Re: CBO rows estimate way out in 2 table join - what to do?
- From: stephen O'D <stephen.odonnell@xxxxxxxxx>
- Date: Mon, 29 Oct 2007 12:27:33 -0700
Hi Stephen,
Have you tried *not* using histograms? If you know you always want a
certain access path because you know your data (business data as
Jonathan refers to it in the book you reference), histograms (as
calculated by oracle) could be "messing" you up.
Can you post the execution plan?
HTH,
Steve
Yea, I started off with no column stats at all on the instance. Then
I added "method_opt all columns size 1" to get column stats on. That
still gave me no luck. I know the data is pretty skewed, so I tried
histogram which got Oracle estimating about 12K rows instead of 7K,
but its still some way from the 70M rows it should be guessing!
I will post the explain plan tomorrow (away from office now).
Should of mentioned its Oracle 9.2.0.7.
Thanks,
Stephen.
.
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- From: stephen O'D
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