SET STANDBY TENANT

Purpose

The ALTER SYSTEM SET STANDBY TENANT statement is used to set the protection mode of the primary tenant.

Limitations and considerations

• For OceanBase Database V4.4.2, the protection mode can be set starting from V4.4.2 BP1.
• The protection mode can only be set on the primary tenant.
• For a primary tenant in maximum performance mode, if you want to set the protection mode to maximum availability or maximum protection, it requires that the primary tenant has a strongly synchronized standby tenant. The SQL statement to set a strongly synchronized standby tenant for the primary tenant is described in SET SYNC_STANDBY_DEST.For a tenant in maximum protection or maximum availability mode, you can directly change the protection mode to maximum performance mode.
• Cascading standby tenants cannot be set to strong synchronization mode.
• When setting the protection mode to maximum protection mode for a tenant in maximum performance or maximum availability mode, the synchronization point of the strongly synchronized standby tenant must not be more than 5 seconds behind the primary tenant's synchronization point.

Privilege requirements

This statement must be executed by the root user of the sys tenant (root@sys) or the administrator of each tenant. Specifically:

• In MySQL mode, the default administrator is the root user.
• In Oracle mode, the default administrator is the SYS user.

Syntax

ALTER SYSTEM SET STANDBY TENANT TO {MAXIMIZE PERFORMANCE} | {MAXIMIZE AVAILABILITY} | {MAXIMIZE PROTECTION} [TENANT = tenant_name];

Parameters

Examples

• The system tenant sets the protection mode of the primary tenant named mysql to maximum availability mode.

obclient(root@sys)[(none)]> ALTER SYSTEM SET STANDBY TENANT TO MAXIMIZE AVAILABILITY TENANT = mysql;

• A user tenant sets the protection mode of its own tenant to maximum availability mode.

obclient> ALTER SYSTEM SET STANDBY TENANT TO MAXIMIZE AVAILABILITY;