Re: Potential dbi memory leak.

It seems to be further documented here, together with a solution:

http://stackoverflow.com/questions/13338308/perl-dbi-memory-leak,

But the solution does not seem to be reliable.  Sometimes it works 
sometimes not.

I'll update you when I know more.

Regards,

Steve.

On 26/05/15 07:07, Steve Cookson - gmail wrote:
> Hi Guys,
>
> You may have seen part of this post on PerlMonks.  If so apologies for 
> the duplication.  This started off as a general search for leaks in my 
> code, and resulted in a few hits, one of which was attached to every 
> database access.
>
> A simple "select ATT_RECORD_NAME_TXT from TBL_TEST; " results in the 
> leak of one scalar value.  It seems to be attached to the ->prepare 
> statement.
>
> At first I assumed it was down to my Firebird driver, which is 
> relatively new, so I switched the driver to ODBC::Firebird, with the 
> same result.  Finally I changed to mysql and again got a memory leak.  
> The only thing I can assume is that either my code is generically 
> wrong (and I hope this is the case), or there is a leak in dbi, which 
> I would be surprised by.
>
> I would appreciate some advice.
>
> Test code follows.  Please install Devel::Leak to pick up leaked 
> scalars and update the dsn to the dsn of your choice.
>
> Thanks for your help.
>
> Regards,
>
> Steve.
>
> #! /usr/bin/perl
>
> package main;
> use strict;
> use warnings;
> use DBI;
> #use DBD::Firebird;
> use DBD::ODBC;
> use Devel::Leak;
>     my $handle;
>     my $count_start;
>     my $count_stop;
>     my $gl_dbh;
>
>     # Just do this 5 times to make sure there is no contribution to 
> $handle count from Devel::Leak
>     for (1..10){
>     print "Handle init: ", Devel::Leak::NoteSV($Launch::handle),"\n";
>     }
> #my $loc_dsn = <<DSN;
> #dbi:ODBC:Driver=Firebird;Dbname=/home/image/Documents/Endoscopia/DB/newEndo.fdb; 
>
> #ib_dialect=3;
> #DSN
> my $loc_dsn = <<DSN;
> DBI:mysql:database=new_schema_test;
> host=localhost;
> port=3306";
> DSN
>     $Launch::gl_dbh=DBI->connect($loc_dsn,"root","password", {
>         PrintError => 1,                    # Report errors via warn
>         RaiseError => 1                    # Report errors via Die
>     }
>     ) or die;
>
>     my @loc_sql_string =();
>     $loc_sql_string[0]="CREATE TABLE TBL_TEST_LEAK ( 
> ATTR_RECORD_ID_TXT VARCHAR(10) NOT NULL, ATT_RECORD_NAME_TXT 
> VARCHAR(255), CONSTRAINT PK_TBL_TEST_LEAK PRIMARY KEY 
> (ATTR_RECORD_ID_TXT) ); ";
>     $loc_sql_string[1]="GRANT DELETE, INSERT, REFERENCES, SELECT, 
> UPDATE ON TBL_TEST_LEAK TO  SYSDBA WITH GRANT OPTION";
>     $loc_sql_string[2]="INSERT INTO TBL_TEST_LEAK (ATTR_RECORD_ID_TXT, 
> ATT_RECORD_NAME_TXT) VALUES ('206', 'Delay Test 1' )";
>     $loc_sql_string[3]="select ATT_RECORD_NAME_TXT from TBL_TEST_LEAK; ";
>     $loc_sql_string[4]= $loc_sql_string[3];
>     $loc_sql_string[5]= $loc_sql_string[3];
>     $loc_sql_string[6]= $loc_sql_string[3];
>     $loc_sql_string[7]= $loc_sql_string[3];
>     $loc_sql_string[8]= $loc_sql_string[3];
>     $loc_sql_string[9]="drop table TBL_TEST_LEAK; ";
>
>     for (my $i=1;$i<=9;$i++){
>     $count_start=Devel::Leak::NoteSV($Launch::handle);
>     print "DBD start: ", $count_start,"\n";
>     print $loc_sql_string[$i], "\n";
>     dbd_select($loc_sql_string[$i]);
>     # You can use
>     #$count_stop=Devel::Leak::CheckSV($Launch::handle);
>     $count_stop=Devel::Leak::NoteSV($Launch::handle);
>     print "Handle stop: ", $count_stop,"\n";
>     print "Count difference: ", $count_stop-$count_start,"\n";
>     }
>     $Launch::gl_dbh->disconnect;
>
> sub dbd_select{
>     my $loc_sql_string=shift;
>     my $loc_sth=$Launch::gl_dbh->prepare($loc_sql_string) or die;
>     #$loc_sth->execute() or die;
>     #$loc_sth->finish();
>     return;
> }
>
> 1;
>
>