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From: Thom Brown <thom@linux.com>
Date: Mon, 17 Jul 2023 17:32:51 +0100
Message-ID: <CAA-aLv5EDpYBaZrPjE_kkaoERQmAPHO=fm-FwDsw3xJG5gb8Lg@mail.gmail.com>
Subject: Re: generic plans and "initial" pruning
To: Amit Langote <amitlangote09@gmail.com>
Cc: Daniel Gustafsson <daniel@yesql.se>, Tom Lane <tgl@sss.pgh.pa.us>, 
	Alvaro Herrera <alvherre@alvh.no-ip.org>, Andres Freund <andres@anarazel.de>, 
	David Rowley <dgrowleyml@gmail.com>, Jacob Champion <jchampion@timescale.com>, 
	PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>
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On Thu, 13 Jul 2023 at 13:59, Amit Langote <amitlangote09@gmail.com> wrote:
> In an absolutely brown-paper-bag moment, I realized that I had not
> updated src/backend/executor/README to reflect the changes to the
> executor's control flow that this patch makes.   That is, after
> scrapping the old design back in January whose details *were*
> reflected in the patches before that redesign.
>
> Anyway, the attached fixes that.
>
> Tom, do you think you have bandwidth in the near future to give this
> another look?  I think I've addressed the comments that you had given
> back in April, though as mentioned in the previous message, there may
> still be some funny-looking aspects still remaining.  In any case, I
> have no intention of pressing ahead with the patch without another
> committer having had a chance to sign off on it.

I've only just started taking a look at this, and my first test drive
yields very impressive results:

8192 partitions (3 runs, 10000 rows)
Head 391.294989 382.622481 379.252236
Patched 13088.145995 13406.135531 13431.828051

Looking at your changes to README, I would like to suggest rewording
the following:

+table during planning.  This means that inheritance child tables, which are
+added to the query's range table during planning, if they are present in a
+cached plan tree would not have been locked.

To:

This means that inheritance child tables present in a cached plan
tree, which are added to the query's range table during planning,
would not have been locked.

Also, further down:

s/intiatialize/initialize/

I'll carry on taking a closer look and see if I can break it.

Thom