Dedicated server process

Question

1)How can we limit the max number of dedicted server processes in a adatabase? or it will be a memory dependent?or any parameter to limit the dedicated server processes?
2)when i connect through database:
a) sqlplus "/as sysdba" or
b)sqlplus
connect sys/password
in the above two a and b cases, the user connects to the database through dedicted server process...right? so i want to over write this default connection means in above two cases i need to connect to the database through shared server process. how its possible...can any one explain?
3)In dedicated connection the resources are fully utilized and in shared server connection the resources are splitted to various users because shared server connection supports multiple user environment. How the resources fully utilzed in dedicated connection and splitted to various users in shared server connection?
Can any one explain this?

Answer 1

1)How can we limit the max number of dedicted server processes in a adatabase? or it will be a memory dependent?or any parameter to limit the dedicated server processes?You cannot limit the number of dedicated connections. There is no such parameter. The only restriction that you can impose here is via the PROCESSES parameter.
Doing so, will restrict the number of connections to a particular database (irrespective of dedicated or shared server connection).
in the above two a and b cases, the user connects to the database through dedicted server process...right? so i want to over write this default connection means in above two cases i need to connect to the database through shared server process. how its possible...can any one explain?That's right and I don't think you can override this behaviour. You can get a shared server connection by using TNS alias when your database is running in shared server mode.
3)In dedicated connection the resources are fully utilized and in shared server connection the resources are splitted to various users because shared server connection supports multiple user environment. How the resources fully utilzed in dedicated connection and splitted to various users in shared server connection?Well you need to understand the configuration difference in first place.
Whenever a client connects to an Oracle database (via SQL * Plus, any application etc.), the client connection asks the database server to create a process on the server which will service the client's requests. Then this newly spawned server process would take all the requests from the client and process them and send the results of the same back to the client. This is “dedicated” server configuration.
Each of these client connections takes up some resources (memory, CPU time, net-work bandwidth…) on the database server. More the number of client connections, more is the resource consumption, more is the delay is processing the requests.
The clients can be working continuously or working at intervals. If the clients are working at intervals (e.g. inserting a record in approximately 10-12 minutes), then the “dedicated” server process spawned by this client connection is idle for more than 95% of the time and still consuming valuable resources on the database server.
A database serving an application, where-in most of the server processes spawned by the client requests are idle for 90+% of the connect time, is a good candidate for Oracle Shared server mode configuration.
Shared server is configuration method in which one server process can handle more than one client connections/processes/requests. As there are a few number of server processes created on server, the server resources are utilised to a minimum. This en-ables the database administrator to define more number of dispatcher processes to handle the requests from the clients and more number of shared server processes that handle and process the requests between these dispatchers and database kernel.
Edit: "Hub" beat me while I was typing the whole story :-(
Edited by: Satish Kandi on Nov 18, 2008 5:41 PM