From: Tom Lane <tgl@sss.pgh.pa.us>
To: Shaheed Haque <shaheedhaque@gmail.com>
cc: pgsql-general list <pgsql-general@lists.postgresql.org>
Subject: Re: Unexpected deadlock across two separate rows, using Postgres 17 and Django's select_for_update()
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Comments: In-reply-to Shaheed Haque <shaheedhaque@gmail.com>
	message dated "Sat, 07 Mar 2026 09:24:32 +0000"
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Shaheed Haque <shaheedhaque@gmail.com> writes:
> How can there be a deadlock between updates to different rows (as per the
> bolded WHERE clauses)?

In isolation, there couldn't be ... but you've told us nothing of
what these transactions did beforehand.  The simplest explanation
is that each one is already holding a lock on the row the other
one wants.

Maybe you are not committing between row updates?

If you have no better debugging ideas, try setting log_statements = all
and then examining everything the transactions did up to the failure.

			regards, tom lane