CSV data import "retry" on timeout causing duplicate entries

[blms]

When importing a large quantity of data, it is possible to trigger a Heroku timeout (30+sec request), which apparently triggers a "retry" and results in duplicate data.

2024-12-12T19:14:14.750757+00:00 heroku[router]: at=error code=H12 desc="Request timeout" method=POST path="/core_data/projects/116/import_data" host=staging.coredata.cloud request_id=6e93b2b2-a01e-4fa0-93d7-b7ec4f864f38 fwd="##.##.##.###" dyno=web.1 connect=0ms service=30114ms status=503 bytes=0 protocol=https

Possible solutions:

• Not retrying on timeout, and instead allowing whatever is in process to complete, with a message to the user that while the application timed out, their data may be partially present.
• Not retrying on timeout, and instead deleting all data that was imported during the request. (Maybe some kind of atomic transactions?)
• Moving the actual import processes to a background task instead of during the request. The only time during which the request needs to stay alive would be during the file upload, which is relatively quick. Of course, this would require resources for a background queue.