On 2019-Apr-30, John Naylor wrote: > On Fri, Apr 26, 2019 at 11:52 AM Amit Kapila <amit.kapil...@gmail.com> wrote: > > As discussed above, we need to issue an > > invalidation for following points: (a) when vacuum finds there is no > > FSM and page has more space now, I think you can detect this in > > RecordPageWithFreeSpace > > I took a brief look and we'd have to know how much space was there > before. That doesn't seem possible without first implementing the idea > to save free space locally in the same way the FSM does. Even if we > have consensus on that, there's no code for it, and we're running out > of time.
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, but that seems correct. Sounds better than keeping outdated entries indicating no-space-available. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
