Re: Index help
- From: Daniel Fink <Daniel.Fink@xxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Mon, 26 Jul 2004 07:46:24 -0600
Assuming a uniform distribution, an index would probably make sense. If the
data is skewed (1 value is in 80% of the rows, etc.), an
index may not make sense. If the CBO uses bind peeking at parse time, you could
end up with a poor execution plan. For example, the
first call uses the 80% value in the predicate, so Oracle decides to use a FTS.
Subsequent executions use the other values or even a
value that does not exist. These executions are also going to use an FTS, when
an index lookup is probably faster.
Daniel
M.Godlewski wrote:
> 6 distinct values for ida3a5
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