Hi There,

Even though there are statistics, sometimes our index is faster. The higher the value, the more it would disregard our index.

Anyway, we were running queries and could see that it was not going faster. We used hints to force usage of our index and wham it was great. We wanted the system to consider our index even without hints, so I tried changing per session, and it was great.

Anyway I am not sure if it would address your problem, but there is so much new stuff (and fewer people that know about it), I just thought it was worth a check out.

Good luck, and let me know if it helps.
Nirasha