Failed Aggregation On Tornado/Motor: Yielded Unknown Object MotorAggregationCursor

I'm having issue to execute MongoDB aggregation operation on Tornado. This is the code, pipeline = [ {'$match': { '$or': [ {'owner.id': '56dfdaa4082024b9384c00

Solution 1:

The actual .aggregate() method is not itself "async". But the cursor iteration is.

So instead:

cursor = db.activities.aggregate(pipeline)
while (yield cursor.fetch_next):
    doc = cursor.next_object()
    print(doc)

Just like the docs say.