"Marko Niinimaki" <manzikki@xxxxxxxxx> writes: > I'm having a surprising performance problem with the following simple > 'highscore report' > select studentid, (select max(score) from > studentprofile prof where prof.studentid = students.studentid) from students; > I have indexes on students(studentid) and studentprofile(studentid). The optimal index for this would be on studentprofile(studentid,score). A quick test says that PG 8.1 knows what to do with such an index --- what does EXPLAIN show for this query? regards, tom lane
