Re: Index help

From: Daniel Fink <Daniel.Fink_at_Sun.COM>
Date: Mon, 26 Jul 2004 07:46:24 -0600
Message-id: <41050B30.1020301@sun.com>

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

Please see the official ORACLE-L FAQ: http://www.orafaq.com

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Received on Mon Jul 26 2004 - 08:43:00 CDT