Server Process,”Oracle creates server processes to handle the requests of user processes connected to the instance. In some situations when the application and Oracle operate on the same machine, it is possible to combine the user process and corresponding server process into a single process to reduce system overhead. However, when the application and Oracle operate on different machines, a user process always communicates with Oracle through a separate server process.Server processes (or the server portion of combined user/server processes) created on behalf of each user’s application can perform one or more of the following:Parse and run SQL statements issued through the applicationRead necessary data blocks from datafiles on disk into the shared database buffers of the SGA
if the blocks are not already present in the SGAReturn results in such a way that the application can process the information”