On Wed, Aug 24, 2022 at 04:01:21PM +0100, Dave Page wrote: > On Wed, 24 Aug 2022 at 15:18, Bruce Momjian <br...@momjian.us> wrote: > > On Tue, Aug 23, 2022 at 10:55:09AM +0100, Dave Page wrote: > > Often it is beneficial to review one's schema with a view to removing > indexes > > (and sometimes tables) that are no longer required. It's very difficult > to > > understand when that is the case by looking at the number of scans of a > > relation as, for example, an index may be used infrequently but may be > critical > > in those times when it is used. > > > > The attached patch against HEAD adds optional tracking of the last scan > time > > for relations. It updates pg_stat_*_tables with new last_seq_scan and > > last_idx_scan columns, and pg_stat_*_indexes with a last_idx_scan column > to > > help with this. > > Would it be simpler to allow the sequential and index scan columns to be > cleared so you can look later to see if it is non-zero? Should we allow > > I don't think so, because then stat values wouldn't necessarily correlate with > each other, and you wouldn't know when any of them were last reset unless we > started tracking each individual reset. At least now you can see when they > were > all reset, and you know they were reset at the same time.
Yeah, true. I was more asking if these two columns are in some way special or if people would want a more general solution, and if so, is that something we want in core Postgres. -- Bruce Momjian <br...@momjian.us> https://momjian.us EDB https://enterprisedb.com Indecision is a decision. Inaction is an action. Mark Batterson