On 01/16/2015 04:17 PM, Mark Kirkwood wrote: > On 16/01/15 16:06, Mark Kirkwood wrote: > >> A bit more poking about shows that the major factor (which this fake >> dataset anyway) is the default for effective_cache_size (changes from >> 128MB to 4GB in 9.4). Increasing this makes 9.2 start using the >> files_in_flight index in a plain index scan too. >> > > Arrg - misread the planner output....in 9.2 what changes is a plan that > uses an index scan on the *file_state* index (not > files_in_flight)...which appears much faster than the bitmap scan on > file_state. Apologies for the confusion. > > I'm thinking that I'm seeing the effect Tom has just mentioned.
It's not using a bitmapscan in either case; it's a straight indexscan. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
