Re: Allow to specify (auto-)vacuum cost limits relative to the database/cluster size?

On 02/24/2016 08:54 AM, Alvaro Herrera wrote:
> Joe Conway wrote:
>
>> In my experience it is almost always best to run autovacuum very often
>> and very aggressively. That generally means tuning scaling factor and
>> thresholds as well, such that there are never more than say 50-100k dead
>> rows. Then running vacuum with no delays or limits runs quite fast is is
>> generally not noticeable/impactful.
>>
>> However that strategy does not work well for vacuums which run long,
>> such as an anti-wraparound vacuum. So in my opinion we need to think
>> about this as at least two distinct cases requiring different solutions.
>
> With the freeze map there is no need for anti-wraparound vacuums to be
> terribly costly, since they don't need to scan the whole table each
> time.  That patch probably changes things a lot in this area.

Yes, I had forgotten about that. It would be a huge help.


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