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RE: Count(*) not doing a FTS??

From: Mark W. Farnham <mwf_at_rsiz.com>
Date: Fri, 3 Sep 2004 07:48:43 -0400
Message-ID: <KNEIIDHFLNJDHOOCFCDKGEBEFFAA.mwf@rsiz.com>


Not sure and I'm nowhere near ready to kick those particular tires, but if you have computed statistics in 10g+, never shut down any way but consistently, and you are running some combination of AWR, AMT, and/or ADDM it might be the case that Oracle can definitely know the number of rows from summary information.

If Graham or someone who actually knows is lurking he may want to comment. Frankly I cannot remember whether this was speculation of something that might be possible with dynamic statistics collection or something that was either implemented or slated to be implemented. If something like that is there, presumably we would start seeing new stuff popping out in Wolfgangs (10053). I haven't come across anything like that in the FMs yet, but I'm mostly looking at installation stuff at this point.

On Thu, 2 Sep 2004, rjamya wrote:

> I am sitting in a class and instructor told us that count(*) reads
> rowcount from segment header in some (or most?) cases ...

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Received on Fri Sep 03 2004 - 06:45:02 CDT

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