Re: Performance off "count(*)"

From: Greg Rahn <>
Date: Fri, 18 Jul 2008 14:44:15 -0700
Message-ID: <>

On Fri, Jul 18, 2008 at 10:28 AM, Marco Gralike <> wrote:


> Am I correct in my "small understanding" of Oracle that "count(*)" has
> been optimized.

A count(*) that uses TABLE ACCESS FULL access does not have to read each block in its entirety, it just reads the header to see how many rows are in the block. I guess you could call that "optimized".

Greg Rahn
Received on Fri Jul 18 2008 - 16:44:15 CDT

Original text of this message