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help / color / mirror / Atom feedFrom: Antonin Houska <ah@cybertec.at>
To: shihao zhong <zhong950419@gmail.com>
Cc: Robert Treat <rob@xzilla.net>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Manu <manuelreyesbravo@gmail.com>
Cc: Thom Brown <thom@linux.com>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: REPACK (CONCURRENTLY) can silently lose updates when the toast table is rewritten
Date: Fri, 25 Sep 2026 08:24:15 +0200
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shihao zhong <zhong950419@gmail.com> wrote:
> > (What I said does not mean that I'm in favor of restarting the decoding worker
> > either. I still prefer locking the TOAST relation early, as I noted elsewhere
> > in the thread.)
>
> OK. v3 locks the TOAST relation before the worker starts, as Sawada-san
> first suggested. A rewrite of the TOAST relation now waits for REPACK,
> which I think is also what Robert asked for.
Thanks for the patch. I'm just not sure this is the best place to lock the
TOAST table: note that copy_table_data() locks it again.
I'd prefer locking it close to the place we lock the main table (perhaps in
cluster_rel(), after all the checks have been done?) and replace the locking
statements (both in the copy_table_data() and in your patch) with
Assert(CheckRelationLockedByMe(...)).
--
Antonin Houska
Web: https://www.cybertec-postgresql.com
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To: pgsql-hackers@postgresql.org
Cc: ah@cybertec.at, zhong950419@gmail.com, rob@xzilla.net, sawada.mshk@gmail.com, manuelreyesbravo@gmail.com, thom@linux.com, pgsql-hackers@lists.postgresql.org
Subject: Re: REPACK (CONCURRENTLY) can silently lose updates when the toast table is rewritten
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