Adding a LIMIT 1 in the subplan may also help -- as you only need a single match to make it true so additional finds are useless -- it'll stop sooner or will be more likely to use an index than a full table scan. -- Rod Taylor There are always four sides to every story: your side, their side, the truth, and what really happened. ----- Original Message ----- From: "Tom Lane" <[EMAIL PROTECTED]> To: "Christian Fritze" <[EMAIL PROTECTED]> Cc: "Stephan Szabo" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Tuesday, April 17, 2001 10:33 AM Subject: Re: [GENERAL] index not used with subselect in where clause ? > Christian Fritze <[EMAIL PROTECTED]> writes: > > explain select * from allmain where exists (select distinct > > dokids_as_int from allslwfull where dokids_as_int = idn and > > wort_nouml_lower like 'gen%') > > Try dropping the "distinct" on the inner select. As a moment's thought > will reveal, it's not buying you anything; and it's costing you sort > and unique passes over the subplan result. > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 5: Have you checked our extensive FAQ? > > http://www.postgresql.org/users-lounge/docs/faq.html > ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
