[SERVER-79635] [CQF] Consider the number of projections produced by a PhysicalScan when determining its cost Created: 02/Aug/23 Updated: 10/Aug/23 Resolved: 10/Aug/23 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Improvement | Priority: | Major - P3 |
| Reporter: | Ben Shteinfeld | Assignee: | Backlog - Query Optimization |
| Resolution: | Duplicate | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Assigned Teams: |
Query Optimization
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| Description |
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Currently the cost of a PhysicalScan node (and Seek and IndexScan) is a function of its cardinality estimate and startup/marginal cost coefficients. It ignores the number of projections it must produce. This leads to plans that incorrectly have identical costs according to the cost model, but in reality have different runtimes. |