Hadoop Map/Reduce
  1. Hadoop Map/Reduce
  2. MAPREDUCE-239

Attribute to mark Mappers and Reducers as side-effect free

    Details

    • Type: Improvement Improvement
    • Status: Resolved
    • Priority: Major Major
    • Resolution: Won't Fix
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: None
    • Labels:
      None

      Description

      There should be an annotation to mark Mapper and Reducer classes as side-effect free. This annotation could then be used to disable speculative execution for such classes. Furthermore, defining a class without the NoSideEffect attribute as a combiner would be a run-time error.

      @NoSideEffects
      class MyMapper extends MapReduceBase implements Mapper

      { ... }

      would declare that MyMapper may be run speculatively.

      @NoSideEffects
      class MyReducer extends MapReduceBase implements Reducer

      { ...}

      declares that MyReducer can be run speculative and as a combiner.

        Activity

        Harsh J made changes -
        Status Open [ 1 ] Resolved [ 5 ]
        Resolution Won't Fix [ 2 ]
        Hide
        Harsh J added a comment -

        I think this is pretty much covered by map and reduce speculative option separation.

        Show
        Harsh J added a comment - I think this is pretty much covered by map and reduce speculative option separation.
        Owen O'Malley made changes -
        Project Hadoop Common [ 12310240 ] Hadoop Map/Reduce [ 12310941 ]
        Key HADOOP-981 MAPREDUCE-239
        Affects Version/s 0.11.0 [ 12312257 ]
        Component/s mapred [ 12310690 ]
        Doug Cutting made changes -
        Field Original Value New Value
        Fix Version/s 0.12.0 [ 12312293 ]
        Owen O'Malley created issue -

          People

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

            Dates

            • Created:
              Updated:
              Resolved:

              Development