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  1. Core Server
  2. SERVER-7926

Map Reduce with sharded output can apply reduce on duplicate documents if a migration happened

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    • Type: Icon: Bug Bug
    • Resolution: Done
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: None
    • Component/s: MapReduce, Sharding
    • None
    • ALL
    • Sharding 2018-02-12

      Buildbot failure:

      http://buildbot.mongodb.org/builders/Linux%2032-bit/builds/5402

      If a migration happened on the map reduce job output collection right before the mapreduce.shardedfinish is called, there is a possibility that one of the shard still thinks he owns the chunk, whereas it has already donated it to another shard.

        1. mrShardedOutput_with_cmdResult.txt
          698 kB
        2. mrShardedOutput.js
          3.70 MB

            Assignee:
            randolph@mongodb.com Randolph Tan
            Reporter:
            ian@mongodb.com Ian Whalen (Inactive)
            Votes:
            4 Vote for this issue
            Watchers:
            11 Start watching this issue

              Created:
              Updated:
              Resolved: