During peak business hours, It is not advised to export data from production .(as it might impact the performance).
So if we have a physical standby database, we can export data using datapump from standby database.

PRE-REQUISITES:

1. Physical standby database should be in READ-ONLY MODE (ACTIVE DATAGUARD)
2.We cannot run expdp directly on physical standby database. Because datapump job can be created only on a read-write database(OPEN).
So to achieve this, we will use the NETWORK_LINK parameter and run the expdp job from any non-standby database(OPEN database)

 

Refer open physical standby database in read only mode 

STEPS:

1. Check whether standby database is in read only mode:

SQL> select database_name,DATABASE_ROLE,open_mode  from v$database;

DATABASE_NAME  DATABASE_ROLE    OPEN_MODE
-------------- ---------------- --------------------
SALPROD        PHYSICAL STANDBY READ ONLY WITH APPLY

2. create a database link on non standby database.[POINTING TO STANDBY DB]

SQL>  create public database link LINK_EXPDP connect to BSSDBA identified by BSSDBA442 using 'SALdbr';

Database link created.


SQL> select sysdate from [email protected]_EXPDP;

SYSDATE
---------
30-JAN-18

3. Create db directory on non-standby server:

create directory ERIC_DUMP as '/dumparea/dump/ERIC_DUMP'

4. Run expdp from non-standby database server:

expdp  directory=ERIC_DUMP network_link=LINK_EXPDP dumpfile=standby_schema.dmp logfile=standby_schema.log tables=EMP_USER.CHANNEL_NUMBER


Export: Release 12.1.0.2.0 - Production on Tue Jan 30 10:38:59 2018

Copyright (c) 1982, 2014, Oracle and/or its affiliates.  All rights reserved.

Username: / as sysdba


Connected to: Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP, Advanced Analytics
and Real Application Testing options
FLASHBACK automatically enabled to preserve database integrity.
Starting "SYS"."SYS_EXPORT_TABLE_01":  /******** AS SYSDBA directory=ERIC_DUMP network_link=LINK_EXPDP dumpfile=standby_schema.dmp logfile=standby_schema.log tables=EMP_USER.CHANNEL_NUMBER
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 320 KB
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/GRANT/OWNER_GRANT/OBJECT_GRANT
Processing object type TABLE_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
Processing object type TABLE_EXPORT/TABLE/STATISTICS/MARKER
. . exported "EMP_USER"."CHANNEL_NUMBER"                 171.2 KB   20000 rows
Master table "SYS"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for SYS.SYS_EXPORT_TABLE_01 is:
  /dumparea/dump/ERIC_DUMP/standby_schema.dmp
Job "SYS"."SYS_EXPORT_TABLE_01" successfully completed at Tue Jan 30 10:47:54 2018 elapsed 0 00:07:14

We have successfully generated the export dump from standby database.

datapumpEXPDP DATAGUARD