Feedback-ID: ia2694551:Fastmail
Date: Thu, 30 Jan 2025 16:29:35 +0100
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Michael Banck <mbanck@gmx.net>
Cc: Antonin Houska <ah@cybertec.at>, Junwang Zhao <zhjwpku@gmail.com>,
	Kirill Reshke <reshkekirill@gmail.com>,
 Pavel Stehule <pavel.stehule@gmail.com>,
	Michael Paquier <michael@paquier.xyz>,
 PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: why there is not VACUUM FULL CONCURRENTLY?
Message-ID: <202501301529.ejggbtao2skr@alvherre.pgsql>
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On 2025-Jan-30, Michael Banck wrote:

> > I haven't addressed the problem of a new command yet - for that I'd like to
> > see some sort of consensus, so that I do not have to do all the related
> > changes many times.
> 
> Well, looks like this patch-set is blocked on the bikeshedding part?
> 
> Somebody should call a shot here, then.

A bunch of people discussed this patch in today's developer meeting in
Brussels.  There's pretty much a consensus on using the verb REPACK
CONCURRENTLY for this new command -- where unadorned REPACK would be
VACUUM FULL, and we'd have something like REPACK WITH INDEX or maybe
REPACK USING INDEX to take the CLUSTER place.

For the record, there was an observation that 1) if logical decoding is
not enabled, REPACK CONCURRENTLY would not work, and 2) that sites being
forced to enable logical decoding (even if transiently) to allow this,
might take a considerable performance hit, and that we shouldn't
entangle our features in that way.  I don't have an opinion on these
things at this point; knowing more about exactly what the performance
impact is would be good.  Regarding logical decoding, the conversation
continued that maybe it'd be good if the feature can be automatically
enabled transiently for that particular table for as long as needed, and
disabled afterwards.  But like with the previous concern, I don't really
have an opinion without understanding it more deeply.

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/