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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Scott Ribe <scott_ribe@elevated-dev.com>
cc: Pgsql-admin <pgsql-admin@lists.postgresql.org>
Subject: Re: regression in PG 15.1
In-reply-to: <D86D21A2-20CB-4E28-AF0A-8C2C0139DA97@elevated-dev.com>
References: <D86D21A2-20CB-4E28-AF0A-8C2C0139DA97@elevated-dev.com>
Comments: In-reply-to Scott Ribe <scott_ribe@elevated-dev.com>
	message dated "Mon, 28 Nov 2022 07:41:24 -0700"
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Date: Mon, 28 Nov 2022 09:44:50 -0500
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Scott Ribe <scott_ribe@elevated-dev.com> writes:
>   select * from tbl where txid > something and tbl_id =3D (select id fro=
m reftbl where name =3D 'someval');
> ^^^ fails to exclude partitions, kicks off parallel scans on all 142, ta=
kes 23,170ms

Why do you say this is a regression?  From what I know of the partition
pruning logic (admittedly not a whole lot), I don't think we'd have
ever pruned on the basis of such a constraint.

			regards, tom lane