[SERVER-79885] Oplog fetching getMore should not set null lastKnownCommittedOpTime if it is not using exhaust cursors Created: 09/Aug/23 Updated: 29/Oct/23 Resolved: 11/Aug/23 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | 7.1.0-rc0, 7.0.1, 6.0.10, 5.0.21, 4.4.25 |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Lingzhi Deng | Assignee: | Lingzhi Deng |
| 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 | ||||||||||||||||||||
| Backport Requested: |
v7.0, v6.0, v5.0, v4.4
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| Sprint: | Repl 2023-08-21 | ||||||||||||||||||||
| Participants: | |||||||||||||||||||||
| Linked BF Score: | 70 | ||||||||||||||||||||
| Description |
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However, this is not desirable for non-exhaust cursors especially when the syncing node isn't able to advance its commit point after receiving oplog batches (e.g. during initial sync as we don't set lastCommitted until after initial sync finishes). So this means that the oplog getMore sent by the syncing node would always have a null lastKnownCommittedOpTime, triggering empty batches unnecessarily every single time towards the end of initial sync (after the initial syncing node catches up). 4.4+ by default should use exhaust cursors, so this by default isn't an issue. But exhaust cursor could be turned off manually via oplogFetcherUsesExhaust. And then it would become an issue. Additionally, 4.4 in FCV 4.2 will also by default use non-exhaust cursors. So fixing this will help backporting |
| Comments |
| Comment by Githook User [ 22/Aug/23 ] |
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Author: {'name': 'Lingzhi Deng', 'email': 'lingzhi.deng@mongodb.com', 'username': 'ldennis'}Message: (cherry picked from commit eeac78cd8de74ca1cffb18eb4b798b8392df6192) |
| Comment by Githook User [ 22/Aug/23 ] |
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Author: {'name': 'Lingzhi Deng', 'email': 'lingzhi.deng@mongodb.com', 'username': 'ldennis'}Message: (cherry picked from commit eeac78cd8de74ca1cffb18eb4b798b8392df6192) |
| Comment by Githook User [ 15/Aug/23 ] |
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Author: {'name': 'Lingzhi Deng', 'email': 'lingzhi.deng@mongodb.com', 'username': 'ldennis'}Message: (cherry picked from commit eeac78cd8de74ca1cffb18eb4b798b8392df6192) |
| Comment by Githook User [ 14/Aug/23 ] |
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Author: {'name': 'Lingzhi Deng', 'email': 'lingzhi.deng@mongodb.com', 'username': 'ldennis'}Message: (cherry picked from commit eeac78cd8de74ca1cffb18eb4b798b8392df6192) |
| Comment by Githook User [ 11/Aug/23 ] |
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Author: {'name': 'Lingzhi Deng', 'email': 'lingzhi.deng@mongodb.com', 'username': 'ldennis'}Message: |