Re: Memory leak in WAL sender with pgoutput (v10~)

On Thu, Dec 5, 2024 at 1:32 PM Zhijie Hou (Fujitsu)
<houzj.fnst@fujitsu.com> wrote:
>
> On Wednesday, December 4, 2024 7:39 PM Michael Paquier <michael@paquier.xyz> wrote:
> >
> > On Wed, Dec 04, 2024 at 06:42:55AM +0000, Zhijie Hou (Fujitsu) wrote:
> > > I can try to write a patch if no one else is working on this.
> >
> > If you have some room to write a patch, that would be really nice.
> > Thanks.
>
> No problem. Here is the patch for the HEAD. This patch introduces a new memory
> context within PGOutputData, specifically for allocating memory for
> publication_names. The new memory context is nested under the logical decoding
> context, ensuring it is freed at the end of decoding through
> FreeDecodingContext.

+1 for using new memory context to fix the issue for HEAD.

>
> I realized that this patch cannot be backpatched because it introduces a new
> field into the public PGOutputData structure. Therefore, I think we may need to
> use Alvaro's version [1] for the back branches.

FWIW for back branches, I prefer using the foreach-pfree pattern
Michael first proposed, just in case. It's not elegant but it can
solve the problem while there is no risk of breaking non-core
extensions. I think we can live with such (a bit of) ugliness on back
branches.

Regards,

--
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com