--> The user process and the server process are separate all together.
--> In a dedicated server environment each user process has its own server process.
--> To take the advantage of distributed processing the user process and server process can run on different machines.
--> The dedicated server exists even when a user process is not making any database requests, at this particular point of time the server process remains idle.
--> The ratio between the user process and server process in a dedicated server environment will be one – to – one.
If the user and server process are on the same machine then the interface in use will be IPC (Inter Process Communication) mechanism.
--> Generally we go to shared server in order to increase the server efficiency.
--> In an OLTP (On Line Transaction Processing) environment, at the time of order entry the server process will be in the idle state for almost 90 % of the time. Due to this we are not able to actually utilize the system resources which are getting wasted.
--> Unlike dedicated server processes, a shared server process can process can process any request which comes, instead waiting for a particular request.
--> In a shared server the client (User) process hits the dispatcher which in turn assigns the request to any one of the server processes which is free at that particular point of time.
--> The PMON process registers the location and load of the dispatcher with the listener, enabling the listener to forward the requests to least utilized dispatcher.
--> A dispatched can support multiple client connection concurrently.
Benefits of Shared server:
--> Reduces the number of server process which are idle.
--> Reduces the umber of processes against an instance.
--> Load balancing is achieved.
--> The number of possible users can be increased.
A dedicated server can be used at –
--> The time of connecting as a SYSDBA to start up / shutdown / at the time of performing recovery.
--> When batch jobs are executed as there will be minimal / no idle time as such.
Subscribe to Oracle Bullets by Email