Contents Lab128 - Tools for Advanced Oracler Tuning and Monitoring. Reference Guide.

Ratio, Buffer access - disk

Buffer access - disk - percentage of blocks read from disk into the cache to the total number of blocks requested by sessions. In OLTP applications it is desirable to maintain this ratio low because phycal reads is the slowest way to access database blocks.

This ration is calculcated as:

1 - physical reads cache / Logical Reads