On Tue, 22 Nov 2022 at 16:53, Tom Lane <t...@sss.pgh.pa.us> wrote: > > Simon Riggs <simon.ri...@enterprisedb.com> writes: > > On Tue, 22 Nov 2022 at 16:28, Tom Lane <t...@sss.pgh.pa.us> wrote: > >> If we do those things, do we need a wasted-work counter at all? > > > The wasted work counter works well to respond to heavy read-only > > traffic and also avoids wasted compressions for write-heavy workloads. > > So I still like it the best. > > This argument presumes that maintenance of the counter is free, > which it surely is not. I don't know how bad contention on that > atomically-updated variable could get, but it seems like it could > be an issue when lots of processes are acquiring snapshots.
I understand. I was assuming that you and Andres liked that approach. In the absence of that approach, falling back to a counter that compresses every N xids would be best, in addition to the two new forced compression events. -- Simon Riggs http://www.EnterpriseDB.com/
