On Fri, Apr 22, 2016 at 12:25 AM, Noah Misch <noah@leadboat.com> wrote:
> Folks run clusters with ~1000 databases; we previously accepted at least one
> complex performance improvement[1] based on that use case. On the faster of
> the two machines I tested, the present thread's commits slowed "pg_dumpall
> --schema-only --binary-upgrade" by 1-2s per database. That doubles pg_dump
> runtime against the installcheck regression database. A run against a cluster
> of one hundred empty databases slowed fifteen-fold, from 8.6s to 131s.
> "pg_upgrade -j50" probably will keep things tolerable for the 1000-database
> case, but the performance regression remains jarring. I think we should not
> release 9.6 with pg_dump performance as it stands today.
As someone that is responsible for many such clusters, I strongly agree.
--
Peter Geoghegan
