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  1. IMPALA
  2. IMPALA-2684

Fragment start latencies reported in wrong unit

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Minor
    • Resolution: Fixed
    • Affects Version/s: Impala 2.2.4
    • Fix Version/s: Impala 2.5.0
    • Component/s: Distributed Exec
    • Labels:
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      Description

      The metric Fragment start latencies is reported in nanoseconds:

      Fragment start latencies: count: 39, last: 0.078961ns, min: 0.011105ns, max: 0.541386ns, mean: 0.375923ns, stddev: 0.124721ns

      According to my research, and I am probably wrong, but I think it should be reported in seconds (or code which divides it's value by 1000 * 1000 * 1000 should be removed).

      Coordinator uses MonotonicStopWatch here:

      https://github.com/cloudera/Impala/blob/0849c12423dd790c4244566ef3882770222fa155/be/src/runtime/coordinator.cc#L108

      which returns elapsed time in nanoseconds here:

      https://github.com/cloudera/Impala/blob/0849c12423dd790c4244566ef3882770222fa155/be/src/util/stopwatch.h#L120

      The problem occurs when elapsed time is converted to seconds here:

      https://github.com/cloudera/Impala/blob/0849c12423dd790c4244566ef3882770222fa155/be/src/runtime/parallel-executor.cc#L54

      despite the fact that the metric definition is already in nanoseconds here:

      https://github.com/cloudera/Impala/blob/0849c12423dd790c4244566ef3882770222fa155/be/src/runtime/coordinator.cc#L405

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              • Assignee:
                henryr Henry Robinson
                Reporter:
                flumeqa Flume QA
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                  Updated:
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