Re: Multi-Block read count

Look at the package dbms_stats, which
includes gather_, import_, export_, get_ and even set_, system_stats.

The data ends up in sys.aux_stats$

There are then two undocumented hints:

    cpu_costing
tells Oracle to use estimates of CPU costing if no system stats are set

    nocpu_costing
tell oracle to ignore any system stats that are set

--
Jonathan Lewis
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Herman de Boer wrote in message ...


>Jonathan,

>

>do you have - regarding this - pointers to relevant

>v$-views, parameters or oracle doc?

>

>> Oracle has taken note of this in Oracle 9 by

>> allowing you to collect "system statistics"

>> over a typical time period so that it can incorporate

>> I/O rates into its costing calculations.  The interesting

>> thing to note is that it records three things for I/O

>>

>> Average time for a single block read over the period.

>>

>> Average time for a multi block read over the period.

>>

>> Average ACTUAL size requested for a multiblock read

>> over the period.

>

>Kind Regards,

>

>Herman de Boer.