Note
The parameter name is changed from merge_thread_count to compaction_low_thread_score starting from OceanBase Database V4.0.0.
Purpose
merge_thread_count specifies the number of worker threads for a daily compaction.
Permission requirements
Query the parameter
Both the
systenant and all user tenants can use theSHOW PARAMETERSstatement or viewGV$OB_PARAMETERSto query this parameter. Thesystenant can also query this parameter through the viewinformation_schema.PARAMETERS.Modify the parameter
Only the
systenant can modify this parameter. User tenants cannot modify this parameter.
Attributes
| Attribute | Description |
|---|---|
| Type | Integer |
| Default value | 0 |
| Value range | [0, 256] |
| Modifiable | Yes. You can modify it by using the ALTER SYSTEM SET statement. |
| Effective upon OBServer node restart | No. This parameter takes effect immediately. |
Considerations
If the value of this parameter is 0, the formula for calculating the number of worker threads for a compaction is min{10,cpu_cnt}, where cpu_cnt indicates the number of CPU cores in the system.
Examples
obclient> ALTER SYSTEM SET merge_thread_count=100;