Hadoop Common
  1. Hadoop Common
  2. HADOOP-1986

Add support for a general serialization mechanism for Map Reduce

    Details

    • Type: New Feature New Feature
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 0.17.0
    • Component/s: None
    • Labels:
      None
    • Hadoop Flags:
      Incompatible change, Reviewed
    • Release Note:
      Hide
      Programs that implement the raw Mapper or Reducer interfaces will need modification to compile with this release. For example,

      class MyMapper implements Mapper {
        public void map(WritableComparable key, Writable val,
          OutputCollector out, Reporter reporter) throws IOException {
          // ...
        }
        // ...
      }

      will need to be changed to refer to the parameterized type. For example:

      class MyMapper implements Mapper<WritableComparable, Writable, WritableComparable, Writable> {
        public void map(WritableComparable key, Writable val,
          OutputCollector<WritableComparable, Writable> out, Reporter reporter) throws IOException {
          // ...
        }
        // ...
      }

      Similarly implementations of the following raw interfaces will need modification: InputFormat, OutputCollector, OutputFormat, Partitioner, RecordReader, RecordWriter
      Show
      Programs that implement the raw Mapper or Reducer interfaces will need modification to compile with this release. For example, class MyMapper implements Mapper {   public void map(WritableComparable key, Writable val,     OutputCollector out, Reporter reporter) throws IOException {     // ...   }   // ... } will need to be changed to refer to the parameterized type. For example: class MyMapper implements Mapper<WritableComparable, Writable, WritableComparable, Writable> {   public void map(WritableComparable key, Writable val,     OutputCollector<WritableComparable, Writable> out, Reporter reporter) throws IOException {     // ...   }   // ... } Similarly implementations of the following raw interfaces will need modification: InputFormat, OutputCollector, OutputFormat, Partitioner, RecordReader, RecordWriter

      Description

      Currently Map Reduce programs have to use WritableComparable-Writable key-value pairs. While it's possible to write Writable wrappers for other serialization frameworks (such as Thrift), this is not very convenient: it would be nicer to be able to use arbitrary types directly, without explicit wrapping and unwrapping.

      1. serializer-v7.patch
        103 kB
        Tom White
      2. serializer-v6.patch
        94 kB
        Tom White
      3. SequenceFileWriterBenchmark.java
        3 kB
        Tom White
      4. serializer-v5.patch
        94 kB
        Tom White
      5. serializer-v4.patch
        93 kB
        Tom White
      6. serializer-v3.patch
        97 kB
        Tom White
      7. hadoop-serializer-v2.tar.gz
        1.36 MB
        Tom White
      8. serializer-v2.patch
        70 kB
        Tom White
      9. serializer-v1.patch
        70 kB
        Tom White
      10. SerializableWritable.java
        3 kB
        Dennis Kubes

        Activity

        No work has yet been logged on this issue.

          People

          • Assignee:
            Tom White
            Reporter:
            Tom White
          • Votes:
            0 Vote for this issue
            Watchers:
            6 Start watching this issue

            Dates

            • Created:
              Updated:
              Resolved:

              Development