From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Richard Guo <rguo@postgresql.org>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: pgsql: Ignore PlaceHolderVars when looking up statistics
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Fri, 02 Jan 2026 15:46:13 -0500"
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Date: Fri, 02 Jan 2026 16:20:41 -0500
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Robert Haas <robertmhaas@gmail.com> writes:
> On Sun, Dec 28, 2025 at 9:45=E2=80=AFPM Richard Guo <rguo@postgresql.org=
> wrote:
>> Back-patch to v18.  Although this issue exists before that, changes in
>> this version made it common enough to notice.  Given the lack of field
>> reports for older versions, I am not back-patching further.

> Generally we don't back-patch fixes that could change plans, because
> it tends to produce user complaints. It's maybe more justifiable in
> this case because v18 is quite new and you didn't back-patch to older
> releases, but are we sure that it's warranted even there?

It's a regression if we don't.  See nearby complaint at

https://www.postgresql.org/message-id/flat/b75866aa-bb54-456b-8f88-6b5bc52=
064ca%40app.fastmail.com

That case was correctly handled in v17 and before.

			regards, tom lane