Advanced data replication is the mechanism available in the advanced version of Oracle. Recurrence of advanced database allows one or more sources, and several schemes that have been determined, or even a particular segment in each database to be replicated to the target database and one or more replication systems with single or multi-way manner. Thus, both the source and target database at a time can be dealt with reading and writing. All databases that participate in the scheme of repetition of the formation of a distributed database environment. Advanced data redundancy in version 7.1.6 and Oracle is called replication.
However, in Oracle 7, suffering from various disabilities, particularly the performance and configuration and the “slow and snails.” However, with the newer version, it re-christened the advanced replication, and little by little has gained maturity and industrial power, and acceptance as a result of the new features, powerful and easy to use. Staring with Oracle 7.3, integrated in the Advanced Replication for Oracle database. However, only with Oracle 8 and later versions do not ultimately take the form of a solution should be seriously considered by any failure of the site search capabilities, features of the budget, and increased scalability, or the only copy of a separate database for reporting purposes. All the reasons are legitimate and worthy of replication and the investment environment in advance. Not determine the steps necessary to implement the AR. These steps are documented in the documentation for the Oracle server.
From the logical point of view, and hot standby database provides advanced copy. Contrary to what happens in a traditional database standby scenario, and the target database is open and available for immediate failover if the database is the source of accidents. Ideally, the goal must be maintained on a separate device at the remote site for disaster recovery. Given the goal to be open continuously, can be used as an example the report, DSS allows the end user or the application of the kind used to issue complex queries that usually can not be excluded in the production of online transaction processing database, for fear of hurting the performance of production.
Under the advanced replication, multiple copies of the database, the entire database or specific sub-groups, and can be written at one time and one-to-be kept in sync in near real time mode. Called like this configuration, multi-master configuration (because there are no large multi-copy). If synchronization is not needed immediately, and then be able to take an approach based on the dissemination activities of all major transactions in the other. For example, can be based on the time of deployment, where deployment occurs within a few hours of special use. However, if the failure is being replicated for these purposes, synchronization is usually immediate. And therefore, can be maintained at each database in a “peer to peer” manner. All the writing was originally stored locally and then sent to each of the target database through the mechanism of “push” against the repetition of a simple methodology, a “pull” data from the source database.