[SERVER-59772] Enable setWindowFields in transactions or with readConcern snapshot Created: 03/Sep/21 Updated: 29/Oct/23 Resolved: 15/Dec/21 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | 5.3.0 |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Ted Tuckman | Assignee: | Ted Tuckman |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | qopt-team, query-director-triage | ||
| 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: | QO 2021-09-20, QO 2021-12-27 | ||||||||||||||||||||||||||||
| Participants: | |||||||||||||||||||||||||||||
| Comments |
| Comment by Githook User [ 15/Dec/21 ] |
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Author: {'name': 'Ted Tuckman', 'email': 'ted.tuckman@mongodb.com', 'username': 'TedTuckman'}Message: |
| Comment by Charlie Swanson [ 10/Sep/21 ] |
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After discussing with ted.tuckman, we believe there is risk that a read which specifies readConcern: {level: "snapshot"} will either not observe snapshot isolation (bad), or will enter an unknown and potentially corrupted state within the WiredTiger storage engine, with unknown consequences. We believe there is risk because the implementation of spilling to disk within a WiredTiger temporary table repeatedly "abandons snapshot" to ensure that new reads and writes will read from the most recent snapshot. We realized recently that this (potentially) has broader implications for the rest of the operation. As far as I know, we don't yet know if this is a real problem, and what a fix might look like. I recommend putting this in "Investigating" on my team steve.la. Tagging with "query-director-triage" for visibility. |