Improve index seek estimation

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    • Type: Improvement
    • Resolution: Unresolved
    • Priority: Major - P3
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    • Affects Version/s: None
    • Component/s: None
    • Query Optimization
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      It is arbitrarily biased in both directions even after SERVER-135566:

      db.adminCommand({ setParameter: 1, internalQueryPlanRanker: 'costBased' })
db.a.drop()
// range range point
db.a.createIndex({a:1, c: 1, d: 1})
db.a.insertMany(Array.from({length: 100}, (_, i) => {return {a: i, c: -1};}))
printjson(db.a.explain("executionStats").find({a: {$gt: 0}, c: {$gt: 0}, d: 0}).finish().executionStats.executionStages.inputStage)

       
      This underestimates: 1 vs 100

      db.adminCommand({ setParameter: 1, internalQueryPlanRanker: 'costBased' })
db.a.drop()
db.a.createIndex({a:1, b:1, c:1, d: 1})
db.a.insertMany(Array.from({length: 100}, (_, i) => {return {a: i%10, b: 1, c: i, d: 0};}))
db.a.explain("executionStats").find({a: {$gt: 0}, b: 0, c: {$gt: 0}, d: 0})

      This overestimates: 100 vs 10

        1. server_136561_seek_estimate_experiments.js
          10 kB

            Assignee:
            Unassigned
            Reporter:
            Kartal Kaan Bozdogan
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              Created:
              Updated: