https://docs.mongodb.com/manual/reference/operator/query/all/#performance
Queries that use the $all operator must scan all the documents that match the first element in the $all expression. As a result, even with an index to support the query, the operation may be long running, particularly when the first element in the $all expression is not very selective.
With SERVER-16042 fixed I think it's not the case anymore
- is related to
-
SERVER-16042 Optimise $all/$and to select smallest subset as initial index bounds
-
- Closed
-