Active Data Guard – what does it mean?

There are misconceptions and half-truths about that term that I see time after time again in forums, postings and comments.

Some people think that Active Data Guard is a fancy marketing term for Standby Databases in Oracle. Wrong, that is just plain Data Guard :-)

Most people think that Active Data Guard means that a Physical Standby Database can be used for queries while it is still applying redo. Not the whole truth, because that is just one featureReal-Time Query – which is included in the Active Data Guard option.

Active Data Guard is an option, coming with an extra charge. Active is supposed to indicate that you can use the standby database for production usage – it is not just waiting for the primary database to fail.

In 11g, Active Data Guard includes three features:

  • Real-Time Query
  • Automatic Block Media Recovery
  • Block Change Tracking on the physical standby

In 12c, Active Data Guard got even more enhanced and includes now the features:

  • Real-time Query
  • Automatic Block Media Recovery
  • Block Change Tracking on the physical standby
  • Far Sync
  • Real-Time Cascade
  • Global Data Services
  • Application Continuity
  • Rolling Upgrade using DBMS_ROLLING

The bad news is that many of the 12c Data Guard New Features require Active Data Guard

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  1. #1 by Arthur A. on May 27, 2014 - 09:25

    Can standard rolling upgrade still be used on 12c without ADG?

  2. #2 by Uwe Hesse on May 29, 2014 - 10:41

    Arthur, yes, you can still do it without using DBMS_ROLLING the old way. Then Active Data Guard is not required.

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