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Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

Motivation

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Ensure atomicity between share‑group acknowledgments and downstream side effects (e.g., Kafka transactions) so a record is either both processed and acknowledged or neither.

1. Share consumer polls records -> broker sets them to ACQUIRED.
2. Framework processes and acknowledges records (implicit or explicit).
3. Checkpoint fails before sink outputs are committed.
4. Records are permanently ACKNOWLEDGED (not redelivered) -> data loss.
5. Note:
   1. Share records become terminal when acked: RecordState
   2. Ack path today is irreversible once ACKNOWLEDGED: SharePartition.acknowledge(

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1. 1. )

Goal: Enable exactly-once read semantics via transactional acknowledgements.

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