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  1. Core Server
  2. SERVER-12261

Map Reduce with sharded output collection creates orphan documents

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Details

    • Icon: Bug Bug
    • Resolution: Done
    • Icon: Major - P3 Major - P3
    • None
    • None
    • MapReduce, Sharding
    • ALL
    • Sharding 2019-01-28, Sharding 2019-02-11

    Description

      During the post-processing phase of a map reduce run, when a shard pulls the documents for the chunks (of the output collection) that it owns from other shard(s), those documents are not deleted from the source shard(s). This may result in a large number of orphan documents which greatly increases the storage size of the output collection.

      When documents are migrated across shards during post-processing, they should be removed from the source shard.

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            randolph@mongodb.com Randolph Tan
            jon.rangel@mongodb.com Jon Rangel (Inactive)
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              Created:
              Updated:
              Resolved: