Does the latest mongo3.2 support row-level locking? If so, what is it like? How about concurrent performance for a collection of more than 2 million data?
Since 3.0, the WiredTiger engine has supported document-level locks, which is what you call line-level locks.
I don’t know how to answer the concurrent performance. There are many online evaluations. If you cannot satisfy what you want to know, can you be more specific?