {
         my @display_lines = '';
         push @display_lines, create_caption('Editor key mappings',
         create_table2(
            [ sort keys %plugin_editor_action ],
            { map { $_ => $_ } keys %plugin_editor_action },
            { map { $_ => $plugin_editor_action{$_}->{note} } keys %plugin_editor_action },
            { sep => '  ' }));
         draw_screen(\@display_lines);
         pause();
         $key = '';
      }

      # Do the action specified
      else {
         $selected ||= 0;
         if ( $key && $plugin_editor_action{$key} ) {
            $selected = $plugin_editor_action{$key}->{func}->(\@rows, $selected);
            $selected ||= 0;
         }

         # Build the table of plugins.
         foreach my $row ( 0.. $#rows ) {
            $rows[$row]->{''} = $row eq $selected ? '>' : ' ';
         }
         my @display_lines = create_table(\@cols, $info, \@rows);

         # Highlight selected entry
         for my $i ( 0 .. $#display_lines ) {
            if ( $display_lines[$i] =~ m/^>/ ) {
               $display_lines[$i] = [ $display_lines[$i], 'reverse' ];
            }
         }

         # Draw the screen and wait for a command.
         unshift @display_lines, '',
            "Plugin Management.  Press ? for help, q to quit.", '';
         draw_screen(\@display_lines);
         $key = pause('');
      }
   } while ( $key ne 'q' );
}

# edit_table {{{3
sub edit_table {
   $clear_screen_sub->();
   my ( $tbl ) = @_;
   $tbl ||= choose_visible_table();
   if ( $tbl && exists($tbl_meta{$tbl}) ) {
      my $meta = $tbl_meta{$tbl};
      my @cols = ('', qw(name hdr label src));
      my $info = { map { $_ => { hdr => $_, just => '-', } }  @cols };
      $info->{label}->{maxw} = 30;
      my $key;
      my $selected_column;

      # This loop builds a tabular view of the tbl_meta's structure, showing each column
      # in the entry as a row.
      do {

         # Show help
         if ( $key && $key eq '?' ) {
            my @display_lines = '';
            push @display_lines, create_caption('Editor key mappings',
            create_table2(
               [ sort keys %tbl_editor_action ],
               { map { $_ => $_ } keys %tbl_editor_action },
               { map { $_ => $tbl_editor_action{$_}->{note} } keys %tbl_editor_action },
               { sep => '  ' }));
            draw_screen(\@display_lines);
            pause();
            $key = '';
         }
         else {

            # Do the action specified
            $selected_column ||= $meta->{visible}->[0];
            if ( $key && $tbl_editor_action{$key} ) {
               $selected_column = $tbl_editor_action{$key}->{func}->($tbl, $selected_column);
               $selected_column ||= $meta->{visible}->[0];
            }

            # Build the pivoted view of the table's meta-data.  If the terminal has color,
            # The selected row will be highlighted; otherwise a > at the left will indicate.
            my $data = [];
            foreach my $row ( @{$meta->{visible}} ) {
               my %hash;
               @hash{ @cols } = @{$meta->{cols}->{$row}}{@cols};
               $hash{src}  = '' if ref $hash{src};
               $hash{name} = $row;
               $hash{''}   = $row eq $selected_column ? '>' : ' ';
               push @$data, \%hash;
            }
            my @display_lines = create_table(\@cols, $info, $data);

            # Highlight selected entry
            for my $i ( 0 .. $#display_lines ) {
               if ( $display_lines[$i] =~ m/^>/ ) {
                  $display_lines[$i] = [ $display_lines[$i], 'reverse' ];
               }
            }

            # Draw the screen and wait for a command.
            unshift @display_lines, '',
               "Editing table definition for $meta->{capt}.  Press ? for help, q to quit.", '';
            draw_screen(\@display_lines, { clear => 1 });
            $key = pause('');
         }
      } while ( $key ne 'q' );
   }
}

# choose_mode_tables {{{3
# Choose which table(s), and in what order, to display in a given mode.
sub choose_mode_tables {
   my $mode = $config{mode}->{val};
   my @tbls = @{$modes{$mode}->{visible_tables}};
   my $new  = prompt_list(
      "Choose tables to display",
      join(' ', @tbls),
      sub { return @{$modes{$mode}->{tables}} },
      { map { $_ => $tbl_meta{$_}->{capt} } @{$modes{$mode}->{tables}} }
   );
   $modes{$mode}->{visible_tables} =
      [ unique(grep { $_ && exists $tbl_meta{$_} } split(/\s+/, $new)) ];
   $modes{$mode}->{cust}->{visible_tables} = 1;
}

# choose_visible_table {{{3
sub choose_visible_table {
   my ( $grep_cond ) = @_;
   my $mode = $config{mode}->{val};
   my @tbls
      = grep { $grep_cond ? $grep_cond->($_) : 1 }
        @{$modes{$mode}->{visible_tables}};
   my $tbl = $tbls[0];
   if ( @tbls > 1 ) {
      $tbl = prompt_list(
         "Choose a table",
         '',
         sub { return @tbls },
         { map { $_ => $tbl_meta{$_}->{capt} } @tbls }
      );
   }
   return $tbl;
}

sub toggle_aggregate {
   my ( $tbl ) = @_;
   $tbl ||= choose_visible_table();
   return unless $tbl && exists $tbl_meta{$tbl};
   my $meta = $tbl_meta{$tbl};
   $meta->{aggregate} ^= 1;
}

sub choose_filters {
   my ( $tbl ) = @_;
   $tbl ||= choose_visible_table();
   return unless $tbl && exists $tbl_meta{$tbl};
   my $meta = $tbl_meta{$tbl};
   $clear_screen_sub->();

   print "Choose filters for $meta->{capt}:\n";

   my $ini = join(' ', @{$meta->{filters}});
   my $val = prompt_list(
      'Choose filters',
      $ini,
      sub { return keys %filters },
      {
         map  { $_ => $filters{$_}->{note} }
         grep { grep { $tbl eq $_ } @{$filters{$_}->{tbls}} }
         keys %filters
      }
   );

   my @choices = unique(split(/\s+/, $val));
   foreach my $new ( grep { !exists($filters{$_}) } @choices ) {
      my $answer = prompt("There is no filter called '$new'.  Create it?", undef, 'y');
      if ( $answer eq 'y' ) {
         create_new_filter($new, $tbl);
      }
   }
   @choices = grep { exists $filters{$_} } @choices;
   @choices = grep { grep { $tbl eq $_ } @{$filters{$_}->{tbls}} } @choices;
   $meta->{filters} = [ @choices ];
   $meta->{cust}->{filters} = 1;
}

sub choose_group_cols {
   my ( $tbl ) = @_;
   $tbl ||= choose_visible_table();
   return unless $tbl && exists $tbl_meta{$tbl};
   $clear_screen_sub->();
   my $meta = $tbl_meta{$tbl};
   my $curr = join(', ', @{$meta->{group_by}});
   my $val = prompt_list(
      'Group-by columns',
      $curr,
      sub { return keys %{$meta->{cols}} },
      { map { $_ => $meta->{cols}->{$_}->{label} } keys %{$meta->{cols}} });
   if ( $curr ne $val ) {
      $meta->{group_by} = [ grep { exists $meta->{cols}->{$_} } $val =~ m/(\w+)/g ];
      $meta->{cust}->{group_by} = 1;
   }
}

sub choose_sort_cols {
   my ( $tbl ) = @_;
   $tbl ||= choose_visible_table();
   return unless $tbl && exists $tbl_meta{$tbl};
   $clear_screen_sub->();
   my $meta = $tbl_meta{$tbl};

   my ( $cols, $hints );
   if ( $meta->{pivot} ) {
      $cols  = sub { qw(name set_0) };
      $hints = { name => 'name', set_0 => 'set_0' };
   }
   else {
      $cols  = sub { return keys %{$meta->{cols}} };
      $hints = { map { $_ => $meta->{cols}->{$_}->{label} } keys %{$meta->{cols}} };
   }

   my $val = prompt_list(
      'Sort columns (reverse sort with -col)',
      $meta->{sort_cols},
      $cols,
      $hints );
   if ( $meta->{sort_cols} ne $val ) {
      $meta->{sort_cols} = $val;
      $meta->{cust}->{sort_cols} = 1;
      $tbl_meta{$tbl}->{sort_func} = make_sort_func($tbl_meta{$tbl});
   }
}

# create_new_filter {{{3
sub create_new_filter {
   my ( $filter, $tbl ) = @_;
   $clear_screen_sub->();

   if ( !$filter || $filter =~ m/\W/ ) {
      print word_wrap("Choose a name for the filter.  This name is not displayed, and is only used "
            . "for internal reference.  It can only contain lowercase letters, numbers, and underscores.");
      print "\n\n";
      do {
         $filter = prompt("Enter filter name");
      } while ( !$filter || $filter =~ m/\W/ );
   }

   my $completion = sub { keys %{$tbl_meta{$tbl}->{cols}} };
   my ( $err, $sub, $body );
   do {
      $clear_screen_sub->();
      print word_wrap("A filter is a Perl subroutine that accepts a hashref of columns "
         . "called \$set, and returns a true value if the filter accepts the row.  Example:\n"
         . "   \$set->{active_secs} > 5\n"
         . "will only allow rows if their active_secs column is greater than 5.");
      print "\n\n";
      if ( $err ) {
         print "There's an error in your filter expression: $err\n\n";
      }
      $body = prompt("Enter subroutine body", undef, undef, $completion);
      ( $sub, $err ) = compile_filter($body);
   } while ( $err );

   $filters{$filter} = {
      func => $sub,
      text => $body,
      user => 1,
      name => $filter,
      note => 'User-defined filter',
      tbls => [$tbl],
   };
}

# get_config_interactive {{{3
sub get_config_interactive {
   my $key = shift;
   $clear_screen_sub->();

   # Print help first.
   print "Enter a new value for '$key' ($config{$key}->{note}).\n";

   my $current = ref($config{$key}->{val}) ? join(" ", @{$config{$key}->{val}}) : $config{$key}->{val};

   my $new_value = prompt('Enter a value', $config{$key}->{pat}, $current);
   $config{$key}->{val} = $new_value;
}

sub edit_current_var_set {
   my $mode = $config{mode}->{val};
   my $name = $config{"${mode}_set"}->{val};
   my $variables = $var_sets{$name}->{text};

   my $new = $variables;
   do {
      $clear_screen_sub->();
      $new = prompt("Enter variables for $name", undef, $variables);
   } until ( $new );

   if ( $new ne $variables ) {
      @{$var_sets{$name}}{qw(text user)} = ( $new, 1);
   }
}


sub choose_var_set {
   my ( $key ) = @_;
   $clear_screen_sub->();

   my $new_value = prompt_list(
      'Choose a set of values to display, or enter the name of a new one',
      $config{$key}->{val},
      sub { return keys %var_sets },
      { map { $_ => $var_sets{$_}->{text} } keys %var_sets });

   if ( !exists $var_sets{$new_value} ) {
      add_new_var_set($new_value);
   }

   $config{$key}->{val} = $new_value if exists $var_sets{$new_value};
}

sub switch_var_set {
   my ( $cfg_var, $dir ) = @_;
   my @var_sets = sort keys %var_sets;
   my $cur      = $config{$cfg_var}->{val};
   my $pos      = grep { $_ lt $cur } @var_sets;
   my $newpos   = ($pos + $dir) % @var_sets;
   $config{$cfg_var}->{val} = $var_sets[$newpos];
   $clear_screen_sub->();
}

# Online configuration and prompting functions {{{2

# edit_stmt_sleep_times {{{3
sub edit_stmt_sleep_times {
   $clear_screen_sub->();
   my $stmt = prompt_list('Specify a statement', '', sub { return sort keys %stmt_maker_for });
   return unless $stmt && exists $stmt_maker_for{$stmt};
   $clear_screen_sub->();
   my $curr_val = $stmt_sleep_time_for{$stmt} || 0;
   my $new_val  = prompt('Specify a sleep delay after calling this SQL', $num_regex, $curr_val);
   if ( $new_val ) {
      $stmt_sleep_time_for{$stmt} = $new_val;
   }
   else {
      delete $stmt_sleep_time_for{$stmt};
   }
}

