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

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              Assignee:
              michael.cahill Michael Cahill
              Reporter:
              lukemorfitt Luke Morfitt
              Participants:
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                Dates

                Created:
                Updated:
                Resolved: