Hadoop Common
  1. Hadoop Common
  2. HADOOP-6881

The efficient comparators aren't always used except for BytesWritable and Text

    Details

    • Type: Bug Bug
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: 0.20.0
    • Fix Version/s: 0.20.3, 0.21.0
    • Component/s: None
    • Labels:
      None
    • Hadoop Flags:
      Reviewed

      Description

      When we moved from Java 4 to Java 5 (and then 6), there was a change in the JVM semantics such that references to a class such as IntWritable.class no longer forces initialization. Since all of the Writables depend on their class static blocks to register their fast comparators, that can happen after we look up the comparator. In that case, the framework will fall back to the generic comparator that deserializes both keys and does the object compare, which may cause a huge slow down in the sort.

      1. h-6881.patch
        2 kB
        Owen O'Malley
      2. HADOOP-6881.patch
        3 kB
        Doug Cutting
      3. HADOOP-6881.patch
        3 kB
        Doug Cutting

        Activity

          People

          • Assignee:
            Owen O'Malley
            Reporter:
            Owen O'Malley
          • Votes:
            0 Vote for this issue
            Watchers:
            5 Start watching this issue

            Dates

            • Created:
              Updated:
              Resolved:

              Development