When Resume Is Worth It

resume = true is valuable when redoing work is expensive. It is not the default fastest path.

Use resume when

• the migration is long enough that a restart would be painful
• large chunkable tables dominate runtime
• network or maintenance-window reliability is uncertain
• you need a documented recovery story for operations

Do not reach for resume automatically when

• the target schema is disposable and cheap to recreate
• the migration is short enough that a full rerun is acceptable
• you are optimizing for the fastest possible dev or staging loop

Required pairing

resume = true
unlogged_tables = false

Why: checkpoints only make sense when the target data survives a crash.

If you use table filters, treat table_filter_mode, include_tables, and exclude_tables as part of the checkpoint contract. Changing them between runs can change the selected table set, and pgferry will reject the old checkpoint when the resolved migration scope no longer matches.

Practical tradeoff

You give up the fastest UNLOGGED full-load path, but you gain:

• chunk-level restartability
• lower cost after interruptions
• a safer operational story for large runs

If you are deciding between recreate-fast and chunked-resume, ask one question first: is the real risk load time, or is the real risk having to start over?