Re: Memory leak in DBI ?

I trust the script is destroying the results and, where appropriate,
the $sth before calling Devel::Leak::CheckSV.

Could you post the script?

Tim.

On Thu, Apr 10, 2008 at 01:00:09PM +0200, Philippe Bruhat (BooK) wrote:
> Hi,
> 
> While looking for memory leaks in our code using Devel::Leak, we
> pinpointed one of them to a call to selectcol_arrayref().
> 
> The attached script tries several DBI commands on various DBD drivers
> (it's easy to add one, or to add code to be tested for leakage), and
> reports how much leakage Devel::Leak caught.
> 
> Just to be sure that we're not mistaking for a leak some Perl/DBI internal
> structures that are initialized the first time the code is called,
> we run every command twice, and only look for leakage the second time.
> 
> It is very possible that the test script takes something expected for
> a memory leak, but I've tried to make it only report valid leaks. (try
> removing the first eval $cmd from the test script to see the difference)
> 
> Devel::Leak is *very* verbose (even more with a Perl compiled for
> debugging), so if you're only interested in the results, run:
> 
>     perl dbi_leak.t 2>&1 | grep ok
> 
> Here, with Perl 5.8.8, DBI 1.602, DBD::CSV 0.22, DBD::SQLite 1.14,
> DBD::mysql 4.006, I get the following results:
> 
>     ok 1 - leak = 0 for csv     my $sanity = 1;
>     not ok 2 - leak = 9 for csv     my $s = $dbh->prepare( $sql ); $s->execute(); 1 while $s->fetchrow_arrayref(); $s->finish;
>     not ok 3 - leak = 1 for csv     my $s = $dbh->prepare_cached( $sql ); $s->execute(); 1 while $s->fetchrow_arrayref(); $s->finish;
>     not ok 4 - leak = 2 for csv     my $c = $dbh->selectcol_arrayref( $sql, { Column => [1] } )
>     not ok 5 - leak = 2 for csv     my @a = $dbh->selectrow_array( $sql )
>     not ok 6 - leak = 2 for csv     my $a = $dbh->selectrow_arrayref( $sql )
>     ok 7 - leak = 0 for mysql   my $sanity = 1;
>     not ok 8 - leak = 1 for mysql   my $s = $dbh->prepare( $sql ); $s->execute(); 1 while $s->fetchrow_arrayref(); $s->finish;
>     ok 9 - leak = 0 for mysql   my $s = $dbh->prepare_cached( $sql ); $s->execute(); 1 while $s->fetchrow_arrayref(); $s->finish;
>     not ok 10 - leak = 1 for mysql   my $c = $dbh->selectcol_arrayref( $sql, { Column => [1] } )
>     not ok 11 - leak = 1 for mysql   my @a = $dbh->selectrow_array( $sql )
>     not ok 12 - leak = 1 for mysql   my $a = $dbh->selectrow_arrayref( $sql )
>     ok 13 - leak = 0 for sqlite  my $sanity = 1;
>     not ok 14 - leak = 1 for sqlite  my $s = $dbh->prepare( $sql ); $s->execute(); 1 while $s->fetchrow_arrayref(); $s->finish;
>     ok 15 - leak = 0 for sqlite  my $s = $dbh->prepare_cached( $sql ); $s->execute(); 1 while $s->fetchrow_arrayref(); $s->finish;
>     not ok 16 - leak = 1 for sqlite  my $c = $dbh->selectcol_arrayref( $sql, { Column => [1] } )
>     not ok 17 - leak = 1 for sqlite  my @a = $dbh->selectrow_array( $sql )
>     not ok 18 - leak = 1 for sqlite  my $a = $dbh->selectrow_arrayref( $sql )
>     # Looks like you failed 13 tests of 18.
> 
> I've been told that it also leaks on 5.10.0.
> 
> 
> -- 
>  Philippe Bruhat (BooK)
> 
>  The truly stupid always find a way to create disaster.
>                                                 (Moral from Groo #10 (Image))