Always choose covering plan if it satisfies superset of predicates compared to other plans

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    • Type: Improvement
    • Resolution: Unresolved
    • Priority: Major - P3
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    • Query Optimization
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      In one of the high value workloads we multiplan a few index + fetch plans along with a covering index plan that satisfies a superset of the predicates covered in the non-covering plans.

      db.c.insert({a: 1, b: 1})
db.c.createIndex({a: 1})
db.c.createIndex({a: 1, b: 1})
db.c.explain().aggregate([{$match: {a: 1, b: {$ne: null}}}, {$count: "c"}])

      We consider {a: 1} and {a: 1, b: 1} even though the covering {a: 1, b:1} will always be more efficient.

              Assignee:
              Unassigned
              Reporter:
              Matt Boros
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                Created:
                Updated: