DBI - Perl - 记录 MySQL 警告

Question

我正在使用 DBI 并希望将 MySQL 警告的日志记录添加到此脚本中。我能够毫无问题地记录真正的 MySQL 错误，但此时我需要跟踪正在生成的 MySQL 警告。如果 mysql 语句失败，我可以将错误的 sql 语句打印到 bad_sql.txt 并自动生成电子邮件。我需要做出两项改变，但我真的陷入困境 1）如果语句执行但有一个mysql警告我想将其捕获到last_sql_warning.txt 2）如果语句因锁定超时而失败，我想重新提交查询最多两次。

这就是现在转储到日志中的内容。

MiscLibs::MySQL::MySQLDoCmd，MySQL.pm 第 564 行：
-->UPDATE tbl_xxx_files SET ReloadStart=123" WHERE (FileName="image.txt")<--

相关代码块

#=====================================================================================
# Execute MySQL commands and handle errors
#=====================================================================================

sub MySQLDoCmd ($;$) {

my ($MySQLCmd, $Quite) = @_;

 if ( eval { $DBHandle->do($MySQLCmd) } ) {
   open (MYFILE2, '>/bb/bin/fa/logs/last_sql_warning.txt');
   # trying to write warning to log.  As a first pass I was attempting to write 
   # each statement to the log and include any warnings.  What I would like code to
   # do is check if there is a warning and only then write that statement to the log. 

   print MYFILE2 MySQLMakeID() . ": $DBHandle->errstr\n-->$MySQLCmd<--\n";

return 0;

} elsif ( ! $Quite ) {
  open (MYFILE, '>>/bb/bin/fa/logs/badsql.txt');
  print MYFILE  MySQLMakeID() . ": $@\n-->$MySQLCmd<--\n";

#=========SENDS EMAIL ON STATEMENT FAILURE===================
 while (my ($addressee, $address) = each (%emailList))
 {
     print STDERR "INFO: Sending email to $addressee at address $address\n";
     $message =~ s/ADDRESSEE/$addressee/g;
     $message =~ s/ERRORREASON/$errMessage/g;
     &sendMail($addressee, $address, $message);
     $message =~ s/$addressee/ADDRESSEE/g;
     $message =~ s/$errMessage/ERRORREASON/g;
  }

return 1;

 } else {
  return 1;

 }

}

完整代码块

use strict;                        # Everything must be defined before it is used
use warnings;                      # Print warnings
use POSIX;                         # Provides POSIX functions
use English '-no_match_vars';      # Provides access to English version of builtin variables
use Net::SMTP;

#===================================================================================================

package MiscLibs::MySQL;
use Exporter ();

our ($VERSION, @ISA, @EXPORT, @EXPORT_OK);

$VERSION = '1.00';
@ISA = qw(Exporter);
@EXPORT_OK = ( );
@EXPORT = qw( 

MySQLOpenConnection
MySQLCloseConnection

MySQLCloseHandle

MySQLErrNo
MySQLError
MySQLHostInfo
MySQLInfo
MySQLInsertID
MySQLProtoInfo
MySQLServerInfo
MySQLStat
MySQLThreadID
MySQLDBDStats
MySQLAutoReconnect
MySQLUseResult
MySQLShowTables
MySQLShowColumns
MySQLValidateFields
MySQLNumOfFields
MySQLErrStr
MySQLUseResults

MySQLDoCmd

MySQLDeleteRows
MySQLDeleteRowsICS
MySQLInsertRow
MySQLUpdateRows

MySQLSelectRows
MySQLGetHashRef
MySQLGetArray
MySQLSetLastUpdate
MySQLSetReportState

MySQLTruncateTable
MySQLDisableKeys
MySQLEnableKeys
MySQLOptimizeTable

MySQLCacheAddTable
MySQLCacheAddBuffer
MySQLCacheFlush

);
#=====================================================================================
my %emailList = (
                   "bob"=>"\@bog.com",
               );

my $errMessage = "error_message";
my $message = "MySQl Query Timed out - check logs/";

#======================================================================================
 sub sendMail()
{
 #not relevant - smtp code

     print "EXECUTE: Mail sent successfully\n";
}

#======================================================================================

use File::Basename;                # Provides basename, dirname and fileparse functions
use Data::Dumper;
use DBI;                           # Interface to MySQL

my $DBHandle;

my %CacheFieldNameStrings;
my %CacheFieldNameArrays;
my %CacheSizes;
my %CacheFieldValues;
my %CacheDupKeyCmds;

my %ValidateFieldNames;

my $MaxCacheSize = 50;

