Database replication for disconnected operations with quasi real-time synchronization

Database replication is a way to improve system throughput or achieve high availability. In most cases, the use of an active-active replica architecture is efficient and easy to deploy. Such a system has CP properties (from the CAP theorem: consistency, availability, and network-partition tolerance). Creating an AP (available and partition-tolerant) system requires the use of multi-primary replication. Because of the many difficulties in its implementation, this approach is not widely used; however, ALICE’s deployment of CCDB (experiment conditions and calibration database) needs to be an AP system in two locations. This necessity became the inspiration for examining the state-of-the-art methods in this field and testing the available solutions. The tests that were performed evaluated the performance of the chosen replication tools: Bucardo, and EDB Replication Server; these showed that the tested tools could be successfully used for the continuous synchronization of two independent database instances.