# edit_server_groups {{{3
# Choose which server connections are in a server group.  First choose a group,
# then choose which connections are in it.
sub edit_server_groups {
   $clear_screen_sub->();
   my $mode  = $config{mode}->{val};
   my $group = $modes{$mode}->{server_group};
   my %curr  = %server_groups;
   my $new   = choose_or_create_server_group($group, 'to edit');
   $clear_screen_sub->();
   if ( exists $curr{$new} ) {
      # Don't do this step if the user just created a new server group,
      # because part of that process was to choose connections.
      my $cxns  = join(' ', @{$server_groups{$new}});
      my @conns = choose_or_create_connection($cxns, 'for this group');
      $server_groups{$new} = \@conns;
   }
}

# choose_server_groups {{{3
sub choose_server_groups {
   $clear_screen_sub->();
   my $mode  = $config{mode}->{val};
   my $group = $modes{$mode}->{server_group};
   my $new   = choose_or_create_server_group($group, 'for this mode');
   $modes{$mode}->{server_group} = $new if exists $server_groups{$new};
}

sub choose_or_create_server_group {
   my ( $group, $prompt ) = @_;
   my $new   = '';

   my @available = sort keys %server_groups;

   if ( @available ) {
      print "You can enter the name of a new group to create it.\n";

      $new = prompt_list(
         "Choose a server group $prompt",
         $group,
         sub { return @available },
         { map { $_ => join(' ', @{$server_groups{$_}}) } @available });

      $new =~ s/\s.*//;

      if ( !exists $server_groups{$new} ) {
         my $answer = prompt("There is no server group called '$new'.  Create it?", undef, "y");
         if ( $answer eq 'y' ) {
            add_new_server_group($new);
         }
      }
   }
   else {
      $new = add_new_server_group();
   }
   return $new;
}

sub choose_or_create_connection {
   my ( $cxns, $prompt ) = @_;
   print "You can enter the name of a new connection to create it.\n";

   my @available = sort keys %connections;
   my $new_cxns = prompt_list(
      "Choose connections $prompt",
      $cxns,
      sub { return @available },
      { map { $_ => $connections{$_}->{dsn} } @available });

   my @new = unique(grep { !exists $connections{$_} } split(/\s+/, $new_cxns));
   foreach my $new ( @new ) {
      my $answer = prompt("There is no connection called '$new'.  Create it?", undef, "y");
      if ( $answer eq 'y' ) {
         add_new_dsn($new);
      }
   }

   return unique(grep { exists $connections{$_} } split(/\s+/, $new_cxns));
}

# choose_servers {{{3
sub choose_servers {
   $clear_screen_sub->();
   my $mode = $config{mode}->{val};
   my $cxns = join(' ', get_connections());
   my @chosen = choose_or_create_connection($cxns, 'for this mode');
   $modes{$mode}->{connections} = \@chosen;
   $modes{$mode}->{server_group} = ''; # Clear this because it overrides {connections}
}

# display_license {{{3
sub display_license {
   $clear_screen_sub->();

   print $innotop_license;

   pause();
}

# Data-retrieval functions {{{2
# get_status_info {{{3
# Get SHOW STATUS and SHOW VARIABLES together.
sub get_status_info {
   my @cxns = @_;
   if ( !$info_gotten{status}++ ) {
      foreach my $cxn ( @cxns ) {
         $vars{$cxn}->{$clock} ||= {};
         my $vars = $vars{$cxn}->{$clock};

         my $sth = do_stmt($cxn, 'SHOW_STATUS') or next;
         my $res = $sth->fetchall_arrayref();
         map { $vars->{$_->[0]} = $_->[1] || 0 } @$res;

         # Calculate hi-res uptime and add cxn to the hash.  This duplicates get_driver_status,
         # but it's most important to have consistency.
         $vars->{Uptime_hires} ||= get_uptime($cxn);
         $vars->{cxn} = $cxn;

         # Add SHOW VARIABLES to the hash
         $sth = do_stmt($cxn, 'SHOW_VARIABLES') or next;
         $res = $sth->fetchall_arrayref();
         map { $vars->{$_->[0]} = $_->[1] || 0 } @$res;
      }
   }
}

# Chooses a thread for explaining, killing, etc...
# First arg is a func that can be called in grep.
sub choose_thread {
   my ( $grep_cond, $prompt ) = @_;

   # Narrow the list to queries that can be explained.
   my %thread_for = map {
      # Eliminate innotop's own threads.
      $_ => $dbhs{$_}->{dbh} ? $dbhs{$_}->{dbh}->{mysql_thread_id} : 0
   } keys %connections;

   my @candidates = grep {
      $_->{id} != $thread_for{$_->{cxn}} && $grep_cond->($_)
   } @current_queries;
   return unless @candidates;

   # Find out which server.
   my @cxns = unique map { $_->{cxn} } @candidates;
   my ( $cxn ) = select_cxn('On which server', @cxns);
   return unless $cxn && exists($connections{$cxn});

   # Re-filter the list of candidates to only those on this server
   @candidates = grep { $_->{cxn} eq $cxn } @candidates;

   # Find out which thread to do.
   my $info;
   if ( @candidates > 1 ) {

      # Sort longest-active first, then longest-idle.
      my $sort_func = sub {
         my ( $a, $b ) = @_;
         return  $a->{query} && !$b->{query} ? 1
               : $b->{query} && !$a->{query} ? -1
               : ($a->{time} || 0) <=> ($b->{time} || 0);
      };
      my @threads = map { $_->{id} } reverse sort { $sort_func->($a, $b) } @candidates;

      print "\n";
      my $thread = prompt_list($prompt,
         $threads[0],
         sub { return @threads });
      return unless $thread && $thread =~ m/$int_regex/;

      # Find the info hash of that query on that server.
      ( $info ) = grep { $thread == $_->{id} } @candidates;
   }
   else {
      $info = $candidates[0];
   }
   return $info;
}

# analyze_query {{{3
# Allows the user to show fulltext, explain, show optimized...
sub analyze_query {
   my ( $action ) = @_;

   my $info = choose_thread(
      sub { $_[0]->{query} },
      'Select a thread to analyze',
   );
   return unless $info;

   my %actions = (
      e => \&display_explain,
      f => \&show_full_query,
      o => \&show_optimized_query,
   );
   do {
      $actions{$action}->($info);
      print "\n";
      $action = pause('Press e to explain, f for full query, o for optimized query');
   } while ( exists($actions{$action}) );
}

# inc {{{3
# Returns the difference between two sets of variables/status/innodb stuff.
sub inc {
   my ( $offset, $cxn ) = @_;
   my $vars = $vars{$cxn};
   if ( $offset < 0 ) {
      return $vars->{$clock};
   }
   elsif ( exists $vars{$clock - $offset} && !exists $vars->{$clock - $offset - 1} ) {
      return $vars->{$clock - $offset};
   }
   my $cur = $vars->{$clock - $offset};
   my $pre = $vars->{$clock - $offset - 1};
   return {
      # Numeric variables get subtracted, non-numeric get passed straight through.
      map  {
         $_ =>
            ( (defined $cur->{$_} && $cur->{$_} =~ m/$num_regex/)
            ?  $cur->{$_} - ($pre->{$_} || 0)
            :  $cur->{$_} )
      } keys %{$cur}
   };
}

# extract_values {{{3
# Arguments are a set of values (which may be incremental, derived from
# current and previous), current, and previous values.
# TODO: there are a few places that don't remember prev set so can't pass it.
sub extract_values {
   my ( $set, $cur, $pre, $tbl ) = @_;

   # Hook in event listeners
   foreach my $listener ( @{$event_listener_for{extract_values}} ) {
      $listener->extract_values($set, $cur, $pre, $tbl);
   }

   my $result = {};
   my $meta   = $tbl_meta{$tbl};
   my $cols   = $meta->{cols};
   foreach my $key ( keys %$cols ) {
      my $info = $cols->{$key}
         or die "Column '$key' doesn't exist in $tbl";
      die "No func defined for '$key' in $tbl"
         unless $info->{func};
      eval {
         $result->{$key} = $info->{func}->($set, $cur, $pre)
      };
      if ( $EVAL_ERROR ) {
         if ( $config{debug}->{val} ) {
            die $EVAL_ERROR;
         }
         $result->{$key} = $info->{num} ? 0 : '';
      }
   }
   return $result;
}

# get_full_processlist {{{3
sub get_full_processlist {
   my @cxns = @_;
   my @result;
   foreach my $cxn ( @cxns ) {
      my $stmt = do_stmt($cxn, 'PROCESSLIST') or next;
      my $arr  = $stmt->fetchall_arrayref({});
      push @result, map { $_->{cxn} = $cxn; $_ } @$arr;
   }
   return @result;
}

# get_open_tables {{{3
sub get_open_tables {
   my @cxns = @_;
   my @result;
   foreach my $cxn ( @cxns ) {
      my $stmt = do_stmt($cxn, 'OPEN_TABLES') or next;
      my $arr  = $stmt->fetchall_arrayref({});
      push @result, map { $_->{cxn} = $cxn; $_ } @$arr;
   }
   return @result;
}

# get_innodb_status {{{3
sub get_innodb_status {
   my ( $cxns, $addl_sections ) = @_;
   if ( !$config{skip_innodb}->{val} && !$info_gotten{innodb_status}++ ) {

      # Determine which sections need to be parsed
      my %sections_required =
         map  { $tbl_meta{$_}->{innodb} => 1 }
         grep { $_ && $tbl_meta{$_}->{innodb} }
         get_visible_tables();

      # Add in any other sections the caller requested.
      foreach my $sec ( @$addl_sections ) {
         $sections_required{$sec} = 1;
      }

      foreach my $cxn ( @$cxns ) {
         my $innodb_status_text;

         if ( $file ) { # Try to fetch status text from the file.
            my @stat = stat($file);

            # Initialize the file.
            if ( !$file_mtime ) {
               # Initialize to 130k from the end of the file (because the limit
               # on the size of innodb status is 128k even with Google's patches)
               # and try to grab the last status from the file.
               sysseek($file, (-128 * 1_024), 2);
            }

            # Read from the file.
            my $buffer;
            if ( !$file_mtime || $file_mtime != $stat[9] ) {
               $file_data = '';
               while ( sysread($file, $buffer, 4096) ) {
                  $file_data .= $buffer;
               }
               $file_mtime = $stat[9];
            }

            # Delete everything but the last InnoDB status text from the file.
            $file_data =~ s/\A.*(?=^=====================================\n...... ........ INNODB MONITOR OUTPUT)//ms;
            $innodb_status_text = $file_data;
         }

         else {
            my $stmt = do_stmt($cxn, 'INNODB_STATUS') or next;
            $innodb_status_text = $stmt->fetchrow_hashref()->{status};
         }

         next unless $innodb_status_text
            && substr($innodb_status_text, 0, 100) =~ m/INNODB MONITOR OUTPUT/;

         # Parse and merge into %vars storage
         my %innodb_status = (
            $innodb_parser->get_status_hash(
               $innodb_status_text,
               $config{debug}->{val},
               \%sections_required,
               0, # don't parse full lock information
            )
         );
         if ( !$innodb_status{IB_got_all} && $config{auto_wipe_dl}->{val} ) {
            clear_deadlock($cxn);
         }

         # Merge using a hash slice, which is the fastest way
         $vars{$cxn}->{$clock} ||= {};
         my $hash = $vars{$cxn}->{$clock};
         @{$hash}{ keys %innodb_status } = values %innodb_status;
         $hash->{cxn} = $cxn;
         $hash->{Uptime_hires} ||= get_uptime($cxn);
      }
   }
}

# clear_deadlock {{{3
sub clear_deadlock {
   my ( $cxn ) = @_;
   return if $clearing_deadlocks++;
   my $tbl = $connections{$cxn}->{dl_table};
   return unless $tbl;

   eval {
      # Set up the table for creating a deadlock.
      my $engine = version_ge($dbhs{$cxn}->{dbh}, '4.1.2') ? 'engine' : 'type';
      return unless do_query($cxn, "drop table if exists $tbl");
      return unless do_query($cxn, "create table $tbl(a int) $engine=innodb");
      return unless do_query($cxn, "delete from $tbl");
      return unless do_query($cxn, "insert into $tbl(a) values(0), (1)");
      return unless do_query($cxn, "commit"); # Or the children will block against the parent

      # Fork off two children to deadlock against each other.
      my %children;
      foreach my $child ( 0..1 ) {
         my $pid = fork();
         if ( defined($pid) && $pid == 0 ) { # I am a child
            deadlock_thread( $child, $tbl, $cxn );
         }
         elsif ( !defined($pid) ) {
            die("Unable to fork for clearing deadlocks!\n");
         }
         # I already exited if I'm a child, so I'm the parent.
         $children{$child} = $pid;
      }

      # Wait for the children to exit.
      foreach my $child ( keys %children ) {
         my $pid = waitpid($children{$child}, 0);
      }

      # Clean up.
      do_query($cxn, "drop table $tbl");
   };
   if ( $EVAL_ERROR ) {
      print $EVAL_ERROR;
      pause();
   }

   $clearing_deadlocks = 0;
}

sub get_master_logs {
   my @cxns = @_;
   my @result;
   if ( !$info_gotten{master_logs}++ ) {
      foreach my $cxn ( @cxns ) {
         my $stmt = do_stmt($cxn, 'SHOW_MASTER_LOGS') or next;
         push @result, @{$stmt->fetchall_arrayref({})};
      }
   }
   return @result;
}

# get_master_slave_status {{{3
sub get_master_slave_status {
   my @cxns = @_;
   if ( !$info_gotten{replication_status}++ ) {
      foreach my $cxn ( @cxns ) {
         $vars{$cxn}->{$clock} ||= {};
         my $vars = $vars{$cxn}->{$clock};
         $vars->{cxn} = $cxn;

         my $stmt = do_stmt($cxn, 'SHOW_MASTER_STATUS') or next;
         my $res = $stmt->fetchall_arrayref({})->[0];
         @{$vars}{ keys %$res } = values %$res;
         $stmt = do_stmt($cxn, 'SHOW_SLAVE_STATUS') or next;
         $res = $stmt->fetchall_arrayref({})->[0];
         @{$vars}{ keys %$res } = values %$res;
         $vars->{Uptime_hires} ||= get_uptime($cxn);
      }
   }
}

sub is_func {
   my ( $word ) = @_;
   return defined(&$word)
      || eval "my \$x= sub { $word  }; 1"
      || $EVAL_ERROR !~ m/^Bareword/;
}

# Documentation {{{1
# ############################################################################
# I put this last as per the Dog book.
# ############################################################################
=pod

=head1 NAME

innotop - MySQL and InnoDB transaction/status monitor.

