[fuzzer] handle null/missing values in comparison of a covered plan results

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    • Type: Task
    • Resolution: Unresolved
    • Priority: Major - P3
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    • Affects Version/s: None
    • Component/s: None
    • Query Optimization
    • 200
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      Due to the issue explained in SERVER-23229 the covered index plan can return null for missing fields in unoptimized plan. E.g.

      • Optimized (covered index scan) plan output:
      {a: 2, b: null}
      • Unoptimized plan output:
      {a: 2}

      Script to reproduce

      Enterprise test> db.coll.drop()
true
Enterprise test> const docs = [{a: 1, b: null}, {a: 2}, {a: 3, b: "string"}]

Enterprise test> db.coll.insertMany(docs)
{
  acknowledged: true,
  insertedIds: {
    '0': ObjectId('6a7de3ae5242dedc1cf36bc8'),
    '1': ObjectId('6a7de3ae5242dedc1cf36bc9'),
    '2': ObjectId('6a7de3ae5242dedc1cf36bca')
  }
}
Enterprise test> db.coll.find({a: 2}, {_id: 0, a: 1, b: 1})
[ { a: 2 } ]
Enterprise test> db.coll.createIndex({a: 1, b: 1})
a_1_b_1
Enterprise test> db.coll.find({a: 1}, {_id: 0, a: 1, b: 1})
[ { a: 2, b: null } ]

            Assignee:
            Unassigned
            Reporter:
            Alexander Ignatyev
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              Created:
              Updated: