Oracle 参数 DISK_ASYNCH_IO 官方解释，作用，如何配置最优化建议
本站中文解释
DISK_ASYNCH_IO参数用于指定Oracle如何使用异步机制与硬盘I/O交互。默认情况下，DISK_ASYNCH_IO参数的值设置为FALSE，表示使用同步I/O，即当一个I/O调用完成之前，该调用不会返回控制流。如果DISK_ASYNCH_IO参数的值设置为TRUE，则启用异步I/O，当一个I/O调用完成之前，该调用可以返回控制流。
正确设置DISK_ASYNCH_IO参数的方法依赖于使用的操作系统以及主机系统，但一般来说，对于典型的应用场景，我们建议将DISK_ASYNCH_IO参数设置为TRUE。
官方英文解释
DISK_ASYNCH_IO controls whether I/O to datafiles, control files, and logfiles is asynchronous (that is, whether parallel server processes can overlap I/O requests with CPU processing during table scans).
| Property | Description |
|---|---|
|
Parameter type |
Boolean |
|
Default value |
|
|
Modifiable |
No |
|
Modifiable in a PDB |
No |
|
Range of values |
|
|
Basic |
No |
If your platform supports asynchronous I/O to disk, Oracle recommends that you leave this parameter set to its default value. However, if the asynchronous I/O implementation is not stable, you can set this parameter to false to disable asynchronous I/O. If your platform does not support asynchronous I/O to disk, this parameter has no effect.
If you set DISK_ASYNCH_IO to false, then you can increase DB_WRITER_PROCESSES or use DBWR_IO_SLAVES to simulate asynchronous I/O.
See Also:
-
“DB_WRITER_PROCESSES”
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“DBWR_IO_SLAVES”
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Oracle Database
Performance Tuning Guide for more information about choosing between multiple DBWR processes and I/O slaves