=head1 SYNOPSIS

To monitor servers normally:

 innotop

To monitor InnoDB status information from a file:

 innotop /var/log/mysql/mysqld.err

To run innotop non-interactively in a pipe-and-filter configuration:

 innotop --count 5 -d 1 -n

To monitor a database on another system using a particular username and password:

 innotop -u <username> -p <password> -h <hostname>

=head1 DESCRIPTION

innotop monitors MySQL servers.  Each of its modes shows you a different aspect
of what's happening in the server.  For example, there's a mode for monitoring
replication, one for queries, and one for transactions.  innotop refreshes its
data periodically, so you see an updating view.

innotop has lots of features for power users, but you can start and run it with
virtually no configuration.  If you're just getting started, see
L<"QUICK-START">.  Press '?' at any time while running innotop for
context-sensitive help.

=head1 QUICK-START

To start innotop, open a terminal or command prompt.  If you have installed
innotop on your system, you should be able to just type "innotop" and press
Enter; otherwise, you will need to change to innotop's directory and type "perl
innotop".

With no options specified, innotop will attempt to connect to a MySQL server on
localhost using mysql_read_default_group=client for other connection
parameters.  If you need to specify a different username and password, use the
-u and -p options, respectively.  To monitor a MySQL database on another
host, use the -h option.

After you've connected, innotop should show you something like the following:

 [RO] Query List (? for help) localhost, 01:11:19, 449.44 QPS, 14/7/163 con/run
 
 CXN        When   Load  QPS    Slow  QCacheHit  KCacheHit  BpsIn    BpsOut 
 localhost  Total  0.00  1.07k   697      0.00%     98.17%  476.83k  242.83k

 CXN        Cmd    ID         User  Host      DB   Time   Query
 localhost  Query  766446598  test  10.0.0.1  foo  00:02  INSERT INTO table (


(This sample is truncated at the right so it will fit on a terminal when running
'man innotop')

If your server is busy, you'll see more output.  Notice the first line on the
screen, which tells you that readonly is set to true ([RO]), what mode you're
in and what server you're connected to.  You can change to other modes with
keystrokes; press 'T' to switch to a list of InnoDB transactions, for example.

Press the '?' key to see what keys are active in the current mode.  You can
press any of these keys and innotop will either take the requested action or
prompt you for more input.  If your system has Term::ReadLine support, you can
use TAB and other keys to auto-complete and edit input.

To quit innotop, press the 'q' key.

=head1 OPTIONS

innotop is mostly configured via its configuration file, but some of the
configuration options can come from the command line.  You can also specify a
file to monitor for InnoDB status output; see L<"MONITORING A FILE"> for more
details.

You can negate some options by prefixing the option name with --no.  For
example, --noinc (or --no-inc) negates L<"--inc">.

=over

=item --color

Enable or disable terminal coloring.  Corresponds to the L<"color"> config file
setting.

=item --config

Specifies a configuration file to read.  This option is non-sticky, that is to
say it does not persist to the configuration file itself.

=item --count

Refresh only the specified number of times (ticks) before exiting.  Each refresh
is a pause for L<"interval"> seconds, followed by requesting data from MySQL
connections and printing it to the terminal.

=item --delay

Specifies the amount of time to pause between ticks (refreshes).  Corresponds to
the configuration option L<"interval">.

=item --help

Print a summary of command-line usage and exit.

=item --host

Host to connect to.

=item --inc

Specifies whether innotop should display absolute numbers or relative numbers
(offsets from their previous values).  Corresponds to the configuration option
L<"status_inc">.

=item --mode

Specifies the mode in which innotop should start.  Corresponds to the
configuration option L<"mode">.

=item --nonint

Enable non-interactive operation.  See L<"NON-INTERACTIVE OPERATION"> for more.

=item --password

Password to use for connection.

=item --port

Port to use for connection.

=item --skipcentral

Don't read the central configuration file.

=item --user

User to use for connection.

=item --version

Output version information and exit.

=item --write

Sets the configuration option L<"readonly"> to 0, making innotop write the
running configuration to ~/.innotop/innotop.conf on exit, if no configuration
file was loaded at start-up.

=back

=head1 HOTKEYS

innotop is interactive, and you control it with key-presses.

=over

=item *

Uppercase keys switch between modes.

=item *

Lowercase keys initiate some action within the current mode.

=item *

Other keys do something special like change configuration or show the
innotop license.

=back

Press '?' at any time to see the currently active keys and what they do.

=head1 MODES

Each of innotop's modes retrieves and displays a particular type of data from
the servers you're monitoring.  You switch between modes with uppercase keys.
The following is a brief description of each mode, in alphabetical order.  To
switch to the mode, press the key listed in front of its heading in the
following list:

=over

=item B: InnoDB Buffers

This mode displays information about the InnoDB buffer pool, page statistics,
insert buffer, and adaptive hash index.  The data comes from SHOW INNODB STATUS.

This mode contains the L<"buffer_pool">, L<"page_statistics">,
L<"insert_buffers">, and L<"adaptive_hash_index"> tables by default.

=item C: Command Summary

This mode is similar to mytop's Command Summary mode.  It shows the
L<"cmd_summary"> table, which looks something like the following:

 Command Summary (? for help) localhost, 25+07:16:43, 2.45 QPS, 3 thd, 5.0.40
 _____________________ Command Summary _____________________
 Name                    Value    Pct     Last Incr  Pct    
 Select_scan             3244858  69.89%          2  100.00%
 Select_range            1354177  29.17%          0    0.00%
 Select_full_join          39479   0.85%          0    0.00%
 Select_full_range_join     4097   0.09%          0    0.00%
 Select_range_check            0   0.00%          0    0.00%

The command summary table is built by extracting variables from
L<"STATUS_VARIABLES">.  The variables must be numeric and must match the prefix
given by the L<"cmd_filter"> configuration variable.  The variables are then
sorted by value descending and compared to the last variable, as shown above.
The percentage columns are percentage of the total of all variables in the
table, so you can see the relative weight of the variables.

The example shows what you see if the prefix is "Select_".  The default
prefix is "Com_".  You can choose a prefix with the 's' key.

It's rather like running SHOW VARIABLES LIKE "prefix%" with memory and
nice formatting.

Values are aggregated across all servers.  The Pct columns are not correctly
aggregated across multiple servers.  This is a known limitation of the grouping
algorithm that may be fixed in the future.

=item D: InnoDB Deadlocks

This mode shows the transactions involved in the last InnoDB deadlock.  A second
table shows the locks each transaction held and waited for.  A deadlock is
caused by a cycle in the waits-for graph, so there should be two locks held and
one waited for unless the deadlock information is truncated.

InnoDB puts deadlock information before some other information in the SHOW
INNODB STATUS output.  If there are a lot of locks, the deadlock information can
grow very large, and there is a limit on the size of the SHOW INNODB
STATUS output.  A large deadlock can fill the entire output, or even be
truncated, and prevent you from seeing other information at all.  If you are
running innotop in another mode, for example T mode, and suddenly you don't see
anything, you might want to check and see if a deadlock has wiped out the data
you need.

If it has, you can create a small deadlock to replace the large one.  Use the
'w' key to 'wipe' the large deadlock with a small one.  This will not work
unless you have defined a deadlock table for the connection (see L<"SERVER
CONNECTIONS">).

You can also configure innotop to automatically detect when a large deadlock
needs to be replaced with a small one (see L<"auto_wipe_dl">).

This mode displays the L<"deadlock_transactions"> and L<"deadlock_locks"> tables
by default.

=item F: InnoDB Foreign Key Errors

This mode shows the last InnoDB foreign key error information, such as the
table where it happened, when and who and what query caused it, and so on.

InnoDB has a huge variety of foreign key error messages, and many of them are
just hard to parse.  innotop doesn't always do the best job here, but there's
so much code devoted to parsing this messy, unparseable output that innotop is
likely never to be perfect in this regard.  If innotop doesn't show you what
you need to see, just look at the status text directly.

This mode displays the L<"fk_error"> table by default.

=item I: InnoDB I/O Info

This mode shows InnoDB's I/O statistics, including the I/O threads, pending I/O,
file I/O miscellaneous, and log statistics.  It displays the L<"io_threads">,
L<"pending_io">, L<"file_io_misc">, and L<"log_statistics"> tables by default.

=item L: Locks

This mode shows information about current locks.  At the moment only InnoDB
locks are supported, and by default you'll only see locks for which transactions
are waiting.  This information comes from the TRANSACTIONS section of the InnoDB
status text.  If you have a very busy server, you may have frequent lock waits;
it helps to be able to see which tables and indexes are the "hot spot" for
locks.  If your server is running pretty well, this mode should show nothing.

You can configure MySQL and innotop to monitor not only locks for which a
transaction is waiting, but those currently held, too.  You can do this with the
InnoDB Lock Monitor (L<http://dev.mysql.com/doc/en/innodb-monitor.html>).  It's
not documented in the MySQL manual, but creating the lock monitor with the
following statement also affects the output of SHOW INNODB STATUS, which innotop
uses:

  CREATE TABLE innodb_lock_monitor(a int) ENGINE=INNODB;

This causes InnoDB to print its output to the MySQL file every 16 seconds or so,
as stated in the manual, but it also makes the normal SHOW INNODB STATUS output
include lock information, which innotop can parse and display (that's the
undocumented feature).

This means you can do what may have seemed impossible: to a limited extent
(InnoDB truncates some information in the output), you can see which transaction
holds the locks something else is waiting for.  You can also enable and disable
the InnoDB Lock Monitor with the key mappings in this mode.

This mode displays the L<"innodb_locks"> table by default.  Here's a sample of
the screen when one connection is waiting for locks another connection holds:

 _________________________________ InnoDB Locks __________________________
 CXN        ID  Type    Waiting  Wait   Active  Mode  DB    Table  Index
 localhost  12  RECORD        1  00:10   00:10  X     test  t1     PRIMARY
 localhost  12  TABLE         0  00:10   00:10  IX    test  t1
 localhost  12  RECORD        1  00:10   00:10  X     test  t1     PRIMARY
 localhost  11  TABLE         0  00:00   00:25  IX    test  t1
 localhost  11  RECORD        0  00:00   00:25  X     test  t1     PRIMARY

You can see the first connection, ID 12, is waiting for a lock on the PRIMARY
key on test.t1, and has been waiting for 10 seconds.  The second connection
isn't waiting, because the Waiting column is 0, but it holds locks on the same
index.  That tells you connection 11 is blocking connection 12.

=item M: Master/Slave Replication Status

This mode shows the output of SHOW SLAVE STATUS and SHOW MASTER STATUS in three
tables.  The first two divide the slave's status into SQL and I/O thread status,
and the last shows master status.  Filters are applied to eliminate non-slave
servers from the slave tables, and non-master servers from the master table.

