We have got a error from OEM "The Data Guard status of xxxx is Error ORA-03135: connection lost contact."After that, we have resolve the error using below steps,
Step:1
Check the command in primary database side
SQL> select status,error from v$archive_dest where dest_id=2;
STATUS ERROR
--------- -----------------------------------------------------------------
ERROR ORA-12541: TNS:no listener
Step:2
Start the listener in standby side
lsnrctl status
lsnrctl start listener_dbname
Step:3
Mount the standby database and enable MRP Process
Startup mount
alter database recover managed standby database disconnect from session;
Step:4
After login to primary database side,defer and enable the standby destination log_archive_dest
SQL>Show parameter log_archive_dest_state;
SQL> alter system set log_archive_dest_state_2=defer;
System altered.
SQL> alter system set log_archive_dest_state_2=enable;
System altered.
Step 5:
Check the status of standby side from primary database
SQL> select status,error from v$archive_dest where dest_id=2;
STATUS ERROR
--------- -----------------------------------------------------------------
VALID
Step:6
Check both primary and standby database sync now.....
SELECT ARCH.THREAD# "Thread", ARCH.SEQUENCE# "Last Sequence Received", APPL.SEQUENCE# "Last Sequence Applied", (ARCH.SEQUENCE# - APPL.SEQUENCE#) "Difference" FROM (SELECT THREAD# ,SEQUENCE# FROM V$ARCHIVED_LOG WHERE (THREAD#,FIRST_TIME ) IN (SELECT THREAD#,MAX(FIRST_TIME) FROM V$ARCHIVED_LOG GROUP BY THREAD#)) ARCH,(SELECT THREAD# ,SEQUENCE# FROM V$LOG_HISTORY WHERE (THREAD#,FIRST_TIME ) IN (SELECT THREAD#,MAX(FIRST_TIME) FROM V$LOG_HISTORY GROUP BY THREAD#)) APPL WHERE ARCH.THREAD# = APPL.THREAD# ORDER BY 1;
Thread Last Sequence Received Last Sequence Applied Difference
--------- ---------------------- --------------------- ----------
1 51031 51031 0
2 49482 49482 0