Note
This parameter was introduced in OceanBase Database V4.2.1.
Description
ddl_thread_score is used to set the number of threads used for DDL tasks.
Privilege requirements
Query the parameter
The
systenant and all user tenants can execute theSHOW PARAMETERSstatement or query theGV$OB_PARAMETERSview to obtain the value of this parameter.Modify the parameter
The
systenant and user tenants can modify this parameter.
Attributes
| Attribute | Description |
|---|---|
| Type | Int |
| Default value | 0, which means the default number of threads is 2. |
| Value range | [0, 100] |
| Modifiable | Yes. You can execute the ALTER SYSTEM SET statement to modify this parameter. |
| Effective upon OBServer node restart | No. The parameter takes effect immediately after it is set. |
Considerations
This parameter can be used to control the parallelism of DDL column drop operations as well as the parallelism during the cross-tenant table import phase of table-level recovery.
- For a detailed introduction to the table-level recovery process, see Recovery Process.
If you find that low-priority tasks are running too slowly, you can increase the value of this parameter appropriately. It is recommended to double the value each time.
Examples
Set the number of threads for DDL tasks under the current tenant to 4.
obclient> ALTER SYSTEM SET ddl_thread_score = 4;
