Overflow sort stage buffered data usage exceeds internal limit

Question

Using the code:

all_reviews = db_handle.find().sort('reviewDate', pymongo.ASCENDING)
print all_reviews.count()

print all_reviews[0]
print all_reviews[2000000]

The count prints 2043484, and it prints all_reviews[0].

However when printing all_reviews[2000000], I get the error:

pymongo.errors.OperationFailure: database error: Runner error: Overflow sort stage buffered data usage of 33554495 bytes exceeds internal limit of 33554432 bytes

How do I handle this?

Answer 1

You're running into the 32MB limit on an in-memory sort:

https://docs.mongodb.com/manual/reference/limits/#Sort-Operations

Add an index to the sort field. That allows MongoDB to stream documents to you in sorted order, rather than attempting to load them all into memory on the server and sort them in memory before sending them to the client.