The Multi-threaded Server alarm occurs when all or most multi-threaded server (MTS) or dispatcher processes are busy.
In an MTS environment, multiple sessions share a smaller number of shared server processes that perform database activities on their behalf. The servers are usually allocated by a smaller number of dispatcher processes.
The number of dispatchers and servers can increase up to the limits set by the configuration parameters MAX_DISPATCHERS and MAX_SHARED_SERVERS. If the demand for the processes causes all servers to become busy, sessions may experience long wait times before a server becomes available.
Note: See the Activity | Server Page to obtain the precise load on MTS servers and dispatchers. If sessions are waiting on servers, either increase the number of servers or use dedicated server processes.