Horton

Re: The documentation for READ COMMITTED may be incomplete or wrong

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Aleksander Alekseev <aleksander@timescale.com>
Cc: Amit Langote <amitlangote09@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-05-18T15:22:54Z
Lists: pgsql-hackers 
I wrote:
> Aleksander Alekseev <aleksander@timescale.com> writes:
>> A colleague of mine, Ante Krešić, got puzzled by the following behavior:

> That's not a documentation problem.  That's a bug, and an extremely
> nasty one.  A quick check shows that it works as expected up through
> v13, but fails as described in v14 and later.  Needs bisecting ...

Ugh.  Bisecting says it broke at

86dc90056dfdbd9d1b891718d2e5614e3e432f35 is the first bad commit
commit 86dc90056dfdbd9d1b891718d2e5614e3e432f35
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date:   Wed Mar 31 11:52:34 2021 -0400

    Rework planning and execution of UPDATE and DELETE.

which was absolutely not supposed to be breaking any concurrent-execution
guarantees.  I wonder what we got wrong.

			regards, tom lane

Commits

  1. Fix misbehavior of EvalPlanQual checks with multiple result relations.

  2. Rework planning and execution of UPDATE and DELETE.