[SERVER-48054] 4.2 nodes that use auth and initial sync will fail to start in 4.4 Created: 08/May/20 Updated: 29/Oct/23 Resolved: 13/May/20 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Index Maintenance, Upgrade/Downgrade |
| Affects Version/s: | 4.2.0 |
| Fix Version/s: | 4.4.0-rc6 |
| Type: | Bug | Priority: | Critical - P2 |
| Reporter: | Louis Williams | Assignee: | Louis Williams |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Backwards Compatibility: | Fully Compatible | ||||||||||||||||||||||||
| Operating System: | ALL | ||||||||||||||||||||||||
| Sprint: | Execution Team 2020-05-18 | ||||||||||||||||||||||||
| Participants: | |||||||||||||||||||||||||
| Description |
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Initial sync clones collections alphabetically. This means the "admin.system.roles" collection gets cloned after "admin.system.version" which holds the featureCompatibilityVersion document. The "admin.system.roles" collection has a unique index on {role: 1, db: 1 }. In 4.4 we require all unique indexes to be upgraded to the latest format version. This normally happens as a part of upgrading the FCV to 4.2 using the command or when the index is first created. If an index is created before the FCV is initialized, then it will have an incorrect format version and cause 4.4 to fail to start up. This affects 4.2 nodes that experience an initial sync and do not go through a restart before upgrading to 4.4. Repro coming soon. Workaround: Due to the work done in |
| Comments |
| Comment by Githook User [ 13/May/20 ] |
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Author: {'name': 'Louis Williams', 'email': 'louis.williams@mongodb.com', 'username': 'louiswilliams'}Message: |
| Comment by Louis Williams [ 11/May/20 ] |
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We have decided to have 4.4 self-correct this problem at startup, rather than fatally asserting, which is the case today. As far as unique indexes go, we are not aware of any user-visible issues that would be caused by allowing this bug to remain in 4.2. |
| Comment by Louis Williams [ 08/May/20 ] |
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louisa.berger we aren't sure yet. We are considering a fix in 4.4 to avoid introducing new upgrade requirements. Be on the lookout for an update when we can make that determination. |
| Comment by Louisa Berger [ 08/May/20 ] |
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louis.williams will this mean a fix in 4.4, or will there be a required 4.2.x version we need to upgrade to as an intermediate step? |