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  1. Core Server
  2. SERVER-13088

Scalability of distinct is sub-optimal

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    • Type: Icon: Bug Bug
    • Resolution: Won't Fix
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: 2.6.0-rc1
    • Component/s: Concurrency, MMAPv1, Querying
    • Labels:
    • Query
    • ALL
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      Get mongo-perf at https://github.com/mongodb/mongo , build, and run

      ./benchmark --test command --raw

      and wait for the output of Distinct

      {With,Without}

      Index.

      Show
      Get mongo-perf at https://github.com/mongodb/mongo , build, and run ./benchmark --test command --raw and wait for the output of Distinct {With,Without} Index.

      mongo-perf shows distinct doesn't scale very well, and the problem gets evident after 4 threads. This is tested on a recent 12-core Xeon. The problem affects every version of mongo I was able to test on (namely 2.2, 2.4, 2.6). Screenshot attached.

        1. distinct.png
          distinct.png
          60 kB

            Assignee:
            backlog-server-query Backlog - Query Team (Inactive)
            Reporter:
            davide.italiano Davide Italiano
            Votes:
            2 Vote for this issue
            Watchers:
            8 Start watching this issue

              Created:
              Updated:
              Resolved: