Date: Mon, 17 Mar 2025 09:23:56 -0500
From: Nathan Bossart <nathandbossart@gmail.com>
To: Corey Huinker <corey.huinker@gmail.com>
Cc: Jeff Davis <pgsql@j-davis.com>, Robert Treat <rob@xzilla.net>,
	Robert Haas <robertmhaas@gmail.com>,
	Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>,
	Michael Paquier <michael@paquier.xyz>,
	jian he <jian.universality@gmail.com>,
	Bruce Momjian <bruce@momjian.us>,
	Matthias van de Meent <boekewurm+postgres@gmail.com>,
	Magnus Hagander <magnus@hagander.net>,
	Stephen Frost <sfrost@snowman.net>,
	Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>,
	Peter Smith <smithpb2250@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
	alvherre@alvh.no-ip.org
Subject: Re: Statistics Import and Export
Message-ID: <Z9gwfFP-eTx-MTqr@nathan>
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On Sun, Mar 16, 2025 at 05:32:15PM -0400, Corey Huinker wrote:
>>
>> * The custom format actually does two WriteToc() calls, and since these
>>   patches move the queries to this part of pg_dump, it means we'll run all
>>   the queries twice.  The comments around this code suggest that the second
>>   pass isn't strictly necessary and that it is really only useful for
>>   data/parallel restore, so we could probably skip it for no-data dumps.
>>
> 
> Is there any reason we couldn't have stats objects remove themselves from
> the list after completion?

I'm assuming that writing a completely different TOC on the second pass
would corrupt the dump file.  Perhaps we could teach it to skip stats
entries on the second pass or something, but I'm not too wild about adding
to the list of invasive changes we're making last-minute for v18.

-- 
nathan