Command

Lock

find()

S

it() (query cursor)

S

insert()

X

remove()

X

update()

X

mapreduce()

Both S and X, depending on the case. Some MapReduce chunks can run in parallel.

index()

Foreground indexing: Database lock.

Background indexing: No lock, except for administrative commands which will return an error. Also, background indexing will take considerably more time.

aggregate()

S