This mode displays the L<"slave_sql_status">, L<"slave_io_status">, and
L<"master_status"> tables by default.

=item O: Open Tables

This section comes from MySQL's SHOW OPEN TABLES command.  By default it is
filtered to show tables which are in use by one or more queries, so you can
get a quick look at which tables are 'hot'.  You can use this to guess which
tables might be locked implicitly.

This mode displays the L<"open_tables"> mode by default.

=item Q: Query List

This mode displays the output from SHOW FULL PROCESSLIST, much like B<mytop>'s
query list mode.  This mode does B<not> show InnoDB-related information.  This
is probably one of the most useful modes for general usage.

There is an informative header that shows general status information about
your server.  You can toggle it on and off with the 'h' key.  By default,
innotop hides inactive processes and its own process.  You can toggle these on
and off with the 'i' and 'a' keys.

You can EXPLAIN a query from this mode with the 'e' key.  This displays the
query's full text, the results of EXPLAIN, and in newer MySQL versions, even
the optimized query resulting from EXPLAIN EXTENDED.  innotop also tries to
rewrite certain queries to make them EXPLAIN-able.  For example, INSERT/SELECT
statements are rewritable.

This mode displays the L<"q_header"> and L<"processlist"> tables by default.

=item R: InnoDB Row Operations and Semaphores

This mode shows InnoDB row operations, row operation miscellaneous, semaphores,
and information from the wait array.  It displays the L<"row_operations">,
L<"row_operation_misc">, L<"semaphores">, and L<"wait_array"> tables by default.

=item S: Variables & Status

This mode calculates statistics, such as queries per second, and prints them out
in several different styles.  You can show absolute values, or incremental values
between ticks.

You can switch between the views by pressing a key.  The 's' key prints a
single line each time the screen updates, in the style of B<vmstat>.  The 'g'
key changes the view to a graph of the same numbers, sort of like B<tload>.
The 'v' key changes the view to a pivoted table of variable names on the left,
with successive updates scrolling across the screen from left to right.  You can
choose how many updates to put on the screen with the L<"num_status_sets">
configuration variable.

Headers may be abbreviated to fit on the screen in interactive operation.  You
choose which variables to display with the 'c' key, which selects from
predefined sets, or lets you create your own sets.  You can edit the current set
with the 'e' key.

This mode doesn't really display any tables like other modes.  Instead, it uses
a table definition to extract and format the data, but it then transforms the
result in special ways before outputting it.  It uses the L<"var_status"> table
definition for this.

=item T: InnoDB Transactions

This mode shows transactions from the InnoDB monitor's output, in B<top>-like
format.  This mode is the reason I wrote innotop.

You can kill queries or processes with the 'k' and 'x' keys, and EXPLAIN a query
with the 'e' or 'f' keys.  InnoDB doesn't print the full query in transactions,
so explaining may not work right if the query is truncated.

The informational header can be toggled on and off with the 'h' key.  By
default, innotop hides inactive transactions and its own transaction.  You can
toggle this on and off with the 'i' and 'a' keys.

This mode displays the L<"t_header"> and L<"innodb_transactions"> tables by
default.

=back

=head1 INNOTOP STATUS

The first line innotop displays is a "status bar" of sorts.  What it contains
depends on the mode you're in, and what servers you're monitoring.  The first
few words are always [RO] (if readonly is set to 1), the innotop mode, such as
"InnoDB Txns" for T mode, followed by a reminder to press '?' for help at any
time.

=head2 ONE SERVER

The simplest case is when you're monitoring a single server.  In this case, the
name of the connection is next on the status line.  This is the name you gave
when you created the connection -- most likely the MySQL server's hostname.
This is followed by the server's uptime.

If you're in an InnoDB mode, such as T or B, the next word is "InnoDB" followed
by some information about the SHOW INNODB STATUS output used to render the
screen.  The first word is the number of seconds since the last SHOW INNODB
STATUS, which InnoDB uses to calculate some per-second statistics.  The next is
a smiley face indicating whether the InnoDB output is truncated.  If the smiley
face is a :-), all is well; there is no truncation.  A :^| means the transaction
list is so long, InnoDB has only printed out some of the transactions.  Finally,
a frown :-( means the output is incomplete, which is probably due to a deadlock
printing too much lock information (see L<"D: InnoDB Deadlocks">).

The next two words indicate the server's queries per second (QPS) and how many
threads (connections) exist.  Finally, the server's version number is the last
thing on the line.

=head2 MULTIPLE SERVERS

If you are monitoring multiple servers (see L<"SERVER CONNECTIONS">), the status
line does not show any details about individual servers.  Instead, it shows the
names of the connections that are active.  Again, these are connection names you
specified, which are likely to be the server's hostname.  A connection that has
an error is prefixed with an exclamation point.

If you are monitoring a group of servers (see L<"SERVER GROUPS">), the status
line shows the name of the group.  If any connection in the group has an
error, the group's name is followed by the fraction of the connections that
don't have errors.

See L<"ERROR HANDLING"> for more details about innotop's error handling.

=head2 MONITORING A FILE

If you give a filename on the command line, innotop will not connect to ANY
servers at all.  It will watch the specified file for InnoDB status output and
use that as its data source.  It will always show a single connection called
'file'.  And since it can't connect to a server, it can't determine how long the
server it's monitoring has been up; so it calculates the server's uptime as time
since innotop started running.

=head1 SERVER ADMINISTRATION

While innotop is primarily a monitor that lets you watch and analyze your
servers, it can also send commands to servers.  The most frequently useful
commands are killing queries and stopping or starting slaves.

You can kill a connection, or in newer versions of MySQL kill a query but not a
connection, from L<"Q: Query List"> and L<"T: InnoDB Transactions"> modes.
Press 'k' to issue a KILL command, or 'x' to issue a KILL QUERY command.
innotop will prompt you for the server and/or connection ID to kill (innotop
does not prompt you if there is only one possible choice for any input).
innotop pre-selects the longest-running query, or the oldest connection.
Confirm the command with 'y'.

In L<"M: Master/Slave Replication Status"> mode, you can start and stop slaves
with the 'a' and 'o' keys, respectively.  You can send these commands to many
slaves at once.  innotop fills in a default command of START SLAVE or STOP SLAVE
for you, but you can actually edit the command and send anything you wish, such
as SET GLOBAL SQL_SLAVE_SKIP_COUNTER=1 to make the slave skip one binlog event
when it starts.

You can also ask innotop to calculate the earliest binlog in use by any slave
and issue a PURGE MASTER LOGS on the master.  Use the 'b' key for this.  innotop
will prompt you for a master to run the command on, then prompt you for the
connection names of that master's slaves (there is no way for innotop to
determine this reliably itself).  innotop will find the minimum binlog in use by
these slave connections and suggest it as the argument to PURGE MASTER LOGS.

=head1 SERVER CONNECTIONS

When you create a server connection using '@', innotop asks you for a series of
inputs, as follows:

=over

=item DSN

A DSN is a Data Source Name, which is the initial argument passed to the DBI
module for connecting to a server.  It is usually of the form

 DBI:mysql:;mysql_read_default_group=mysql;host=HOSTNAME

Since this DSN is passed to the DBD::mysql driver, you should read the driver's
documentation at L<"http://search.cpan.org/dist/DBD-mysql/lib/DBD/mysql.pm"> for
the exact details on all the options you can pass the driver in the DSN.  You
can read more about DBI at L<http://dbi.perl.org/docs/>, and especially at
L<http://search.cpan.org/~timb/DBI/DBI.pm>.

The mysql_read_default_group=mysql option lets the DBD driver read your MySQL
options files, such as ~/.my.cnf on UNIX-ish systems.  You can use this to avoid
specifying a username or password for the connection.

=item InnoDB Deadlock Table

This optional item tells innotop a table name it can use to deliberately create
a small deadlock (see L<"D: InnoDB Deadlocks">).  If you specify this option,
you just need to be sure the table doesn't exist, and that innotop can create
and drop the table with the InnoDB storage engine.  You can safely omit or just
accept the default if you don't intend to use this.

=item Username

innotop will ask you if you want to specify a username.  If you say 'y', it will
then prompt you for a user name.  If you have a MySQL option file that specifies
your username, you don't have to specify a username.

The username defaults to your login name on the system you're running innotop on.

=item Password

innotop will ask you if you want to specify a password.  Like the username, the
password is optional, but there's an additional prompt that asks if you want to
save the password in the innotop configuration file.  If you don't save it in
the configuration file, innotop will prompt you for a password each time it
starts.  Passwords in the innotop configuration file are saved in plain text,
not encrypted in any way.

=back

Once you finish answering these questions, you should be connected to a server.
But innotop isn't limited to monitoring a single server; you can define many
server connections and switch between them by pressing the '@' key.  See
L<"SWITCHING BETWEEN CONNECTIONS">.

=head1 SERVER GROUPS

If you have multiple MySQL instances, you can put them into named groups, such
as 'all', 'masters', and 'slaves', which innotop can monitor all together.

You can choose which group to monitor with the '#' key, and you can press the
TAB key to switch to the next group.  If you're not currently monitoring a
group, pressing TAB selects the first group.

To create a group, press the '#' key and type the name of your new group, then
type the names of the connections you want the group to contain.

=head1 SWITCHING BETWEEN CONNECTIONS

innotop lets you quickly switch which servers you're monitoring.  The most basic
way is by pressing the '@' key and typing the name(s) of the connection(s) you
want to use.  This setting is per-mode, so you can monitor different connections
in each mode, and innotop remembers which connections you choose.

You can quickly switch to the 'next' connection in alphabetical order with the
'n' key.  If you're monitoring a server group (see L<"SERVER GROUPS">) this will
switch to the first connection.

You can also type many connection names, and innotop will fetch and display data
from them all.  Just separate the connection names with spaces, for example
"server1 server2."  Again, if you type the name of a connection that doesn't
exist, innotop will prompt you for connection information and create the
connection.

Another way to monitor multiple connections at once is with server groups.  You
can use the TAB key to switch to the 'next' group in alphabetical order, or if
you're not monitoring any groups, TAB will switch to the first group.

innotop does not fetch data in parallel from connections, so if you are
monitoring a large group or many connections, you may notice increased delay
between ticks.

When you monitor more than one connection, innotop's status bar changes.  See
L<"INNOTOP STATUS">.

=head1 ERROR HANDLING

Error handling is not that important when monitoring a single connection, but is
crucial when you have many active connections.  A crashed server or lost
connection should not crash innotop.  As a result, innotop will continue to run
even when there is an error; it just won't display any information from the
connection that had an error.  Because of this, innotop's behavior might confuse
you.  It's a feature, not a bug!

innotop does not continue to query connections that have errors, because they
may slow innotop and make it hard to use, especially if the error is a problem
connecting and causes a long time-out.  Instead, innotop retries the connection
occasionally to see if the error still exists.  If so, it will wait until some
point in the future.  The wait time increases in ticks as the Fibonacci series,
so it tries less frequently as time passes.

Since errors might only happen in certain modes because of the SQL commands
issued in those modes, innotop keeps track of which mode caused the error.  If
you switch to a different mode, innotop will retry the connection instead of
waiting.

By default innotop will display the problem in red text at the bottom of the
first table on the screen.  You can disable this behavior with the
L<"show_cxn_errors_in_tbl"> configuration option, which is enabled by default.
If the L<"debug"> option is enabled, innotop will display the error at the
bottom of every table, not just the first.  And if L<"show_cxn_errors"> is
enabled, innotop will print the error text to STDOUT as well.  Error messages
might only display in the mode that caused the error, depending on the mode and
whether innotop is avoiding querying that connection.

=head1 NON-INTERACTIVE OPERATION

You can run innotop in non-interactive mode, in which case it is entirely
controlled from the configuration file and command-line options.  To start
innotop in non-interactive mode, give the L"<--nonint"> command-line option.
This changes innotop's behavior in the following ways:

=over

=item *

Certain Perl modules are not loaded.  Term::Readline is not loaded, since
innotop doesn't prompt interactively.  Term::ANSIColor and Win32::Console::ANSI
modules are not loaded.  Term::ReadKey is still used, since innotop may have to
prompt for connection passwords when starting up.

=item *

innotop does not clear the screen after each tick.

=item *

innotop does not persist any changes to the configuration file.

=item *

If L<"--count"> is given and innotop is in incremental mode (see L<"status_inc">
and L<"--inc">), innotop actually refreshes one more time than specified so it
can print incremental statistics.  This suppresses output during the first
tick, so innotop may appear to hang.