1;

#=====================================================================================
# Create an ID string for error reporting
#=====================================================================================

sub MySQLMakeID {

  my ($package, $filepath, $line, $subroutine, $hasargs,
      $wantarray, $evaltext, $is_require, $hints, $bitmask) = caller(1);

  $subroutine =~ s/main:://;

  my $filename = basename($filepath);

  my $id = "$subroutine, $filename line $line";

  # print "ID: '$id'\n";

  return $id;

}

#=====================================================================================
# Open MySQL connection and get reference information
#=====================================================================================

sub MySQLOpenConnection (;$) {

  my ( $NewMaxCacheSize ) = @_;

  my $Database;
  my $Host;
  my $Port;
  my $DSN;
  my $User;
  my $Password;
  my %Options;

  if ( defined($NewMaxCacheSize) && ($NewMaxCacheSize > 1) ) { $MaxCacheSize = $NewMaxCacheSize }

  $Database = $ENV{MySQLDatabase}; if ( ! defined($Database) ) { $Database = "database" }
  $Host     = $ENV{MySQLHost};     if ( ! defined($Host)     ) { $Host     = "host" }
  $Port     = $ENV{MySQLPort};     if ( ! defined($Port)     ) { $Port     = 123 }

  $DSN = "DBI:mysql";
  $DSN = $DSN . ":$Database";
  $DSN = $DSN . ";host=$Host";
  $DSN = $DSN . ";port=$Port";
  $DSN = $DSN . ";mysql_compression=1";

  $User     = 'user';
  $Password = 'pw';

  %Options = ( RaiseError => 1 );

  $DBHandle = DBI->connect($DSN, $User, $Password, \%Options);

  return $DBHandle;

}

#=====================================================================================
# Close MySQL connection opened above or a handle that is passed
#=====================================================================================

sub MySQLCloseConnection {
  if ( $DBHandle ) { $DBHandle->disconnect }
  return 0;
}

sub MySQLCloseHandle ($) { 
  my ($sh) = @_;
  if ( $sh ) { $sh->finish() }
  return 0;
}

#=====================================================================================
# Return a various database handle values and conditions
#=====================================================================================

sub MySQLErrNo      () { return $DBHandle->{'mysql_errno'}      }
sub MySQLError      () { return $DBHandle->{'mysql_error'}      }
sub MySQLHostInfo   () { return $DBHandle->{'mysql_hostinfo'}   }
sub MySQLInfo       () { return $DBHandle->{'mysql_info'}       }
sub MySQLInsertID   () { return $DBHandle->{'mysql_insertid'}   }
sub MySQLProtoInfo  () { return $DBHandle->{'mysql_protoinfo'}  }
sub MySQLServerInfo () { return $DBHandle->{'mysql_serverinfo'} }
sub MySQLStat       () { return $DBHandle->{'mysql_stat'}       }
sub MySQLThreadID   () { return $DBHandle->{'mysql_thread_id'}  }
sub MySQLDBDStats   () { return $DBHandle->{'mysql_dbd_stats'}  }

#=====================================================================================
# Optionally set but always return various database handle values and conditions
#=====================================================================================

sub MySQLAutoReconnect (;$) { 
  my $val = $_[0];
  if ( defined($val) ) { $DBHandle->{'mysql_auto_reconnect'} = $val }
  return $DBHandle->{'mysql_auto_reconnect'};
}

sub MySQLUseResult (;$) { 
  my $val = $_[0];
  if ( defined($val) ) { $DBHandle->{'mysql_use_result'} = $val }
  return $DBHandle->{'mysql_use_result'};
}

#=====================================================================================
# Execute MySQL commands and handle errors
#=====================================================================================

sub MySQLDoCmd ($;$) {

  my ($MySQLCmd, $Quite) = @_;

  if ( eval { $DBHandle->do($MySQLCmd) } ) {
       open (MYFILE2, '>>/bb/bin/fa/logs/last_sql.txt');
       #!!!!! trying to write warning to log 
       print MYFILE2 MySQLMakeID() . ": $DBHandle->errstr\n-->$MySQLCmd<--\n";
      return 0;

  } elsif ( ! $Quite ) {
      open (MYFILE, '>>/bb/bin/fa/logs/badsql.txt');
      print MYFILE  MySQLMakeID() . ": $@\n-->$MySQLCmd<--\n";

