MODIFY PAXOS_REPLICA_NUM

Purpose

This statement is used to modify the paxos_replica_num of a log stream, which specifies the number of required members for the leader of the log stream.

Limitations and considerations

• This statement can only modify the paxos_replica_num of one log stream at a time.

• For the same log stream in a tenant, only one disaster recovery task (excluding replica migration tasks) can be executed at a time. This includes tasks such as adding a replica, deleting a replica, changing the replica type, and modifying the number of required members for the leader of the log stream.

  Note

  The sys tenant can check the CDB_OB_LS_REPLICA_TASKS view to confirm if there are any ongoing disaster recovery tasks. User tenants can check the DBA_OB_LS_REPLICA_TASKS view for the same information.

Privilege requirements

The user executing this statement must have the ALTER SYSTEM privilege. For more information about OceanBase Database privileges, see Privilege classification in MySQL mode and Privilege classification in Oracle mode.

Syntax

ALTER SYSTEM MODIFY
    LS [=] ls_id
    PAXOS_REPLICA_NUM [=] paxos_replica_num
    [TENANT [=] 'tenant_name'];

Parameters

Examples

Execute the following command in the sys tenant to change the PAXOS_REPLICA_NUM of the log stream (1002) in the mysql001 tenant to 2.

ALTER SYSTEM MODIFY
    LS = 1002
    PAXOS_REPLICA_NUM = 2
    TENANT = 'mysql001';

For more examples on modifying the paxos_replica_num of a log stream, see Modify the number of required members for the leader of a log stream.

References

• For information about manually adding a log stream replica, see ADD REPLICA.
• For information about deleting a log stream replica, see REMOVE REPLICA.
• For information about changing the type of a log stream replica, see MODIFY REPLICA.
• For information about migrating a log stream replica, see MIGRATE REPLICA.
• For information about canceling a log stream replica task, see CANCEL REPLICA TASK.