Because after the find, loop execution time is too long cause timeout, cusor failure
There are several solutions:
1. Use the batch_size ()
cursor = collection.find({}).batch_size(30)
2. Remove the cursor into the list
result = list(collection.find({}))
3. cancel timeout limit, to close after using the cursor
cursor = collection.find({}, no_cursor_timeout=True)
cursor.close()
# Finally a way that still appear in the use of exception, the reason is not clear, know a friend please let me know.