From: | Euler Taveira de Oliveira <euler(at)timbira(dot)com> |
---|---|
To: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
Cc: | Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: autovacuum workers warning |
Date: | 2011-10-26 19:57:18 |
Message-ID: | 4EA8661E.4060908@timbira.com |
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Lists: | pgsql-hackers |
On 26-10-2011 16:14, Alvaro Herrera wrote:
> Well, just increasing the number of workers would do nothing to solve
> the problem, because the more workers there are, the slower they work.
> The actual solution to the problem would be decreasing
> autovacuum_vacuum_delay_cost, and/or related knobs.
>
Why not? You're saying that parallelizing the work won't help? As about
autovacuum_vacuum_cost_delay, don't you think that 20ms isn't small enough to
suggest decreasing instead of increasing the number of workers?
> Wasn't there some discussion recently on measuring the length of the
> work queue, or something like that?
>
Yes, there is. As I said, it is an expensive and approximate measure. I'm not
saying that is not the right direction, I'm arguing that a hint is better than
nothing. Right now the only way to know if it is out of workers is to query
pg_stat_activity frequently.
--
Euler Taveira de Oliveira - Timbira http://www.timbira.com.br/
PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento
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