Re: X$BH.TCH What does it means ?

"Miguel Zunda" <mzunda_at_polar.es> wrote in message news:3EE5AF58.9010003_at_polar.es...
> Hello.
>
> When I look at my x$bh I see hundreds of rows with a tch higher than
> 150. Loads of them are blocks of the same index or of the same table.
>
> 1/What does it mean?.

As others have said touch count. The number of times the block has been 'visited' recently.

> 2/What can I do to minimize this value?.

Don't visit the block so often :( (Tune queries accessing the objects)

Alternatively or concurrently, you might consider that a block that is visted this frequently is a "hot" block and so do two things about it.

1. Make sure that two "hot" objects don't sit on the same physical device. X$BH gives an indication of "hot" objects
2. Place the objects concerned in the keep pool.

-- 
Niall Litchfield
Oracle DBA
Audit Commission UK
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