Oracle GoldenGate

While Oracle needs no introduction, GoldenGate Software was founded in 1995 to provide transactional data management solutions. It was acquired by Oracle in 2009 to support that company’s fusion middleware platform.

Oracle GoldenGate, which is currently in version 11g R2, is a software application for real-time transactional change data capture, transformation and delivery with log-based, bi-directional data replication. While Oracle GoldenGate can be profitably used within a number of different use case one of its major strengths is in enabling zero-downtime migrations.

While its forté is zero-downtime migration, the guaranteed failback offered by Oracle GoldenGate is at least as important as the elimination of downtime itself, as a part of the migration landscape. It is, if you like, the equivalent of disaster recovery (with no loss of data and migration of user connections) within operational environments and to provide continuously available applications you need to be able to cater for both downtime (zero-downtime migration) and disaster (failback). In the increasingly real-time, 24 hour world that customers demand, migrating applications, databases and platforms may seem scarier than ever. Fortunately, Oracle GoldenGate’s zero-downtime migration is available to take some of that fear away.

In terms of industry sectors Oracle is, of course, all pervasive. Historically, GoldenGate was agnostic across database vendors but of course this is no longer true and the product has especially strong integration with the Oracle Database and MySQL although it, of course, still supports other popular databases. Nevertheless, it is likely that the emphasis of Oracle salespeople will be to focus on the existing client base rather than non-Oracle users.

Customers that have used Oracle GoldenGate for data migrations include Fujitsu, Overstock.com, DirectTV and Swedbank amongst many others.

In practice, GoldenGate offers three different approaches to zero-downtime migration. In each case the idea is that you have two systems, running in parallel, with data incrementally migrating to the new system. The point at which you turn off the old system and run solely on the new one is entirely up to you, and this is regardless of which approach to zero-downtime you adopt. The first method support is so-called unidirectional migration, in which the target system is synchronised with the source but there is no bi-directional synchronisation; the second is an active-passive approach which is essentially the same as the unidirectional methodology except that downgrade logic is embedded in the model so that you can failback to your original source system in the event of a problem; and the third method is active-active in which the user population is distributed between the target and source systems simultaneously, which are synchronised in a bi-directional fashion, with both upgrade and downgrade logic being applied in flight.

GoldenGate Veridata is an optional add-on module that allows you to compare the before and after states of your databases.

Oracle, of course, provides all the services one could wish for and it also has an extensive partner community that also provides relevant services.