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oracle 10g owi增强 系统视图查询各命中率

owi (oracle wait interface)从oracle 7开始提供,开始是为了帮助oracle开发人员查询oracle性能,后来对外开放,帮助oracle用户的管理者和开发者分析数据库各模块的所需要时间

oracle 10g开始对owi进行了一系列增强,比如metric 抽样从系统每60秒,有的15秒收集一次

命中率网上有很多算法在这不做评价,命中率有几个经验值,如lc hits 大于99%,buffer cache hist 大于90% ,查询方法从一个系统视图可以查询到,那就是metric提供的抽样当前值,也有_history 查询历史记录

sys@ANBOB> select end_time,metric_name,value,metric_unit from v$sysmetric where metric_name like '%Hit%' order by 1;

END_TIME            METRIC_NAME                         VALUE METRIC_UNIT
------------------- ------------------------------ ---------- ------------------------------
2011-10-11 22:13:51 Buffer Cache Hit Ratio                100 % (LogRead - PhyRead)/LogRead
2011-10-11 22:13:51 Redo Allocation Hit Ratio             100 % (#Redo - RedoSpaceReq)/#Redo
2011-10-11 22:13:51 Cursor Cache Hit Ratio         6.66666667 % CursorCacheHit/SoftParse
2011-10-11 22:13:51 Row Cache Hit Ratio                   100 % Hits/Gets
2011-10-11 22:13:51 PGA Cache Hit %                99.4885695 % Bytes/TotalBytes
2011-10-11 22:13:51 Library Cache Hit Ratio        99.2633517 % Hits/Pins
2011-10-11 22:14:21 Buffer Cache Hit Ratio                100 % (LogRead - PhyRead)/LogRead
2011-10-11 22:14:21 Library Cache Hit Ratio               100 % Hits/Pins

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  1. Lindsay Sabir | #1
    2011-12-21 at 06:23

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