Re: Per table autovacuum vacuum cost limit behaviour strange

On Wed, Aug 27, 2014 at 8:27 AM, Alvaro Herrera
<alvherre(at)2ndquadrant(dot)com> wrote:
> Alvaro Herrera wrote:
>
>> So my proposal is a bit more complicated. First we introduce the notion
>> of a single number, to enable sorting and computations: the "delay
>> equivalent", which is the cost_limit divided by cost_delay.
>
> Here's a patch that implements this idea. As you see this is quite a
> bit more complicated that Haribabu's proposal.
>
> There are two holes in this:
>
> 1. if you ALTER DATABASE to change vacuum delay for a database, those
> values are not considered in the global equiv delay. I don't think this
> is very important and anyway we haven't considered this very much, so
> it's okay if we don't handle it.
>
> 2. If you have a "fast worker" that's only slightly faster than regular
> workers, it will become slower in some cases. This is explained in a
> FIXME comment in the patch.
>
> I don't really have any more time to invest in this, but I would like to
> see it in 9.4. Mark, would you test this? Haribabu, how open are you
> to fixing point (2) above?

Thanks Alvaro. I will check the point(2).

Regards,
Hari Babu
Fujitsu Australia