Re: Further pg_upgrade analysis for many tables

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Magnus Hagander <magnus(at)hagander(dot)net>
Subject: Re: Further pg_upgrade analysis for many tables
Date: 2012-11-10 17:18:11
Message-ID: 20121110171811.GC31383@momjian.us
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On Fri, Nov 9, 2012 at 04:23:40PM -0800, Jeff Janes wrote:
> > Actually, pg_upgrade needs pg_dump to restore all those sequence values.
>
> I did an experiment where I had pg_dump just output dummy values
> rather than hitting the database. Once pg_upgrade moves the relation
> files over, the dummy values disappear and are set back to their
> originals. So I think that pg_upgrade depends on pg_dump only in a
> trivial way--they need to be there, but it doesn't matter what they
> are.

FYI, thanks everyone for testing this. I will keep going on my tests
--- seems I have even more things to try in my benchmarks. I will
publish my results soon.

In general, I think we are getting some complaints about dump/restore
performance with a large number of tables, irregardless of pg_upgrade,
so it seems worthwhile to try to find the cause.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +

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