From: Tom Lane <tgl@sss.pgh.pa.us>
To: joan@sanchezsabe.com
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18851: Queries with xxx NOT IN (SELECT xxx FROM table) fail to run (or run very slowly) on v17 (v14 ok)
Date: Fri, 14 Mar 2025 12:56:54 -0400
Message-ID: <3086084.1741971414@sss.pgh.pa.us> (raw)
In-Reply-To: <18851-5a0a9801290135d7@postgresql.org>
References: <18851-5a0a9801290135d7@postgresql.org>
PG Bug reporting form <noreply@postgresql.org> writes:
> I have experienced a misbehaviour (IMHO) in PostgreSQL 17 that didn't occur
> in PostgreSQL 14.
What have you got work_mem set to in the two installations?
For me, both versions switch to the cheap hashed plan if work_mem
is large enough that the inner table is estimated to fit in it
(somewhere around 10MB-20MB for this specific example). If anything
the newer code seems to have a smaller threshold.
regards, tom lane
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To: pgsql-bugs@postgresql.org
Cc: tgl@sss.pgh.pa.us, joan@sanchezsabe.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18851: Queries with xxx NOT IN (SELECT xxx FROM table) fail to run (or run very slowly) on v17 (v14 ok)
In-Reply-To: <3086084.1741971414@sss.pgh.pa.us>
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