SWITCHOVER主库出现LOG SWITCH GAP和RESOLVABLE GAP解决一例-优快云博客

本文链接：https://blog.youkuaiyun.com/aaron8219/article/details/10035547

本文详细记录了一次在执行SWITCHOVER操作后，Oracle数据库出现LOG SWITCH GAP和RESOLVABLE GAP的问题及解决过程，涉及Data Guard (DG)环境，讨论了故障切换（FAILOVER）后的日志同步问题，并提供了有效的解决策略。

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今天做switchover，环境是11.2.0.3+OEL5.7，开始时主备库状态都是正常的，符合直接切换条件：
主库：
SQL> select open_mode,database_role,switchover_status from v$database;

OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS
-------------------- ---------------- --------------------
READ WRITE PRIMARY TO STANDBY

备库：
SQL> select open_mode,database_role,switchover_status from v$database;

OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS
-------------------- ---------------- --------------------
READ ONLY WITH APPLY PHYSICAL STANDBY NOT ALLOWED

主库直接进行swichover：
SQL> alter database commit to switchover to physical standby;
alter database commit to switchover to physical standby
*
ERROR at line 1:
ORA-01093: ALTER DATABASE CLOSE only permitted with no sessions connected

SQL> select open_mode,database_role,switchover_status from v$database;

OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS
-------------------- ---------------- --------------------
READ WRITE PRIMARY LOG SWITCH GAP

提示有日志切换GAP，于是直接重启主库：
SQL> startup force
ORACLE instance started.

Total System Global Area 413372416 bytes
Fixed Size 2228904 bytes
Variable Size 322964824 bytes
Database Buffers 83886080 bytes
Redo Buffers 4292608 bytes
Database mounted.
Database opened.
SQL> select open_mode,database_role,switchover_status from v$database;

OPEN_MODE DATABASE_ROLE SWITCHOVER_STATUS
-------------------- ---------------- --------------------
READ WRITE PRIMARY RESOLVABLE GAP

状态由LOG SWITCH GAP变成了RESOLVABLE GAP，从字面理解是主备库之间存在GAP，于是执行：

SQL&