Migrating Legacy and Proprietary Databases to PostgreSQL (clt26)

European organisations and companies are increasingly re-evaluating proprietary database dependencies as digital sovereignty becomes more critical than ever. This talk serves as a pragmatic field guide for migrating from legacy or vendor-locked databases (Oracle, SQL Server, Sybase ASE, Db2) to PostgreSQL. Drawing from years of hands-on experience in heterogeneous migrations and tool development, we will explore a comprehensive decision framework for successful transitions. The session compares offline strategies (dump/restore, ETL, bulk COPY) against online, near-zero-downtime approaches (CDC, logical replication, dual-write), with a special focus on designing reversible cutovers to minimize operational risk. We will discuss a toolbox for schema and SQL translation, addressing challenges like LOBs, time zones, collations, and procedural code conversion. We will show validation techniques leveraging checksums, reconciliation queries, and end-to-end testing beyond simple row counts. The talk with show a comparative matrix of different solutions, and highlight lessons learned from real-world migrations ranging from small applications to multi-TB enterprise systems. Licensed to the public under http://creativecommons.org/licenses/by/4.0 about this event: https://chemnitzer.linux-tage.de/2026/de/programm/beitrag/284