Simple query on _id with $eq should use IDHACK

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    • Type: Improvement
    • Resolution: Won't Fix
    • Priority: Minor - P4
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    • Affects Version/s: 2.8.0-rc0
    • Component/s: Querying
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    • 3
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      A simple equality query against _id results in IDHACK. When the $eq operator is supplied, the equivalent query uses IXSCAN.

      db.simpleid.find({ "_id" : 1 }).explain()
db.simpleid.find({ "_id" : { "$eq" : 1 } }).explain()

      Other equivalent queries, which may not be considered simple, also use IXSCAN:

      db.simpleid.find({ $or : [{ _id : { $eq : 1 } }] }).explain()
db.simpleid.find({ $and : [{ _id : { $all : [1] } }] }).explain()

            Assignee:
            Unassigned
            Reporter:
            Jonathan Abrahams (Inactive)
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              Created:
              Updated:
              Resolved: