public inbox for [email protected]  

help / color / mirror / Atom feed

From: Amit Langote <[email protected]>
To: David Rowley <[email protected]>
Cc: [email protected]
Subject: Re: pgsql: Doc: add information about partition locking
Date: Fri, 27 Mar 2026 16:09:07 +0900
Message-ID: <CA+HiwqFT0fPPoYBr0iUFWNB-Og7bEXB9hB=6ogk_qD9=OM8Vbw@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>

Hi David,

On Wed, Apr 2, 2025 at 10:03 AM David Rowley <[email protected]> wrote:
>
> Doc: add information about partition locking
>
> The documentation around locking of partitions for the executor startup
> phase of run-time partition pruning wasn't clear about which partitions
> were being locked.  Fix that.
>
> Reviewed-by: Tender Wang <[email protected]>
> Discussion: https://postgr.es/m/CAApHDvp738G75HfkKcfXaf3a8s%3D6mmtOLh46tMD0D2hAo1UCzA%40mail.gmail.com
> Backpatch-through: 13
>
> Branch
> ------
> master
>
> Details
> -------
> https://git.postgresql.org/pg/commitdiff/121d774caea4c93c8b36fb20a17ef774e60894d6

-       <command>EXPLAIN</command> output.
+       <command>EXPLAIN</command> output.  The query planner obtains locks for
+       all partitions which are part of the plan.  However, when the executor
+       uses a cached plan, locks are only obtained on the partitions which
+       remain after partition pruning done during the initialization phase of
+       execution, i.e., the ones shown in the <command>EXPLAIN</command>
+       output and not the ones referred to by the
+       <quote>Subplans Removed</quote> property.
       </para>
      </listitem>

This text was correct when committed, but became incorrect after I
reverted 525392d57 in May 2025. Sorry for not catching it sooner.

I think we should change the text in both master and REL_18_STABLE to
match what you added in the older branches.  I can change it back to
this when we get pruning-aware locking again.

-- 
Thanks, Amit Langote

view thread (9+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected]
  Subject: Re: pgsql: Doc: add information about partition locking
  In-Reply-To: <CA+HiwqFT0fPPoYBr0iUFWNB-Og7bEXB9hB=6ogk_qD9=OM8Vbw@mail.gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox