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 operations.
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. This 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
This parameter specifies the parallelism of DDL operations for dropping columns and the cross-tenant data import phase 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 specify the parallelism of DDL operations for dropping columns, see Optimize the execution speed of data reorganization DDL operations.
If low-priority tasks run slowly, you can increase the value of this parameter. We recommend that you double the value each time.
Examples
Set the DDL thread weight of the MySQL tenant to 4 in the sys tenant.
obclient> ALTER SYSTEM SET ddl_thread_score = 4 TENANT = 'mysql';