Re: Partial Index Usage Performance Question

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

>Hi
>
>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,
>Peter

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