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  1. Core Server
  2. SERVER-49018

v4.4 FCV downgrade must check that no recordPreImages flag is set on any collection

    • Type: Icon: Bug Bug
    • Resolution: Won't Fix
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: None
    • Component/s: Storage
    • None
    • Storage Execution

      Currently on v4.4, a v4.4 FCV 4.4 node can

      • set recordPreImages on a collection
      • downgrade FCV from 4.4 to 4.2
      • shutdown and restart, in FCV 4.2, and find that recordPreImages is set on a collection, which crashes the node on startup.
        We shouldn't have any possible crashing behavior. And I'm not sure there's a recovery path, unless v4.2 binaries ignore unknown fields in collection options.

      There is a test that showcases this FCV 4.2 crashing on startup behavior.

      The setFeatureCompatibilityVersion command has hooks for FCV downgrade and upgrade checks and changes. A hook should be added to the downgrade code to check that the recordPreImages flag is not set on any collection.

      Alternatively, the flag could be unset on downgrade, but I'm not familiar with the feature repercussions that might cause.

            Assignee:
            backlog-server-execution [DO NOT USE] Backlog - Storage Execution Team
            Reporter:
            dianna.hohensee@mongodb.com Dianna Hohensee (Inactive)
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              Created:
              Updated:
              Resolved: