On 2/7/06, Jim C. Nasby <[EMAIL PROTECTED]> wrote: > On Tue, Feb 07, 2006 at 07:06:26AM +0100, Nemanja Corlija wrote: > > On 2/7/06, Jim C. Nasby <[EMAIL PROTECTED]> wrote: > > > For test 8 on PostgreSQL, what's EXPLAIN ANALYZE for one of those show? > > test=# EXPLAIN ANALYZE SELECT count(*), avg(b) FROM t2 WHERE b>=0 AND b<100; > > QUERY PLAN > > > > --------------------------------------------------------------------------------------------------------- > > ------ > > Aggregate (cost=6.02..6.03 rows=1 width=4) (actual time=0.183..0.185 > > rows=1 loops=1) > > -> Index Scan using i2b on t2 (cost=0.00..6.01 rows=1 width=4) > > (actual time=0.030..0.108 rows=12 loo > > ps=1) > > Index Cond: ((b >= 0) AND (b < 100)) > > Total runtime: 0.510 ms > > (4 rows) > > Well, it expected 1 row and got 12. In this example it probably doesn't > matter, but for other parameters it probably will. > > Did you happen to do an analyze? Nope. All databases are run as default as possible. And, they all get same scripts to execute.
> > > What changes have you made to the default postgresql.conf? > > None. > > Well, that certainly won't help things... at a minimum, on your machine, > you should change the following: > shared_buffers=10000 > effective_cache_size=100000 > > The following should also help: > work_mem=10000 > vacuum_cost_delay=50 > autovacuum=on > autovacuum_vacuum_scale_factor=0.2 Sure, I could do that. But then I'd also need to tune all other databases to make things fair and that's not really what I intended to do here. I want to keep things as "out of the box" as possible. -- Nemanja Corlija <[EMAIL PROTECTED]>
