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Understanding Buffer Pool Performance and ... - Quest Software

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Evaluating <strong>Performance</strong> Metrics<br />

LCR<br />

Log Cleans Ratio<br />

You Can Expect More<br />

⎛<br />

⎞<br />

⎜<br />

⎟<br />

⎜<br />

lsn.<br />

gap.<br />

cleaner.<br />

triggers<br />

⎟<br />

= ⎜<br />

* 100<br />

⎛ dirt.<br />

page.<br />

steal.<br />

cleaner.<br />

triggers + lsn.<br />

gap.<br />

cleaner.<br />

triggers ⎞<br />

⎟<br />

⎜<br />

⎟<br />

⎜<br />

⎜<br />

⎟<br />

. . . .<br />

⎟<br />

⎝ ⎝ + dirty page threshold cleaners triggers ⎠ ⎠<br />

– Has an affect on recovery times<br />

– Too small or too large could be detrimental to buffer<br />

pool performance<br />

– Affected by SOFTMAX DB CONFIG parameter<br />

– 0 if ALTERNATE_PAGE_CLEANING=ON

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