Home  >  Oracle Database Administration (DBA)  >  Architecture  >  Oracle Shared vs. Dedicated Server Architecture (Q & A)

1.  Which is the main difference between a MTS (Shared Server) and Dedicated Server?

In a Shared Server architecture MANY sessions (user connections) have ONE server process associated.

In a Dedicated Server architecture ONLY ONE sessions (user connections) have ONLY ONE server process associated.

Because a Shared Server architecture use a multi-thread architecture (one server process has more threads), a Shared Server is named MTS (Multi-Thread Server) as well.

2.  Is is possible to have MTS and Dedicated Servers in the same time for the same database?

Yes, is possible. A database could be configured to have both architecture in the same time. However, because the RAM memory is not longer a big constraint, the Dedicated Server Architecture must be used as general rule.  

3.  How could I know if the database use a Shared Server architecture?

The following select give us the response:  SELECT sid, username, server FROM v$session WHERE type='USER';

However a dispatcher could be configured and running even if is not used (the dispatcher is used by the MTS architecture ONLY). To see if a dispatcher is used, that means to see if a dispatcher process was created, we have to run the following select:

SELECT * FROM v$dispatcher;

4.  How could I set up a Shared Server?

This is possible by adding the following line in the init.ora: 

DISPATCHERS = '(ADDRESS=(PROTOCOL=TCP)(HOST=<host_name>)(PORT=<port_name>))'

There are some optional attributes which can be included in the DISPATCHERS parameter: CONNECTIONS, DISPATCHERS,  LISTENER, MULTIPLEX,  SERVICE, SESSIONS, MAX_DISPATCHERS,  SHARED_SERVERS, 

MAX_SHARED_SERVER, etc.

ATTENTION: The listener must be started when the database is starting up, because during the database startup the dispatcher is registered with the listener.

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