1. Kappa vs Lambda advanced

    A finance-reporting platform runs a nightly batch job and a streaming job that compute the same daily revenue figure, and the batch number is the one the controller signs. You are asked to retire the batch path. Sequence it so every step is reversible and say where the point of no return is.

    3 min answer lambdareconciliationauditparallel run
  2. Kappa vs Lambda advanced

    A platform maintains separate batch and streaming implementations of the same logic. What does that cost, and what are the alternatives?

    2 min answer lambdakappaduplicationskew
  3. Kappa vs Lambda advanced

    A publisher keeps every piece of published content in one ordered Kafka log and rebuilds every downstream store by replaying it, as The New York Times described in 2017. What does that buy, what does the ordering requirement cost, and where would copying it be a mistake?

    3 min answer new york timeskafkalogreplay
  4. Kappa vs Lambda advanced

    A team replays 60 days of order events through the current job to correct a tax calculation. Side effects are already handled - the replay writes to a shadow table and emits no notifications. The job enriches each order by calling the pricing service for the item's list price. What does the shadow table contain when the replay finishes?

    3 min answer replaydeterminismenrichmenttemporal-join
  5. Kappa vs Lambda advanced

    Walk me through how you would decide whether a new analytics platform needs a batch processing path at all. The team already runs a stream processor, and nobody has asked for historical reprocessing yet.

    3 min answer kappareplayretentionidempotency