On 2019-May-01, Amit Kapila wrote: > On Tue, Apr 30, 2019 at 7:52 PM Alvaro Herrera <alvhe...@2ndquadrant.com> > wrote:
> > Hmm ... so, if vacuum runs and frees up any space from any of the pages, > > then it should send out an invalidation -- it doesn't matter what the > > FSM had, just that there is more free space now. That means every other > > process will need to determine a fresh FSM, > > I think you intend to say the local space map because once FSM is > created we will send invalidation and we won't further build relcache > entry having local space map. Yeah, I mean the map that records free space. > > but that seems correct. Sounds better than keeping outdated entries > > indicating no-space-available. > > Agreed, but as mentioned in one of the above emails, I am also bit > scared that it should not lead to many invalidation messages for small > relations, so may be we should send the invalidation message only when > the entire page is empty. I don't think that's a concern, is it? You typically won't be running multiple vacuums per second, or even multiple vacuums per minute. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services