To get the most out of PQO you need large data sets. Else certain queries will take longer, due to the extra overhead.
Once you have enough data and your queries will benefit from PQO, you need to plan. Becuase PQO can saturate resources to the point they are useless. I had a 8 processor Sun machine slow to a crawl, becuase of two parallel queries and slightly-higher average load. So, you might want to implement profiles/resource mgt. to control parallel query and give it to who needs it. Else, you may end up saturating resources like: CPU or I/O.
______________________ Applications come and go,
but the data remains!