Hadoop Map/Reduce
  1. Hadoop Map/Reduce
  2. MAPREDUCE-884

TestReduceFetchFromPartialMem fails sometimes

    Details

    • Type: Bug Bug
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: 0.20.1
    • Fix Version/s: 0.21.0
    • Component/s: test
    • Labels:
      None

      Description

      TestReduceFetchFromPartialMem failed with the following exception trace :

      Expected some records not spilled during reduce40980)
      junit.framework.AssertionFailedError: Expected some records not spilled during reduce40980)
              at org.apache.hadoop.mapred.TestReduceFetchFromPartialMem.testReduceFromPartialMem(TestReduceFetchFromPartialMem.java:94)
              at junit.extensions.TestDecorator.basicRun(TestDecorator.java:24)
              at junit.extensions.TestSetup$1.protect(TestSetup.java:23)
              at junit.extensions.TestSetup.run(TestSetup.java:27)
      
      1. mapred-884.patch
        0.7 kB
        Jothi Padmanabhan

        Activity

        Hide
        Jothi Padmanabhan added a comment -

        I think I know what is happening here. All the maps are shuffled to memory, but when the last map is shuffled, it just happens that the memory limit is reached and a memory to disk merge is triggered and all the output touches the disk. As a result, spill counter is the same as map output records. A simple fix would be to increase the number of maps so that the last few maps reside in memory and so the assert condition is met.

        I will fix this as a part of MAPREDUCE-157

        Show
        Jothi Padmanabhan added a comment - I think I know what is happening here. All the maps are shuffled to memory, but when the last map is shuffled, it just happens that the memory limit is reached and a memory to disk merge is triggered and all the output touches the disk. As a result, spill counter is the same as map output records. A simple fix would be to increase the number of maps so that the last few maps reside in memory and so the assert condition is met. I will fix this as a part of MAPREDUCE-157
        Hide
        Jothi Padmanabhan added a comment -

        I will fix this as a part of MAPREDUCE-157

        I meant, MAPREDUCE-318

        Show
        Jothi Padmanabhan added a comment - I will fix this as a part of MAPREDUCE-157 I meant, MAPREDUCE-318
        Hide
        Jothi Padmanabhan added a comment -

        Simple patch to increase the number of map tasks

        Show
        Jothi Padmanabhan added a comment - Simple patch to increase the number of map tasks
        Hide
        Hadoop QA added a comment -

        +1 overall. Here are the results of testing the latest attachment
        http://issues.apache.org/jira/secure/attachment/12418339/mapred-884.patch
        against trunk revision 810330.

        +1 @author. The patch does not contain any @author tags.

        +1 tests included. The patch appears to include 3 new or modified tests.

        +1 javadoc. The javadoc tool did not generate any warning messages.

        +1 javac. The applied patch does not increase the total number of javac compiler warnings.

        +1 findbugs. The patch does not introduce any new Findbugs warnings.

        +1 release audit. The applied patch does not increase the total number of release audit warnings.

        +1 core tests. The patch passed core unit tests.

        +1 contrib tests. The patch passed contrib unit tests.

        Test results: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/33/testReport/
        Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/33/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
        Checkstyle results: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/33/artifact/trunk/build/test/checkstyle-errors.html
        Console output: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/33/console

        This message is automatically generated.

        Show
        Hadoop QA added a comment - +1 overall. Here are the results of testing the latest attachment http://issues.apache.org/jira/secure/attachment/12418339/mapred-884.patch against trunk revision 810330. +1 @author. The patch does not contain any @author tags. +1 tests included. The patch appears to include 3 new or modified tests. +1 javadoc. The javadoc tool did not generate any warning messages. +1 javac. The applied patch does not increase the total number of javac compiler warnings. +1 findbugs. The patch does not introduce any new Findbugs warnings. +1 release audit. The applied patch does not increase the total number of release audit warnings. +1 core tests. The patch passed core unit tests. +1 contrib tests. The patch passed contrib unit tests. Test results: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/33/testReport/ Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/33/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html Checkstyle results: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/33/artifact/trunk/build/test/checkstyle-errors.html Console output: http://hudson.zones.apache.org/hudson/job/Mapreduce-Patch-h6.grid.sp2.yahoo.net/33/console This message is automatically generated.
        Hide
        Jothi Padmanabhan added a comment -

        Fixed as a part of MR-318

        Show
        Jothi Padmanabhan added a comment - Fixed as a part of MR-318

          People

          • Assignee:
            Jothi Padmanabhan
            Reporter:
            Amar Kamat
          • Votes:
            0 Vote for this issue
            Watchers:
            3 Start watching this issue

            Dates

            • Created:
              Updated:
              Resolved:

              Development