From: Tom Lane <tgl@sss.pgh.pa.us>
To: Nikhil Shetty <nikhil.dba04@gmail.com>
cc: Laurenz Albe <laurenz.albe@cybertec.at>,
        Pgsql-admin <pgsql-admin@lists.postgresql.org>
Subject: Re: statement_timeout has no effect if sync standby is unavailable
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Comments: In-reply-to Nikhil Shetty <nikhil.dba04@gmail.com>
	message dated "Thu, 02 Nov 2023 21:25:02 +0530"
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Date: Thu, 02 Nov 2023 12:08:53 -0400
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Nikhil Shetty <nikhil.dba04@gmail.com> writes:
> I need to check the process state but statement_timeout should timeout such
> queries, no?

No, I don't think that should be the policy, and if it doesn't do so
now I'm content to leave it like that.  Once we have committed locally
and started to wait for a sync standby, we are between a rock and a
hard place: we can't back out the commit.  If we were to allow a
timeout error to occur, we'd have a choice of reporting that the
commit failed (a lie) or that it succeeded (also a lie, given that
the promise of sync commit is that we don't report commit until it's
persisted on the standby too).  Neither of these are preferable to
ignoring the timeout.

tl;dr: if your standby is not 100% reliable, enabling sync standby
is a poor choice.

			regards, tom lane