Re: no index used

UPDATE STATISTICS? From: steinhoefel@dcs-systeme.de > >CREATE INDEX projKeyIndex on table1 ( projKey ASC); >CREATE INDEX kmiIndex on table1 ( kmi ASC); >CREATE INDEX mtiIndex on table1 ( kmi ASC, mti); >CREATE INDEX mmmIndex on table1 (mti); >CREATE INDEX cmiIndex on table1 ( kmi ASC, mti, cmi); >CREATE INDEX ktiIndex on table1 ( kti ASC);> >I tried the following selects: >select kmi from table1 where kmi = 5 -> table scan >select mti from table1 where mti = 5 -> table scan >select * from table1 where kmi=5 and mti=5 ->index mtiIndex used> >The result set of the first and third select is 0 rows, of the middle one >100 >rows. >There are 12 distinct values in the column kmi (that means 20.000 rows have >the same kmi) and >2500 distinct values in mti (100 rows per mti) >In my opinion the answer to the first and third statement should be there >in >no time, just look into the index, nothing there with that value - zero >rows >answer. > >I'm still interested in how to specify a query plan manually in informix. You can't, but you can issue "directives" to the compiler. It's in the manual. ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com