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  1. Core Server
  2. SERVER-15998

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

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 2.8.0-rc0
    • Component/s: Concurrency, Write Ops
    • Labels:
      None
    • Operating System:
      ALL
    • Steps To Reproduce:
      Hide

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

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

      Description

      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.

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                • Created:
                  Updated:
                  Resolved: