Re: [PATCH] doc: clarify pg_stat_lock.fastpath_exceeded scope

From: Tatsuya Kawata <kawatatatsuya0913(at)gmail(dot)com>
To: Bertrand Drouvot <bertranddrouvot(dot)pg(at)gmail(dot)com>
Cc: Michael Paquier <michael(at)paquier(dot)xyz>, Postgres hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: [PATCH] doc: clarify pg_stat_lock.fastpath_exceeded scope
Date: 2026-06-22 11:34:12
Message-ID: CAHza6qej7PATweXhE-Q3ihZGtWgdoNEjC==FLeaNF_4r6+PEgg@mail.gmail.com
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Hi Bertrand-san,

Thanks for the review.

> Should we add a description of the consequences of not being able to
> acquire the lock in fast-path (when there are no available slots)?
> For example, we could say that this is considerably more expensive
> and may be subject to contention.

Agreed. v3 adds the following paragraph at the end of the Fast-Path
Locking subsection:

+ <para>
+ Acquiring a lock via the main lock table is considerably more
+ expensive than the fast path, and under heavy concurrent lock
+ activity can become a point of contention (observable as the
+ <literal>LockManager</literal> wait event).
+ </para>

Other parts of the patch are unchanged from v2.
v3 attached.

Regards,
Tatsuya Kawata

Attachment Content-Type Size
v3-0001-doc-add-Fast-Path-Locking-section.patch application/octet-stream 4.9 KB

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