mongodb - Pymongo can not perform aggregating with pipeline in too large collection -

i have billions records in patients colletion, have no idea how filter pipeline.

or limit on mongodb, couldn't aggregate pipeline on large collection ?

i've add allowdiskuse=true option, doesn't work too.

how filtered result pipeline ?

how store filtered result collection ?

sample code (i use pymongo follows in python syntax )

import datetime pipeline = [         {"$project": {"birthday":1, "id":1}     },     {              "$match": { "birthday":{"$gte":datetime.datetime(1987, 1, 1, 0, 0)} }          },{"$group": ~~~      }     ] res =db.patients.aggregate(pipeline,allowdiskuse=true) 

exception message

operationfailure: command son([('aggregate', u'patients'), ('pipeline', [{'$match': {'birthday': {'$gte': datetime.datetime(1987, 1, 1, 0, 0)}}}]), ('allowdiskuse', true)]) on namespace tw_insurance_security_development.$cmd failed: exception: aggregation result exceeds maximum document size (16mb)     

how

store result in collection, aggregation pass on it. it's limitation of mongo, can read more here.