Re: Potential dbi memory leak.

Hi Tim,

Oh yes for (1..500) does exactly that.  Thank you.  No memory leak at all!

Regards

Steve.

On 26/05/15 10:13, Tim Bunce wrote:
> I've added this as a note:
>
>      Note that the ChildHandles array holds weak references and that 'from
>      time to time' the old slots get freed up. This isn't a leak, it just
>      appears to be if you're not familiar with the caching that DBI does
>      internally. You can rest assured that if the DBI did have a real leak
>      a) a great many people would be affected and b) it would get fixed very quickly.
>
> I think 'from time to time' is every 120 or so newly created child handles.
>
> Tim.
>
> On Tue, May 26, 2015 at 07:57:53AM -0300, Steve Cookson - gmail wrote:
>> 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;
>>>
>>>