#=========SENDS EMAIL ON STATEMENT FAILURE===================    
 while (my ($addressee, $address) = each (%emailList))
     {
         print STDERR "INFO: Sending email to $addressee at address $address\n";
         $message =~ s/ADDRESSEE/$addressee/g;
         $message =~ s/ERRORREASON/$errMessage/g;
         &sendMail($addressee, $address, $message);
         $message =~ s/$addressee/ADDRESSEE/g;
         $message =~ s/$errMessage/ERRORREASON/g;
      }

    return 1;

  } else {
    return 1;

  }

}

#=====================================================================================
# Delete rows from a MySQL table
#=====================================================================================

sub MySQLDeleteRows ($;$) {

  my ($Table, $WhereRef) = @_;

  my $WhereList;

  my $MySQLCmd = 'DELETE FROM ' . $Table;

  if ( $WhereRef ) {
    $WhereList = BuildLists ('where', $WhereRef);
    $MySQLCmd = $MySQLCmd . $WhereList;
  }

  return MySQLDoCmd($MySQLCmd);

}


#=====================================================================================
# Select rows from a MySQL table and return a statement handle
#=====================================================================================

sub MySQLSelectRows ($$;$$) {

  my ($What, $Table, $WhereRef, $OrderRef) = @_;

  my $MySQLCmd = "SELECT $What FROM $Table";

  if ( $WhereRef ) { $MySQLCmd = $MySQLCmd . BuildLists ('Where'  , $WhereRef) }
  if ( $OrderRef ) { $MySQLCmd = $MySQLCmd . BuildLists ('OrderBy', $OrderRef) }

  # print "MySQLSelectRows: MySQLCmd '$MySQLCmd'\n";

  my $StmtHandle;

  if ( ! eval {  $StmtHandle = $DBHandle->prepare($MySQLCmd) } ) {
    print STDERR MySQLMakeID() . ": $@\n-->$MySQLCmd<--\n";
    return undef;

  } elsif ( ! eval { $StmtHandle->execute() } ) {
    print STDERR MySQLMakeID() . ": $StmtHandle->errstr\n-->$MySQLCmd<--\n";
    return undef;

  } else {
    return $StmtHandle;

  }

}

#=====================================================================================
# Return a various statement handle values and conditions
#====================================================================================

sub MySQLNumOfFields ($) { my ($sh) = @_; return $sh->{'NUM_OF_FIELDS'}      }
sub MySQLErrStr      ($) { my ($sh) = @_; return $sh->errstr                 }

sub MySQLGetHashRef  ($) { my ($sh) = @_;
  if ( my $Ref = $sh->fetchrow_hashref() ) { return $Ref }
  else                                     { MySQLCloseHandle($sh); return undef } 
}

sub MySQLGetArray ($) { my ($sh) = @_; 
  if ( my $Ref = $sh->fetchrow_array()   ) { return $Ref }
  else                                     { MySQLCloseHandle($sh); return undef } 
}

#=====================================================================================
# Optionally set but always return various statement handle values and conditions
#=====================================================================================

sub MySQLUseResults ($;$) { 
  my ($sh, $val) = @_;
  if ( defined($val) ) { $sh->{'mysql_use_result'} = $val }
  return $sh->{'mysql_use_result'};
}

#=====================================================================================
# Update a row in a MySQL table
#=====================================================================================

sub MySQLUpdateRows ($$;$) {

  my ($Table, $SetRef, $WhereRef) = @_;

  my $MySQLCmd;
  my $SetList;
  my $WhereList;

  $MySQLCmd = 'UPDATE ' . $Table;

  $SetList = BuildLists ('set', $SetRef);

  $MySQLCmd = $MySQLCmd . $SetList;

  if ( $WhereRef ) {
    $WhereList = BuildLists ('where', $WhereRef);
    $MySQLCmd = $MySQLCmd . $WhereList ;
  }

  # print "MySQLUpdateRows: MySQLCmd '$MySQLCmd'\n";

  return MySQLDoCmd($MySQLCmd);

}



#=====================================================================================
# Truncate a MySQL table
#=====================================================================================

sub MySQLTruncateTable ($) {

  my ($Table) = @_;

  my $MySQLCmd = 'TRUNCATE TABLE ' . $Table;

  return MySQLDoCmd($MySQLCmd);

}




#=====================================================================================
#
# The routines below maintain a cache of MySQL values to allow inserting multiple
# rows at a time to improve efficiency
#
#=====================================================================================

