On Fri, Apr 22, 2016 at 3:30 AM, Peter Geoghegan <pg@heroku.com> wrote:
> 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.
Stephen: This is a CRITICAL ISSUE. Unless I'm missing something, this
hasn't gone anywhere in well over a week, and we're wrapping beta next
Monday. Please fix it.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
