Note
This parameter is available starting with V4.0.0.
Description
ha_low_thread_score specifies the current number of working threads for low-priority high-availability threads.
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 | 0, which indicates that the default number of working threads is 2 |
| 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
In V4.x, tasks related to high availability (HA), such as migration replication and backup and restore, are scheduled and executed by the DagScheduler at the tenant level. To ensure efficient resource utilization, instead of differentiating parameters based on task types, three HA-related parameters are set based on task priority and importance. Each parameter corresponds to different task types:
ha_high_thread_score: specifies the number of threads for high-priority, high-availability tasks such as replication, rebuild, and restore.ha_mid_thread_score: specifies the number of threads for medium-priority, high-availability tasks such as migration.ha_low_thread_score: specifies the number of threads for low-priority, high-availability tasks such as backup, backup of backups, and backup cleanup.
Examples
Set the current number of working threads for low-priority high-availability threads to 4.
obclient> ALTER SYSTEM SET ha_low_thread_score =4;
References
- Set the current number of working threads for high-priority high-availability threads: ha_high_thread_score
- Set the current number of working threads for medium-priority high-availability threads: ha_mid_thread_score