On Tue, May 5, 2009 at 2:03 PM, Emmanuel Cecchet <emmanuel.cecc...@asterdata.com> wrote: > So what is the rationale behind not being able to use indexes and optimizing > empty tables as in the following example: > > manu=# create table father (id int, val int, tex varchar(100), primary > key(id)); > manu=# create table other (id1 int, id2 int, data varchar(10), primary > key(id1,id2)); > insert some data > manu=# explain select father.*,id2 from father left join other on > father.id=other.id1 where id2=2 order by id;
Just because the table was empty at the time statistics were most recently gathered doesn't mean it's still empty at the time the query is executed. ANALYZE; PREPARE foo AS SELECT ...; INSERT INTO ...some previously empty child table... EXECUTE foo; In order to rely on this for query planning, you'd need some way to invalidate any cached plans when inserting into an empty table. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
