Re: First steps with 8.3 and autovacuum launcher - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: First steps with 8.3 and autovacuum launcher
Date
Msg-id 20071001195916.GE20792@alvh.no-ip.org
Whole thread Raw
In response to Re: First steps with 8.3 and autovacuum launcher  (Heikki Linnakangas <heikki@enterprisedb.com>)
Responses Re: First steps with 8.3 and autovacuum launcher
List pgsql-hackers
Heikki Linnakangas escribió:

> In my opinion, CREATE INDEX shouldn't need to wait for autovacuum to
> finish, regardless of who issued it. This is like priority inversion;
> the autovacuum is not urgent, and runs slowly to avoid disturbing
> others. But if it keeps the higher priority CREATE INDEX from starting,
> it is disturbing others. Could we arrange things so that the effective
> cost delay of the autovacuum process that's in the way gets set to 0
> (like priority inheritance)?

This is an interesting idea, but I think it's attacking the wrong
problem.  To me, the problem here is that an ANALYZE should not block
CREATE INDEX or certain forms of ALTER TABLE.

We do have a mechanism for changing the cost-delay parameters of an
autovac worker, but even if we made it to work, it would still delay the
other operation needlessly until the end of the analyze.

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


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