DBI-Link - why is it so buggy?

I've spent several hours trying to make dbi-link work - I had errors related to table names and errors related to dbi_link.shadow_trigger_func(). However, I couldn't just get up - I was asked to suggest a sollution for MySQL <=> PostgreSQL replication and this module could help me to do the job...
So, I've found the following post , which helped me a lot, so I modified dbi_link.shadow_trigger_func to look the following way:

 CREATE OR REPLACE FUNCTION dbi_link.shadow_trigger_func()  
 RETURNS TRIGGER  
 LANGUAGE plperlu  
 AS $$  
 require 5.8.3;  
 ######################################################  
 #                          #  
 # Immediately reject anything that is not an INSERT. #  
 #                          #  
 ######################################################  
 if ($_TD->{event} ne 'INSERT') {  
   return "SKIP";  
 }  
 spi_exec_query('SELECT dbi_link.dbi_link_init()');  
 my $data_source_id = shift;  
 die "In shadow_trigger_function, data_source_id must be an integer"  
   unless ($data_source_id =~ /^\d+$/);  
 my $query = "SELECT dbi_link.cache_connection( $data_source_id )";  
 warn "In shadow_trigger_function, calling\n  $query" if $_SHARED{debug};  
 warn "In shadow_trigger_function, the trigger payload is\n". Dump(\$_TD) if $_SHARED{debug};  
 my $rv = spi_exec_query($query);  
 my $remote_schema = $_SHARED{get_connection_info}->({  
   data_source_id => $data_source_id  
 })->{remote_schema};  
 my $table = $_TD->{relname};  
 warn "Raw table name is $table" if $_SHARED{debug};  
 warn "In trigger on $table, action is $_TD->{new}{iud_action}" if $_SHARED{debug};  
 $table =~ s{  
   \A         # Beginning of string.  
   (.*)        # Actual table name.  
   _shadow       # Strip off shadow.  
   \z         # End of string.  
 }  
 {$1}sx;  
 $table = $remote_schema . "." . $table if defined $remote_schema;  
 warn "Cooked table name is $table" if $_SHARED{debug};  
 my $iud = {  
   I => \&do_insert,  
   U => \&do_update,  
   D => \&do_delete,  
 };  
 if ($iud->{ $_TD->{new}{iud_action} }) {  
   $iud->{ $_TD->{new}{iud_action} }->({  
     payload => $_TD->{new},  
     tbl => $table,  
     source_id => $data_source_id  
   });  
 }  
 else {  
   die "Trigger event was $_TD->{new}{iud_action}<, but should have been one of I, U or D!"  
 }  
 return 'SKIP';  
 sub do_insert {  
   my ($params) = @_;  
   die "In do_insert, must pass a payload!"  
     unless (defined $params->{payload});  
   die "In do_insert, payload must be a hash reference!"  
     unless (ref $params->{payload} eq 'HASH');  
   my (@keys, @values);  
   foreach my $key (sort keys %{ $params->{payload} } ) {  
     next unless $key =~ /^.?new_(.*)/;  
     my $real_key = $1;  
     push @keys, $real_key;  
     push @values, $_SHARED{dbh}{ $params->{source_id} }->quote(  
       $params->{payload}{$key}  
     );  
   }  
   my $sql = <<SQL;  
 INSERT INTO $params->{tbl} (  
   @{[  
     join(  
       ",\n  ",  
       @keys  
     )  
   ]}  
 )  
 VALUES (  
   @{[  
     join(  
       ",\n  ",  
       @values  
     )  
   ]}  
 )  
 SQL  
   warn "SQL is\n$sql" if $_SHARED{debug};  
   $_SHARED{dbh}{ $params->{source_id} }->do($sql);  
 }  
 sub do_update {  
   my ($params) = @_;  
   die "In do_update, must pass a payload!"  
     unless (defined $params->{payload});  
   die "In do_update, payload must be a hash reference!"  
     unless (ref $params->{payload} eq 'HASH');  
   my $sql = <<SQL;  
 UPDATE $params->{tbl}  
 SET  
   @{[ make_pairs({  
     payload => $params->{payload},  
     which => 'new',  
     joiner => ",\n  ",  
      transform_null => 'false',  
      source_id => "$params->{source_id}"  
   }) ]}  
 WHERE  
   @{[ make_pairs({  
     payload => $params->{payload},  
     which => 'old',  
     joiner => "\nAND ",  
     transform_null => 'true',  
      source_id => "$params->{source_id}"  
   }) ]}  
 SQL  
   warn "SQL is\n$sql" if $_SHARED{debug};  
   $_SHARED{dbh}{ $params->{source_id} }->do($sql);  
 }  
 sub do_delete {  
   my ($params) = @_;  
   die "In do_delete, must pass a payload!"  
     unless (defined $params->{payload});  
   die "In do_delete, payload must be a hash reference!"  
     unless (ref $params->{payload} eq 'HASH');  
   my $sql = <<SQL;  
 DELETE FROM $params->{tbl}  
 WHERE  
   @{[ make_pairs({  
     payload => $params->{payload},  
     which => 'old',  
     joiner => "\nAND ",  
     transform_null => 'true',  
      source_id => "$params->{source_id}"  
   }) ]}  
 SQL  
   warn "SQL is\n$sql" if $_SHARED{debug};  
   $_SHARED{dbh}{ $params->{source_id} }->do($sql);  
 }  
 sub make_pairs {  
   my ($params) = @_;  
   die "In make_pairs, must pass a payload!"  
     unless (defined $params->{payload});  
   die "In make_pairs, payload must be a hash reference!"  
     unless (ref $params->{payload} eq 'HASH');  
   warn "In make_pairs, parameters are:\n". Dump($params) if $_SHARED{debug};  
   my @pairs;  
   foreach my $key (  
     keys %{ $params->{payload} }  
   ) {  
     next unless $key =~ m/^(.?)$params->{which}_(.*)/;  
     my $left = "$1$2";       
     warn "In make_pairs, raw key is $key, cooked key is $left" if $_SHARED{debug};           
      warn "In make_pairs, pairs are @pairs" if $_SHARED{debug};            
      $bl=!defined $params->{payload}{$key};  
      $bl1=defined $params->{transform_null};  
    if (  
       defined $params->{transform_null} && # In a WHERE clause,  
       !defined $params->{payload}{$key}   # turn undef into IS NULL  
     ) {         
        push (@pairs, "$left");  
     }  
     else {         
        warn "o, fuck";    
        warn "params->source_id is $params->{source_id}";          
       push @pairs, "$left = " . $_SHARED{dbh}{ $params->{source_id} }->quote(  
         $params->{payload}{$key}  
       );  
     }  
   }  
   my $ret =  
     join (  
       $params->{joiner},  
       @pairs,  
     );  
   warn "In make_pairs, the pairs are:\n". Dump(\@pairs) if $_SHARED{debug};  
   return $ret;  
 }  
 $$;  

And this worked! Now I just can create after each row triggers on local PostgreSQL table and promote data to MySQL. I like DBI-Link, however, if I were to use it in production I would examine its code attentively...