Re: autovacuum stress-testing our system

On 27 September 2012 15:57, Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
> Excerpts from Simon Riggs's message of jue sep 27 06:51:28 -0300 2012:
>> On 26 September 2012 15:47, Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
>> >
>> > Really, as far as autovacuum is concerned, it would be much more useful
>> > to be able to reliably detect that a table has been recently vacuumed,
>> > without having to request a 10ms-recent pgstat snapshot.  That would
>> > greatly reduce the amount of time autovac spends on pgstat requests.
>>
>> VACUUMing generates a relcache invalidation. Can we arrange for those
>> invalidations to be received by autovac launcher, so it gets immediate
>> feedback of recent activity without polling?
>
> Hmm, this is an interesting idea worth exploring, I think.  Maybe we
> should sort tables in the autovac worker to-do list by age of last
> invalidation messages received, or something like that.  Totally unclear
> on the details, but as I said, worth exploring.

Just put them to back of queue if an inval is received.

There is already support for listening and yet never generating to
relcache inval messages.

-- Simon Riggs                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services