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  1. Core Server
  2. SERVER-22490

Casted type-change updates are discarded

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    • Type: Icon: Bug Bug
    • Resolution: Duplicate
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: 3.2.1
    • Component/s: Shell
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      A simple example:

      // insert a document into a new table; number is interpreted as a double
db.example.insert({"foo": 1})
//--> WriteResult({ "nInserted" : 1 })

// good so far
db.example.find()
//--> { "_id" : ObjectId("56b4c6dcbfa50a533004158a"), "foo" : 1 }

// confirm the field is of type double
// ref: https://docs.mongodb.org/manual/reference/operator/query/type
db.example.count({"foo": {"$type": 1}})
//--> 1

// attempt to update field from double to integer; fails
db.example.update({"foo": {"$type": 1}}, {"$set": {"foo": NumberInt(1) }})
//--> WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 0 })

// doc still has a double
db.example.count({"foo": {"$type": 1}})
//--> 1

// update field from double to integer of a different value; succeeds
db.example.update({"foo": {"$type": 1}}, {"$set": {"foo": NumberInt(2) }})
// WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

// doc no longer has a double
db.example.count({"foo": {"$type": 1}})
//--> 0

// confirm doc now has an int
db.example.count({"foo": {"$type": 16}})
//--> 1
      Show
      A simple example: // insert a document into a new table; number is interpreted as a double db.example.insert({ "foo" : 1}) //--> WriteResult({ "nInserted" : 1 }) // good so far db.example.find() //--> { "_id" : ObjectId( "56b4c6dcbfa50a533004158a" ), "foo" : 1 } // confirm the field is of type double // ref: https://docs.mongodb.org/manual/reference/ operator /query/type db.example.count({ "foo" : { "$type" : 1}}) //--> 1 // attempt to update field from double to integer; fails db.example.update({ "foo" : { "$type" : 1}}, { "$set" : { "foo" : NumberInt(1) }}) //--> WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 0 }) // doc still has a double db.example.count({ "foo" : { "$type" : 1}}) //--> 1 // update field from double to integer of a different value; succeeds db.example.update({ "foo" : { "$type" : 1}}, { "$set" : { "foo" : NumberInt(2) }}) // WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) // doc no longer has a double db.example.count({ "foo" : { "$type" : 1}}) //--> 0 // confirm doc now has an int db.example.count({ "foo" : { "$type" : 16}}) //--> 1

      When attempting to update a document by changing the type of a field, that update appears to be discarded if the result is casted-equivalent. So far, I've observed this behavior when attempting to replace a double with an int of the same value.

      Combined with SERVER-22489, this became an irritating problem; the only workaround I have so far is to update with some erroneous value, then update a second time to fix it.

            Assignee:
            Unassigned Unassigned
            Reporter:
            NathanielKofalt Nathaniel Kofalt
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              Created:
              Updated:
              Resolved: