Align Telemetry Streams and Publish Versioned Corrections

Two telemetry streams contain timestamped numeric observations. You need to subtract the streams and then handle late events that can change an earlier result. Explain the timestamp-alignment contract, an ordered-stream processing approach, and a reconciliation protocol that lets consumers distinguish initial results from corrections.

Requirements and Constraints

Within each initially supplied stream, timestamps are nondecreasing. A timestamp may occur in only one stream, and nondecreasing order does not rule out duplicate timestamps. The behavior for a missing counterpart and the meaning of duplicates have not been specified. Identify those decisions before proposing an algorithm. Later events may arrive after an initial result has been emitted.

This is an engineering discussion about defining and maintaining the result contract. No fixed missing-value policy, event schema, lateness bound, or exactly-once delivery guarantee is assumed.

Clarifying Questions

• Are observations independent point measurements, additive contributions, or updates to a value that remains in effect until replaced?
• At a timestamp present in only one stream, should the result be omitted, marked incomplete, interpolated, or computed using a defined default?
• Do repeated timestamps represent distinct measurements, duplicates of one event, or revisions to an earlier value?
• How late can events arrive, and must consumers support replacement values, delta corrections, or both?