Note
For V4.2.1, this parameter is available starting with V4.2.1.
Description
ddl_thread_score specifies the number of threads used for DDL 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 that the default number of 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
You can use this parameter to control the parallelism of DDL operations such as dropping columns and the cross-tenant table import stage of table-level restore.
For more information about the table-level restore process, see Restore process.
For more information about how to use
ddl_thread_scoreto control the parallelism of DDL operations, see Optimize the execution speed of DDL operations.
If you find that low-priority tasks are running slowly, you can increase the value of this parameter. We recommend that you double the value each time.
Examples
Set the number of threads for DDL tasks in the current tenant to 4.
obclient> ALTER SYSTEM SET ddl_thread_score = 4;