Re: Calculating LIOs

Hi!


> UNIQUE SCAN followed by a TABLE ACCESS BY ROWID.  Well, how big is the =
> index?  How many levels?  Remember that regardless of the value =
> specified in the pk_column predicate, the number of levels from the =
> index root block to any leaf block is always the same.  So, if the index =
> has a BELVEL of, say, 3, then to get from the root to the leaf =
> containing 123 will be 4 buffer gets.  The TABLE ACCESS BY ROWID is one =
> more buffer get.  So, that's a total of 5 buffer gets. =20


Also, the LIO count may increase when Oracle has to construct a read
consistent clone of index/datablocks...


Tanel.


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