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  1. Core Server
  2. SERVER-15998

Don't fall-through on WriteConflictExceptions in write command update

    • Type: Icon: Bug Bug
    • Resolution: Done
    • Priority: Icon: Major - P3 Major - P3
    • 2.8.0-rc0
    • Affects Version/s: None
    • Component/s: Concurrency, Write Ops
    • None
    • ALL
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      python benchrun.py -f testcases/simple_update_mms.js -t 1 2 4 8 --nodyno --mongo-repo-path ../mongo/

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      python benchrun.py -f testcases/simple_update_mms.js -t 1 2 4 8 --nodyno --mongo-repo-path ../mongo/

      WriteConflictException was not being handled properly by the write command update executor. This caused them to erroneously appear to succeed.

      Original Description
      The update_mms tests suddenly stopped scaling at all, where last week they did. This is something in the mongo tree, not the WT library as I keep that constant during my testing here and see very different results.

      I spent a bit of time today narrowing it down and the issue happens between changeset c84d5ea and changeset 7f9e3f3 (FYI, c84d5ea is a parent of 7f9e3f3). The diff between these two changesets is very small and attached.

      Here is the page of commits from GitHub:
      https://github.com/wiredtiger/mongo/commits/master?page=9

      Here are the results. I only show Update.MmsIncShallow1 although all show similar patterns.

      GOOD:
      db version: 2.7.9-pre-
      c84d5ea9f484948ba4f52bf00274bd84e45b837e
      
      Update.MmsIncShallow1
      1       10495.389587181788
      1       10455.777272892861
      2       15549.864735174962
      2       15670.030276924275
      4       25134.398199163585
      4       25159.574244737894
      8       32214.23890536317
      8       32237.931283570488
      Finished Testing.
      
      BAD:
      db version: 2.7.9-pre-
      7f9e3f383b0bd77e5119a5d57883631950c1a6ff
      
      Update.MmsIncShallow1
      1       10431.11424139814
      1       10637.16293351225
      2       11245.63626083444
      2       11264.545902335614
      4       10201.82719233331
      4       11287.419799605117
      8       12088.974243081819
      8       12127.817603989664
      Finished Testing.
      

            Assignee:
            greg_10gen Greg Studer
            Reporter:
            dan@mongodb.com Daniel Pasette (Inactive)
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              Created:
              Updated:
              Resolved: