1

I have a 12c Dataguard configuration between apple (primary) and orange (physical standby). The following is my entry in ldap:

apple=
(DESCRIPTION_LIST=
 (DESCRIPTION=
  (ADDRESS_LIST=
   (ADDRESS=(PROTOCOL=TCP)(HOST=apple_home)(PORT=15940))
   (ADDRESS=(PROTOCOL=TCP)(HOST=orange_home)(PORT=15940)))
    (CONNECT_DATA=(SERVICE_NAME=virtual_apple)(FAILOVER_MODE=(TYPE=SESSION)(METHOD=basic)))
 )
  (DESCRIPTION=
   (ADDRESS=(PROTOCOL=TCP)(HOST=apple_home)(PORT=15940))
    (CONNECT_DATA=(SERVICE_NAME=apple)(FAILOVER_MODE=(TYPE=SESSION)(METHOD=basic)))
 )
)

My goal with this is to allow clients to sqlplus user@apple regardless of which database is the current primary. This is why you see virtual_apple in the connect string, it is a service created that only runs on current primary. I added the second DESCRIPTION so that in the event of a switchover where apple is the standby, Broker can connect from orange to apple (see orange parameter below). It will otherwise fail to connect because it will be looking for the virtual_apple service on the standby which is undesirable due to the fact that users would then be redirected to the standby when running sqlplus user@apple.

The problem that I have been encountering is that redo shipping and applying seems "spotty". One minute there will no problems and the next I will get ORA-16857: standby disconnected from redo source for longer than specified threshold and redo logs stop applying. I then set TransportDisconnectedThreshold='120' as I have found in articles. However, the problem persists.

I suspect this is due to my network service name description. Perhaps Broker takes too long trying to reach the wrong service name which throws ORA-16857 but then hits the right one but then loses it again. Is my connection string wrong/problematic? Is there a parameter I could add to help solve this issue? Is my issue elsewhere?

On orange:

log_archive_dest_2='service="apple"','ASYNC NOAFFIRM delay=0 optional compression=disable max_failure=0 max_connections=1 reopen=300 db_unique_name="apple" net_timeout=30','valid_for=(online_logfile,all_roles)'

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.