lately i have been seeing a lot of "CPU + Wait for CPU" as a wait in the sql performance issues i am handling...i see that even though CPU is only 50% utilized the wait event is still seen. what is it exactly and is there a way to reduce this wait ... Elapsed time of a s...
lately i have been seeing a lot of "CPU + Wait for CPU" as a wait in the sql performance issues i am handling...i see that even though CPU is only 50% utilized the wait event is still seen. what is it exactly and is there a way to reduce this wait ... Elapsed time of a s...
execute dbms_scheduler.set_attribute('','RESOURCE_PLAN',''); 以上是针对Oracle 11g的一种解决方案. 从以下的Event Class中也可以看到Scheduler的属性: Top User Events EventEvent Class% ActivityAvg Active Sessions resmgr:cpu quantumScheduler34.692.90 CPU + Wait for CPUCPU26.622.23 latch: library cache...
resmgr:cpu quantumScheduler34.692.90 CPU + Wait for CPUCPU26.622.23 latch: library cacheConcurrency25.912.17 latch: shared poolConcurrency5.050.42 latch freeOther4.150.35 Top Event P1/P2/P3 Values Event% EventP1 Value, P2 Value, P3 Value% ActivityParameter 1Parameter 2Parameter 3 ...
每个调用的函数里面又执行了sql语句查询,所以大多这些不存在I/O瓶颈的语句行源都在等待CPU + Wait for CPU,该事件只能说明cpu很忙,至于是否cpu过载要看情况,一般来说逻辑读写不是特别多的话而且cpu整体不忙的话,很大程度上可以认为sql语句应该使用并行执行来加快速度。
CPU + Wait for CPU 8.18 TABLE ACCESS - FULL 8.18 select count(*) from user_test15 where old_id=:1 7ug3juzr5ta3z 1393919968 11750 8.20 CPU + Wait for CPU 8.17 TABLE ACCESS - FULL 8.16 select count(*) from user_test13 where old_id=:1 ...
DB Time=所有前台会话等待的时间=CPU时间+IO时间+非空闲等待时间+在CPU队列中等待的时间。其中在CPU队列中等待的时间就是CPU Wait,在ASH中可以清楚的看到CPU +Wait for CPU,这个状态代表了一个会话正在使用CPU或者正在等待CPU来执行,是不算做Oracle的任何一种等待事件的。
DB Time=所有前台会话等待的时间=CPU时间+IO时间+非空闲等待时间+在CPU队列中等待的时间。其中在CPU队列中等待的时间就是CPU Wait,在ASH中可以清楚的看到CPU +Wait for CPU,这个状态代表了一个会话正在使用CPU或者正在等待CPU来执行,是不算做Oracle的任何一种等待事件的。
Oracle Cloud Infrastructure - Database Service - Version N/A and later: High "gc cr grant 2-way" / "gc current block 2-way" Wait due to Different CPU Count on Cluste
HIGH CPU的时候观察了下，主机层面user大约92%，sys的约7，几乎没有io wait的CPU，也没有页交换出现，CPU消耗高的进程基本上都是Oracle用户的。反复运行以上命令后，CPU使用率勉强稳定到了90%，基本上可以开始分析性能故障了。二、AWR报告信息AWR报告开始生成不出来，一些常规操作后，拿到了故障时间段的AWR报告。先...