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Type: Bug
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Resolution: Fixed
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Priority: Major - P3
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Affects Version/s: None
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Component/s: Replication
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None
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Fully Compatible
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ALL
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v4.4
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Repl 2020-04-20
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46
replica_set_multiversion will randomly choose between "latest" and "last-stable" when starting up a mongod instance. The passthrough logic is smart enough to downgrade the FCV and clean shutdown, but that's not sufficient for ensuring "last-stable" is always able to start up in more complicated restart sequences. Consider the following (using 4.4/4.2 as an example):
- Start MongoDB 4.4 + ReplSet
- SetFCV 4.2
- Shutdown (MongoDB 4.2 can restart on these data files)
- Start MongoDB 4.4 + Standalone
- Shutdown (MongoDB 4.2 can not restart on these data files)