I have been seeing a lot of sortoverflows for some of our databases. I have observed sortflows of upto 50% on some of them. I have read the guidelines for tuning DB2 for better sorting performance. But apart from changing sortheap and the threshold is there anything else that I should be looking into. Or increasing sortheap and the threshold, the only option I have.

Thank you

DB2 v8.2 and 9.1 on AIX 5.3

Sorts don't happen by themselves, they are a part of SQL execution plans. I would look at the dynamic sql snapshots to determine which queries cause most overflows and then study their plans to see how the sorts could be optimized or eliminated by adding indexes or rewriting the queries.