Feedback-ID: i0fe9450f:Fastmail
Date: Thu, 9 Jul 2026 07:45:54 +0900
From: Michael Paquier <michael@paquier.xyz>
To: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Cc: Kouber Saparev <kouber@gmail.com>, pgsql-hackers@lists.postgresql.org
Subject: Re: BF mamba failure
Message-ID: <ak7TIsbToN2iMs4K@paquier.xyz>
References: 
 <CAN4RuQt_Sr9h2NG0-fr7XSmU=DeHkzTeysCuOAWhWrkuhw8Puw@mail.gmail.com>
 <CAN4RuQs6ht4T7ph8NbxHZ+NmDmTrvczAxpyZmcqk+74tzsciuw@mail.gmail.com>
 <aMIJozPEP5OLI3Yj@paquier.xyz>
 <CAN4RuQv3OTJ1Owqn2U+7ZbvL-N-nZYAUjF_NG8o12ayFN-=0GQ@mail.gmail.com>
 <aMNrSgJt6_oRqh45@paquier.xyz>
 <CAN4RuQvQ3ATcYvfTR1LzJnUJXpo_F8mgz-+WxoZsyusLLmCwYA@mail.gmail.com>
 <aMor2AHvdbZWTwCD@paquier.xyz>
 <CAN4RuQv2tk6ELko_M8YC6eM1YgV1Z2r-Lht22b0ObCTPTTG5Aw@mail.gmail.com>
 <ak2S5046X1aaagr4@paquier.xyz>
 <ak4sO/IINIBT7y0J@bdtpg>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha512;
	protocol="application/pgp-signature"; boundary="A4VhDQ8lYyPB57aW"
Content-Disposition: inline
In-Reply-To: <ak4sO/IINIBT7y0J@bdtpg>
Archived-At: 
 <https://www.postgresql.org/message-id/ak7TIsbToN2iMs4K%40paquier.xyz>
Precedence: bulk


--A4VhDQ8lYyPB57aW
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

On Wed, Jul 08, 2026 at 10:53:47AM +0000, Bertrand Drouvot wrote:
> So given that Kouber said that "we have around 150 entries added and deleted
> per second in pg_class, and around 800 in pg_attribute. So something is actively
> creating and dropping tables all the time.", OID reused is likely the culprit (
> doable in months at this rate).

That would mean keeping around a session on the standby for long time.
With a connection pooler, why not.

> The good news is that it does not reproduce on the 17 STABLE branch, I guess it's
> due to 850b9218c8e being backpatched to stable branches. So a fix will be in the
> next minor versions.

Due to the decision of using missing_ok=true in the end-of-transaction
drops, that could indeed help.  I'd be curious to hear back after the
next minor release.  If I have nothing more to do, I'll take it.

> Michael, I wonder if that would make sense to add this "set_next_oid" kind of
> thing to a contrib module to test this kind of OID reuse issue. Same idea as
> xid_wraparound.

That's probably larger than just the OIDs.  Maybe something that's
able to do what pg_resetwal does for the control file could be useful.
Publishing another footgun sounds a bit annoying, but we also have
stuff like pg_surgery, that serve a similar purpose to shortcut the
backend.
--
Michael

--A4VhDQ8lYyPB57aW
Content-Type: application/pgp-signature; name=signature.asc

-----BEGIN PGP SIGNATURE-----
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=Xw8Z
-----END PGP SIGNATURE-----

--A4VhDQ8lYyPB57aW--