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  1. WiredTiger
  2. WT-6011

Bump the compatibility version for MongoDB v4.5 to distinguish from 4.4

    • Type: Icon: Improvement Improvement
    • Resolution: Gone away
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: None
    • Component/s: None
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    • 5
    • Storage - Ra 2020-04-20, Storage - Ra 2021-05-17

      There's a MongoDB binary downgrade contract with the following requirements (among other caveats):

      1. FCV must be set to the previous version
      2. MongoDB must perform a clean shutdown

      Right now, MongoDB validates that FCV is set appropriately, however, the clean shutdown part is only enforced by WT. The two ways WT can enforce this are:

      1. Bumping the log version
      2. Advancing the release compatibility (with coordination of changing MongoDB compatibility=(release,min,max) calls into WT)

      There's a (testing) cost associated with branching a new development version of MongoDB, but delaying the bumping of WT versioning (via either mechanism):

      1. "implicit" multiversion tests can perform illegal downgrades (typically via crashing the process, or having some restarts in standalone mode). But that illegal downgrade won't be noticed until a formal versioning change is made, which results in a bunch of fallout at once that lands on the wrong team.
      2. explicit multiversion tests can depend on MongoDB startup failing. Right now, a "bug" where startup works after an illegal downgrade results in a test hang.

            Assignee:
            backlog-server-storage-engines [DO NOT USE] Backlog - Storage Engines Team
            Reporter:
            daniel.gottlieb@mongodb.com Daniel Gottlieb (Inactive)
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              Created:
              Updated:
              Resolved: