Note
This parameter was introduced in OceanBase Database V4.3.5.
Description
The replica_parallel_migration_mode parameter specifies the mode of the log stream replica parallel migration feature.
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 | String |
| Default value | auto |
| Valid values |
|
| 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
Consider the following points when you set this parameter:
In a physical standby scenario, the primary and standby tenants have different requirements for the parallel migration of log stream replicas:
In a typical scenario, the primary tenant does not need to use the parallel migration feature. This is because the data volume of multiple replicas that are migrated simultaneously can affect the I/O performance of the leader replica.
The standby tenant has a high demand for parallel migration. This feature can reduce the probability of replica rebuild on the standby tenant.
When you use the parallel migration feature, try to minimize the impact on the business of the existing primary database (primary tenant). If you want to accelerate scaling out or scaling in, you can enable the parallel migration feature.
In a physical standby scenario, you must set this parameter for both the primary and standby tenants.
Examples
A user tenant enables the parallel migration feature for this tenant.
obclient> ALTER SYSTEM SET replica_parallel_migration_mode = 'on';