Horton

Re: Why our Valgrind reports suck

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Richard Guo <guofenglinux@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Álvaro Herrera <alvherre@kurilemu.de>, pgsql-hackers@lists.postgresql.org
Date: 2025-07-10T18:16:04Z
Lists: pgsql-hackers 
Richard Guo <guofenglinux@gmail.com> writes:
> I'm just skimming through the changes and happened to spot two minor
> things.

> In 0008:
>         if (pq_mq_handle != NULL)
> +       {
>             shm_mq_detach(pq_mq_handle);
> +           pfree(pq_mq_handle);
> +       }
>         pq_mq_handle = NULL;
> Maybe we could move "pq_mq_handle = NULL;" inside the if branch?
> Though I see we're doing it in your way on master.

Yeah, we could make it be like that.  I was just trying to do the
minimal change from master.

> In 0015:
> I noticed that we're freeing the list returned from
> logicalrep_workers_find().  Should we do the same for the "workers"
> list in AtEOXact_LogicalRepWorkers()?

Seems probably unnecessary.  AtEOXact functions should run in the
transaction's CurTransactionContext, which will be reset or deleted
once the transaction is done.  If we were talking about a large amount
of memory it might be worth reclaiming sooner, but surely we are not.

> This is very useful work; I hope we can get it in soon.

Thanks for looking at it!

			regards, tom lane

Commits

  1. Undo thinko in commit e78d1d6d4.

  2. Avoid leakage of zero-length arrays in partition_bounds_copy().

  3. Fix MemoryContextAllocAligned's interaction with Valgrind.

  4. Fix assorted pretty-trivial memory leaks in the backend.

  5. Improve our support for Valgrind's leak tracking.

  6. Reduce leakage during PL/pgSQL function compilation.

  7. Silence Valgrind leakage complaints in more-or-less-hackish ways.

  8. Silence complaints about leaks in PlanCacheComputeResultDesc.

  9. Suppress complaints about leaks in TS dictionary loading.

  10. Suppress complaints about leaks in function cache loading.

  11. Fix per-relation memory leakage in autovacuum.

  12. Fix AlignedAllocRealloc to cope sanely with OOM.