Mnesia is _not_ the storage layer for messages (except for delayed messages).
Mnesia stores vhosts, users, permissions, queue definitions and more. This is being transitioned to Khepri, which improves a lot of things (maybe most importantly netsplits) but not directly message speeds.
Mnesia stores vhosts, users, permissions, queue definitions and more. This is being transitioned to Khepri, which improves a lot of things (maybe most importantly netsplits) but not directly message speeds.