User`s guide
Shared Server Architecture
9-4 Oracle Database Installation and Administration Guide
■ Is used for local connections where an Oracle Database client application, such as
SQL*Plus, communicates with an Oracle Database instance running on the same
computer.
■ Only works in Dedicated Server mode. It cannot be used in a Shared Server mode.
Note: If clients are running under a user ID different from the
DBA
user ID, then Oracle recommends using a net service name to connect
through a listener to the destination database.
9.2 Shared Server Architecture
The initialization parameters that control the shared server architecture are as follows:
■
LOCAL_LISTENER
■
DISPATCHERS
■
MAX_DISPATCHERS
■
SHARED_SERVERS
■
MAX_SHARED_SERVERS
■
SHARED_SERVER_SESSIONS
■
CIRCUITS
For detailed information about the shared server architecture, refer to the Oracle
Database Net Services Administrator's Guide.
The shared server architecture and the dedicated server architecture can work
concurr
ently in an instance. Provide information in the connect descriptor to indicate
whether a connecting application should use the shared server or the dedicated server
architecture. By default, the listener process uses the shared server architecture and if
you want the application to use the dedicated server architecture instead, you must set
USE_DEDICATED_SERVER=ON
in the
SQLNET.ORA
file or specify a
net_service_name
with
the parameter
SERVER
in the used naming method. The
SQLNET.ORA
parameter
USE_
DEDICATED_SERVER=ON
overwrites the parameter
SERVER
.
The following example shows how to reference a dedicated server in a shared server
configuration by
using a specially defined net service name:
FINANCE_DED=(DESCRIPTION=
(ADDRESS=
(PROTOCOL=TCP)
(HOST=sales-server)
(PORT=1521))
(CONNECT_DATA=
(SERVICE_NAME=sales.us.acme.com)
(SERVER=dedicated)))
For more information, refer to the Oracle Database Net Services Reference guide.
In choosing whether to use the shared server or the dedicated server architecture, you
must cons
ider the CPU overhead versus resource allocation, such as tasks, memory
and so on. In a situation where many clients need to work only occasionally with the
Oracle Database, it would be best to use the shared server architecture, whereas, in a
situation where just a few clients need to work with the Oracle Database regularly, it
would be best to use the dedicated server architecture. Your decision may not always
be as clear-cut as that in these examples. If this is the case, then you can use the