1. Problem description
Check the alert to find the following error:
Wed Jun 08 23:03:50 2016
LNS: Attempting destination LOG_ARCHIVE_DEST_2 network reconnect (19502)
LNS: Destination LOG_ARCHIVE_DEST_2 network reconnect abandoned
Error 19502 for archive log file 5 to ‘PRODS’
Errors in file /u01/PROD/oracle/diag/rdbms/prod/PROD1/trace/PROD1_nsa2_25439.trc:
Ora-19502: write error on file “”, block number (block size=)
LNS: Failed to archive log 5 thread 1 sequence 22037 (19502)
Check DG:
Dragon Boat Festival holiday found a few days of archiving has not been applied in the library, nor has it passed
SQL>
1* select dest_name, error from v$archive_dest
SQL> /

DEST_NAME ERROR
—————————————- —————————————————————–
LOG_ARCHIVE_DEST_1
LOG_ARCHIVE_DEST_2 ORA-19502: Write error on file “”, block number (block size=)
LOG_ARCHIVE_DEST_3
2. Problem analysis
According to the alert, the LOG_ARCHIVE_DEST_2 error should be reported due to network reasons
Go back to the library and apply the process MRP0 and it’s stopped
3. Problem solving
Check the logs in the main library in recent days (11g will be retained if the backup library logs are not applied)
First enable the main library LOG_ARCHIVE_DEST_2
SQL> The alter system set log_archive_dest_state_2 = enable;
System altered.
SQL>
SQL> select dest_name, error from v$archive_dest;
DEST_NAME ERROR
—————————————- —————————————————————–
LOG_ARCHIVE_DEST_1
LOG_ARCHIVE_DEST_2
LOG_ARCHIVE_DEST_3
LOG_ARCHIVE_DEST_4
LOG_ARCHIVE_DEST_5
Disable as follows:

The alter system set log_archive_dest_state_2 = defer;  

Logs have also been transferred:
Reserve the library to start the application process:
SQL> alter database recover managed standby database disconnect from session;
Check the backup storage again. DG is running normally
SQL> L
1* select PROCESS,STATUS, THREAD#,SEQUENCE# from v$managed_standby
SQL>/

the PROCESS STATUS THREAD# SEQUENCE#
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
the ARCH CLOSING 1 22036
ARCH CLOSING 2 15425
ARCH CLOSING 2 15116
ARCH CLOSING 1 22197
RFS WRITING 1 22198
RFS WRITING 2 15485
APPLYING_LOG1
RFS WRITING 1 22088
RFS WRITING 1 22089
RFS WRITING 2 15532
RFS OPENING 2 15486

PROCESS STATUS THREAD# SEQUENCE#
—- — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
RFS CLOSING 2 15484
RFS WRITING 1, 22087,

13 rows selected.

SQL>
In another case, the MRP is not applied after the log transfer, showing the log that has been waiting to exist, and the MRP can be restarted
SQL> alter database recover managed standby database cancel;

Database altered.

SQL> alter database recover managed standby database using current logfile disconnect from session;

Database altered.

SQL> select PROCESS,STATUS, THREAD#,SEQUENCE# from v$managed_standby;

the PROCESS STATUS THREAD# SEQUENCE#
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
the ARCH CLOSING 2 7450
the ARCH CLOSING 1 6856
the ARCH CLOSING 2 7449
the ARCH WRITING 2 Br> RFS RECEIVING1 7471
RFS WRITING 2 7568
RFS RECEIVING2 7495
RFS RECEIVING1 7470
RFS WRITING 1 7522
RFS WRITING 1 7472
MRP0 APPLYING_LOG2 7459
RFS RECEIVING2 7496

13 rows selected.

SQL>