Re: Vacuuming anything zeroes shared table stats - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: Vacuuming anything zeroes shared table stats
Date
Msg-id 20070607152543.GK3664@alvh.no-ip.org
Whole thread Raw
In response to Vacuuming anything zeroes shared table stats  (Michael Fuhr <mike@fuhr.org>)
Responses Re: Vacuuming anything zeroes shared table stats
List pgsql-hackers
Michael Fuhr wrote:
> Is vacuuming any table supposed to zero the statistics for all
> shared tables?  Doesn't that have implications for autovacuum?  The
> example below is in 8.2.4 but I'm seeing similar behavior in 8.1.9
> and 8.3devel.

The problem is that the database hash is cleared of databases that no
longer exist, and the database list is constructed by scanning
pg_database.  Since no entry exist for the database we use for shared
tables (InvalidOid), the hash table is dropped.  The attached patch
fixes this.

> Additionally, in 8.3devel doing anything that queries or modifies a
> shared table seems to zero the statistics for all shared tables.

I'm not sure if this is fixed by the patch; can you verify, or provide a
more specific description of the problem?

--
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

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