5.3 SQL replication

Replication is the copying of data from one place to another. From a business's point of view, replication plays a critical role in business transactions. The general considerations are:

• Distribution of data to other locations
• Consolidation of data from other locations
• Bidirectional exchange of data with other locations
• Some variation or combination of the above

Data can be extracted by specific programs, transported to some predefined location, and then loaded to the target location. A more efficient alternative is to extract only the changes since the last processing cycle and transport/apply those to the receiving location. From the other hand, data may be filtered and transformed during replication. At the same time, there may be other requirements for replication, such as time constraints. Replication processes need to be monitored, since replication must have minimal impact on production systems, which bring significant benefit to the software system.

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