Oracle等待事件的種類

1. administrative(管理)
   由於DBA命令導致的等待， 如索引的重建
2. application
  由於應用原因導致的等待。如行級鎖等待或明確的鎖命令（for update應該可以算其中一種）
3.叢集
 與Oracle Real Application Clusters資源有關的等待（如global cache resources such as 'gc cr block busy'）
4. commit
  這個等待事件型別只包含一種等待事件-wait for redo log write confirmation after a commit(log file sync)
5. Concurrency 
  等待內部資料庫資源（如，latches）
6. Configuration
  Waits caused by inadequate configuration of database or instance resources(如undersized log file sizes, share pool sizes)
 簡單來說就是由於資料庫或者例項資源配置，如過小的redo日誌檔案，過小的共享池導致的等待事件
7. Idle 
 空閒等待。 Waits that signify the session is inactive, waiting for work(for example, 'SQL*Net message from client')
 由於會話處於非活動狀態，等待工作訊號？
8.Network
  與網路訊息有關的等待， 如SQL*Net more data to dblink
9.Other
 Waits which should not typically occur on a system(如，'wait for Emon to spawn')
10. Queue
 Contains events that signify delays in obtaining additional data in a pipelined environment. The time spent on these wait evens indicates inefficiency or other problems
in the pipeline, It affects features such as Oracle Streams, parallel queries,  or DBMS_PIPE PL/SQL packages.
11. Scheduler
  Resource Manager related waits(for example, 'resmgr: become active')
12. System I/O
 Waits for background process I/O, for example DBWR wait for 'db file parallel write'
13. User I/O
 Waits for user I/O, for example db file sequential read

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