Re: analyze index

From: Holger Baer <holger.baer_at_science-computing.de>
Date: Tue, 25 Jan 2005 14:45:34 +0100
Message-ID: <ct5ihu$7qj$1@news.BelWue.DE>

Richard Foote wrote:
> "Holger Baer" <holger.baer_at_science-computing.de> wrote in message
> news:ct4udr$d3p$1_at_news.BelWue.DE...
>

>>Oradba Linux wrote:
>>
>>>Why would analyze index command read table segments?
>>>
>>>
>>
>>Because it has to?
>>
>>Or how should it be able to determine the clustering_factor?
>>

>
>
> Hi Holger
>
> Actually, it doesn't need to visit the table in order to calculate the CF as
> it has all the info it needs within the rowids contained in the index.
>
> Basically, as it reads through the rowids in the leaf pages, if the block id
> (or of course file no) changes from one index entry to the next, the CF is
> incremented. If consecutive index entries point to the same block, the CF is
> not incremented.
>
> Cheers
>
> Richard
>
>

Thanks. I didn't know that and didn't think about it properly either. Not that thinking about it would've improved matters, I fear.

Cheers

Holger Received on Tue Jan 25 2005 - 07:45:34 CST