[SERVER-42616] $stdDev accumulator can return imprecise results when spilling to disk Created: 02/Aug/19 Updated: 06/Dec/22 |
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| Status: | Backlog |
| Project: | Core Server |
| Component/s: | Aggregation Framework |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Nicholas Zolnierz | Assignee: | Backlog - Query Execution |
| Resolution: | Unresolved | Votes: | 0 |
| Labels: | afz, query-44-grooming | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Assigned Teams: |
Query Execution
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| Operating System: | ALL | ||||||||||||||||
| Participants: | |||||||||||||||||
| Linked BF Score: | 48 | ||||||||||||||||
| Description |
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When merging intermediate results which have spilled to disk, the $stdDev accumulator executes the variance calculation involving some arithmetic over the previously calculated mean and . If the mean is a precise double, then this could result in precision loss. |