problem with updating document's field that was used to query documents

[Luke]

Hi All,

I have a weird problem. I am querying docs using below query:

query := bson.M{

            "brandid": 1003,

            "$or": []bson.M{

                bson.M{

                    "st": bson.M{

                        "$exists": false,

                    },

                },

                bson.M{

                    "mt": bson.M{

                        "$gte": time.Date(2016, time.November, 10, 23, 0, 0, 0, time.UTC),

                    },

                },

            },

        }

Then I am looping through the result and I am updating the "st" field, for example:

col.Update(tran.Id,bson.M{"$set":bson.M{"st":time.Now()}})

The Find query returns 12K documents when I do 

col.Find(query).Count()

, however when I loop through the result, the loop keeps going forever and after 12k documents, I start getting the same documents that I have already updated. Here is an example of the loop:

col := s.db.C("transactions")

data := col.Find(query)
c, _ := data.Count()

iter := data.Iter()

i := 0

RETRIEVER_LOOP:

for {

tran := Transaction{}

if !iter.Next(&tran) {

break RETRIEVER_LOOP

}

i++

fmt.Printf("\rDone docs: %v of ", i, c)
                //DO some work here
                col.Update(tran.Id,bson.M{"$set":bson.M{"st":time.Now()}})
        }

Did anybody had a similar issue? 

If I remove from the query 

bson.M{

                    "st": bson.M{

                        "$exists": false,

                    },

                },

thank everything works as expected

Thank, 

Luke