Pymongo cursor not looping

问题

This works-

cursor = collection.find(query).limit(10678)
for doc in cursor: print "entered loop"

This doesn't-

cursor = collection.find(query).limit(10679)
for doc in cursor: print "entered loop"  

It just doesn't enter the loop. Ofcourse this upper-limit-number is different for different collections, which may be because of difference in size of each doc. So is there any size limitation for cursors in pymongo ?
Any clues?

来源：https://stackoverflow.com/questions/14685492/pymongo-cursor-not-looping