Date: Wed, 28 Dec 2022 13:21:50 -0800
From: Nathan Bossart <nathandbossart@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Peter Geoghegan <pg@bowt.ie>, postgresql@taljaren.se,
	pgsql-hackers@lists.postgresql.org,
	Michael Paquier <michael@paquier.xyz>
Subject: Re: BUG #17717: Regression in vacuumdb (15 is slower than 10/11 and
 possible memory issue)
Message-ID: <20221228212150.GA4009813@nathanxps13>
References: <17717-6c50eb1c7d23a886@postgresql.org>
 <3439037.1671130590@sss.pgh.pa.us>
 <CAH2-Wzne4Wgaaruq-VSY2qWNhxcPRqWUbdwVQPkM81TpaHY_kQ@mail.gmail.com>
 <3544447.1671141436@sss.pgh.pa.us>
 <CAH2-WzkXmYt-K+pQqMqjFgwU7jiykD3amngd5-jkqQF=gST7Og@mail.gmail.com>
 <3672943.1671202149@sss.pgh.pa.us>
 <CAH2-WzkHRxcE-0Mub9N0Rr09SGEEF1Ex4pUbcOBSRoNGNVy93w@mail.gmail.com>
 <407579.1672258403@sss.pgh.pa.us>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <407579.1672258403@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/20221228212150.GA4009813%40nathanxps13>
Precedence: bulk

On Wed, Dec 28, 2022 at 03:13:23PM -0500, Tom Lane wrote:
> +	/* If we used SKIP_DATABASE_STATS, mop up with ONLY_DATABASE_STATS */
> +	if (vacopts->skip_database_stats && stage == ANALYZE_NO_STAGE && !failed)
> +	{
> +		executeCommand(conn, "VACUUM (ONLY_DATABASE_STATS);", echo);
> +	}

When I looked at this, I thought it would be better to send the command
through the parallel slot machinery so that failures would use the same
code path as the rest of the VACUUM commands.  However, you also need to
adjust ParallelSlotsWaitCompletion() to mark the slots as idle so that the
slot array can be reused after it is called.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com