Shared Server Configuration

Doc ID:
Note:274130.1
Subject: SHARED SERVER CONFIGURATION
Type: BULLETIN
Status: PUBLISHED
Content Type: TEXT/X-HTML
Creation Date: 25-MAY-2004
Last Revision Date: 24-JUN-2004

PURPOSE
-------

This article discusses about the configuration of shared servers on 9i DB.

SHARED SERVER CONFIGURATION:
===========================

1. Add the parameter shared_servers in the init.ora

SHARED_SERVERS specifies the number of server processes that you want to create when an instance is started up. If system load decreases, this minimum number of servers is maintained. Therefore, you should take care not to set SHARED_SERVERS too high at system startup.

Parameter type Integer

Parameter class Dynamic: ALTER SYSTEM

2. Add the parameter DISPATCHERS in the init.ora DISPATCHERS configures dispatcher processes in the shared server architecture.

USAGE:
-----

DISPATCHERS = "(PROTOCOL=TCP)(DISPATCHERS=3)"

3. Save the init.ora file.

4. Change the connect string in tnsnames.ora from

ORACLE.IDC.ORACLE.COM =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = xyzac)(PORT = 1521))
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = oracle)
)
)

to

ORACLE.IDC.ORACLE.COM =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = xyzac)(PORT = 1521))
)
(CONNECT_DATA =
(SERVER = SHARED)
(SERVICE_NAME = Oracle)
)
)

Change SERVER=SHARED.

5. Shutdown and startup the database.

6. Make a new connection to database other than SYSDBA.

(NOTE: SYSDBA will always acquire dedicated connection by default.)

7. Check whether the connection is done through server server.

> Select server from v$session.

SERVER
---------

DEDICATED
DEDICATED
DEDICATED
SHARED
DEDICATED

NOTE:
====


The following parameters are optional (if not specified, Oracle selects defaults):

MAX_DISPATCHERS:
===============
Specifies the maximum number of dispatcher processes that can run simultaneously.

SHARED_SERVERS:
==============
Specifies the number of shared server processes created when an instance is started up.

MAX_SHARED_SERVERS:
==================
Specifies the maximum number of shared server processes that can run simultaneously.

CIRCUITS:
========
Specifies the total number of virtual circuits that are available for inbound and outbound network sessions.

SHARED_SERVER_SESSIONS:
======================
Specifies the total number of shared server user sessions to allow. Setting this parameter enables you to reserve user sessions for dedicated servers. Other parameters affected by shared server that may require adjustment:

LARGE_POOL_SIZE:
===============
Specifies the size in bytes of the large pool allocation heap. Shared server may force the default value to be set too high, causing performance problems or problems starting the database.

SESSIONS:
========
Specifies the maximum number of sessions that can be created in the system. May need to be adjusted for shared server.