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In-Reply-To: <20260613.212530.63949290085162247.ishii@postgresql.org>
From: jian he <jian.universality@gmail.com>
Date: Sun, 14 Jun 2026 10:39:42 +0800
Message-ID: 
 <CACJufxF3WB=juHAU5DwbyeNCtiUe5VOOfNTuqOYPTGEkaKf94A@mail.gmail.com>
Subject: Re: Row pattern recognition
To: Tatsuo Ishii <ishii@postgresql.org>
Cc: assam258@gmail.com, zsolt.parragi@percona.com, sjjang112233@gmail.com,
	vik@postgresfriends.org, er@xs4all.nl, jacob.champion@enterprisedb.com,
	david.g.johnston@gmail.com, peter@eisentraut.org, li.evan.chao@gmail.com,
	pgsql-hackers@postgresql.org
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On Sat, Jun 13, 2026 at 8:26=E2=80=AFPM Tatsuo Ishii <ishii@postgresql.org>=
 wrote:
>
> I have created v48 RPR (Row pattern recognition) patches based on the
> attached incremental patches against v47 patches. I have briefly
> looked through all the incremental patches. If I have missed
> something, I will follow up later.  The patches are based on the
> commit 3e3d7875e95 on the master branch.
>

get_windowclause_startup_tuples
do we need some comments for WindowClause->defineClause

src/backend/executor/README.rpr
  (2) Transcription to WindowClause
      - Copies rpPattern, rpSkipTo, initial fields

In transformRPR, we did this:
``wc->rpPattern =3D windef->rpCommonSyntax->rpPattern;``
Since this is an assignment, not a copy, is "Copies rpPattern" incorrect?

ISO reference typo: most occurrences use {ISO/IEC 19075},
but rpr_integration.sql and some places reference 9075-2:2016 instead of 19=
075.
We may need check all occurrences to ensure consistency.

In struct ResultRelInfo, we have fields like {ri_CheckConstraintExprs,
ri_WithCheckOptionExprs}.
Similarly, I want to rename WindowAggState->defineClauseList to
defineClauseExprs

I think the comment on function contain_rpr_walker can be removed,
since transformWithClause already explains it.

Is "judgment" really the right word?

I don't fully understand the purpose of eval_nav_offset_helper now.
Also, the branch where (isnull =3D=3D true) and (offset < 0) appears
unreachable; it's never hit in the regression tests.
We should add some regression tests for these scenarios.


--
jian
https://www.enterprisedb.com/