[HBASE-22045] Mutable range histogram reports incorrect outliers

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha-1, 1.5.0, 2.0.0, 1.4.9, 2.1.3, 2.2.1
• Fix Version/s: 3.0.0-alpha-1, 2.2.0, 1.4.10, 2.3.0, 2.1.5
• Hadoop Flags: Reviewed
• Assignee: Abhishek Singh Chouhan
• Reporter: Abhishek Singh Chouhan
• Created: 12/Mar/19 18:24
• Updated: 07/Oct/19 18:32
• Resolved: 18/Mar/19 20:41

Description

MutableRangeHistogram during the snapshot calculates the outliers (eg. mutate_TimeRange_600000-inf) and adds the counter with incorrect calculation by using the overall count of event and not the number of events in the snapshot.

    long val = histogram.getCount();
    if (val - cumNum > 0) {
      metricsRecordBuilder.addCounter(
          Interns.info(name + "_" + rangeType + "_" + ranges[ranges.length - 1] + "-inf", desc),
          val - cumNum);
    }