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  1. Core Server
  2. SERVER-88167

Expose information about change event being from a migration event when change streams run with showMigrationEvents:true

    • Type: Icon: Improvement Improvement
    • Resolution: Unresolved
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: None
    • Component/s: Change streams
    • None
    • Query Execution

      The undocumented {showMigrationEvents: true} option to $changeStreams causes oplog entries with {fromMigrate: true} to be returned. This behavior was initially introduced for Atlas Search as part of SERVER-38682. One idea for detecting when mongosync would be impacted by REP-4188 was to open a {showMigrationEvents: true} change stream and detect the range deleter running from its delete change events. Unfortunately the {fromMigrate: true} designation is not preserved between the oplog entry and the change event and so there is no way to distinguish application client deletes from range deleter deletes. While a different approach will ultimately be taken for mongosync, we should improve the behavior for the {showMigrationEvents: true} option such that it preserves more information from the underlying oplog entry.

            Assignee:
            backlog-query-execution [DO NOT USE] Backlog - Query Execution
            Reporter:
            max.hirschhorn@mongodb.com Max Hirschhorn
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              Created:
              Updated: