Re: clustering factor

thuge wrote:
>
> I use Oracle 8.0.6 with SAP R/3. I have a lot of indexes with big
> values for "clustering factor" (998745 for an index of about 12 million
> rows). I remember i've read something on this item and it has something
> to do with performance.
> I don't remember what this means and i've never found further
> explaination on it since this moment.
> Could someone explain
> 1. what it has to do with performance problem (if it has) ?
> 2. what is bad ? a big number or a little one ?
> 3. How can i solve it ?
>
> Regards,
>
> --
> Thierry HUGE
> AIX/Oracle/SAP Administrator
> STEELCASE STRAFOR (FRANCE)
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.

Its a measure of how "good" the index is in terms of reading blocks from disk. If its close to the number of blocks in the index, your index and table rows are reasonably "well aligned", and thus index should perform well (for its given cardinality). If its close to the number of rows in the table, then it can be expected to perform not as well (for its given cardinality)...

HTH
Connor

-- 
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Connor McDonald
http://www.oracledba.co.uk (mirrored at
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"Some days you're the pigeon, some days you're the statue"