[HBASE-24615] MutableRangeHistogram#updateSnapshotRangeMetrics doesn't calculate the distribution for last bucket.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3.0, 1.3.7, 2.2.6
• Fix Version/s: 3.0.0-alpha-1, 2.3.1, 1.7.0, 2.4.0, 2.2.6
• Component/s: metrics
• Hadoop Flags: Reviewed
• Assignee: wenfeiyi666
• Reporter: Rushabh Shah
• Created: 22/Jun/20 22:24
• Updated: 11/Aug/20 18:12
• Resolved: 15/Jul/20 11:14

Description

We are not processing the distribution for last bucket.

https://github.com/apache/hbase/blob/master/hbase-hadoop-compat/src/main/java/org/apache/hadoop/metrics2/lib/MutableRangeHistogram.java#L70

  public void updateSnapshotRangeMetrics(MetricsRecordBuilder metricsRecordBuilder,
                                         Snapshot snapshot) {
    long priorRange = 0;
    long cumNum = 0;

    final long[] ranges = getRanges();
    final String rangeType = getRangeType();
    for (int i = 0; i < ranges.length - 1; i++) {         -----> The bug lies here. We are not processing last bucket.
      long val = snapshot.getCountAtOrBelow(ranges[i]);
      if (val - cumNum > 0) {
        metricsRecordBuilder.addCounter(
            Interns.info(name + "_" + rangeType + "_" + priorRange + "-" + ranges[i], desc),
            val - cumNum);
      }
      priorRange = ranges[i];
      cumNum = val;
    }
    long val = snapshot.getCount();
    if (val - cumNum > 0) {
      metricsRecordBuilder.addCounter(
          Interns.info(name + "_" + rangeType + "_" + ranges[ranges.length - 1] + "-inf", desc),
          val - cumNum);
    }
  }

Issue Links

• links to: GitHub Pull Request #1962
• links to: GitHub Pull Request #2069
• links to: GitHub Pull Request #2070