Greg, > > 1) You have n^2 possible two-column combinations. That's a lot of > > processing and storage. > > Yes, that's the hard problem to solve. Actually, btw, it's n!, not n^2.
Ooops, bad math. Andrew pointed out it's actually n*(n-1)/2, not n!. Also, we could omit columns unlikely to correlate, such as large text columns, bytea and numerics with high precisions. Also, we probably don't need to correlate UNIQUE columns inside ... I think. -- --Josh Josh Berkus PostgreSQL @ Sun San Francisco ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq