Converting shared server architecture to dedicated architecture in Oracle

shared server architecture vs dedicated architecture in Oracle

About Share server architecture :
When client load causes a strain on memory and other system resources, database administrators can alleviate load issues by starting shared server resources. The shared server architecture enables a database server to allow many client processes to share very few server processes, so the number of users that can be supported is increased. With the shared server architecture, many client processes connect to a dispatcher. The dispatcher directs multiple incoming network session requests to a common queue. An idle shared server process from a shared pool of server processes picks up a request from the queue. This means a small pool of server processes can serve a large number of clients. This is useful when a system is overloaded or has limited memory.


About Dedicated architecture:
A server process that is dedicated to one client connection. Contrast with shared server.

Note: UGA is resides in SGA in case of Share server but it resides in PGA in case of dedicated architecture. Usually in case of huge no. of user connections are controlled with shared-server architecture but typical customaized applications (OLTP) are always configuring with dedicated architecture now a days.

If you system is confugured with shared-server, then follow the bellow steps to convert into dedicated:

Step: 1 :Do the following in mount stage:

*.dispatchers='(PROTOCOL=TCP)(dispatchers=0) (SERVICE=MYDB)'
alter system set shared_servers=0;
alter system set max_shared_servers=0;
alter system set shared_server_sessions=0;
alter system set max_dispatchers=0;

Step:2 : Restart the database

Step:3 : Use (server=dedicated) in client tnsnames.ora

For details follow the bellow link from Oracle site.
http://docs.oracle.com/cd/B28359_01/server.111/b28310/manproc001.htm#ADMIN11166