MongoDB remove mapreduce collection

Question

Due to error in client code, mongodb have created many \"mr.mapreduce....\" collections, how to remove them all (by mask maybe).

Answer 1

Temporary map-reduce table should be cleaned up when the connection which created them is closed:

map/reduce is invoked via a database command. The database creates a temporary collection to hold output of the operation. The collection is cleaned up when the client connection closes, or when explicitly dropped. Alternatively, one can specify a permanent output collection name. map and reduce functions are written in JavaScript and execute on the server.

-- MongoDB docs

If not, you could delete them using them same method you would delete any other collection. It might get a bit repetitive though.