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Re: BUG #18851: Queries with xxx NOT IN (SELECT xxx FROM table) fail to run (or run very slowly) on v17 (v14 ok) - Mailing list pgsql-bugs

From Tom Lane
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
Msg-id 3086084.1741971414@sss.pgh.pa.us
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In response to BUG #18851: Queries with xxx NOT IN (SELECT xxx FROM table) fail to run (or run very slowly) on v17 (v14 ok)  (PG Bug reporting form <noreply@postgresql.org>)
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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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