Note
This parameter is available starting with V4.3.4.
Description
sync_io_thread_count specifies the number of threads for synchronous I/O requests. By default, the system automatically adjusts the number of threads to fully utilize the bandwidth of synchronous I/O devices. If the delay of synchronous I/O requests is too high, you can increase the number of threads for synchronous I/O.
Privilege requirements
Query the parameter
The
systenant and all user tenants can use theSHOW PARAMETERSstatement or theGV$OB_PARAMETERSview to query this parameter.Modify the parameter
Only the
systenant can modify this parameter. User tenants cannot modify this parameter.
Attributes
| Attribute | Description |
|---|---|
| Type | Int |
| Default value | 0 |
| Value range | [0,1024] |
| Modifiable | Yes. You can use the ALTER SYSTEM SET statement to modify the parameter. |
| Effective upon OBServer node restart | No. The setting takes effect immediately. |
Considerations
When the value of this parameter is 0, the number of threads is calculated as follows:
If the number of CPU cores is less than or equal to 16, the number of threads is
CPU cores * 6.If the number of CPU cores is greater than 16, the number of threads is
16 * 6 + (CPU cores - 16) * 2.
Examples
Set the number of threads for synchronous I/O requests to 200.
obclient> ALTER SYSTEM SET sync_io_thread_count = 200;