IBM i (AS400) real-time data replication: Gluesync upgrades to native CDC APIs

Unlocking data from legacy infrastructures without impacting core operations has always been one of the biggest challenges in enterprise data integration. To solve this, today we are announcing a major architectural upgrade to our IBM i (AS/400) agent. Specifically, it fundamentally redefines how Gluesyncreplicates data from this platform. 

From DSPJRN to QjoRetrieveJournalEntries: why it matters

We have officially migrated our IBM i connector from the traditional, file-based Display Journal (DSPJRN) approach to the IBM’s native QjoRetrieveJournalEntries system API.

DSPJRN was a well-established but inherently limited method. For instance, it reads journal data by spawning system commands, introducing latency and consuming CPU cycles.
In contrast, QjoRetrieveJournalEntries is a different paradigm entirely. It reads journal entries directly via IBM’s programmatic API layer. As a result, it enables event-driven, low-overhead change data capture with no intermediate file generation.

The results are significant:

• Ultra-low latency: true real-time CDC with throughput speeds consistently under 500-350ms. Consequently, data moves seamlessly from IBM i to targets like Kafka, Snowflake, or PostgreSQL.

• Minimal host impact: dramatic reduction in CPU overhead on the IBM i machine, preserving the performance of ERP and mission-critical business systems running on the same infrastructure.
• Enterprise-grade scalability: capable of handling high-throughput transaction volumes without risk of data loss or bottlenecks.

A modern alternative to legacy IBM i replication software

Implementing stable, production-grade CDC on IBM i via QjoRetrieveJournalEntries requires deep, low-level system expertise. Historically, this level of native integration was restricted to a select few legacy replication suites, such as Precisely with MiMiX.

However, with this update, Gluesync joins an extremely narrow group of modern data integration platforms worldwide to offer this level of IBM i replication. The same engineering depth as traditional industry incumbents delivered within a cloud-native, container-based and cost-effective platform built for modern data architectures.

The updated IBM i agent is fully production-ready and available for enterprise deployments. For technical requirements, journal configuration and permission setup, refer to the official IBM i Series Agent documentation.