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  1. WiredTiger
  2. WT-6011

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

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    Details

    • Type: Improvement
    • Status: Open
    • Priority: Major - P3
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: 5.0 Required
    • Component/s: None
    • Labels:
      None
    • Story Points:
      5
    • Sprint:
      Storage - Ra 2020-04-20

      Description

      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.

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              Assignee:
              backlog-server-storage-engines Backlog - Storage Engines Team
              Reporter:
              daniel.gottlieb Daniel Gottlieb
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                Dates

                Created:
                Updated: