The Database as a Networked Server - Implementing Database Security and Auditing - page 77

Figure 3.10
Handling of client
requests in Oracle:
high-level process
flow.
tions directly with the dispatcher. The request and response queues are
managed by the dispatchers and are part of the System Global Area (SGA).
The dispatcher's only responsibility is to populate the request queues and
communicate results from the response queues back to the client; the Ora-
cle server processes do the actual processing of the SQL requests, as shown
in Figure 3.10.
The software modules that allow a client application to talk to Oracle
are collectively called the Program Interface. This includes the following:
The Oracle Call Interface (OCI)
The Oracle runtime library (SQLLIB)
The Oracle Net (or SQL*Net/Net8/Net9) protocol-specific drivers
The server-side modules that receive the requests. These are called the
Oracle Program Interface (OPI).
The Oracle listener can be configured to use several network protocols,
including TCP/IP, Named Pipes, IPX/SPX, and LU6.2/APPC. The actual
specification of which protocols are enabled per listener are defined in lis-
tener.ora . Alternately, you can use either Oracle Net Configuration Assis-
tant or the Oracle Net Manager to enable or disable protocols.
The Oracle Net Configuration Assistant can help you configure both
the server-side or the client-side protocols that will be used. In the first case,
the file that will be changed is listener.ora and in the second case it is