how do i clear oracle execution plan cache for benchmarking?

Question

On oracle 10gr2, i have several sql queries that i am comparing performance, but after first run, the v$sql table has the execution plan stored for caching, so for one of th

Answer 1

We've been doing a lot of work lately with performance tuning queries, and one culprit for inconsistent query performance is the file system cache that Oracle is sitting on.

It's possible that while you're flushing the Oracle cache the file system still has the data your query is asking for meaning that the query will still return fast.

Unfortunately I don't know how to clear the file system cache - I just use a very helpful script from our very helpful sysadmins.