RE: Optimizer not using histogram to calculate estimated number of rows?
- From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
- To: "info@xxxxxxxxxxxxxxx" <info@xxxxxxxxxxxxxxx>, "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 10 Jun 2009 16:19:43 -0700
I wouldn't consider "over 100 rows" vs "3 rows" to be "highly skewed" in
relation to a total of 166,067 rows. You're talking about .0006% of the table
vs. .0018% of the table - a very small percentage either way, and .0018%, or
100 rows, probably isn't nearly enough to warrant a full scan instead of an
index scan if that's what you have in mind. Is that what you had in mind?
You might want to test with a FULL() hint to see just how much worse the
performance is with a full scan.
Regards,
Brandon
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