Tomas Vondra <tomas.vondra@xxxxxxxxxxxxxxx> wrote: > On 10/26/2016 03:48 PM, Filip Rembiałkowski wrote: >> Hi. >> >> Query run time degraded after migration from Pg 9.0 + postgis 1.5 to Pg >> 9.4 + postgis 2.2. >> EXPLAIN shows heap scan cost increase. What can be the reason for >> 40-fold increase in page scans needed to run Bitmap Heap Scan with >> Filter and Recheck? >> > > On 9.0 the the scan accesses only 8 buffers: > > Buffers: shared hit=8 > > while on 9.4 it has to inspect 316 of them: > > Buffers: shared hit=316 nice point ;-) > > Perhaps the table is organized / sorted differently, or something like > that. How did you do the upgrade? Maybe table-bloat? Filip, check if autovacuum runs properly. Regards, Andreas Kretschmer -- Andreas Kretschmer http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
