From: Tom Lane <tgl@sss.pgh.pa.us>
To: Nathan Bossart <nathandbossart@gmail.com>
cc: Justin Pryzby <pryzby@telsasoft.com>, 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)
In-reply-to: <20221229213719.GA301584@nathanxps13>
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Comments: In-reply-to Nathan Bossart <nathandbossart@gmail.com>
	message dated "Thu, 29 Dec 2022 13:37:19 -0800"
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Date: Fri, 06 Jan 2023 12:53:07 -0500
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Nathan Bossart <nathandbossart@gmail.com> writes:
> On Thu, Dec 29, 2022 at 03:29:15PM -0500, Tom Lane wrote:
>> I tried to make a patch along these lines, and soon hit a stumbling
>> block: ONLY is a fully-reserved SQL keyword.  I don't think this
>> syntax is attractive enough to justify requiring people to
>> double-quote the option, so we are back to square one.  Anybody
>> have a different suggestion?

> ... adding both SKIP_DATABASE_STATS and ONLY_DATABASE_STATS might be the
> best bet.

Nobody has proposed a different bikeshed color, so I'm going to
proceed with that syntax.  I'll incorporate the parallel-machinery
fix from your patch and push to HEAD only (since it's hard to argue
this isn't a new feature).

This needn't foreclose pursuing the various ideas about making
vac_update_datfrozenxid faster; but none of those would eliminate
the fundamental O(N^2) issue AFAICS.

			regards, tom lane