On Thu, Feb 2, 2017 at 1:18 AM, Jeff Janes <jeff.janes@xxxxxxxxx> wrote: > On Wed, Feb 1, 2017 at 4:38 AM, Merlin Moncure <mmoncure@xxxxxxxxx> wrote: >> >> I was just troubleshooting a strange performance issue with pg_trgm >> (greatest extension over) that ran great in testing but poor in >> production following a 9.6 in place upgrade from 9.2. By poor I mean >> 7x slower. Problem was resolved by ALTER EXTENSION UPDATE followed by >> a REINDEX on the impacted table. Hope this helps somebody at some >> point :-). > > It was probably the implementation of the triconsistent function for pg_trgm > (or I would like to think so, anyway). Yeah, this is definitely the case. We are seeing 50-80% runtime reduction in many common cases, with the problematic cases being in the upper end of that range. > But if so, the REINDEX should not have been necessary, just the ALTER > EXTENSION UPDATE should do the trick. Rebuiding a large gin index can be > pretty slow. Hm, I thought it *was* necessary, in my poking. However the evidence is destroyed and it's not worth restaging the test, so I'll take your word for it. merlin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
