From: Nathan Bossart <nathandbossart@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Kumar, Sachin <ssetiya@amazon.com>
Cc: Jan Wieck <jan@wi3ck.info>
Cc: Bruce Momjian <bruce@momjian.us>
Cc: Zhihong Yu <zyu@yugabyte.com>
Cc: Andrew Dunstan <andrew@dunslane.net>
Cc: Magnus Hagander <magnus@hagander.net>
Cc: Robins Tharakan <tharakan@gmail.com>
Cc: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Cc: pgsql-hackers@postgresql.org <pgsql-hackers@postgresql.org>
Subject: Re: pg_upgrade failing for 200+ million Large Objects
Date: Wed, 20 Dec 2023 21:16:14 -0600
Message-ID: <20231221031614.GA836232@nathanxps13> (raw)
In-Reply-To: <534746.1703116064@sss.pgh.pa.us>
References: <663393ca-b2ff-26f0-2e2d-adc942aff4fd@timescale.com>
<20220908231807.GA2242918@nathanxps13>
<CAAWbhmgUb8p7ff_ZX5jCvqM=ipPxbbDJTXMNVzH-Ho_CXVkRHA@mail.gmail.com>
<0643CC11-223A-4039-AC34-94E127462796@amazon.com>
<1152134.1699555261@sss.pgh.pa.us>
<83D44BE5-0088-4D41-8AE6-20A05D026F46@amazon.com>
<81D13E16-BA04-43CF-9B89-B8924300B211@amazon.com>
<240D05EC-8B28-4112-BEAB-85ECBAF3F871@amazon.com>
<2055911.1702258962@sss.pgh.pa.us>
<534746.1703116064@sss.pgh.pa.us>
On Wed, Dec 20, 2023 at 06:47:44PM -0500, Tom Lane wrote:
> I have spent some more effort in this area and developed a patch
> series that I think addresses all of the performance issues that
> we've discussed in this thread, both for pg_upgrade and more
> general use of pg_dump/pg_restore. Concretely, it absorbs
> the pg_restore --transaction-size switch that I proposed before
> to cut the number of transactions needed during restore, and
> rearranges the representation of BLOB-related TOC entries to
> reduce the client-side memory requirements, and fixes some
> ancient mistakes that prevent both selective restore of BLOBs
> and parallel restore of BLOBs.
>
> As a demonstration, I made a database containing 100K empty blobs,
> and measured the time needed to dump/restore that using -Fd
> and -j 10. HEAD doesn't get any useful parallelism on blobs,
> but with this patch series we do:
>
> dump restore
> HEAD: 14sec 15sec
> after 0002: 7sec 10sec
> after 0003: 7sec 3sec
Wow, thanks for putting together these patches. I intend to help review,
but I'm not sure I'll find much time to do so before the new year.
--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
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To: pgsql-hackers@postgresql.org
Cc: nathandbossart@gmail.com, tgl@sss.pgh.pa.us, ssetiya@amazon.com, jan@wi3ck.info, bruce@momjian.us, zyu@yugabyte.com, andrew@dunslane.net, magnus@hagander.net, tharakan@gmail.com, peter.eisentraut@enterprisedb.com
Subject: Re: pg_upgrade failing for 200+ million Large Objects
In-Reply-To: <20231221031614.GA836232@nathanxps13>
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