Re: Memory leak in pg_stat_statements when qtext file contains invalid encoding

Daniel Gustafsson <daniel@yesql.se>

From: Daniel Gustafsson <daniel@yesql.se>
To: Lukas Fittl <lukas@fittl.com>
Cc: Gaurav Singh <gaurav.singh@yugabyte.com>, pgsql-bugs@lists.postgresql.org
Date: 2026-03-27T08:51:37Z
Lists: pgsql-bugs
> On 27 Mar 2026, at 09:21, Lukas Fittl <lukas@fittl.com> wrote:

> But I think you're correct about qbuffer - because that buffer is
> using malloc (not palloc), its not part of any memory context, and so
> it will happily leak on abort.
> 
> It appears our use of malloc in pg_stat_statements is so that we can
> fail on OOM and return NULL without a jump. I think that makes sense
> for when a GC cycle was triggered during regular query execution
> (since we don't want to error the original query), but it seems like
> just bubbling up the OOM if needed when querying the
> pg_stat_statements function seems fine.

We could also use palloc_extended() with MCXT_ALLOC_NO_OOM to avoid erroring
out on OOM and be able to return NULL?

--
Daniel Gustafsson




Commits

  1. Avoid memory leak on error while parsing pg_stat_statements dump file