Re: Partial Index Usage Performance Question

From: <>
Date: Tue, 14 Oct 2008 18:34:21 +0200
Message-ID: <>

On Mon, 6 Oct 2008 08:14:30 -0700 (PDT), digory <> wrote:

>I have a table T with columns A, B, C and an index I over all three
>columns. Further, I have a query which uses columns A and B, but not
>C, i.e.
>SELECT * FROM T WHERE a = ? AND b = ?
>I gather Oracle is able to use index I even though the last column is
>not used. My question is the following: If I write a query like
>SELECT * FROM T WHERE a = ? AND b = ? AND c = ?
>with a condition for C that, for the data in T, is known to be true
>always, will that query be generally slower or faster than the one
>above, or is there no difference in performance, or does it depend on
>the complexity of the index?
>Thanks for a little insight,

Answers to a question like this one typically depend on posting a database version.
You were too lazy to do so.
No answer is possible.

Sybrand Bakker
Senior Oracle DBA
Received on Tue Oct 14 2008 - 11:34:21 CDT

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