=item *

innotop only displays the first table in each mode.  This is so the output can
be easily processed with other command-line utilities such as awk and sed.  To
change which tables display in each mode, see L<"TABLES">.  Since L<"Q: Query
List"> mode is so important, innotop automatically disables the L<"q_header">
table.  This ensures you'll see the L<"processlist"> table, even if you have
innotop configured to show the q_header table during interactive operation.
Similarly, in L<"T: InnoDB Transactions"> mode, the L<"t_header"> table is
suppressed so you see only the L<"innodb_transactions"> table.

=item *

All output is tab-separated instead of being column-aligned with whitespace, and
innotop prints the full contents of each table instead of only printing one
screenful at a time.

=item *

innotop only prints column headers once instead of every tick (see
L<"hide_hdr">).  innotop does not print table captions (see
L<"display_table_captions">).  innotop ensures there are no empty lines in the
output.

=item *

innotop does not honor the L<"shorten"> transformation, which normally shortens
some numbers to human-readable formats.

=item *

innotop does not print a status line (see L<"INNOTOP STATUS">).

=back

=head1 CONFIGURING

Nearly everything about innotop is configurable.  Most things are possible to
change with built-in commands, but you can also edit the configuration file.

While running innotop, press the '$' key to bring up the configuration editing
dialog.  Press another key to select the type of data you want to edit:

=over

=item S: Statement Sleep Times

Edits SQL statement sleep delays, which make innotop pause for the specified
amount of time after executing a statement.  See L<"SQL STATEMENTS"> for a
definition of each statement and what it does.  By default innotop does not
delay after any statements.

This feature is included so you can customize the side-effects caused by
monitoring your server.  You may not see any effects, but some innotop users
have noticed that certain MySQL versions under very high load with InnoDB
enabled take longer than usual to execute SHOW GLOBAL STATUS.  If innotop calls
SHOW FULL PROCESSLIST immediately afterward, the processlist contains more
queries than the machine actually averages at any given moment.  Configuring
innotop to pause briefly after calling SHOW GLOBAL STATUS alleviates this
effect.

Sleep times are stored in the L<"stmt_sleep_times"> section of the configuration
file.  Fractional-second sleeps are supported, subject to your hardware's
limitations.

=item c: Edit Columns

Starts the table editor on one of the displayed tables.  See L<"TABLE EDITOR">.
An alternative way to start the table editor without entering the configuration
dialog is with the '^' key.

=item g: General Configuration

Starts the configuration editor to edit global and mode-specific configuration
variables (see L<"MODES">).  innotop prompts you to choose a variable from among
the global and mode-specific ones depending on the current mode.

=item k: Row-Coloring Rules

Starts the row-coloring rules editor on one of the displayed table(s).  See
L<"COLORS"> for details.

=item p: Manage Plugins

Starts the plugin configuration editor.  See L<"PLUGINS"> for details.

=item s: Server Groups

Lets you create and edit server groups.  See L<"SERVER GROUPS">.

=item t: Choose Displayed Tables

Lets you choose which tables to display in this mode.  See L<"MODES"> and
L<"TABLES">.

=back

=head1 CONFIGURATION FILE

innotop's default configuration file locations are $HOME/.innotop and
/etc/innotop/innotop.conf, and they are looked for in that order.  If the first
configuration file exists, the second will not be processed.  Those can be
overridden with the L<"--config"> command-line option.  You can edit it by hand
safely, however innotop reads the configuration file when it starts, and, if
readonly is set to 0, writes it out again when it exits.  Thus, if readonly is
set to 0, any changes you make by hand while innotop is running will be lost.

innotop doesn't store its entire configuration in the configuration file.  It
has a huge set of default configuration values that it holds only in memory,
and the configuration file only overrides these defaults.  When you customize a
default setting, innotop notices, and then stores the customizations into the
file.  This keeps the file size down, makes it easier to edit, and makes
upgrades easier.

A configuration file is read-only be default.  You can override that with
L<"--write">.  See L<"readonly">.

The configuration file is arranged into sections like an INI file.  Each
section begins with [section-name] and ends with [/section-name].  Each
section's entries have a different syntax depending on the data they need to
store.  You can put comments in the file; any line that begins with a #
character is a comment.  innotop will not read the comments, so it won't write
them back out to the file when it exits.  Comments in read-only configuration
files are still useful, though.

The first line in the file is innotop's version number.  This lets innotop
notice when the file format is not backwards-compatible, and upgrade smoothly
without destroying your customized configuration.

The following list describes each section of the configuration file and the data
it contains:

=over

=item general

The 'general' section contains global configuration variables and variables that
may be mode-specific, but don't belong in any other section.  The syntax is a
simple key=value list.  innotop writes a comment above each value to help you
edit the file by hand.

=over

=item S_func

Controls S mode presentation (see L<"S: Variables & Status">).  If g, values are
graphed; if s, values are like vmstat; if p, values are in a pivoted table.

=item S_set

Specifies which set of variables to display in L<"S: Variables & Status"> mode.
See L<"VARIABLE SETS">.

=item auto_wipe_dl

Instructs innotop to automatically wipe large deadlocks when it notices them.
When this happens you may notice a slight delay.  At the next tick, you will
usually see the information that was being truncated by the large deadlock.

=item charset

Specifies what kind of characters to allow through the L<"no_ctrl_char">
transformation.  This keeps non-printable characters from confusing a
terminal when you monitor queries that contain binary data, such as images.

The default is 'ascii', which considers anything outside normal ASCII to be a
control character.  The other allowable values are 'unicode' and 'none'.  'none'
considers every character a control character, which can be useful for
collapsing ALL text fields in queries.

=item cmd_filter

This is the prefix that filters variables in L<"C: Command Summary"> mode.

=item color

Whether terminal coloring is permitted.

=item cxn_timeout

On MySQL versions 4.0.3 and newer, this variable is used to set the connection's
timeout, so MySQL doesn't close the connection if it is not used for a while.
This might happen because a connection isn't monitored in a particular mode, for
example.

=item debug

This option enables more verbose errors and makes innotop more strict in some
places.  It can help in debugging filters and other user-defined code.  It also
makes innotop write a lot of information to L<"debugfile"> when there is a
crash.

=item debugfile

A file to which innotop will write information when there is a crash.  See
L<"FILES">.

=item display_table_captions

innotop displays a table caption above most tables.  This variable suppresses or
shows captions on all tables globally.  Some tables are configured with the
hide_caption property, which overrides this.

=item global

Whether to show GLOBAL variables and status.  innotop only tries to do this on
servers which support the GLOBAL option to SHOW VARIABLES and SHOW STATUS.  In
some MySQL versions, you need certain privileges to do this; if you don't have
them, innotop will not be able to fetch any variable and status data.  This
configuration variable lets you run innotop and fetch what data you can even
without the elevated privileges.

I can no longer find or reproduce the situation where GLOBAL wasn't allowed, but
I know there was one.

=item graph_char

Defines the character to use when drawing graphs in L<"S: Variables & Status">
mode.

=item header_highlight

Defines how to highlight column headers.  This only works if Term::ANSIColor is
available.  Valid values are 'bold' and 'underline'.

=item hide_hdr

Hides column headers globally.

=item interval

The interval at which innotop will refresh its data (ticks).  The interval is
implemented as a sleep time between ticks, so the true interval will vary
depending on how long it takes innotop to fetch and render data.

This variable accepts fractions of a second.

=item mode

The mode in which innotop should start.  Allowable arguments are the same as the
key presses that select a mode interactively.  See L<"MODES">.

=item num_digits

How many digits to show in fractional numbers and percents.  This variable's
range is between 0 and 9 and can be set directly from L<"S: Variables & Status">
mode with the '+' and '-' keys.  It is used in the L<"set_precision">,
L<"shorten">, and L<"percent"> transformations.

=item num_status_sets

Controls how many sets of status variables to display in pivoted L<"S: Variables
& Status"> mode.  It also controls the number of old sets of variables innotop
keeps in its memory, so the larger this variable is, the more memory innotop
uses.

=item plugin_dir

Specifies where plugins can be found.  By default, innotop stores plugins in the
'plugins' subdirectory of your innotop configuration directory.

=item readonly

Whether the configuration file is readonly.  This cannot be set interactively.

=item show_cxn_errors

Makes innotop print connection errors to STDOUT.  See L<"ERROR HANDLING">.

=item show_cxn_errors_in_tbl

Makes innotop display connection errors as rows in the first table on screen.
See L<"ERROR HANDLING">.

=item show_percent

Adds a '%' character after the value returned by the L<"percent">
transformation.

=item show_statusbar

Controls whether to show the status bar in the display.  See L<"INNOTOP
STATUS">.

=item skip_innodb

Disables fetching SHOW INNODB STATUS, in case your server(s) do not have InnoDB
enabled and you don't want innotop to try to fetch it.  This can also be useful
when you don't have the SUPER privilege, required to run SHOW INNODB STATUS.

=item status_inc

Whether to show absolute or incremental values for status variables.
Incremental values are calculated as an offset from the last value innotop saw
for that variable.  This is a global setting, but will probably become
mode-specific at some point.  Right now it is honored a bit inconsistently; some
modes don't pay attention to it.

=back

=item plugins

This section holds a list of package names of active plugins.  If the plugin
exists, innotop will activate it.  See L<"PLUGINS"> for more information.

=item filters

This section holds user-defined filters (see L<"FILTERS">).  Each line is in the
format filter_name=text='filter text' tbls='table list'.

The filter text is the text of the subroutine's code.  The table list is a list
of tables to which the filter can apply.  By default, user-defined filters apply
to the table for which they were created, but you can manually override that by
editing the definition in the configuration file.

=item active_filters

This section stores which filters are active on each table.  Each line is in the
format table_name=filter_list.

=item tbl_meta

This section stores user-defined or user-customized columns (see L<"COLUMNS">).
Each line is in the format col_name=properties, where the properties are a
name=quoted-value list.

=item connections

This section holds the server connections you have defined.  Each line is in
the format name=properties, where the properties are a name=value list.  The
properties are self-explanatory, and the only one that is treated specially is
'pass' which is only present if 'savepass' is set.  This section of the
configuration file will be skipped if any DSN, username, or password
command-line options are used.  See L<"SERVER CONNECTIONS">.

=item active_connections

This section holds a list of which connections are active in each mode.  Each
line is in the format mode_name=connection_list.

=item server_groups

This section holds server groups.  Each line is in the format
name=connection_list.  See L<"SERVER GROUPS">.

=item active_server_groups

This section holds a list of which server group is active in each mode.  Each
line is in the format mode_name=server_group.

=item max_values_seen

This section holds the maximum values seen for variables.  This is used to scale
the graphs in L<"S: Variables & Status"> mode.  Each line is in the format
name=value.

=item active_columns

This section holds table column lists.  Each line is in the format
tbl_name=column_list.  See L<"COLUMNS">.

=item sort_cols

This section holds the sort definition.  Each line is in the format
tbl_name=column_list.  If a column is prefixed with '-', that column sorts
descending.  See L<"SORTING">.

=item visible_tables

This section defines which tables are visible in each mode.  Each line is in the
format mode_name=table_list.  See L<"TABLES">.

=item varsets

This section defines variable sets for use in L<"S: Status & Variables"> mode.
Each line is in the format name=variable_list.  See L<"VARIABLE SETS">.

=item colors

This section defines colorization rules.  Each line is in the format
tbl_name=property_list.  See L<"COLORS">.

=item stmt_sleep_times

This section contains statement sleep times.  Each line is in the format
statement_name=sleep_time.  See L<"S: Statement Sleep Times">.

=item group_by

This section contains column lists for table group_by expressions.  Each line is
in the format tbl_name=column_list.  See L<"GROUPING">.

=back

=head1 CUSTOMIZING

You can customize innotop a great deal.  For example, you can:

=over

=item *

Choose which tables to display, and in what order.

=item *

Choose which columns are in those tables, and create new columns.

=item *

Filter which rows display with built-in filters, user-defined filters, and
quick-filters.

=item *

Sort the rows to put important data first or group together related rows.

=item *

Highlight rows with color.

=item *

Customize the alignment, width, and formatting of columns, and apply
transformations to columns to extract parts of their values or format the values
as you wish (for example, shortening large numbers to familiar units).

=item *

Design your own expressions to extract and combine data as you need.  This gives
you unlimited flexibility.

=back

All these and more are explained in the following sections.

=head2 TABLES

A table is what you'd expect: a collection of columns.  It also has some other
properties, such as a caption.  Filters, sorting rules, and colorization rules
belong to tables and are covered in later sections.

