On Tue, 2006-04-04 at 14:37, Andrus wrote: > I have relatively small tables (toode and rid) in fast server. > Both tables are indexed on toode field. > > Following query takes long time to run. > toode field type is char(20). It is difficult to change this field type. > > Any idea how to speed up this query ? > > UPDATE firma1.rid SET toode=NULL > WHERE toode IS NOT NULL AND > toode NOT IN (SELECT TOODE FROM firma1.TOODE); > > Query returned successfully: 0 rows affected, 594813 ms execution time. > > explain window shows: > > Seq Scan on rid (cost=2581.07..20862553.77 rows=51848 width=1207) > Filter: ((toode IS NOT NULL) AND (NOT (subplan))) > SubPlan > -> Materialize (cost=2581.07..2944.41 rows=14734 width=84) > -> Seq Scan on toode (cost=0.00..2350.34 rows=14734 width=84) Let me guess, you've updated it a lot and aren't familiar with Vacuum? run a vacuum full on your database. schedule a vacuum (plain one) to run every so often (hours or days are a good interval for most folks) If that's NOT your problem, then please, let us know.