#=====================================================================================
# Add a table to the MySQL Cache
#=====================================================================================

sub MySQLCacheAddTable ($$;$) {

  my ( $TableName, $FieldNameArray, $DupKeyCmds ) = @_;

  my $DupKeyCmd;

  my $FieldName;
  my $FieldNameString = '';

  for $FieldName ( @$FieldNameArray ) {
    if ( $FieldNameString ) { $FieldNameString = $FieldNameString . ',' }
    $FieldNameString = $FieldNameString . $FieldName;    
  }

    $CacheFieldNameStrings{$TableName} = $FieldNameString;
  @{$CacheFieldNameArrays{$TableName}} = @$FieldNameArray;
  $CacheDupKeyCmds{$TableName}         = $DupKeyCmds;
  $CacheSizes{$TableName}              = 0;
  $CacheFieldValues{$TableName}        = '';

  return 0;

}

#=====================================================================================
# Add a buffer to the MySQL cache
#=====================================================================================

sub MySQLCacheAddBuffer ($$) {

  my ( $TableName, $AddValues ) = @_;

  my $FieldName;
  my $FieldValue;
  my $FieldValues;

  my $CacheValues;

  if ( ! defined($CacheFieldNameStrings{$TableName}) ) {
    print STDERR MySQLMakeID() . ": Table '$TableName' has not been initialized with the 'AddTable' command\n"; 
    return 1;
  }

  if ( $CacheSizes{$TableName} >= $MaxCacheSize ) { 
    # if ( $TableName eq 'tbl_xyz' ) {
      # print "Flushing $TableName cache before adding buffer: CacheSize = '$CacheSizes{$TableName}'\n" }
    MySQLCacheFlush ($TableName);
  }

  $FieldValues = '';

  for $FieldName ( @{$CacheFieldNameArrays{$TableName}} ) {

    $FieldValue = $AddValues->{$FieldName};

    if ( ! defined($FieldValue) ) { $FieldValue  =  '' }                 # Make sure value is defined
    else                          { $FieldValue  =~ s/(["',\\])/\\$1/g } # Make sure that MySQL special chars are escaped

    if ( $FieldValues ) { $FieldValues =  $FieldValues . "," }

    $FieldValues =  $FieldValues . "'" . $FieldValue . "'";

  }

  $CacheValues = $CacheFieldValues{$TableName};

  if ( $CacheValues ) { $CacheValues = $CacheValues . ',' }

  $CacheValues = $CacheValues . '(' . $FieldValues . ')';

  $CacheFieldValues{$TableName} = $CacheValues;

  $CacheSizes{$TableName}++;

  # if ( $TableName eq 'tbl_xyz' ) {
    # print "Added buffer to $TableName cache: CacheSizes '$CacheSizes{$TableName}', CacheValues '$CacheValues'\n" }

  return 0;

}

#=====================================================================================
# Flush entries from MySQL cache
#=====================================================================================

sub MySQLCacheFlush ($) {

  my ( $TableName ) = @_;

  my $FlushTable;
  my @FlushTables,

  my $FieldNames;
  my $FieldValues;
  my $DupKeyCmd;

  my $MySQLCmd;

  if ( lc($TableName) eq 'all' ) { 
    for $FlushTable ( keys(%CacheFieldNameStrings) ) { push @FlushTables, $FlushTable }

  } elsif ( ! defined($CacheFieldNameStrings{$TableName}) ) {
    print STDERR MySQLMakeID() . ": Table '$TableName' has not been initialized with the 'AddTable' command\n"; 
    return 1;

  } else {
    push @FlushTables, $TableName;

  }

  FlushTable: for $FlushTable ( @FlushTables ) {

    $FieldValues = $CacheFieldValues{$FlushTable};

    $CacheFieldValues{$FlushTable} = '';
    $CacheSizes{$FlushTable}       = 0;

    if ( ! $FieldValues ) { next FlushTable }

    $FieldNames = $CacheFieldNameStrings{$FlushTable};
    $DupKeyCmd  = $CacheDupKeyCmds{$FlushTable};

#Removed DELAYED after moving to innodb
#$MySQLCmd = "INSERT DELAYED INTO $FlushTable ($FieldNames) VALUES $FieldValues";

 $MySQLCmd = "INSERT INTO $FlushTable ($FieldNames) VALUES $FieldValues";

    if ( $DupKeyCmd ) { $MySQLCmd = $MySQLCmd . ' ON DUPLICATE KEY UPDATE ' . $DupKeyCmd }

    return MySQLDoCmd($MySQLCmd);

