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Batch & Streaming · Streaming Processing

What is Kappa architecture?

Mediumstream-27
KappareplayKafkaarchitecture

Question

What is the Kappa architecture, and how does it differ from Lambda?

Solution

Kappa architecture uses a single streaming pipeline (plus a durable log) as the main processing path. Need a recompute? Replay the log through the same stream job (or a batch job that reuses the same logic), instead of maintaining a separate batch system forever.

Lambda:  stream path + batch path (two logics)
Kappa:   log (Kafka) --> one processing job --> serving tables
              \-- replay for backfill / recompute --/

Requirements

  • Durable, replayable event log
  • Idempotent or versioned sinks so replay is safe
  • Enough retention / cold storage of events

Interview tip: "Kappa = unify on the stream/log; Lambda = dual batch+speed." Mention trade-off: replay cost vs dual-code cost.

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