ORACLE等待事件型別【Classes of Wait Events】

每一個等待事件都屬於某一類，下面給出了每一類等待事件的描述。【Every wait event belongs to a class of wait event. The following list describes each of the wait classes.】

管理類：Administrative

此類等待事件是由於DBA的管理命令引起的，這些命令要求使用者處於等待狀態，比如，重建索引。【Waits resulting from DBA commands that cause users to wait (for example, an index rebuild)】

應用程式類：Application

此類等待事件是由於使用者應用程式的程式碼引起的（比如：鎖等待）【Waits resulting from user application code (for example, lock waits caused by row level locking or explicit lock commands)】

群集類：Cluster

此類等待事件和真正應用群集RAC的資源有關。（比如：gc cr block busy等待事件）【Waits related to Real Application Cluster resources (for example, global cache resources such as 'gc cr block busy'】

提交確認類：Commit

此類等待事件只包含一種等待事件－－在執行了一個commit命令後，等待一個重做日誌寫確認（也就是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')】

併發類：Concurrency

此類等待事件是由內部資料庫資源引起的，比如閂鎖。【Waits for internal database resources (for example, latches)】

配置類：Configuration

此類等待事件是由資料庫或例項的不當配置造成的，比如，重做日誌檔案尺寸太小，共享池的大小等。【Waits caused by inadequate configuration of database or instance resources (for example, undersized log file sizes, shared pool size)】

空閒類：Idle

此類等待事件意味著會話不活躍，等待工作。比如,sql * net messages from client。【Waits that signify the session is inactive, waiting for work (for example, 'SQL*Net message from client')】

網路類：Network

和網路環境相關的一些等待事件，比如sql* net more data to dblink。【Waits related to network messaging (for example, 'SQL*Net more data to dblink')】

Other

此類等待事件通常比較少見。【Waits which should not typically occur on a system (for example, 'wait for EMON to spawn')】

排程類：Scheduler

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

系統I/O類：System I/O

此類等待事件通過是由後臺程式的I/O操作引起的，比如DBWR等待，db file paralle write。【Waits for background process IO (for example, DBWR wait for 'db file parallel write')】

使用者I/O類：User I/O

此類等待事件通常是由使用者I/O操作引起的,比如db file sequential read。【Waits for user IO (for example 'db file sequential read')】

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