  }

}

sub BuildLists ($$;$) {

  my ($Type, $Ref1, $Ref2) = @_;

  my $Ref1Type = ref($Ref1);
  my $Ref2Type = ref($Ref2);

  my $Name;
  my $NameList;
  my $Value;
  my $ValueList;

  my %Fields;

  my $RtnVal;

  $Type = lc($Type);

  my $TypeIndex = index('values set where orderby', $Type);

  # print "Type '$Type', TypeIndex '$TypeIndex', Ref1Type '$Ref1Type', Ref1 '$Ref1'\n";

  if ( $TypeIndex < 0 ) {

    print STDERR MySQLMakeID() . ": $Type is not a a valid type. Use 'values', 'set' or 'where'\n";
    return $RtnVal;

  } elsif ( $Ref1Type eq '' ) {

    if ( $Type eq 'values' ) {
      $RtnVal = '(' . $Ref1 . ') VALUES (' . $Ref2 . ')';
    } elsif ( $Type eq 'set' ) {
      $RtnVal = ' SET ' . $Ref1;
    } elsif ( $Type eq 'where' ) {
      $RtnVal = ' WHERE ' . $Ref1;
    } elsif ( $Type eq 'orderby' ) {
      $RtnVal = ' ORDER BY ' . $Ref1;
    }

  } elsif ( $Ref1Type eq 'SCALAR' ) {

    if ( $Type eq 'values' ) {
      $RtnVal = '(' . $$Ref1 . ') VALUES (' . $$Ref2 . ')';
    } elsif ( $Type eq 'set' ) {
      $RtnVal = ' SET ' . $$Ref1;
    } elsif ( $Type eq 'where' ) {
      $RtnVal = ' WHERE ' . $$Ref1;    
    } elsif ( $Type eq 'orderby' ) {
      $RtnVal = ' ORDER BY ' . $$Ref1;
    }

  } elsif ( $Ref1Type eq 'HASH' ) {

    for $Name ( keys(%$Ref1) )  {

      $Value = $Ref1->{$Name};

      if ( ! defined($Value) ) { $Value  =  '' }                 # Make sure value is defined
      else                     { $Value  =~ s/(["',\\])/\\$1/g } # Make sure that MySQL special chars are escaped

      $Fields{$Name} = $Value;

    }

    if ( $Type eq 'values' ) {

      while (($Name, $Value) = each %Fields ) {
        if ( $NameList ) {
          $NameList  = $NameList  . ','  . $Name;
          $ValueList = $ValueList . ',"' . $Value . '"';
        } else {
          $NameList  = $Name;
          $ValueList = '"' . $Value . '"';    
        }
      }

      $RtnVal = " ($NameList) VALUES ($ValueList)";

    } elsif ( $Type eq 'set' ) {
      $RtnVal = '';
      while (($Name, $Value) = each %Fields ) {
        if ( $RtnVal ) { $RtnVal = $RtnVal . ',' }
        $RtnVal = $RtnVal . $Name . '="' . $Value . '"';
      }
      $RtnVal = ' SET ' . $RtnVal;

    } elsif ( $Type eq 'where' ) {
      $RtnVal = '';
      while (($Name, $Value) = each %Fields ) {
        if ( $RtnVal ) { $RtnVal = $RtnVal . ' AND ' }
        $RtnVal = $RtnVal . '(' . $Name . '="' . $Value . '")';
      }
      $RtnVal = ' WHERE ' . $RtnVal;

    }

  } else {

    print STDERR MySQLMakeID() . ": Parameter two is unsupported reference type '$Ref1Type'\n";
    return $RtnVal;

  }

  return $RtnVal;

}

sub BuildListsInt ($$;$) {

  my ($Type, $Ref1, $Ref2) = @_;
  my $Ref1Type = ref($Ref1);
  my $Ref2Type = ref($Ref2);

  my $Name;
  my $NameList;
  my $Value;
  my $ValueList;

  my %Fields;

  my $RtnVal;

  $Type = lc($Type);

  my $TypeIndex = index('values set where orderby', $Type);

  # print "Type '$Type', TypeIndex '$TypeIndex', Ref1Type '$Ref1Type', Ref1 '$Ref1'\n";

  if ( $TypeIndex < 0 ) {

    print STDERR MySQLMakeID() . ": $Type is not a a valid type. Use 'values', 'set' or 'where'\n";
    return $RtnVal;