Internally, table meta-data is defined in a data structure called %tbl_meta.
This hash holds all built-in table definitions, which contain a lot of default
instructions to innotop.  The meta-data includes the caption, a list of columns
the user has customized, a list of columns, a list of visible columns, a list of
filters, color rules, a sort-column list, sort direction, and some information
about the table's data sources.  Most of this is customizable via the table
editor (see L<"TABLE EDITOR">).

You can choose which tables to show by pressing the '$' key.  See L<"MODES"> and
L<"TABLES">.

The table life-cycle is as follows:

=over

=item *

Each table begins with a data source, which is an array of hashes.  See below
for details on data sources.

=item *

Each element of the data source becomes a row in the final table.

=item *

For each element in the data source, innotop extracts values from the source and
creates a row.  This row is another hash, which later steps will refer to as
$set.  The values innotop extracts are determined by the table's columns.  Each
column has an extraction subroutine, compiled from an expression (see
L<"EXPRESSIONS">).  The resulting row is a hash whose keys are named the same as
the column name.

=item *

innotop filters the rows, removing those that don't need to be displayed.  See
L<"FILTERS">.

=item *

innotop sorts the rows.  See L<"SORTING">.

=item *

innotop groups the rows together, if specified.  See L<"GROUPING">.

=item *

innotop colorizes the rows.  See L<"COLORS">.

=item *

innotop transforms the column values in each row.  See L<"TRANSFORMATIONS">.

=item *

innotop optionally pivots the rows (see L<"PIVOTING">), then filters and sorts
them.

=item *

innotop formats and justifies the rows as a table.  During this step, innotop
applies further formatting to the column values, including alignment, maximum
and minimum widths.  innotop also does final error checking to ensure there are
no crashes due to undefined values.  innotop then adds a caption if specified,
and the table is ready to print.

=back

The lifecycle is slightly different if the table is pivoted, as noted above.  To
clarify, if the table is pivoted, the process is extract, group, transform,
pivot, filter, sort, create.  If it's not pivoted, the process is extract,
filter, sort, group, color, transform, create.  This slightly convoluted process
doesn't map all that well to SQL, but pivoting complicates things pretty
thoroughly.  Roughly speaking, filtering and sorting happen as late as needed to
effect the final result as you might expect, but as early as possible for
efficiency.

Each built-in table is described below:

=over

=item adaptive_hash_index

Displays data about InnoDB's adaptive hash index.  Data source:
L<"STATUS_VARIABLES">.

=item buffer_pool

Displays data about InnoDB's buffer pool.  Data source: L<"STATUS_VARIABLES">.

=item cmd_summary

Displays weighted status variables.  Data source: L<"STATUS_VARIABLES">.

=item deadlock_locks

Shows which locks were held and waited for by the last detected deadlock.  Data
source: L<"DEADLOCK_LOCKS">.

=item deadlock_transactions

Shows transactions involved in the last detected deadlock.  Data source:
L<"DEADLOCK_TRANSACTIONS">.

=item explain

Shows the output of EXPLAIN.  Data source: L<"EXPLAIN">.

=item file_io_misc

Displays data about InnoDB's file and I/O operations.  Data source:
L<"STATUS_VARIABLES">.

=item fk_error

Displays various data about InnoDB's last foreign key error.  Data source:
L<"STATUS_VARIABLES">.

=item innodb_locks

Displays InnoDB locks.  Data source: L<"INNODB_LOCKS">.

=item innodb_transactions

Displays data about InnoDB's current transactions.  Data source:
L<"INNODB_TRANSACTIONS">.

=item insert_buffers

Displays data about InnoDB's insert buffer.  Data source: L<"STATUS_VARIABLES">.

=item io_threads

Displays data about InnoDB's I/O threads.  Data source: L<"IO_THREADS">.

=item log_statistics

Displays data about InnoDB's logging system.  Data source: L<"STATUS_VARIABLES">.

=item master_status

Displays replication master status.  Data source: L<"STATUS_VARIABLES">.

=item open_tables

Displays open tables.  Data source: L<"OPEN_TABLES">.

=item page_statistics

Displays InnoDB page statistics.  Data source: L<"STATUS_VARIABLES">.

=item pending_io

Displays InnoDB pending I/O operations.  Data source: L<"STATUS_VARIABLES">.

=item processlist

Displays current MySQL processes (threads/connections).  Data source:
L<"PROCESSLIST">.

=item q_header

Displays various status values.  Data source: L<"STATUS_VARIABLES">.

=item row_operation_misc

Displays data about InnoDB's row operations.  Data source:
L<"STATUS_VARIABLES">.

=item row_operations

Displays data about InnoDB's row operations.  Data source:
L<"STATUS_VARIABLES">.

=item semaphores

Displays data about InnoDB's semaphores and mutexes.  Data source:
L<"STATUS_VARIABLES">.

=item slave_io_status

Displays data about the slave I/O thread.  Data source: 
L<"STATUS_VARIABLES">.

=item slave_sql_status

Displays data about the slave SQL thread.  Data source: L<"STATUS_VARIABLES">.

=item t_header

Displays various InnoDB status values.  Data source: L<"STATUS_VARIABLES">.

=item var_status

Displays user-configurable data.  Data source: L<"STATUS_VARIABLES">.

=item wait_array

Displays data about InnoDB's OS wait array.  Data source: L<"OS_WAIT_ARRAY">.

=back

=head2 COLUMNS

Columns belong to tables.  You can choose a table's columns by pressing the '^'
key, which starts the L<"TABLE EDITOR"> and lets you choose and edit columns.
Pressing 'e' from within the table editor lets you edit the column's properties:

=over

=item *

hdr: a column header.  This appears in the first row of the table.

=item *

just: justification.  '-' means left-justified and '' means right-justified,
just as with printf formatting codes (not a coincidence).

=item *

dec: whether to further align the column on the decimal point.

=item *

num: whether the column is numeric.  This affects how values are sorted
(lexically or numerically).

=item *

label: a small note about the column, which appears in dialogs that help the
user choose columns.

=item *

src: an expression that innotop uses to extract the column's data from its
source (see L<"DATA SOURCES">).  See L<"EXPRESSIONS"> for more on expressions.

=item *

minw: specifies a minimum display width.  This helps stabilize the display,
which makes it easier to read if the data is changing frequently.

=item *

maxw: similar to minw.

=item *

trans: a list of column transformations.  See L<"TRANSFORMATIONS">.

=item *

agg: an aggregate function.  See L<"GROUPING">.  The default is L<"first">.

=item *

aggonly: controls whether the column only shows when grouping is enabled on the
table (see L<"GROUPING">).  By default, this is disabled.  This means columns
will always be shown by default, whether grouping is enabled or not.  If a
column's aggonly is set true, the column will appear when you toggle grouping on
the table.  Several columns are set this way, such as the count column on
L<"processlist"> and L<"innodb_transactions">, so you don't see a count when the
grouping isn't enabled, but you do when it is.

=back

=head2 FILTERS

Filters remove rows from the display.  They behave much like a WHERE clause in
SQL.  innotop has several built-in filters, which remove irrelevant information
like inactive queries, but you can define your own as well.  innotop also lets
you create quick-filters, which do not get saved to the configuration file, and
are just an easy way to quickly view only some rows.

You can enable or disable a filter on any table.  Press the '%' key (mnemonic: %
looks kind of like a line being filtered between two circles) and choose which
table you want to filter, if asked.  You'll then see a list of possible filters
and a list of filters currently enabled for that table.  Type the names of
filters you want to apply and press Enter.

=head3 USER-DEFINED FILTERS

If you type a name that doesn't exist, innotop will prompt you to create the
filter.  Filters are easy to create if you know Perl, and not hard if you don't.
What you're doing is creating a subroutine that returns true if the row should
be displayed.  The row is a hash reference passed to your subroutine as $set.

For example, imagine you want to filter the processlist table so you only see
queries that have been running more than five minutes.  Type a new name for your
filter, and when prompted for the subroutine body, press TAB to initiate your
terminal's auto-completion.  You'll see the names of the columns in the
L<"processlist"> table (innotop generally tries to help you with auto-completion
lists).  You want to filter on the 'time' column.  Type the text "$set->{time} >
300" to return true when the query is more than five minutes old.  That's all
you need to do.

In other words, the code you're typing is surrounded by an implicit context,
which looks like this:

 sub filter {
    my ( $set ) = @_;
    # YOUR CODE HERE
 }

If your filter doesn't work, or if something else suddenly behaves differently,
you might have made an error in your filter, and innotop is silently catching
the error.  Try enabling L<"debug"> to make innotop throw an error instead.

=head3 QUICK-FILTERS

innotop's quick-filters are a shortcut to create a temporary filter that doesn't
persist when you restart innotop.  To create a quick-filter, press the '/' key.
innotop will prompt you for the column name and filter text.  Again, you can use
auto-completion on column names.  The filter text can be just the text you want
to "search for."  For example, to filter the L<"processlist"> table on queries
that refer to the products table, type '/' and then 'info product'.

The filter text can actually be any Perl regular expression, but of course a
literal string like 'product' works fine as a regular expression.

Behind the scenes innotop compiles the quick-filter into a specially tagged
filter that is otherwise like any other filter.  It just isn't saved to the
configuration file.

To clear quick-filters, press the '\' key and innotop will clear them all at
once.

=head2 SORTING

innotop has sensible built-in defaults to sort the most important rows to the
top of the table.  Like anything else in innotop, you can customize how any
table is sorted.

To start the sort dialog, start the L<"TABLE EDITOR"> with the '^' key, choose a
table if necessary, and press the 's' key.  You'll see a list of columns you can
use in the sort expression and the current sort expression, if any.  Enter a
list of columns by which you want to sort and press Enter.  If you want to
reverse sort, prefix the column name with a minus sign.  For example, if you
want to sort by column a ascending, then column b descending, type 'a -b'.  You
can also explicitly add a + in front of columns you want to sort ascending, but
it's not required.

Some modes have keys mapped to open this dialog directly, and to quickly reverse
sort direction.  Press '?' as usual to see which keys are mapped in any mode.

=head2 GROUPING

innotop can group, or aggregate, rows together (the terms are used
interchangeably).  This is quite similar to an SQL GROUP BY clause.  You can
specify to group on certain columns, or if you don't specify any, the entire set
of rows is treated as one group.  This is quite like SQL so far, but unlike SQL,
you can also select un-grouped columns.  innotop actually aggregates every
column.  If you don't explicitly specify a grouping function, the default is
'first'.  This is basically a convenience so you don't have to specify an
aggregate function for every column you want in the result.

You can quickly toggle grouping on a table with the '=' key, which toggles its
aggregate property.  This property doesn't persist to the config file.

The columns by which the table is grouped are specified in its group_by
property.  When you turn grouping on, innotop places the group_by columns at the
far left of the table, even if they're not supposed to be visible.  The rest of
the visible columns appear in order after them.

Two tables have default group_by lists and a count column built in:
L<"processlist"> and L<"innodb_transactions">.  The grouping is by connection
and status, so you can quickly see how many queries or transactions are in a
given status on each server you're monitoring.  The time columns are aggregated
as a sum; other columns are left at the default 'first' aggregation.

By default, the table shown in L<"S: Variables & Status"> mode also uses
grouping so you can monitor variables and status across many servers.  The
default aggregation function in this mode is 'avg'.

Valid grouping functions are defined in the %agg_funcs hash.  They include

=over

=item first

Returns the first element in the group.

=item count

Returns the number of elements in the group, including undefined elements, much
like SQL's COUNT(*).

=item avg

Returns the average of defined elements in the group.

=item sum

Returns the sum of elements in the group.

=back

Here's an example of grouping at work.  Suppose you have a very busy server with
hundreds of open connections, and you want to see how many connections are in
what status.  Using the built-in grouping rules, you can press 'Q' to enter
L<"Q: Query List"> mode.  Press '=' to toggle grouping (if necessary, select the
L<"processlist"> table when prompted).

Your display might now look like the following:

 Query List (? for help) localhost, 32:33, 0.11 QPS, 1 thd, 5.0.38-log
 
 CXN        Cmd        Cnt  ID      User   Host           Time   Query       
 localhost  Query      49    12933  webusr localhost      19:38  SELECT * FROM
 localhost  Sending Da 23     2383  webusr localhost      12:43  SELECT col1,
 localhost  Sleep      120     140  webusr localhost    5:18:12
 localhost  Statistics 12    19213  webusr localhost      01:19  SELECT * FROM

That's actually quite a worrisome picture.  You've got a lot of idle connections
(Sleep), and some connections executing queries (Query and Sending Data).
That's okay, but you also have a lot in Statistics status, collectively spending
over a minute.  That means the query optimizer is having a really hard time
optimizing your statements.  Something is wrong; it should normally take
milliseconds to optimize queries.  You might not have seen this pattern if you
didn't look at your connections in aggregate.  (This is a made-up example, but
it can happen in real life).

