Archive lag and when archives are present in Backup of Primary system.

Archive lag and when archives are present in Backup of Primary system.

1) Standby showing below archive gap:
=================================

SQL> 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                    132                   118         14
         1                    132                   119         13



2) Alert log of Standby reported below error:
=========================================
Fetching gap sequence in thread 1, gap sequence 120-129
Completed: alter database recover managed standby database disconnect from session
Wed Jan 15 21:40:07 2019
FAL[client]: Failed to request gap sequence
 GAP - thread 1 sequence 120-129
 DBID 4134858347 branch 1023738414
FAL[client]: All defined FAL servers have been attempted.

3) Using RMAN recovered mentioned archives ( 120-129 as mentioned step 2 ) , thankfully archives were there in backup
=====================================
rman target /
restore archivelog from logseq 120 until logseq 129;

4) We have to boune MRP and then it started picking archive logs.
=====================================
Stop MRP:

alter database recover managed standby database cancel;

Start MRP:

alter database recover managed standby database disconnect from session;


5) Archive logs are in sync after that:
=====================================

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                    148                   148          0


Thanks,
SM