direct path write temp等待事件

最新推荐文章于 2021-04-08 06:39:36 发布

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最新推荐文章于 2021-04-08 06:39:36 发布

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文章标签：数据库

原文链接：http://www.cnblogs.com/macleanoracle/archive/2013/03/19/2967893.html

在直接路径写操作中，数据异步写入数据库文件。当某些阶段需要确保所有异步I/O操作已完成到磁盘，或者在直接写入过程中没有足够的槽位存储待处理请求时，也会发生这种情况。通过直接路径写入，会允许会话排队I/O写请求并继续处理，同时操作系统处理I/O。若需了解未完成写入是否完成，会等待特定事件。解决方案包括检查临时表空间指示的意外排序操作、确保DISK_ASYNCH_IO设置为TRUE、正确配置OS异步I/O以及确认无磁盘I/O瓶颈。

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During Direct Path operations, the data is asynchronously written to the database files. At some stage the session needs to make sure that all outstanding asynchronous I/O have been completed to disk. This can also happen if, during a direct write, no more slots are available to store outstanding load requests (a load request could consist of multiple I/Os). Direct path writes allow a session to queue an I/O write request and continue processing while the OS handles the I/O. If the session needs to know if an outstanding write is complete then it waits on this wait event. This can happen because the session is out of free slots and just needs an empty buffer (it waits on the oldest I/O) or because it needs to ensure all writes are flushed. Solutions If the file indicates a temporary tablespace, then check for unexpected disk sort operations. Ensure DISK_ASYNCH_IO is TRUE Ensure the OS asynchronous I/O is configured correctly Ensure no disks are I/O bound Review the SQL statement to see if I/O can be reduced

转载于:https://www.cnblogs.com/macleanoracle/archive/2013/03/19/2967893.html