RE: cost
- From: thump604@xxxxxxxxxxx
- To: oracle-l@xxxxxxxxxxxxx
- Date: Mon, 05 Apr 2004 15:20:37 +0000
We analyze compute stats every night and with histograms.
We notice that when degree is set on a table with a full table scan, that the
cost goes sky high.
I wonder if o_i_c_a might be playing a role in that number?
--
- David
> Yes, the CBO will ALWAYS choose the plan with the lowest cost. If you
> have SQLs where higher cost plans are actually more efficient than lower
> cost plans, then you ought to ask yourself why. One solution is always
> to simply add hints and convince the optimizer to do what you want, but,
> a better long-term approach is probably to try to understand WHY the CBO
> thinks a particular plan is lower cost than another and then give the
> CBO better information so that it can more accurately estimate plan
> costs.
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