Date: Wed, 17 Sep 2025 09:34:24 -0500
From: Nathan Bossart <nathandbossart@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Nathan Bossart <nathan@postgresql.org>,
	pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Move named LWLock tranche requests to shared memory.
Message-ID: <aMrG8F-NkiedEugc@nathan>
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On Wed, Sep 17, 2025 at 01:47:19PM +0900, Michael Paquier wrote:
> Perhaps LocalNamedLWLockTrancheRequestArray should be initialized to
> NULL when declared, and I'd rather document the reasons behind what
> this patch is doing in LWLockShmemSize() and when the state is
> initialized in CreateLWLocks(), than have the reader assume why the
> local pointer is needed (aka reinitialized with restart_after_crash).

I've added some commentary to this effect in v3.

> Note: I forgot for a second if shared_preload_libraries was reloaded
> when the postmaster reinitializes a cluster, and the answer is that
> we only go into process_shared_preload_libraries() once at startup..
> I was wondering for a second about a potential case where s_p_l is
> updated with more lwlocks added in-between, where a reinitialization
> would mess up things.

Yeah, this stuff is rather precarious, and I'm a bit surprised there
haven't been more problems in this area.

-- 
nathan

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