From: Nathan Bossart <nathandbossart@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Nathan Bossart <nathan@postgresql.org>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: pgsql: Teach DSM registry to ERROR if attaching to an uninitialized ent
Date: Sat, 22 Nov 2025 13:41:21 -0600
Message-ID: <aSIR4Z4U887f_KcQ@nathan> (raw)
In-Reply-To: <CA+TgmoZsxbVhoxNGTWSd6=vHvyoqOSDNXJZabBZx+St8uPduLQ@mail.gmail.com>
References: <E1vJHUk-006I7r-37@gemulon.postgresql.org>
<CA+TgmoZGFzLJpYANBG9yDyoakVm-P2Acdker-Y+DHvPWfvBE5w@mail.gmail.com>
<aR89_9oYFHNtUTFa@nathan>
<CA+TgmoZCHER55cGmnL_svMjH=k-S0w29ih+ym_+=t032TSsOFA@mail.gmail.com>
<aR-fqzfZYSd3TVKa@nathan>
<CA+TgmoZsxbVhoxNGTWSd6=vHvyoqOSDNXJZabBZx+St8uPduLQ@mail.gmail.com>
On Sat, Nov 22, 2025 at 10:25:48AM -0500, Robert Haas wrote:
> On Thu, Nov 20, 2025 at 6:09 PM Nathan Bossart <nathandbossart@gmail.com> wrote:
>> Unpinning/detaching the segment/DSA/dshash table and deleting the DSM
>> registry entry in a PG_CATCH block scares me a little, but it might be
>> doable.
>
> It seems a bit weird to be doing explicit unpinning in a PG_CATCH
> block. Ideally you'd want to postpone the pinning until initialization
> has succeeded, so that if you fail before that, transaction cleanup
> takes care of it automatically. Alternatively, destroying what existed
> before could be deferred until later, when an as-yet-unfailed
> transaction stumbles across the tombstone.
Oh, yeah, good idea.
> Am I worrying too much? Possibly! But as I said to David on another
> thread this morning, it's better to worry on pgsql-hackers before any
> problem happens than to start worrying after something bad happens in
> a customer situation.
I'll give what you suggested a try. It seems reasonable enough.
--
nathan
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Cc: nathandbossart@gmail.com, robertmhaas@gmail.com, nathan@postgresql.org, pgsql-hackers@lists.postgresql.org
Subject: Re: pgsql: Teach DSM registry to ERROR if attaching to an uninitialized ent
In-Reply-To: <aSIR4Z4U887f_KcQ@nathan>
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