replica_parallel_migration_mode

Description

replica_parallel_migration_mode specifies the parallel migration mode for log stream replicas.

Limitations

• Query the parameter

  In the sys tenant or a user tenant, you can execute the SHOW PARAMETERS statement to query the parameter or query the GV$OB_PARAMETERS view for the parameter.

• Modify the parameter

  You can modify the parameter in the sys tenant or a user tenant.

Attributes

Considerations

When you specify this parameter, take note of the following considerations:

• In the Physical Standby Database solution, the primary and standby tenants have different requirements for parallel migration of log stream replicas.

  • In regular scenarios, the primary tenant does not require parallel migration. This is because a large amount of data needs to be replicated during parallel replica migration, which may compromise the I/O performance of the leader.

  • The standby tenant requires parallel migration to reduce the probability of replica rebuilding.

• When you use parallel migration, minimize the impact on the existing business of the primary tenant. You can enable parallel migration for the primary tenant if you want to accelerate scaling.

• In the Physical Standby Database solution, you must specify this parameter for both the primary and standby tenants.

Examples

Enable parallel migration for the current user tenant.

obclient> ALTER SYSTEM SET replica_parallel_migration_mode = 'on';