Oracle 11g 等待事件

等待事件分类： 

===============================================================================================================

Administrative： 等待DBA命令执行结果导致的用户等待（例如：重建索引）

Waits resulting from DBA commands that cause users to wait (for example, an index rebuild)

Application：等待用户应用程序代码结果（例如：行级锁或者显式锁命令导致的锁等待）

Waits resulting from user application code (for example, lock waits caused by row level locking or explicit lock commands)

Cluster：与RAC资源相关的等待（例如：全局缓存资源'gc cr block busy'）

Waits related to Real Application Clusters resources (for example, global cache resources such as 'gc cr block busy')

Commit: 这类等待事件只包含一种等待事件-一次提交之后等待重做日志确认（日志文件同步 'log file sync'）

This wait class only comprises one wait event - wait for redo log write confirmation after a commit (that is, 'log file sync')

Concurrency：等待内部数据库资源（例如：闩）

Waits for internal database resources (for example, latches)

Configuration：这种等待由数据库或者实例资源配置不足造成（例如：较小的日志文件大小，共享池大小）

Waits caused by inadequate configuration of database or instance resources (for example, undersized log file sizes, shared pool size)

Idle：这种等待表明会话不活跃，等待工作（例如：'SQL*Net message from client'）

Waits that signify the session is inactive, waiting for work (for example, 'SQL*Net message from client')

Network：与网络报文传输相关的等待（例如：'SQL*Net more data to dblink'）

Waits related to network messaging (for example, 'SQL*Net more data to dblink')

Other：系统中不常见的等待事件（例如：'wait for EMON to spawn'）

Waits which should not typically occur on a system (for example, 'wait for EMON to spawn')

Scheduler：资源管理器相关等待（例如：'resmgr: become active'）

Resource Manager related waits (for example, 'resmgr: become active')

System I/O：等待后台进程I/O(例如：DBWR等待'db file parallel write')

Waits for background process I/O (for example, DBWR wait for 'db file parallel write')

User I/O：等待用户I/O(例如：'db file sequential read')

Waits for user I/O (for example 'db file sequential read')

===============================================================================================================

等待事件信息可以查询以下三个动态性能视图：

V$SESSION_WAIT displays the events for which sessions have just completed waiting or are currently waiting.显示刚结束等待或者在进行等待的会话的等待事件

V$SYSTEM_EVENT displays the total number of times all the sessions have waited for the events in that view.显示视图中事件在所有会话中的等待总次数

 EVENT：等待事件名称； TOTAL_WAITS：事件总等待次数； TIME_WAITED：事件的总等待时间(单位：百分之一秒)

 AVERAGE_WAIT：事件的平均等待用时(单位：百分之一秒)(time_waited/total_waits)； TOTAL_TIMEOUTS：事件总等待超时次数

V$SESSION_EVENT is similar to V$SYSTEM_EVENT, but displays all waits for each session. 显示每次会话中的所有等待。

本文来自互联网用户投稿，文章观点仅代表作者本人，不代表本站立场，不承担相关法律责任。如若转载，请注明出处。 如若内容造成侵权/违法违规/事实不符，请点击【内容举报】进行投诉反馈！