ORA-16171当DG出现GAP的时候,如何强制启动备库

How to Perform Failover When GAP on Standby (Doc ID 846087.1)

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In this Document

Goal

Solution

APPLIES TO:

Oracle Database - Enterprise Edition - Version 10.2.0.1 to 11.2.0.3 [Release 10.2 to 11.2]
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Information in this document applies to any platform. *** ***
***Checked for relevance on 10-Dec-2015***

GOAL

How to Perform Failover When GAP on Standby?

If GAP is present then failover will fail with:

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH FORCE;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH FORCE
*
ERROR at line 1:
ORA-00283: recovery session canceled due to errors
ORA-16171: RECOVER...FINISH not allowed due to gap for thr 1, seq 4398-4398

SOLUTION

There are two ways to do this.

1. Resolve the GAP
2. Without resolving GAP

1. Resolve the GAP

a. If primary server is up then copy the missing log files to standby and then register them.

SQL> ALTER DATABASE REGISTER LOGFILE '<name of file>';

example:

SQL> ALTER DATABASE REGISTER LOGFILE '/tmp/arc_1652321.arc';

b. Finish the recovery

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH FORCE;

c. Perform the failover

SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;

d. If the physical standby database has been opened read-only since the instance was started, perform this step. Otherwise, skip to next step.

SQL> STARTUP MOUNT FORCE;

e. Set the protection mode to maximum performance and open the database for read/write access:

SQL> ALTER DATABASE SET STANDBY DATABASE TO MAXIMIZE PERFORMANCE;
SQL> ALTER DATABASE OPEN;

2. Without resolving GAP.

a. Cancel managed recovery if it is working:

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;

If managed recovery is not working then this command will fails with:

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL
*
ERROR at line 1:
ORA-16136: Managed Standby Recovery not active

b. Activate standby database:

SQL> ALTER DATABASE ACTIVATE STANDBY DATABASE;

Please be aware that you may have to recreate the standby database after activating the former standby database!
For more details please see

Oracle® Data Guard
Concepts and Administration
10g Release 2 (10.2)
8.4 Recovering Through the OPEN RESETLOGS Statement

c. If the physical standby database has been opened read-only since the instance was started, perform this step. Otherwise, skip to next step.

SQL> STARTUP MOUNT FORCE;

d. Set the protection mode to maximum performance and open the database for read/write access:

SQL> ALTER DATABASE SET STANDBY DATABASE TO MAXIMIZE PERFORMANCE;
SQL> ALTER DATABASE OPEN;