Diago · fishbone

Investigate checkout latency

Illustrative engineering example. Sources and findings are fictional.

Investigate checkout latency Observed effect: Checkout p99 exceeded 2 seconds. Categories group investigation findings; hypotheses and ruled-out candidates are not confirmed causes. Multiple contributing causes are allowed. Investigation map · branches group candidates; they do not prove causationData accessIllustrative query plan: missing index produces a scan.Full table scanconfirmedIllustrative lock sampling: no concurrent lock waits.Row lock contentionruled-outRuntimeOpen question: correlate pool saturation with slow requests.Connection pool exhaustedhypothesisIllustrative runtime trace: pauses under 10 ms.Long GC pauseruled-outReleaseIllustrative diff: pagination was removed from a hot path.New unbounded queryconfirmedTrafficOpen question: inspect request-rate measurements.Unexpected request bursthypothesisOBSERVED EFFECTCheckout p99 exceeded 2seconds Investigate checkout latency Observed effect: Checkout p99 exceeded 2 seconds. Categories group investigation findings; hypotheses and ruled-out candidates are not confirmed causes. Multiple contributing causes are allowed. OBSERVED EFFECTCheckout p99 exceeded 2secondsData accessFull table scanconfirmedRow lock contentionruled-outRuntimeConnection pool exhaustedhypothesisLong GC pauseruled-outReleaseNew unbounded queryconfirmedTrafficUnexpected request bursthypothesis
hypothesisconfirmedruled-out

Investigation evidence

Investigation evidence — complete authored values
CategoryFindingStatusEvidence
Observed effectCheckout p99 exceeded 2 secondsobservedIllustrative incident metric: p99 = 2.4 s during the release window.
Data accessFull table scanconfirmedIllustrative query plan: missing index produces a scan.
Data accessRow lock contentionruled-outIllustrative lock sampling: no concurrent lock waits.
RuntimeConnection pool exhaustedhypothesisOpen question: correlate pool saturation with slow requests.
RuntimeLong GC pauseruled-outIllustrative runtime trace: pauses under 10 ms.
ReleaseNew unbounded queryconfirmedIllustrative diff: pagination was removed from a hot path.
TrafficUnexpected request bursthypothesisOpen question: inspect request-rate measurements.