Note
For V4.0.0, this parameter is available starting with V4.0.0.
Description
ha_low_thread_score specifies the number of working threads for low-priority high-availability (HA) tasks.
Privilege requirements
Query the parameter
systenant and all user tenants can query this parameter by using theSHOW PARAMETERSstatement or theGV$OB_PARAMETERSview.Modify the parameter
systenant and user tenants can modify this parameter.
Attributes
Attribute |
Description |
|---|---|
| Parameter 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 reliability (such as migration replication and backup recovery) are scheduled and executed by the DagScheduler at the tenant level. To ensure sufficient thread resources for each tenant, three HA-related parameters are set based on task priority and importance instead of task type. Each parameter corresponds to different task types:
Notice
The task categories corresponding to the following parameters may vary across V4.x versions.
ha_high_thread_score: specifies the number of threads for high-priority HA tasks such as replication, rebuild, and recovery.ha_mid_thread_score: specifies the number of threads for medium-priority HA tasks such as migration.ha_low_thread_score: specifies the number of threads for low-priority HA tasks such as backup, backup of backup, and backup cleanup.
Examples
Set the number of working threads for low-priority HA tasks of the current tenant to 4.
obclient> ALTER SYSTEM SET ha_low_thread_score =4;
References
- Set the number of working threads for high-priority HA tasks: ha_high_thread_score
- Set the number of working threads for medium-priority HA tasks: ha_mid_thread_score