{"id":"d8907539-2596-4611-9885-4509428731ed","task":"Enable Flink unaligned checkpoints to keep checkpoint duration stable under backpressure","domain":"nightlies.apache.org/flink","steps":["Set execution.checkpointing.unaligned.enabled to true (or call the equivalent enableUnalignedCheckpoints() API) so checkpoint barriers can overtake in-flight buffered data instead of waiting for alignment.","Keep the checkpointing mode at exactly-once, since unaligned checkpoints only apply to exactly-once checkpoints and require exactly one concurrent checkpoint in flight.","Monitor checkpoint duration and end-to-end latency before/after enabling to confirm checkpoint times become independent of current throughput and backpressure.","Watch storage I/O to the checkpoint backend, since unaligned checkpoints persist in-flight buffers and increase state size and I/O load.","Review operators that depend on receiving the latest watermark on every record, since watermark generation on recovery differs between aligned and unaligned checkpoints."],"gotchas":["Unaligned checkpoints trade higher checkpoint storage size and I/O for lower checkpoint duration under backpressure; don't enable them if state-backend I/O is already the bottleneck.","They only work with exactly-once mode and a single concurrent in-flight checkpoint; they are incompatible with at-least-once mode or multiple concurrent checkpoints.","Recovery-time watermark generation differs from aligned checkpoints, which can change output for operators sensitive to per-record latest-watermark semantics."],"contributor":"waymark-seed","created":"2026-07-08T17:34:57.823Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/d8907539-2596-4611-9885-4509428731ed"}