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...
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。
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 ...
4. DB CPU是CPU运转的时间,不包含数据库进程在等待CPU的时间,同样以微秒(microseconds)为单位。在v$sys_time_model中的STAT_NAME是”DB CPU”。 5. 我们在ASH报告中经常看到的’CPU + Wait for CPU’指的是DB time,而CPU就是DB CPU。 转:http://www.dbform.com/html/2010/1309.html...
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 ...
由oracle的两份快照而产生的差异报告,通常一小时一次,问题情况下可通过手动生成,缩小分析问题时段的范围 一般可在问题出现时以及几分钟后,各运行exec dbms_workload_repository.create_snapshot一次 SQL>execdbms_workload_repository.create_snapshot; PL/SQLproceduresuccessfully completed.SQL>execdbms_workload_reposito...
76jg6df5tvqgp 1393919968 11726 8.18 CPU + Wait for CPU 8.15 TABLE ACCESS - FULL 8.14 select count(*) from user_test22 where old_id=:1这些操作都是在做一个查询数据条数的操作,其实关联的表名都是同一个。但是归属于不同的schema下。 那么到底有多少呢,是不是碰到一个问题就修复一个,还是抓住本...
oracle是比较常见的字符方式读写硬盘。 字符设备还是块设备的定义属于操作系统的设备访问层,与实际物理设备的特性无必然联系。设备访问层下面是驱动程序,所以只要驱动程序提供的方式,都可以。 也就是说驱动程序支持stream方式,那么就可以用这种方式访问,驱动程序如果还支持block方式,那么你想用哪种方式访问都可以,典型的...
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...