Preserve Change Data Capture Bookmark When Journal Assignment Changes on IBM i (AS400)

Problem Statement

When IBM CDC captures changes from an IBM i (AS400) source database, the product relies on the associated journal to track transactional changes.

If the source table's journal is changed (for example, the existing journal is removed and a new journal is assigned, or journaling is temporarily disabled and later re-enabled), CDC treats the table as requiring a complete refresh. The existing capture bookmark/checkpoint cannot be reused.

As a result:

• A full refresh of the table is required.
• Downstream systems lose continuity in incremental change processing.
• Consumers that rely on CDC to identify only changed records receive a complete reload.
• Additional operational effort is required to reload large tables.
• Business applications may experience processing delays and duplicate processing logic.

Current Behaviour

• Journal change/removal invalidates the existing CDC bookmark.
• CDC requires table refresh before replication can continue.
• Incremental replication cannot resume from the previous synchronization point.

Expected Behaviour

IBM CDC should provide an option to preserve replication continuity when the journal associated with a table changes.

Possible approaches include:

• Maintaining the replication bookmark independent of the physical journal object where feasible.
• Automatically detecting journal reassignment and continuing capture from the appropriate point.
• Providing an administrative option to remap the bookmark to the new journal when continuity can be validated.
• Allowing administrators to manually associate an existing bookmark with a new journal after verification instead of forcing a full table refresh.