Category Archives: Oracle

In this we are handling Oracle Database Administration and development task. If provide solution of ORA Errors and configuration Steps for setup in Oracle.

Check and fix the dataguard issue with commands in Oracle

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On Primary Server:

Check and verify that we are working on Primary side of database:

Oracle AI Database 26ai Enterprise Edition Release 23.26.1.0.0 - Production
Version 23.26.1.0.0
SQL> Select name,open_mode,database_role from v$database;
NAME	  OPEN_MODE	       DATABASE_ROLE
--------- -------------------- ----------------
ORCL	  READ WRITE	       PRIMARY

Check if the gap is resolvable or not

SQL> select status,gap_Status from v$archive_Dest_Status where dest_id=2;
STATUS	  GAP_STATUS
--------- ------------------------
ERROR	  RESOLVABLE GAP

If the gap is resolvable then we have to check the error detail why it occurs:

SQL> SELECT dest_id, status, error FROM v$archive_dest WHERE status <> 'INACTIVE'; 
   DEST_ID STATUS     ERROR
---------- ---------  ---------------------------------------------
	 1     VALID       ORA-12543: TNS:destination host unreachable

Note: As per error, its seems that Standby database server is down, any network issue, or listener is down because the destination is unreachable.

Check the Primary archive sequence

SQL> select max(sequence#) from v$archived_log;
MAX(SEQUENCE#)
--------------
	    41

On Standby Server:

In my case, Our Standby Server is rebooted so its listener service and database is stopped. So, i first start the listener service with following command.

lsnrctl start

Verify the Standby Database Server 

SQL> Select name,open_mode,database_role from v$database;
NAME	  OPEN_MODE	       DATABASE_ROLE
--------- -------------------- ----------------
ORCL	  MOUNTED	       PHYSICAL STANDBY

Now we have to check that our MRP process is running or not

SQL> SELECT process, status, sequence#
FROM v$managed_standby;  2  
PROCESS   STATUS		SEQUENCE#
--------- -------------------- ----------
DGRD	  ALLOCATED			0
DGRD	  ALLOCATED			0
ARCH	  CONNECTED			0
ARCH	  CONNECTED			0
ARCH	  CONNECTED			0
ARCH	  CONNECTED			0
6 rows selected.

Note: As you can see, MRP process is not running so we will start the recovery process

Verify the applied archive in current situation:

SQL> select max(sequence#) from v$archived_log where applied='YES';
MAX(SEQUENCE#)
--------------
	    38

Start the MRP process:


SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE disconnect;

Database altered.

Once started, we have to again run and check the process is started or not

SQL> SELECT process, status, sequence#
  2  FROM v$managed_standby;
PROCESS   STATUS		SEQUENCE#
--------- -------------------- ----------
    DGRD	  ALLOCATED			0
    DGRD	  ALLOCATED			0
    ARCH	  CLOSING	       39
    ARCH	  CONNECTED			0
    ARCH	  CONNECTED			0
    ARCH	  CONNECTED			0
     RFS	  IDLE				0
     RFS	  IDLE		       42
     RFS	  IDLE				0
     RFS	  IDLE				0
     RFS	  IDLE				0
    MRP0	  APPLYING_LOG	   42
12 rows selected.

Note: As you see MRP process is started, so we have to have for 5 to 10 minutes depend upon the archive gap and this will fixed the issue.