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  1. WiredTiger
  2. WT-11384

Create a perf test to assess r/w latency while stressing the maximum page size at eviction

    • Type: Icon: Task Task
    • Resolution: Unresolved
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: None
    • Component/s: None
    • 5
    • StorEng - Defined Pipeline, ASeasonTooMany-2023-08-22, BermudaTriangle- 2023-09-05, TheMoon-StorEng - 2023-09-19

      This task aims to understand something that has been observed more and more lately that is a problem: the maximum page size seen when being evicted.

      By stressing a page with many updates, we would make the page grow more and more which should be ultimately evicted. The size of the page when being evicted is tracked by the metric "ss wt cache maximum page size at eviction". We have seen in the field that this can go up to hundreds of MB which is unexpected and much more than the expected value (< 10 MB).

      The test should reproduce the problem and eventually expose the root cause. The cppsuite could be used for this purpose.

      Now the problem could be reproduced easily, see this comment for the next steps. TLDR; create a test to assess the r/w latency while stressing the maximum page size at eviction.

        1. repro_stats.png
          130 kB
          Etienne Petrel
        2. size_seen_at_eviction_1GB.png
          25 kB
          Etienne Petrel
        3. test_eviction01.py
          6 kB
          Etienne Petrel

            Assignee:
            backlog-server-storage-engines [DO NOT USE] Backlog - Storage Engines Team
            Reporter:
            etienne.petrel@mongodb.com Etienne Petrel
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              Created:
              Updated: