Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-36447

[3.6] MapReduce uses the output collection's UUID when creating the temp collection

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Won't Fix
    • Affects Version/s: 3.6.0
    • Fix Version/s: None
    • Component/s: Catalog, MapReduce
    • Labels:
      None
    • Operating System:
      ALL
    • Linked BF Score:
      15

      Description

      If a mapReduce runs in FCV 3.4, the temp collection will automatically pick up the collection options from the out collection, if the out collection exists. If we're running concurrent mapReduces, the out collection has a chance to exist. Take this scenario:

      Steps to reproduce (sequentially):

      1. MapReduce 1 creates an out collection "xyz" with a generated UUID "a."
      2. MapReduce 2 (same in/out) creates a temp collection that uses the same UUID "a" picked up from the now-existing "xyz."
      3. The out collection "xyz" gets dropped.
      4. MapReduce 2 renames the temp collection to "xyz." It will have the same UUID "a."

      We should not be propagating UUIDs in this fashion.

      The relevant code is here

        Attachments

          Issue Links

            Activity

              People

              Assignee:
              backlog-server-query Backlog - Query Team (Inactive)
              Reporter:
              blake.oler Blake Oler
              Participants:
              Votes:
              0 Vote for this issue
              Watchers:
              7 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved: