Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-61458

Calling RSLocalClient::queryOnce(kMajorityReadConcern) causes subsequent local writes in same OperationContext to also read stale data

XMLWordPrintableJSON

    • Type: Icon: Bug Bug
    • Resolution: Fixed
    • Priority: Icon: Major - P3 Major - P3
    • 5.2.0
    • Affects Version/s: 4.0.0, 4.2.0, 4.4.0, 5.0.0, 5.1.0
    • Component/s: Internal Client
    • None
    • Fully Compatible
    • ALL
    • Execution Team 2021-11-29
    • 152

      RSLocalClient::queryOnce(kMajorityReadConcern) will modify the ReadSource for the RecoveryUnit to be kMajorityCommitted. It won't restore the original ReadSource upon returning from the function. This issue was discovered during SERVER-59831 because it caused a later write using the same OperationContext to still be using kMajorityCommitted as its ReadSource and for the later write not to see the effects of an earlier write from secondary batch application.

      if (readConcernLevel == repl::ReadConcernLevel::kMajorityReadConcern) {
    // Set up operation context with majority read snapshot so correct optime can be retrieved.
    opCtx->recoveryUnit()->setTimestampReadSource(RecoveryUnit::ReadSource::kMajorityCommitted);
    ...
}

      My thought here would be to introduce a new RAII type to enable the ReadSource to be temporarily overridden and to use it in RSLocalClient::queryOnce().

            Assignee:
            yuhong.zhang@mongodb.com Yuhong Zhang
            Reporter:
            max.hirschhorn@mongodb.com Max Hirschhorn
            Votes:
            0 Vote for this issue
            Watchers:
            4 Start watching this issue

              Created:
              Updated:
              Resolved: