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  1. WiredTiger
  2. WT-6664

Cache eviction causes high latency during py-tpcc.

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    Details

    • Type: Bug
    • Status: Open
    • Priority: Major - P3
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: 5.1 Required
    • Component/s: None
    • Labels:
      None
    • Story Points:
      5
    • Sprint:
      Storage - Ra 2020-10-05, Storage - Ra 2020-10-19, Storage - Ra 2020-11-02, Storage - Ra 2020-11-16, Storage - Ra 2020-11-30, Storage - Ra 2021-01-11

      Description

      SERVER-50749 identifies some performance problems when loading data in py-tpcc.

      In attempting to reproduce the problem, I saw some high latency  insert operations that seem to be caused by WT cache eviction pressure.

      In particular, during a 25 minute test run, I saw 15 operations of 16+ seconds. All of these stalls correlated with aggressive eviction, high numbers of pages evicted by application threads, and evictions requiring restoration.

        Attachments

        1. 4-2-10-vs-master-closeup.png
          4-2-10-vs-master-closeup.png
          420 kB
        2. 4-2-10-vs-master-flow.png
          4-2-10-vs-master-flow.png
          232 kB
        3. compare_different_versions.png
          compare_different_versions.png
          301 kB
        4. compare-all.png
          compare-all.png
          257 kB
        5. flowcontrol-compare.png
          flowcontrol-compare.png
          216 kB
        6. flow-on-vs-flow-off.png
          flow-on-vs-flow-off.png
          194 kB
        7. metrics.2020-09-09T20-02-23Z-00000
          1.56 MB
        8. Screen Shot 2020-09-09 at 6.16.19 PM.png
          Screen Shot 2020-09-09 at 6.16.19 PM.png
          157 kB

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              Assignee:
              sulabh.mahajan Sulabh Mahajan
              Reporter:
              keith.smith Keith Smith
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                Dates

                Created:
                Updated: