Andreas Martens: Dekomposition komplexer Datenstrukturen in Legacy-Systemen zur stufenweisen Datenmigration

Sooner or later, in almost every company, the maintenance and further development of large enterprise IT applications reaches its limit. From the point of view of cost as well as technical capability, legacy applications must eventually be replaced by new enterprise IT applications. Data migration is an inevitable part of making this switch. While different data migration strategies can be applied, incremental data migration is one of the most popular strategies, due to its low level of risk and high flexibility: The entire data volume is split into several data tranches, which are then migrated in individual migration steps. The key to a successful migration is the strategy for decomposing the data into suitable tranches.

This work presents an approach for data decomposition where the entire data volume of a monolithic IT enterprise application is split into independent data migration tranches. Each tranche comprises the data to be migrated in one migration step, which is usually executed during the application’s downtime window. Unlike other approaches, which describe data migration in a highly abstract way, specific heuristics for data decomposition into independent
data packages are proposed here. The data migration approach described here was evaluated in two case studies, one of which was one of the largest migration projects in the European healthcare sector in last years, comprising millions of customer records.