Horton

Re: Shmem allocated wrong for custom cumulative stats

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2026-04-06T03:14:06Z
Lists: pgsql-hackers

Attachments

On Mon, Apr 06, 2026 at 11:36:21AM +0900, Michael Paquier wrote:
> On Mon, Apr 06, 2026 at 09:55:14AM +0900, Michael Paquier wrote:
>> Right, down to v18 where this has been introduced.  That's my bug, so
>> I'd be OK to take care of it myself, if you are OK with that of
>> course.
> 
> Note: something is wrong with -m32, for both patches.  Digging into
> that..

And I have been puzzled for a few minutes here, trying to figure out
if this was something in v18 or something with the new shmem routines.
It is nothing of the kind: test_custom_stats has been underestimating
its shared_size, using PgStat_StatCustomFixedEntry instead of
PgStatShared_CustomFixedEntry.  Interesting copy-pasto, HEAD-only,
second bug.

The attached is working correctly.  The v18 flavor is slightly
simpler.
--
Michael

Commits

  1. Fix shmem allocation of fixed-sized custom stats kind

  2. Fix shared memory size of template code for custom fixed-sized pgstats