=head2 PIVOTING

innotop can pivot a table for more compact display, similar to a Pivot Table in
a spreadsheet (also known as a crosstab).  Pivoting a table makes columns into
rows.  Assume you start with this table:

 foo bar
 === ===
 1   3
 2   4

After pivoting, the table will look like this:

 name set0 set1
 ==== ==== ====
 foo  1    2
 bar  3    4

To get reasonable results, you might need to group as well as pivoting.
innotop currently does this for L<"S: Variables & Status"> mode.

=head2 COLORS

By default, innotop highlights rows with color so you can see at a glance which
rows are more important.  You can customize the colorization rules and add your
own to any table.  Open the table editor with the '^' key, choose a table if
needed, and press 'o' to open the color editor dialog.

The color editor dialog displays the rules applied to the table, in the order
they are evaluated.  Each row is evaluated against each rule to see if the rule
matches the row; if it does, the row gets the specified color, and no further
rules are evaluated.  The rules look like the following:

 state  eq  Locked       black on_red
 cmd    eq  Sleep        white       
 user   eq  system user  white       
 cmd    eq  Connect      white       
 cmd    eq  Binlog Dump  white       
 time   >   600          red         
 time   >   120          yellow      
 time   >   60           green       
 time   >   30           cyan        

This is the default rule set for the L<"processlist"> table.  In order of
priority, these rules make locked queries black on a red background, "gray out"
connections from replication and sleeping queries, and make queries turn from
cyan to red as they run longer.

(For some reason, the ANSI color code "white" is actually a light gray.  Your
terminal's display may vary; experiment to find colors you like).

You can use keystrokes to move the rules up and down, which re-orders their
priority.  You can also delete rules and add new ones.  If you add a new rule,
innotop prompts you for the column, an operator for the comparison, a value
against which to compare the column, and a color to assign if the rule matches.
There is auto-completion and prompting at each step.

The value in the third step needs to be correctly quoted.  innotop does not try
to quote the value because it doesn't know whether it should treat the value as
a string or a number.  If you want to compare the column against a string, as
for example in the first rule above, you should enter 'Locked' surrounded by
quotes.  If you get an error message about a bareword, you probably should have
quoted something.

=head2 EXPRESSIONS

Expressions are at the core of how innotop works, and are what enables you to
extend innotop as you wish.  Recall the table lifecycle explained in
L<"TABLES">.  Expressions are used in the earliest step, where it extracts
values from a data source to form rows.

It does this by calling a subroutine for each column, passing it the source data
set, a set of current values, and a set of previous values.  These are all
needed so the subroutine can calculate things like the difference between this
tick and the previous tick.

The subroutines that extract the data from the set are compiled from
expressions.  This gives significantly more power than just naming the values to
fill the columns, because it allows the column's value to be calculated from
whatever data is necessary, but avoids the need to write complicated and lengthy
Perl code.

innotop begins with a string of text that can look as simple as a value's name
or as complicated as a full-fledged Perl expression.  It looks at each
'bareword' token in the string and decides whether it's supposed to be a key
into the $set hash.  A bareword is an unquoted value that isn't already
surrounded by code-ish things like dollar signs or curly brackets.  If innotop
decides that the bareword isn't a function or other valid Perl code, it converts
it into a hash access.  After the whole string is processed, innotop compiles a
subroutine, like this:

 sub compute_column_value {
    my ( $set, $cur, $pre ) = @_;
    my $val = # EXPANDED STRING GOES HERE
    return $val;
 }

Here's a concrete example, taken from the header table L<"q_header"> in L<"Q:
Query List"> mode.  This expression calculates the qps, or Queries Per Second,
column's values, from the values returned by SHOW STATUS:

 Questions/Uptime_hires

innotop decides both words are barewords, and transforms this expression into
the following Perl code:

 $set->{Questions}/$set->{Uptime_hires}

When surrounded by the rest of the subroutine's code, this is executable Perl
that calculates a high-resolution queries-per-second value.

The arguments to the subroutine are named $set, $cur, and $pre.  In most cases,
$set and $cur will be the same values.  However, if L<"status_inc"> is set, $cur
will not be the same as $set, because $set will already contain values that are
the incremental difference between $cur and $pre.

Every column in innotop is computed by subroutines compiled in the same fashion.
There is no difference between innotop's built-in columns and user-defined
columns.  This keeps things consistent and predictable.

=head2 TRANSFORMATIONS

Transformations change how a value is rendered.  For example, they can take a
number of seconds and display it in H:M:S format.  The following transformations
are defined:

=over

=item commify

Adds commas to large numbers every three decimal places.

=item dulint_to_int

Accepts two unsigned integers and converts them into a single longlong.  This is
useful for certain operations with InnoDB, which uses two integers as
transaction identifiers, for example.

=item no_ctrl_char

Removes quoted control characters from the value.  This is affected by the
L<"charset"> configuration variable.

This transformation only operates within quoted strings, for example, values to
a SET clause in an UPDATE statement.  It will not alter the UPDATE statement,
but will collapse the quoted string to [BINARY] or [TEXT], depending on the
charset.

=item percent

Converts a number to a percentage by multiplying it by two, formatting it with
L<"num_digits"> digits after the decimal point, and optionally adding a percent
sign (see L<"show_percent">).

=item secs_to_time

Formats a number of seconds as time in days+hours:minutes:seconds format.

=item set_precision

Formats numbers with L<"num_digits"> number of digits after the decimal point.

=item shorten

Formats a number as a unit of 1024 (k/M/G/T) and with L<"num_digits"> number of
digits after the decimal point.

=back

=head2 TABLE EDITOR

The innotop table editor lets you customize tables with keystrokes.  You start
the table editor with the '^' key.  If there's more than one table on the
screen, it will prompt you to choose one of them.  Once you do, innotop will
show you something like this:

 Editing table definition for Buffer Pool.  Press ? for help, q to quit.
 
 name               hdr          label                  src          
 cxn                CXN          Connection from which  cxn          
 buf_pool_size      Size         Buffer pool size       IB_bp_buf_poo
 buf_free           Free Bufs    Buffers free in the b  IB_bp_buf_fre
 pages_total        Pages        Pages total            IB_bp_pages_t
 pages_modified     Dirty Pages  Pages modified (dirty  IB_bp_pages_m
 buf_pool_hit_rate  Hit Rate     Buffer pool hit rate   IB_bp_buf_poo
 total_mem_alloc    Memory       Total memory allocate  IB_bp_total_m
 add_pool_alloc     Add'l Pool   Additonal pool alloca  IB_bp_add_poo

The first line shows which table you're editing, and reminds you again to press
'?' for a list of key mappings.  The rest is a tabular representation of the
table's columns, because that's likely what you're trying to edit.  However, you
can edit more than just the table's columns; this screen can start the filter
editor, color rule editor, and more.

Each row in the display shows a single column in the table you're editing, along
with a couple of its properties such as its header and source expression (see
L<"EXPRESSIONS">).

The key mappings are Vim-style, as in many other places.  Pressing 'j' and 'k'
moves the highlight up or down.  You can then (d)elete or (e)dit the highlighted
column.  You can also (a)dd a column to the table.  This actually just activates
one of the columns already defined for the table; it prompts you to choose from
among the columns available but not currently displayed.  Finally, you can
re-order the columns with the '+' and '-' keys.

You can do more than just edit the columns with the table editor, you can also
edit other properties, such as the table's sort expression and group-by
expression.  Press '?' to see the full list, of course.

If you want to really customize and create your own column, as opposed to just
activating a built-in one that's not currently displayed, press the (n)ew key,
and innotop will prompt you for the information it needs:

=over

=item *

The column name: this needs to be a word without any funny characters, e.g. just
letters, numbers and underscores.

=item *

The column header: this is the label that appears at the top of the column, in
the table header.  This can have spaces and funny characters, but be careful not
to make it too wide and waste space on-screen.

=item *

The column's data source: this is an expression that determines what data from
the source (see L<"TABLES">) innotop will put into the column.  This can just be
the name of an item in the source, or it can be a more complex expression, as
described in L<"EXPRESSIONS">.

=back

Once you've entered the required data, your table has a new column.  There is no
difference between this column and the built-in ones; it can have all the same
properties and behaviors.  innotop will write the column's definition to the
configuration file, so it will persist across sessions.

Here's an example: suppose you want to track how many times your slaves have
retried transactions.  According to the MySQL manual, the
Slave_retried_transactions status variable gives you that data: "The total
number of times since startup that the replication slave SQL thread has retried
transactions. This variable was added in version 5.0.4."  This is appropriate to
add to the L<"slave_sql_status"> table.

To add the column, switch to the replication-monitoring mode with the 'M' key,
and press the '^' key to start the table editor.  When prompted, choose
slave_sql_status as the table, then press 'n' to create the column.  Type
'retries' as the column name, 'Retries' as the column header, and
'Slave_retried_transactions' as the source.  Now the column is created, and you
see the table editor screen again.  Press 'q' to exit the table editor, and
you'll see your column at the end of the table.

=head1 VARIABLE SETS

Variable sets are used in L<"S: Variables & Status"> mode to define more easily
what variables you want to monitor.  Behind the scenes they are compiled to a
list of expressions, and then into a column list so they can be treated just
like columns in any other table, in terms of data extraction and
transformations.  However, you're protected from the tedious details by a syntax
that ought to feel very natural to you: a SQL SELECT list.

The data source for variable sets, and indeed the entire S mode, is the
combination of SHOW STATUS, SHOW VARIABLES, and SHOW INNODB STATUS.  Imagine
that you had a huge table with one column per variable returned from those
statements.  That's the data source for variable sets.  You can now query this
data source just like you'd expect.  For example:

 Questions, Uptime, Questions/Uptime as QPS

Behind the scenes innotop will split that variable set into three expressions,
compile them and turn them into a table definition, then extract as usual.  This
becomes a "variable set," or a "list of variables you want to monitor."

innotop lets you name and save your variable sets, and writes them to the
configuration file.  You can choose which variable set you want to see with the
'c' key, or activate the next and previous sets with the '>' and '<' keys.
There are many built-in variable sets as well, which should give you a good
start for creating your own.  Press 'e' to edit the current variable set, or
just to see how it's defined.  To create a new one, just press 'c' and type its
name.

You may want to use some of the functions listed in L<"TRANSFORMATIONS"> to help
format the results.  In particular, L<"set_precision"> is often useful to limit
the number of digits you see.  Extending the above example, here's how:

 Questions, Uptime, set_precision(Questions/Uptime) as QPS

Actually, this still needs a little more work.  If your L<"interval"> is less
than one second, you might be dividing by zero because Uptime is incremental in
this mode by default.  Instead, use Uptime_hires:

 Questions, Uptime, set_precision(Questions/Uptime_hires) as QPS

This example is simple, but it shows how easy it is to choose which variables
you want to monitor.

=head1 PLUGINS

innotop has a simple but powerful plugin mechanism by which you can extend
or modify its existing functionality, and add new functionality.  innotop's
plugin functionality is event-based: plugins register themselves to be called
when events happen.  They then have a chance to influence the event.

An innotop plugin is a Perl module placed in innotop's L<"plugin_dir">
directory.  On UNIX systems, you can place a symbolic link to the module instead
of putting the actual file there.  innotop automatically discovers the file.  If
there is a corresponding entry in the L<"plugins"> configuration file section,
innotop loads and activates the plugin.

The module must conform to innotop's plugin interface.  Additionally, the source
code of the module must be written in such a way that innotop can inspect the
file and determine the package name and description.

=head2 Package Source Convention

innotop inspects the plugin module's source to determine the Perl package name.
It looks for a line of the form "package Foo;" and if found, considers the
plugin's package name to be Foo.  Of course the package name can be a valid Perl
package name, with double semicolons and so on.

It also looks for a description in the source code, to make the plugin editor
more human-friendly.  The description is a comment line of the form "#
description: Foo", where "Foo" is the text innotop will consider to be the
plugin's description.

=head2 Plugin Interface

The innotop plugin interface is quite simple: innotop expects the plugin to be
an object-oriented module it can call certain methods on.  The methods are

=over

=item new(%variables)

This is the plugin's constructor.  It is passed a hash of innotop's variables,
which it can manipulate (see L<"Plugin Variables">).  It must return a reference
to the newly created plugin object.

