Horton

Re: BF mamba failure

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Kouber Saparev <kouber@gmail.com>
Cc: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2026-07-07T23:59:35Z
Lists: pgsql-hackers 
On Tue, Jul 07, 2026 at 01:13:59PM +0300, Kouber Saparev wrote:
> We had this issue again, the database just stopped - PostgreSQL 17.6.
> 
> FATAL,XX000,"trying to drop stats entry already dropped: kind=relation
> dboid=16420 objoid=3885511363 refcount=1 generation=0"
> 
> There is no such object present in the database.
> 
> Do you think the issue might be fixed in PostgreSQL 18.4?... Or PostgreSQL
> 19 eventually?

Well, honestly, hard to say.  That's a case where a reproducible
scenario would be useful, as it seems to ve very workload dependent in
terms of handling of the relation entries..  (Aka I have not dug in
details how to do that.)

As one example, the buildfarm seems to be quite silent, but it would
help if we need something like a wraparound for better
reproducibility.
--
Michael

Commits

  1. Add information about "generation" when dropping twice pgstats entry

  2. Fix race conditions with drop of reused pgstats entries