RE: optimizer_ ???

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

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