So, here's the query: SELECT private, COUNT(block_id) FROM blocks WHERE created > 'yesterday' AND shared IS FALSE GROUP BY private
What confuses me is that though this is a largish table (millions of rows) with constant writes, the query is over indexed columns of types timestamp and boolean so I would expect it to be very fast. The clause where created > 'yesterday' is there mostly to speed it up, but apparently it doesn't help much. Here's the *Full Table and Index Schema*: CREATE TABLE blocks ( block_id character(24) NOT NULL, user_id character(24) NOT NULL, created timestamp with time zone, locale character varying, shared boolean, private boolean, moment_type character varying NOT NULL, user_agent character varying, inserted timestamp without time zone NOT NULL DEFAULT now(), networks character varying[], lnglat point, CONSTRAINT blocks_pkey PRIMARY KEY (block_id ) ) WITH ( OIDS=FALSE ); CREATE INDEX blocks_created_idx ON blocks USING btree (created DESC NULLS LAST); CREATE INDEX blocks_lnglat_idx ON blocks USING gist (lnglat ); CREATE INDEX blocks_networks_idx ON blocks USING btree (networks ); CREATE INDEX blocks_private_idx ON blocks USING btree (private ); CREATE INDEX blocks_shared_idx ON blocks USING btree (shared ); Here's the results from *EXPLAIN ANALYZE:* "HashAggregate (cost=156619.01..156619.02 rows=2 width=26) (actual time=43131.154..43131.156 rows=2 loops=1)" *" -> Seq Scan on blocks (cost=0.00..156146.14 rows=472871 width=26) (actual time=274.881..42124.505 rows=562888 loops=1)" **" Filter: ((shared IS FALSE) AND (created > '2012-01-29 00:00:00+00'::timestamp with time zone))" **"Total runtime: 43131.221 ms"* I'm using *Postgres version:* 9.0.5 (courtesy of Heroku) As for *History:* I've only recently started using this query, so there really isn't any. As for *Hardware*: I'm using Heroku's "Ronin" setup which involves 1.7 GB Cache. Beyond that I don't really know. As for *Maintenance Setup*: I let Heroku handle that, so I again, I don't really know. FWIW though, vacuuming should not really be an issue (as I understand it) since I don't really do any updates or deletions. It's pretty much all inserts and selects. As for *WAL Configuration*: I'm afraid I don't even know what that is. The query is normally run from a Python web server though the above explain was run using pgAdmin3, though I doubt that's relevant. As for *GUC Settings*: Again, I don't know what this is. Whatever Heroku defaults to is what I'm using. Thank you in advance! -Alessandro Gagliardi