[SERVER-63233] Incorrect fastcount after FCBIS Created: 02/Feb/22 Updated: 29/Oct/23 Resolved: 02/Mar/22 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | 6.0.0-rc0 |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Lingzhi Deng | Assignee: | Matthew Russotto |
| 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: |
v5.3
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| Sprint: | Repl 2022-02-21, Repl 2022-03-07 | ||||||||||||||||||||
| Participants: | |||||||||||||||||||||
| Description |
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This was discovered in the new test (fcbis_clear_appliedThrough_after_recovery.js) I added with "Extend Backup Cursor" for FCBIS as part of |
| Comments |
| Comment by Githook User [ 01/Mar/22 ] |
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Author: {'name': 'Matthew Russotto', 'email': 'matthew.russotto@mongodb.com', 'username': 'mtrussotto'}Message: |
| Comment by Matthew Russotto [ 09/Feb/22 ] |
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The cause of this issue (fortunately) isn't getting fastcount wrong for extend. Basically it is because FCBIS is like unclean shutdown, and we know unclean shutdown can corrupt fastcounts. Specifically, any oplog record truncated may have (but not necessarily did have) its fastcount updated, which we will then re-do when we do recovery. This test happens to force a condition where it happens all the time – we hang waiting for a particular optime (which is the one we truncate to) to become stable, then we force a later stable checkpoint (which forces fastcount to be flushed) to happen before doing the backup. |