I am a little bit confused about real-time apply services. I've read a documentation about the services and I still have a question. Does archived redo logs required for logical standby or not? I've configure logical standby and there are 3 destination for db_recovery_file dest. 1st is local storage, 2nd transmits logs on standby and the 3d is for switchover. But still I do not purely understand how it works. Please, clarify or give some useful links.


Does archived redo logs required for logical standby or not? Yes, it does.


The archived redo logs (archivelogs, commonly) contain SQL statements to apply the changes being made to the database, as well as SQL statements to undo the work if a rollback occurs later on the primary's activity.

  • So, the achieved redo logs transmits to the standby and RFS processes writing redo data to the standby redo logs to apply changes to the dataguard. Am I correct? – kozlone Jan 11 '17 at 21:50
  • The redo logs (their own specific thing) become archived logs on the primary. The archived logs get shipped to your 3 locations. The archived log is then opened and read by the logical standby to apply the database changes. – Josh Bonello Jan 11 '17 at 22:19
  • Yes, this is what I meant. – kozlone Jan 11 '17 at 22:21

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