Start a service

After creating a service, you can start it by executing the START SERVICE statement.

Limitations

You cannot execute the START SERVICE statement in a session created based on a service name.

Prerequisites

• You have the ALTER SYSTEM privilege to execute the START SERVICE statement.

• The units for the tenant do not contain temporarily offline OBServer nodes. Otherwise, the temporarily offline OBServer nodes cannot provide the service specified by the service name after you execute the START SERVICE statement. Therefore, we recommend that you wait until the temporarily offline OBServer nodes are recovered or permanently offline before you execute the START SERVICE statement.

  For details on confirming whether the tenant's units contain temporarily offline machines, see Prerequisites in Create a service.

Procedure

1. Log in to a user tenant or the sys tenant of the cluster as the tenant administrator.

   Below is an example. Specify the parameters based on your actual environment when connecting.

   obclient -h10.xx.xx.xx -P2883 -uroot@sys#obdemo -p***** -A
   

2. Check whether the service to be started is in the STARTED state.

   For more information, see Query the service status.

   If the tenant's service status is not STARTED, the tenant's SWITCHOVER_STATUS must be NORMAL, which indicates that the tenant is not in an intermediate state during primary/standby switchover. You can query the tenant's SWITCHOVER_STATUS in either of the following ways:

   • Query the SWITCHOVER_STATUS of a specified tenant in the sys tenant.

   obclient [oceanbase]> SELECT TENANT_ID, TENANT_NAME, SWITCHOVER_STATUS FROM oceanbase.DBA_OB_TENANTS WHERE TENANT_NAME = mysql_tenant;
   

   • Query the SWITCHOVER_STATUS of the current tenant in a user tenant.

     MySQL-compatible mode

     Oracle-compatible mode

     Query statement in MySQL-compatible mode:

     obclient [oceanbase]> SELECT TENANT_ID, TENANT_NAME, SWITCHOVER_STATUS FROM oceanbase.DBA_OB_TENANTS;
     

     Query statement in Oracle-compatible mode:

     obclient [SYS]> SELECT TENANT_ID, TENANT_NAME, SWITCHOVER_STATUS FROM SYS.DBA_OB_TENANTS;
     

3. Start the service.

   The statement is as follows:

   ALTER SYSTEM START SERVICE service_name [TENANT [=] tenant_name];
   

   Parameters:

   • service_name: the name of the service to be started.
   • TENANT [=] tenant_name: the name of the tenant for which you want to start the service. Only the sys tenant can specify this parameter. User tenants cannot specify it.

   Examples:

   • Start the service named s_hz for the tenant mysql_tenant in the sys tenant.

     obclient [oceanbase]> ALTER SYSTEM START SERVICE s_hz TENANT = mysql_tenant;
     

   • Start the service named s_hz in a user tenant.

     obclient > ALTER SYSTEM START SERVICE s_hz;
     

   If Query OK is returned, you can connect to all OBServer nodes except the permanently offline ones in the units for the tenant by specifying the service name. If OB_SERVICE_NOT_FULLY_STARTED is returned, you can connect to only some of OBServer nodes except the permanently offline ones in the units for the tenant by specifying the service name. You can query the connectable OBServer nodes from the CDB_OB_TENANT_EVENT_HISTORY view in the sys tenant or the DBA_OB_TENANT_EVENT_HISTORY (MySQL-compatible mode) or DBA_OB_TENANT_EVENT_HISTORY (Oracle-compatible mode) view in a user tenant.

References

• Query the service status
• Stop a service
• Delete a service