关于library cache的命中率：
SQL> desc V$librarycache
NAMESPACE VARCHAR2(64)
GETS NUMBER
GETHITS NUMBER
GETHITRATIO NUMBER
PINS NUMBER
PINHITS NUMBER
PINHITRATIO NUMBER
RELOADS NUMBER
INVALIDATIONS NUMBER
DLM_LOCK_REQUESTS NUMBER
DLM_PIN_REQUESTS NUMBER
DLM_PIN_RELEASES NUMBER
DLM_INVALIDATION_REQUESTS NUMBER
DLM_INVALIDATIONS NUMBER
计算library cache的命中率：
NAMESPACE=SQL AREA
Library Cache Hit Ratio = sum(pinhits) / sum(pins) 以下语句计算librarycache 命中率
库缓存区的命中率应保持在95%，否则应考虑增大shared_pool_size
SYS @ prod >SELECT SUM(pins) "Executions",SUM(reloads) "CacheMisses while Executing", ROUND((SUM(pins)/(SUM(reloads)+SUM(pins)))*100,2) "HitRatio, %" FROM V$LIBRARYCACHE;
Executions CacheMisses while Executing HitRatio, %
---------- --------------------------- ------------------------ ------------------------ -----------
131527 2472 98.16
相关文章：