When multiple keys are put together with an $or expression and the upsert flag is sent to update (and the multi flag is set) objects are not created for the items in the $or expression.

This code using pymongo:

keys = []
for item in items:
key =

{ 'a : item.a, 'b' : item.b, 'c' : item.c }

keys.append(key)

if len(keys) == 0:
return

query =

{ '$or' : keys }

value = {
'$inc' :

{ 'count' : 1 }

}

db.abc_counts.update(query, value, upsert=True, multi=True)

Produces this in the DB:

{ "_id" : ObjectId("4c8e7161010f681721439e58"), "count" : 1 }

if i replace query with keys[0] it works as expected.