Diagram of Apache Flink coordinator and sink operators exchanging pre-commit and commit calls during a checkpoint barrier.

Inside Apache Flink's Two-Phase Commit Sink: Exactly-Once Guarantees Across Sinks

How Apache Flink coordinates checkpoints with sink writers via a two-phase commit protocol to deliver end-to-end exactly-once guarantees across Kafka, filesystems, and databases.

September 5, 2026 · 12 min · 2435 words · martinuke0
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