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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Richard Guo <guofenglinux@gmail.com>
cc: Matheus Alcantara <matheusssilv97@gmail.com>, leis@in.tum.de,
        pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #19553: Wrong results from nested LEFT JOINs over an empty
 subquery (regression since v16)
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Comments: In-reply-to Richard Guo <guofenglinux@gmail.com>
	message dated "Mon, 20 Jul 2026 11:33:23 +0900"
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Date: Sun, 19 Jul 2026 22:35:28 -0400
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Richard Guo <guofenglinux@gmail.com> writes:
> It occurred to me that we can skip the new get_relids_in_jointree()
> scan altogether when there are no PHVs anywhere in the query
> (root->glob->lastPHId==0), since then the find_dependent_phvs() checks
> are no-ops anyway.  This is also consistent with how we check
> root->glob->lastPHId in find_dependent_phvs() and
> find_dependent_phvs_in_jointree().  Attached is a trivial patch doing
> that.

WFM.

			regards, tom lane