From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@gmail.com>
cc: Dmitry Astapov <dastapov@gmail.com>, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17619: AllocSizeIsValid violation in parallel hash join
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Comments: In-reply-to Thomas Munro <thomas.munro@gmail.com>
	message dated "Sat, 24 Sep 2022 11:00:00 +1200"
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Date: Fri, 23 Sep 2022 19:19:33 -0400
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Thomas Munro <thomas.munro@gmail.com> writes:
> While testing with that module I found another bug: the
> per-participant npages counter was not explicitly initialised to zero
> in sts_initialize().  That wasn't exactly a problem when the code was
> written because new DSM memory is always zeroed and this always
> happens in new DSM memory, but it shows up in this test module because
> it uses palloc() memory instead.  It *is* a problem since v14, if you
> use min_dynamic_shared_memory for a pool of recyclable shared memory,
> because then it is not zeroed.

That's a fairly scary observation.  What other places are silently
expecting such memory to be zeroed?  Do we need to fix things so
that min_dynamic_shared_memory doesn't break this API?

			regards, tom lane