Standby MRP needs old log sequence even after restore of incremental backup at standby

At standby applied incremental backup but  MRP  process at standby is looking for very old sequence.

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 23861 23057 804

  2 8553 8259 294

  3 8542 8248 294

SQL>select process,status,sequence# from v$managed_standby where PROCESS ='MRP0';

PROCESS STATUS SEQUENCE#

--------- ------------ ----------

MRP0 WAIT_FOR_GAP 17353

 Standby db has just been restored from incremental backup taken from primary.

CAUSE

 At least one datafile has scn much lower than the rest of the database:

SQL>select distinct to_char(fhscn, '99999999999999999999') as "Stby_datafile_hdr_SCN" from X$KCVFH;

Stby_datafile_hdr_SCN

---------------------

  10571110002345

  10591313115628

  10591313133587

  10591313148383

  10591313156525

  10591313172772

  10591313186729

SQL>select min(to_char(fhscn, '99999999999999999999')) as Standby_Datafile_Header_SCN from X$KCVFH;

STANDBY_DATAFILE_HEAD

---------------------

  10571110002345

x$kcbfh.fhscn gives checkpoint scn for a particular datafile. Datafile recovery should start with this checkpoint scn. If scn is too low, the redo containing this could be found in very old archive redo log which may already been deleted.

SOLUTION

1. Identify the datafile with lowest checkpoint scn:

  a. at standby:

  SQL>col name format a55

  SQL>select file#, name, to_char(checkpoint_change#, '99999999999999999999') from v$datafile_header where checkpoint_change# < 10571110002350;

  FILE# NAME TO_CHAR(CHECKPOINT_CH

  ---------- ------------------------------------------------------- ---------------------

  299 +DATA_DG1/fsolstby/datafile/sysaux.622.811623929 10571110002345

  b. at primary:

  SQL > select file#, name from v$datafile where file# = 299 

2. Copy datafile identified in step 1 from primary to standby database 

3. Recreate standby control file from current control file at primary. And restore at standby.

4. Restart standby recovery.

  sql> alter database recover managed standby database disconnect;