本站中文解释
:
COMMIT_WAIT控制着提交操作的时间间隔，也就是提交操作必须在此时间之后才能完成，以毫秒为单位设置waittime，也就是提交操作在异步I/O模式下必须等待的毫秒数。该参数的值由系统默认设定为0，可以在参数文件中更改，典型值为100。
COMMIT_WAIT参数可以在参数文件中正确设置，可以提供给参数FILE中的值：COMMIT_WAIT = x，其中x表示具体的等待时间（毫秒）。也可以在运行时进行动态设置：ALTER SYSTEM SET COMMIT_WAIT = x SCOPE = SPFILE; 同时复制系统参数对副本SPFILE进行保存。
官方英文解释
COMMIT_WAIT is an advanced parameter used to control when the redo for a commit is flushed to the redo logs.
| Property | Description |
|---|---|
|
Parameter type |
String |
|
Syntax |
|
|
Default value |
There is no default value. |
|
Modifiable |
Yes (at both session-level and system-level) |
|
Modifiable in a PDB |
Yes |
|
Basic |
No |
|
Oracle RAC |
Each instance may have its own setting |
Be aware that the NOWAIT option can cause a failure that occurs after the database receives the commit message, but before the redo log records are written. This can falsely indicate to a transaction that its changes are persistent. Also, it can violate the durability of ACID (Atomicity, Consistency, Isolation, Durability) transactions if the database shuts down unexpectedly.
If the parameter is set to FORCE_WAIT, the default behavior (immediate flushing of the redo log buffer with wait) is used. If this is a system setting, the session level and transaction level options will be ignored. If this is a session level setting, the transaction level options will be ignored. If COMMIT_WAIT is altered after it has been set to FORCE_WAIT, then the FORCE_WAIT option is no longer valid.
