Cost of SORT-LIMIT(1) should be consistent with SORT-LIMIT(2)

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    • Type: Improvement
    • Resolution: Unresolved
    • Priority: Major - P3
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    • Affects Version/s: None
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    • Query Optimization
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    • 3
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      Right now there is a big jump between limit 1 and limit 2, even though both operations should take approximately the same amount of resources:

      Enterprise test> var explain = db.foo.find().sort({a:1}).hint({$natural: 1}).limit(1).explain('executionStats');
Enterprise test> explain.executionStats.executionStages.costEstimate - explain.executionStats.executionStages.inputStage.costEstimate;
0.00009999999999976694

Enterprise test> var explain = db.foo.find().sort({a:1}).hint({$natural: 1}).limit(2).explain('executionStats');
Enterprise test> explain.executionStats.executionStages.costEstimate - explain.executionStats.executionStages.inputStage.costEstimate;
1.0000999999999998

            Assignee:
            Unassigned
            Reporter:
            Philip Stoev
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              Created:
              Updated: