Uploaded image for project: 'Documentation'
  1. Documentation
  2. DOCS-11731

Docs for SERVER-33538: mapReduce "replace" on a sharded output collection can lead to UUIDCatalog inconsistencies

    XMLWordPrintable

    Details

    • Type: Task
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 4.0.0-rc1, 3.6.6, 4.1.1
    • Component/s: None
    • Labels:
      None

      Description

      Description:

      If the out field for mapReduce has 'sharded: true', the output collection cannot be an existing unsharded collection. We fail the mapReduce command in this case.

      Scope of changes:

       

      https://docs.mongodb.com/manual/reference/command/mapReduce/index.html – add a note to the section that describes the "sharded" parameter in the out stage/

      https://docs.mongodb.com/manual/reference/method/db.collection.mapReduce/index.html – ditto

       

      clarify: core/map-reduce-sharded-collections.html

       

      Impact to other docs outside of this product:

      MVP:

      Resources:

      Engineering Ticket Description:

      mapReduce with a sharded output collection assigns the UUID obtained from the config server to the final output collection. mapReduce "replace" will drop the existing output collection, which has the same UUID as the new output collection. Two-phase-drop may cause the dropCollection to finish after the renameCollection finishes, erroneously removing the UUIDCatalog entry for the output collection.

        Attachments

          Issue Links

            Activity

              People

              Assignee:
              sue.kerschbaumer Susan Kerschbaumer (Inactive)
              Reporter:
              kay.kim Kay Kim (Inactive)
              Participants:
              Last commenter:
              Kay Kim Kay Kim (Inactive)
              Votes:
              0 Vote for this issue
              Watchers:
              3 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved:
                Days since reply:
                3 years, 14 weeks, 6 days ago
                Date of 1st Reply: