Re: Relevance of ChildHandles

On Tue, May 07, 2013 at 10:28:29PM +0100, Alberto Simões wrote:
>    Hello
> 
>    Any kind of handle on DBI has a $h->{ChildHandles} that store weakrefs to all child handles created. For
>    instance, on a $dbh, you will get a list of weakrefs to $sth you create.
> 
>    When one of those $sth gets out of scope, its count get to 0. What Perl does to the weakref, is to
>    change it to an undef value (Perl isn't able to remove that element from the array).
> 
>    Although a single undef takes less memory than a complete $sth object, it takes memory space. And if we
>    get a lot of these undef values, things get worse.

The DBI purges undef entries from ChildHandles from time to time.
(Specifically whenever the number of entries is a multiple of 120.)

At this stage in the life of the DBI I think it's reasonable to assume
that there isn't a leak in the DBI itself. If there was then a lot of
people would be affected and complaining about it.

Tim.