Note
For V4.0.0, this parameter is available starting with V4.0.0.
Description
ha_low_thread_score specifies the number of threads used for low-priority high-availability tasks.
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
The
systenant and user tenants can modify this parameter.
Attributes
| Attribute | Description |
|---|---|
| Type | Int |
| Default value | 0, which indicates a default of 2 threads |
| 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 by the DagScheduler at the tenant level. Since each tenant has limited thread resources, the configuration parameters are no longer differentiated by task type but instead by task priority and importance. Three configuration parameters are set for HA tasks, each corresponding to a different task type:
- ha_high_thread_score: specifies the number of threads used for high-priority HA tasks such as replication, rebuild, and restore.
- ha_mid_thread_score: specifies the number of threads used for medium-priority HA tasks such as migration.
- ha_low_thread_score: specifies the number of threads used for low-priority HA tasks such as backup, backup of backups, and backup cleanup.
Examples
Set the number of threads used for low-priority HA tasks to 4.
obclient> ALTER SYSTEM SET ha_low_thread_score=4;
References
- Set the number of threads used for high-priority HA tasks: ha_high_thread_score
- Set the number of threads used for medium-priority HA tasks: ha_mid_thread_score