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.
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