Note
For V4.6.0, this parameter is available starting with V4.6.0.
Description
px_target_high_watermark specifies the percentage threshold of the high watermark for the number of parallel threads. The higher the real-time load approaches this watermark, the greater the degree of parallelism degradation. If the load exceeds this watermark, the parallelism is reduced to 1.
Privilege requirements
Query the parameter
The
systenant and all user tenants can query this parameter by using theSHOW PARAMETERSstatement or theGV$OB_PARAMETERSview.Modify the parameter
The
systenant and user tenants can modify this parameter.
Attributes
Attribute |
Description |
|---|---|
| Type | Int |
| Default value | 80 |
| Value range | [0, 100] |
| 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
The value of the px_target_high_watermark parameter must satisfy the following condition:
px_target_low_watermark <= px_target_high_watermark <= px_target_workers_per_cpu
Examples
Set the percentage threshold of the high watermark for the number of parallel threads to 7.
obclient> ALTER SYSTEM SET px_target_high_watermark = 7;