Horton
Menu

Re: Row pattern recognition

Henson Choi <assam258@gmail.com>

View thread
From: Henson Choi <assam258@gmail.com>
To: jian he <jian.universality@gmail.com>, Tatsuo Ishii <ishii@postgresql.org>
Cc: pgsql-hackers@postgresql.org, 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
Date: 2026-06-26T01:23:53Z
Lists: pgsql-hackers 
Hi all,

A quick heads-up for this thread, cross-referenced from another one.

Haibo Yan has a patch series adding DISTINCT support to plain aggregate
window functions [1]. As it touches window-aggregate frame handling, I
applied it on top of the current RPR patch set and built the two together.
They combine cleanly today: no rebase conflict, and the regression tests
pass with no change to code or tests.

This is structural, not luck. RPR requires the frame to start at CURRENT
ROW, while that feature requires UNBOUNDED PRECEDING, so a single window can
satisfy at most one of them -- no overlap.

That said, the DISTINCT roadmap plans to relax its UNBOUNDED-PRECEDING
restriction (the sliding-frame patches), while RPR's CURRENT-ROW requirement
is fixed by the standard. So as those frame restrictions are lifted the two
could start to overlap, and at that point we'd likely need to review the
related frame-handling changes together. Nothing to act on now -- just
flagging it so we keep an eye on it.

Full review of the DISTINCT series is in the other thread [1].

[1]
https://www.postgresql.org/message-id/CAAAe_zCfVbNrOUF5FaE38EcwYbtXacThR9xdVe2UJJPeDSL2KA@mail.gmail.com

Best,
Henson

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Adjust cross-version upgrade tests for seg_out() fix

  2. Rationalize error comments in partition split/merge tests

  3. Add fast path for foreign key constraint checks

  4. Fix assorted pretty-trivial memory leaks in the backend.

  5. Add temporal FOREIGN KEY contraints

  6. Add trailing commas to enum definitions

  7. Remove obsolete executor cleanup code