Active Data Guard

1. What is Active Data Guard Oracle Active Data Guard lets you read data from a standby database while keeping it updated with changes from the main database. This setup allows for various uses like querying, sorting, reporting, and web access on the standby database.

2. Why do I need the Active Data Guard Option? The Active Data Guard Option is a feature provided by Oracle Database, and it offers several benefits for organizations that require high availability, data protection, and real-time reporting.

3. With the availability of Active Data Guard, what role does SQL Apply (logical standby) continue to play? Use SQL Apply for the following requirements:

when you require read-write access to a synchronized standby database but do not modify primary data,

when you wish to add local tables to the standby database that can also be updated, or

when you wish to create additional indexes to optimize read performance.

4. Why would I use Active Data Guard and not simply use SQL Apply (logical standby) that is included with Data Guard 11g?

* If read-only access satisfies the requirement - Active Data Guard is a closer fit for the requirement, and therefore is much easier to implement than any other approach. Active Data Guard supports all data types and is very simple to implement.

* An Active Data Guard replica can also easily support additional uses - offloading backups from the primary database, serve as an open read-write test system during off-peak hours (Snapshot Standby), and provide an exact copy of the production database for disaster recovery - fully utilizing standby servers, storage and software while in standby role.

5. Active DG Vs Logical Standby Active data guard is mostly about the physical standby. You can open the physical standby read/write - do some destructive things in it (drop tables, change data, whatever - run a test - perhaps with real application testing). While this is happening, redo is still streaming from production, if production fails - you are covered. Use physical standby for reporting while in managed recovery mode. Since physical standby supports all of the datatypes - and logical standby does not (11g added broader support, but not 100%) - there are times when logical standby isn’t sufficient. It also permits fast incremental backups when offloading backups to a physical standby database.