Re: pg_upgrade and statistics

From: Euler Taveira <euler(at)timbira(dot)com>
To: Bruce Momjian <bruce(at)momjian(dot)us>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, Peter Eisentraut <peter_e(at)gmx(dot)net>, Daniel Farina <daniel(at)heroku(dot)com>, Greg Stark <stark(at)mit(dot)edu>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: pg_upgrade and statistics
Date: 2012-03-14 04:03:26
Message-ID: 4F60188E.7090702@timbira.com
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On 13-03-2012 21:34, Bruce Momjian wrote:
> It might be a solution for cases where we don't modify it. I frankly am
> worried that if we copy over statistics even in ASCII that don't match
> what the server expects, it might lead to a crash, which has me back to
> wanting to speed up vacuumdb.
>
That was discussed in another thread some time ago [1]. Adopting a hack
solution is not the way to go. It could lead to bad consequences in a near future.

For 9.2, we could advise users to divide the ANALYZE step into
ANALYZE-per-table steps and run them all in parallel. This ANALYZE-per-table
ranking could be accomplished using a simple approach like '... row_number()
OVER (ORDER BY pg_relation_size(oid) ... WHERE row_number % n = x' (tip stolen
from Simon's book).

[1] http://archives.postgresql.org/message-id/4F10A728.7090403@agliodbs.com

--
Euler Taveira de Oliveira - Timbira http://www.timbira.com.br/
PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento

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