Understanding Buffer Pool Performance and ... - Quest Software

Evaluating Performance Metrics
Overall Hit Rate
You Can Expect More
– Includes all data and index reads into buffer pool
⎡
⎤
⎢
⎥
( . . . . . . )
BuffePoolOHR
⎢ bp datalogical
reads+
bp indexlogical
reads ⎥
BufferpoolOHR
=
* 100
⎢⎛bp.
index.
logical.
reads+
bp.
index.
physical.
reads+
⎞⎥
⎢⎜
⎟⎥
⎣⎝bp.
data.
logical.
reads+
bp.
data.
physical.
reads ⎠⎦
– Low values = more physical IO
– High values = more logical IO
– 85 – 90% is a good starting point