Horton

Re: Proposal: Out-of-Order NOTIFY via GUC to Improve LISTEN/NOTIFY Throughput

Matheus Alcantara <matheusssilv97@gmail.com>

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From: "Matheus Alcantara" <matheusssilv97@gmail.com>
To: "Rishu Bagga" <rishu.postgres@gmail.com>, "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: "Joel Jacobson" <joel@compiler.org>, "pgsql-hackers" <pgsql-hackers@postgresql.org>, "nik@postgres.ai" <nik@postgres.ai>
Date: 2025-09-06T14:52:34Z
Lists: pgsql-hackers

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On Thu Sep 4, 2025 at 7:53 PM -03, Rishu Bagga wrote:
> Attached is an initial patch that implements this idea.
>
Thanks for working on this! I haven't looked at the code yet, but have
some questions related with the issue discussed at [1].

> Additionally, this would help solve the issue being discussed in a
> separate thread [1],
> where listeners currently rely on the transaction log to verify if a
> transaction that it reads
> has indeed committed, but it is possible that the portion of the
> transaction log has
> been truncated by vacuum.
>
Your patch already aims to fix the issue? On [2] I implemented a TAP
test that reproduce the issue and I tried to execute using your patch
and I still see the error. I'm attaching the TAP test isolated and maybe
we could incorporate into your patch series to ensure that the issue is
fixed? What do you think?

[1] https://www.postgresql.org/message-id/CAK98qZ3wZLE-RZJN_Y%2BTFjiTRPPFPBwNBpBi5K5CU8hUHkzDpw%40mail.gmail.com
[2] https://www.postgresql.org/message-id/CAFY6G8cJm73_MM9SuynZUqtqcaTuepUDgDuvS661oLW7U0dgsg%40mail.gmail.com

--
Matheus Alcantara