At construction time, innotop has only loaded the general configuration and
created the default built-in variables with their default contents (which is
quite a lot).  Therefore, the state of the program is exactly as in the innotop
source code, plus the configuration variables from the L<"general"> section in
the config file.

If your plugin manipulates the variables, it is changing global data, which is
shared by innotop and all plugins.  Plugins are loaded in the order they're
listed in the config file.  Your plugin may load before or after another plugin,
so there is a potential for conflict or interaction between plugins if they
modify data other plugins use or modify.

=item register_for_events()

This method must return a list of events in which the plugin is interested, if
any.  See L<"Plugin Events"> for the defined events.  If the plugin returns an
event that's not defined, the event is ignored.

=item event handlers

The plugin must implement a method named the same as each event for which it has
registered.  In other words, if the plugin returns qw(foo bar) from
register_for_events(), it must have foo() and bar() methods.  These methods are
callbacks for the events.  See L<"Plugin Events"> for more details about each
event.

=back

=head2 Plugin Variables

The plugin's constructor is passed a hash of innotop's variables, which it can
manipulate.  It is probably a good idea if the plugin object saves a copy of it
for later use.  The variables are defined in the innotop variable
%pluggable_vars, and are as follows:

=over

=item action_for

A hashref of key mappings.  These are innotop's global hot-keys.

=item agg_funcs

A hashref of functions that can be used for grouping.  See L<"GROUPING">.

=item config

The global configuration hash.

=item connections

A hashref of connection specifications.  These are just specifications of how to
connect to a server.

=item dbhs

A hashref of innotop's database connections.  These are actual DBI connection
objects.

=item filters

A hashref of filters applied to table rows.  See L<"FILTERS"> for more.

=item modes

A hashref of modes.  See L<"MODES"> for more.

=item server_groups

A hashref of server groups.  See L<"SERVER GROUPS">.

=item tbl_meta

A hashref of innotop's table meta-data, with one entry per table (see
L<"TABLES"> for more information).

=item trans_funcs

A hashref of transformation functions.  See L<"TRANSFORMATIONS">.

=item var_sets

A hashref of variable sets.  See L<"VARIABLE SETS">.

=back

=head2 Plugin Events

Each event is defined somewhere in the innotop source code.  When innotop runs
that code, it executes the callback function for each plugin that expressed its
interest in the event.  innotop passes some data for each event.  The events are
defined in the %event_listener_for variable, and are as follows:

=over

=item extract_values($set, $cur, $pre, $tbl)

This event occurs inside the function that extracts values from a data source.
The arguments are the set of values, the current values, the previous values,
and the table name.

=item set_to_tbl

Events are defined at many places in this subroutine, which is responsible for
turning an arrayref of hashrefs into an arrayref of lines that can be printed to
the screen.  The events all pass the same data: an arrayref of rows and the name
of the table being created.  The events are set_to_tbl_pre_filter,
set_to_tbl_pre_sort,set_to_tbl_pre_group, set_to_tbl_pre_colorize,
set_to_tbl_pre_transform, set_to_tbl_pre_pivot, set_to_tbl_pre_create,
set_to_tbl_post_create.

=item draw_screen($lines)

This event occurs inside the subroutine that prints the lines to the screen.
$lines is an arrayref of strings.

=back

=head2 Simple Plugin Example

The easiest way to explain the plugin functionality is probably with a simple
example.  The following module adds a column to the beginning of every table and
sets its value to 1.

 use strict;
 use warnings FATAL => 'all';
 
 package Innotop::Plugin::Example;
 # description: Adds an 'example' column to every table
 
 sub new {
    my ( $class, %vars ) = @_;
    # Store reference to innotop's variables in $self
    my $self = bless { %vars }, $class;
 
    # Design the example column
    my $col = {
       hdr   => 'Example',
       just  => '',
       dec   => 0,
       num   => 1,
       label => 'Example',
       src   => 'example', # Get data from this column in the data source
       tbl   => '',
       trans => [],
    };
 
    # Add the column to every table.
    my $tbl_meta = $vars{tbl_meta};
    foreach my $tbl ( values %$tbl_meta ) {
       # Add the column to the list of defined columns
       $tbl->{cols}->{example} = $col;
       # Add the column to the list of visible columns
       unshift @{$tbl->{visible}}, 'example';
    }
 
    # Be sure to return a reference to the object.
    return $self;
 }
 
 # I'd like to be called when a data set is being rendered into a table, please.
 sub register_for_events {
    my ( $self ) = @_;
    return qw(set_to_tbl_pre_filter);
 }
 
 # This method will be called when the event fires.
 sub set_to_tbl_pre_filter {
    my ( $self, $rows, $tbl ) = @_;
    # Set the example column's data source to the value 1.
    foreach my $row ( @$rows ) {
       $row->{example} = 1;
    }
 }
 
 1;

=head2 Plugin Editor

The plugin editor lets you view the plugins innotop discovered and activate or
deactivate them.  Start the editor by pressing $ to start the configuration
editor from any mode.  Press the 'p' key to start the plugin editor.  You'll see
a list of plugins innotop discovered.  You can use the 'j' and 'k' keys to move
the highlight to the desired one, then press the * key to toggle it active or
inactive.  Exit the editor and restart innotop for the changes to take effect.

=head1 SQL STATEMENTS

innotop uses a limited set of SQL statements to retrieve data from MySQL for
display.  The statements are customized depending on the server version against
which they are executed; for example, on MySQL 5 and newer, INNODB_STATUS
executes "SHOW ENGINE INNODB STATUS", while on earlier versions it executes
"SHOW INNODB STATUS".  The statements are as follows:

 Statement           SQL executed
 =================== ===============================
 INNODB_STATUS       SHOW [ENGINE] INNODB STATUS
 KILL_CONNECTION     KILL
 KILL_QUERY          KILL QUERY
 OPEN_TABLES         SHOW OPEN TABLES
 PROCESSLIST         SHOW FULL PROCESSLIST
 SHOW_MASTER_LOGS    SHOW MASTER LOGS
 SHOW_MASTER_STATUS  SHOW MASTER STATUS
 SHOW_SLAVE_STATUS   SHOW SLAVE STATUS
 SHOW_STATUS         SHOW [GLOBAL] STATUS
 SHOW_VARIABLES      SHOW [GLOBAL] VARIABLES

=head1 DATA SOURCES

Each time innotop extracts values to create a table (see L<"EXPRESSIONS"> and
L<"TABLES">), it does so from a particular data source.  Largely because of the
complex data extracted from SHOW INNODB STATUS, this is slightly messy.  SHOW
INNODB STATUS contains a mixture of single values and repeated values that form
nested data sets.

Whenever innotop fetches data from MySQL, it adds two extra bits to each set:
cxn and Uptime_hires.  cxn is the name of the connection from which the data
came.  Uptime_hires is a high-resolution version of the server's Uptime status
variable, which is important if your L<"interval"> setting is sub-second.

Here are the kinds of data sources from which data is extracted:

=over

=item STATUS_VARIABLES

This is the broadest category, into which the most kinds of data fall.  It
begins with the combination of SHOW STATUS and SHOW VARIABLES, but other sources
may be included as needed, for example, SHOW MASTER STATUS and SHOW SLAVE
STATUS, as well as many of the non-repeated values from SHOW INNODB STATUS.

=item DEADLOCK_LOCKS

This data is extracted from the transaction list in the LATEST DETECTED DEADLOCK
section of SHOW INNODB STATUS.  It is nested two levels deep: transactions, then
locks.

=item DEADLOCK_TRANSACTIONS

This data is from the transaction list in the LATEST DETECTED DEADLOCK
section of SHOW INNODB STATUS.  It is nested one level deep.

=item EXPLAIN

This data is from the result set returned by EXPLAIN.

=item INNODB_TRANSACTIONS

This data is from the TRANSACTIONS section of SHOW INNODB STATUS.

=item IO_THREADS

This data is from the list of threads in the the FILE I/O section of SHOW INNODB
STATUS.

=item INNODB_LOCKS

This data is from the TRANSACTIONS section of SHOW INNODB STATUS and is nested
two levels deep.

=item OPEN_TABLES

This data is from SHOW OPEN TABLES.

=item PROCESSLIST

This data is from SHOW FULL PROCESSLIST.

=item OS_WAIT_ARRAY

This data is from the SEMAPHORES section of SHOW INNODB STATUS and is nested one
level deep.  It comes from the lines that look like this:

 --Thread 1568861104 has waited at btr0cur.c line 424 ....

=back

=head1 MYSQL PRIVILEGES

=over

=item *

You must connect to MySQL as a user who has the SUPER privilege for many of the
functions.

=item *

If you don't have the SUPER privilege, you can still run some functions, but you
won't necessarily see all the same data.

=item *

You need the PROCESS privilege to see the list of currently running queries in Q
mode.

=item *

You need special privileges to start and stop slave servers.

=item *

You need appropriate privileges to create and drop the deadlock tables if needed
(see L<"SERVER CONNECTIONS">).

=back

=head1 SYSTEM REQUIREMENTS

You need Perl to run innotop, of course.  You also need a few Perl modules: DBI,
DBD::mysql,  Term::ReadKey, and Time::HiRes.  These should be included with most
Perl distributions, but in case they are not, I recommend using versions
distributed with your operating system or Perl distribution, not from CPAN.
Term::ReadKey in particular has been known to cause problems if installed from
CPAN.

If you have Term::ANSIColor, innotop will use it to format headers more readably
and compactly.  (Under Microsoft Windows, you also need Win32::Console::ANSI for
terminal formatting codes to be honored).  If you install Term::ReadLine,
preferably Term::ReadLine::Gnu, you'll get nice auto-completion support.

I run innotop on Gentoo GNU/Linux, Debian and Ubuntu, and I've had feedback from
people successfully running it on Red Hat, CentOS, Solaris, and Mac OSX.  I
don't see any reason why it won't work on other UNIX-ish operating systems, but
I don't know for sure.  It also runs on Windows under ActivePerl without
problem.

innotop has been used on MySQL versions 3.23.58, 4.0.27, 4.1.0, 4.1.22, 5.0.26,
5.1.15, and 5.2.3.  If it doesn't run correctly for you, that is a bug that
should be reported.

=head1 FILES

$HOMEDIR/.innotop and/or /etc/innotop are used to store
configuration information.  Files include the configuration file innotop.conf,
the core_dump file which contains verbose error messages if L<"debug"> is
enabled, and the plugins/ subdirectory.

=head1 GLOSSARY OF TERMS

=over

=item tick

A tick is a refresh event, when innotop re-fetches data from connections and
displays it.

=back

=head1 ACKNOWLEDGEMENTS

The following people and organizations are acknowledged for various reasons.
Hopefully no one has been forgotten.

Allen K. Smith,
Aurimas Mikalauskas,
Bartosz Fenski,
Brian Miezejewski,
Christian Hammers, 
Cyril Scetbon,
Dane Miller,
David Multer,
Dr. Frank Ullrich,
Giuseppe Maxia,
Google.com Site Reliability Engineers,
Google Code,
Jan Pieter Kunst,
Jari Aalto,
Jay Pipes,
Jeremy Zawodny,
Johan Idren,
Kristian Kohntopp,
Lenz Grimmer,
Maciej Dobrzanski,
Michiel Betel,
MySQL AB,
Paul McCullagh,
Sebastien Estienne,
Sourceforge.net,
Steven Kreuzer,
The Gentoo MySQL Team,
Trevor Price,
Yaar Schnitman,
and probably more people that have not been included.

(If your name has been misspelled, it's probably out of fear of putting
international characters into this documentation; earlier versions of Perl might
not be able to compile it then).

=head1 COPYRIGHT, LICENSE AND WARRANTY

This program is copyright (c) 2006 Baron Schwartz.
Feedback and improvements are welcome.

THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation, version 2; OR the Perl Artistic License.  On UNIX and similar
systems, you can issue `man perlgpl' or `man perlartistic' to read these
licenses.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA  02111-1307  USA.

Execute innotop and press '!' to see this information at any time.

=head1 AUTHOR

Originally written by Baron Schwartz; currently maintained by Aaron Racine.

=head1 BUGS

You can report bugs, ask for improvements, and get other help and support at
L<http://code.google.com/p/innotop/>.  There are mailing lists, a source code
browser, a bug tracker, etc.  Please use these instead of contacting the
maintainer or author directly, as it makes our job easier and benefits others if the
discussions are permanent and public.  Of course, if you need to contact us in
private, please do.

=cut