RE: Poor performance with Histogram

Hi Wolfgang

> What Oracle version?

10.2.0.2.

But if my memory serves me right I saw the same behavior on different 9i and 10g versions.

> I was thinking of bug 3929552 and could have sworn I saw it
> as fixed in one of the patchsets, or I assumed that it is fixed in
> 9.2.0.6 and up as there is a patch available for 9.2.0.5.

I just checked Metalink. 3929552 references 3485930 which according to note 3485930.8 should be fixed in 9.2.0.6/10.1.0.3/10.2.0.1.

Honestly I don't think it is a bug if data is really skewed. Therefore, I guess, the real bug was only related to that behavior, but it's not this specific behavior the problem.

> So you DO get silly histograms when using "size auto" or "size
> skewonly". I gave dbms_stats more credit than it deserves.

Mhmm... As do you know, my opinion is different than yours. I really see many situations where SIZE AUTO/SKEWONLY does a good job. Of course this doesn't mean that the feature it's perfect!

Regards,
Chris

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