Map runtime and troubleshooting

A Flow Map step loads the Map, opens source for read and destination for output, then calls Map execution. Exceptions are logged as Map errors and stop the normal later-step sequence.

Runtime boundaries

• The Map's standalone Test Map previews rather than persisting its destination.
• A Flow step uses real Definitions. Database-backed destination changes participate in the Flow's later commit/rollback path unless transactions are disabled or work commits independently.
• File output is not a database transaction and can exist even if later work fails.
• Flow Test Run requests database rollback and suppresses normal file movement, but an individual script/module can still perform external effects. Use isolated destinations.
• Record/view counters and SaveData are reset for an execution; they are not long-lived business totals.

Diagnose

Symptom	Check
Map cannot open	Source/destination Definition availability, Connection permissions and synchronised structure.
Field missing/out of sync	Definition rename/removal, view relationship and saved field-name mapping.
No output	Source criteria/parameters, empty-source policy, event branches and destination open/save behaviour.
Wrong detail relationship	Parent/detail view mappings, key mapping and record-level events.
Duplicate destination	Prior attempt outcome, Flow/Transport retry, destination keys and replay controls.
Formula error	Compile in exact event scope; inspect types, nulls, Scriptlet and Variable Group references.

Before rerunning, establish whether the first attempt wrote database rows or files. See Flow transactions/retry and Map step.