Re: Autovaccum with cost_delay does not complete on one solaris 5.10 machine - Mailing list pgsql-performance

From Alvaro Herrera
Subject Re: Autovaccum with cost_delay does not complete on one solaris 5.10 machine
Date
Msg-id 20100415202405.GL7259@alvh.no-ip.org
Whole thread Raw
In response to Re: Autovaccum with cost_delay does not complete on one solaris 5.10 machine  (Tom Lane)
Responses Re: Autovaccum with cost_delay does not complete on one solaris 5.10 machine  (Josh Berkus)
List pgsql-performance
Tom Lane wrote:
> Alvaro Herrera <> writes:
> > We don't call pollsys anywhere.  Something in Solaris must be doing it
> > under the hood.
>
> pg_usleep calls select(), and some googling indicates that select() is
> implemented as pollsys() on recent Solaris versions.  So Josh's
> assumption that those are delay calls seems plausible.  But it shouldn't
> be sleeping after each page with normal cost_delay parameters, should it?

Certainly not ... The only explanation would be that the cost balance
gets over the limit very frequently.  So one of the params would have to
be abnormally high (vacuum_cost_page_hit, vacuum_cost_page_miss,
vacuum_cost_page_dirty).

--
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.

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