Excellent. Applied. Many thanks Doru!
Tim.
On Mon, Jun 12, 2006 at 04:52:44PM +0300, Doru Theodor Petrescu wrote:
>
> Hi,
>
> After a lot of hours I managed to trace a leak in the DBI module.
> The leak is quite small, and only affects long running programms that do
> a lot of queries.
>
> consider this short program:
>
>
> use DBI;
> $DB = DBI->connect( 'DBI:mysql:ttt', 'root', '' ) ;
> $DB->prepare("select 1") foreach ( 1..100000 );
>
> it doesn't acctualy run anything. what it does it creates 100000s of
> statement handles and then destroys them. but this also leaks exactly 16
> bytes for each iteration.
>
> if you use Devel::LeakTrace module you'll notice that it complains about
> 100000s of leaked RVs from DBI.pm line 1188.
> on that line there is a call to _setup_handle() that is implemented in
> XS.
>
> after more digging and a lot of trial and error, it looks like the
> problem is with the caching of ChildHandles.
>
> what it actualy does it keeps a weak reference to each STH that it ever
> allocates. and every 120 or so, it does some house cleaning and remove
> from the array those references that are no longer valid.
>
> the problem is that it NEVER actualy FREE those references. so they will
> leak.
>
> the attached 2 line patch will add a sv_free() to free what is no longer
> needed.
>
>
>
> Best Regards,
> Doru Theodor Petrescu
>
> diff -uBbr orig/DBI-1.51/DBI.xs DBI-1.51/DBI.xs
> --- orig/DBI-1.51/DBI.xs 2006-06-06 12:49:13.000000000 +0300
> +++ DBI-1.51/DBI.xs 2006-06-12 16:26:52.000000000 +0300
> @@ -1069,6 +1069,8 @@
> SV *sv = av_shift(av);
> if (SvOK(sv))
> av_push(av, sv);
> + else
> + sv_free(sv); /* keep it leak-free by Doru
> Petrescu [EMAIL PROTECTED] */
> }
> }
> }
