Peter >How huge can the impact on the response time be=20 >by tweaking oic? Precisely: do you know of an=20 >example where you gain a response time reduction=20 >which is very impressive? Be careful... OIC has no direct impact on the response time, it only has an impact on the=20 generation of an execution plan where joins are involved. Therefore, it wont be a problem to=20 show you examples where: - tweaking OIC led to catastrophic performance - tweaking OIC had no impact on performance=20 - tweaking OIC led to excellent performance But all this examples won't do nothing else that=20 demonstrate that in some specific cases OIC had=20 bad/no/good impact on performance. What does this means? It simply means that you=20 should carefully analyze your system. If you=20 see that the CBO tends to inappropriately choose=20 too few or too many nested loops, it can be=20 beneficial to tune it. HTH Chris -- //www.freelists.org/webpage/oracle-l