From: Laurenz Albe <laurenz.albe@cybertec.at>
To: danielr@neophi.com
To: pgsql-docs@lists.postgresql.org
Subject: Re: Additional Notes
Date: Wed, 15 Nov 2023 19:05:05 +0100
Message-ID: <2e0ffcb3a67e0ece4dd4de34d33541b12f4e78b7.camel@cybertec.at> (raw)
In-Reply-To: <170006991214.398197.16221983243746809180@wrigleys.postgresql.org>
References: <170006991214.398197.16221983243746809180@wrigleys.postgresql.org>
On Wed, 2023-11-15 at 17:38 +0000, PG Doc comments form wrote:
> The following documentation comment has been logged on the website:
>
> Page: https://www.postgresql.org/docs/16/sql-notify.html
> Description:
>
> It would be good to add to the notes section that use of NOTIFY especially
> within a TRIGGER requires an AccessExclusiveLock which may cause performance
> issues. Old thread for reference:
> https://www.postgresql.org/message-id/3598.1363354686%40sss.pgh.pa.us
I don't see what this has to do with triggers. Even deferred triggers run
*before* this notify lock is taken.
The only possibility I see for such a lock to be held for a long time is if
COMMIT spends a long time waiting for a reply from a synchronous standby
server. Is that your problem?
I don't think that would require special documentation, because if your
synchronous standby does not respond in time, you normally have worse
problems than NOTIFY performance.
Yours,
Laurenz Albe
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To: pgsql-docs@postgresql.org
Cc: laurenz.albe@cybertec.at, danielr@neophi.com, pgsql-docs@lists.postgresql.org
Subject: Re: Additional Notes
In-Reply-To: <2e0ffcb3a67e0ece4dd4de34d33541b12f4e78b7.camel@cybertec.at>
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