[HADOOP-13339] MetricsSourceAdapter#updateAttrCache may throw NPE due to NULL lastRecs

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Assignee: Yongjun Zhang
• Reporter: Yongjun Zhang
• Created: 04/Jul/16 22:50
• Updated: 05/Jul/16 19:55
• Resolved: 04/Jul/16 22:56

Description

The for loop below may find lastRecs NULL

  private int updateAttrCache() {
    LOG.debug("Updating attr cache...");
    int recNo = 0;
    int numMetrics = 0;
    for (MetricsRecordImpl record : lastRecs) {
      for (MetricsTag t : record.tags()) {
        setAttrCacheTag(t, recNo);
        ++numMetrics;
      }
      for (AbstractMetric m : record.metrics()) {
        setAttrCacheMetric(m, recNo);
        ++numMetrics;
      }
      ++recNo;
    }
    LOG.debug("Done. # tags & metrics="+ numMetrics);
    return numMetrics;
  }

and throws NPE.

Issue Links

• duplicates: HADOOP-11361 Fix a race condition in MetricsSourceAdapter.updateJmxCache