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  1. Core Server
  2. SERVER-27753

wiredTiger cache 95% performance issues

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Duplicate
    • Affects Version/s: 3.2.11
    • Fix Version/s: None
    • Component/s: WiredTiger
    • Labels:
      None
    • Environment:
      Production
    • Backwards Compatibility:
      Fully Compatible
    • Operating System:
      ALL

      Description

      Hello,
      We are experiencing performance drop off's when the wiredTiger Cache becomes 95% full.

      Performing a mongodump on numerous databases serially causes the wiredTiger cache to become 95% populated.

      In some instances the mongodump halts and our backups do not complete.

      What I think is happening is the cache is growing above 95% used. At this point mongo is trying to clear data from the cache and failing, at which point mongodump hangs.

      Changing the size of the wiredTiger cache (up or down) can cause the process to continue, I suspect its causing a forced flush of some cache data.

      Please can you provide a list of data you would like to me to capture and a upload location for this.

      Kind regards,
      Luke

        Attachments

        1. Cache Filling and hitting 95 image 1.png
          Cache Filling and hitting 95 image 1.png
          104 kB
        2. Cache filling and hitting 95 images 2.png
          Cache filling and hitting 95 images 2.png
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        3. CB Screen Shot 2017-02-28 at 09.24.25.png
          CB Screen Shot 2017-02-28 at 09.24.25.png
          83 kB
        4. CB Screen Shot 2017-02-28 at 09.24.38.png
          CB Screen Shot 2017-02-28 at 09.24.38.png
          80 kB
        5. CB Screen Shot 2017-02-28 at 09.25.02.png
          CB Screen Shot 2017-02-28 at 09.25.02.png
          140 kB
        6. CB Screen Shot 2017-02-28 at 09.25.22.png
          CB Screen Shot 2017-02-28 at 09.25.22.png
          110 kB
        7. CB Screen Shot 2017-02-28 at 09.25.34.png
          CB Screen Shot 2017-02-28 at 09.25.34.png
          100 kB
        8. Resized cache image1.png
          Resized cache image1.png
          109 kB
        9. Resized cahce image 2.png
          Resized cahce image 2.png
          58 kB
        10. server-27753-comparison.png
          server-27753-comparison.png
          157 kB

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                Dates

                • Created:
                  Updated:
                  Resolved: