import time
from bson import Binary
from pymongo import MongoClient, DESCENDING

bucket = MongoClient('127.0.0.1', 27017)['test']['foo']
bucket.drop()
bucket.update({'timestamp': 0}, {'$addToSet': {'_exists_caps': 'cap15'}}, upsert=True, safe=True, w=1, wtimeout=10)
bucket.create_index([('timestamp', DESCENDING)], unique=True)
while True:
    timestamp =  str(int(1000000 * time.time()))
    bucket.update({'timestamp': timestamp}, {'$addToSet': {'_exists_foos': 'fooxxxxx'}}, upsert=True, safe=True, w=1, wtimeout=10)