On Tue, Nov 25, 2008 at 8:39 PM, Clemens Schwaighofer <clemens.schwaighofer@xxxxxxxxxx> wrote: > but on the 8.3 version i get this back > > # explain select * from foo f, bar b where f.foo_id = b.foo_id; > QUERY PLAN > ------------------------------------------------------------------ > Hash Join (cost=1.07..2.14 rows=3 width=24) > Hash Cond: (b.foo_id = f.foo_id) > -> Seq Scan on bar b (cost=0.00..1.03 rows=3 width=14) > -> Hash (cost=1.03..1.03 rows=3 width=10) > -> Seq Scan on foo f (cost=0.00..1.03 rows=3 width=10) Of course it uses a seq scan. All the data fits handily into a single page I assume. > once I insert a million rows he does use the index: > > # explain select * from foo f, bar b where f.foo_id = b.foo_id; > QUERY PLAN > ----------------------------------------------------------------------------------- > Nested Loop (cost=0.00..26.39 rows=9 width=35) > -> Seq Scan on foo f (cost=0.00..1.03 rows=3 width=21) > -> Index Scan using bar_foo_id_idx on bar b (cost=0.00..8.42 rows=3 > width=14) > Index Cond: (b.foo_id = f.foo_id) I don't see a million rows here, only three. Have you run analyze after loading all that data? Or is it retrieving 3 rows out of a million? If so then an index scan does make sense. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