  } elsif ( $Ref1Type eq '' ) {

    if ( $Type eq 'values' ) {
      $RtnVal = '(' . $Ref1 . ') VALUES (' . $Ref2 . ')';
    } elsif ( $Type eq 'set' ) {
      $RtnVal = ' SET ' . $Ref1;
    } elsif ( $Type eq 'where' ) {
      $RtnVal = ' WHERE ' . $Ref1;
    } elsif ( $Type eq 'orderby' ) {
      $RtnVal = ' ORDER BY ' . $Ref1;
    }

  } elsif ( $Ref1Type eq 'SCALAR' ) {

    if ( $Type eq 'values' ) {
      $RtnVal = '(' . $$Ref1 . ') VALUES (' . $$Ref2 . ')';
    } elsif ( $Type eq 'set' ) {
      $RtnVal = ' SET ' . $$Ref1;
    } elsif ( $Type eq 'where' ) {
      $RtnVal = ' WHERE ' . $$Ref1;
    } elsif ( $Type eq 'orderby' ) {
      $RtnVal = ' ORDER BY ' . $$Ref1;
    }

  } elsif ( $Ref1Type eq 'HASH' ) {

    for $Name ( keys(%$Ref1) )  {

      $Value = $Ref1->{$Name};

      if ( ! defined($Value) ) { $Value  =  '' }                 # Make sure value is defined
      else                     { $Value  =~ s/(["',\\])/\\$1/g } # Make sure that MySQL special chars are escaped

      $Fields{$Name} = $Value;

    }

    if ( $Type eq 'values' ) {

      while (($Name, $Value) = each %Fields ) {
        if ( $NameList ) {
          $NameList  = $NameList  . ','  . $Name;
          $ValueList = $ValueList . ',"' . $Value . '"';
        } else {
          $NameList  = $Name;
          $ValueList = '"' . $Value . '"';
        }
      }

      $RtnVal = " ($NameList) VALUES ($ValueList)";

    } elsif ( $Type eq 'set' ) {
      $RtnVal = '';
      while (($Name, $Value) = each %Fields ) {
        if ( $RtnVal ) { $RtnVal = $RtnVal . ',' }
        $RtnVal = $RtnVal . $Name . '="' . $Value . '"';
      }
      $RtnVal = ' SET ' . $RtnVal;

    } elsif ( $Type eq 'where' ) {
      $RtnVal = '';
      while (($Name, $Value) = each %Fields ) {
        if ( $RtnVal ) { $RtnVal = $RtnVal . ' AND ' }
        $RtnVal = $RtnVal . '(' . $Name . '=' . $Value . ')';
      }
      $RtnVal = ' WHERE ' . $RtnVal;

    }

  } else {

    print STDERR MySQLMakeID() . ": Parameter two is unsupported reference type '$Ref1Type'\n";
    return $RtnVal;

  }

  return $RtnVal;

}

Answer 1

你问两个问题。

如何捕获 MySQL 警告？

1）如果语句执行但有一个mysql警告，我想将其捕获到last_sql_warning.txt

最简单的方法执行此操作只是将 MySQL 警告提升为错误，您已经知道可以记录。这样就可以解决问题： $DBHandle->do(q|SET sql_mode='traditional'|);

一个更难的方法是通过 枚举警告SHOW WARNINGS，您可以检查 mysql_warning_count 属性是否报告遇到警告。然而，在撰写本文时，DBD::mysql 仅针对语句（而非数据库）句柄公开该属性，非常不便。

更新： DBD::mysql 自 4.025 (2013-11-05) 起支持数据库句柄上的此属性，因此下面的代码可以简化为 $dbh->{mysql_warning_count} 检查。

因此，您可能会执行以下操作：

my $warnings;
my $ok = eval {
           my $sth = $DBHandle->prepare($MySQLCmd);
           $sth->execute();
           $warnings = $sth->{mysql_warning_count};
           1;
         };

unless ($ok) {                   # Some error encountered
  ... # log it
} elsif ($warnings) {            # Some warning(s) encountered
  ... # open log file

  my $warnings = $DBHandle->selectall_arrayref('SHOW WARNINGS');
  for my $row (@$warnings) {
    # @$row is something like ('Warning', 1265, "Data truncated for column 'col' at row 1")
    ... # log it
  }
}

如何重试因特定错误而失败的语句？

2）如果语句因锁定超时而失败，我想重新提交查询最多两次

在错误处理分支中，检查$DBHandle->err 对于您关心的MySQL错误代码（可能是1205号，ER_LOCK_WAIT_TIMEOUT），并根据需要重试。