While you initially configure MTS in your instance parameter file, there are some changes that you can make while the instance is running. Using the ALTER SYSTEM command, you can manually adjust the number of dispatchers that are running. Also using ALTER SYSTEM, you can increase the minimum number of shared server processes that Oracle keeps around.
The minimum number of shared server processes is controlled by the MTS_SERVERS parameter setting. MTS_SERVERS is a dynamic parameter that you can change while the instance is running. For example:
ALTER SYSTEM SET MTS_SERVERS = 20;
If fewer than 20 shared server processes are running when you issue this command, enough new shared server processes will be started to bring the total up to at least 20. If more than 20 shared server processes are running, this command may not have an immediate effect. Instead, as demand drops off, the number of shared server processes will eventually drop to the minimum number specified by MTS_SERVERS.
The MTS_SERVERS setting can never be greater than MTS_MAX_SERVERS. MTS_MAX_SERVERS places an upper limit on the number of shared server processes that may be running at any given time, and that limit cannot be changed while the instance is running.
Remember that an Oracle instance will automatically adjust the number of shared server processes as demand requires, but that number will always be in the range defined by MTS_SERVERS and MTS_MAX_SERVERS. ...