Usage and Configuration of the Oracle Shared Server Supinfo Oracle Lab. 5

Objectives After completing this lesson, you should be able to do the following: Identify the components of the Oracle Shared Server Describe the Oracle Shared Server architecture Configure the Oracle Shared Server Identify and explain usefulness of related data dictionary views

Server Configurations Dedicated server process Shared server process

Dedicated Server Processes ClientServer User process Server process PMON DBWnSMON LGWRCKPTARCn Instance SGA

Oracle Shared Server Shared server processes Database server client Snnn User process Snnn Instance SGA Dispatcher D003 Dispatcher D001 Dispatcher D002

Benefits of Oracle Shared Server Reduces the number of processes against an instance Increases the number of possible users Achieves load balancing Reduces the number of idle server processes Reduces memory usage and system overhead

Connecting 2 1 Database server client User process Listener Dispatcher process D001 Dispatcher process D002 3

Processing a Request PMON DBWn SMON LGWRCKPTARCn Request Queue for all Dispatchers Response queue for (D002) Response queue for (D003) Instance SGA 6 1 Shared server processes Database server client Snnn User process Listener Dispatcher D002 Dispatcher D003 Snnn Dispatcher D Response queue for (D001)

The SGA and PGA SGA Oracle Shared Server: User session data is held in the SGA SGA Shared pool and other memory structures User session data Cursor state Shared pool and other memory structures Stack space PGA Dedicated Server: User session data is kept in the PGA Stack space User session data Cursor state PGA

Configuring Oracle Shared Server initSID.ora parameters Required Parameters –DISPATCHERS –SHARED_SERVERS Optional Parameters –MAX_DISPATCHERS –MAX_SHARED_SERVERS –CIRCUITS –SHARED_SERVER_SESSIONS

DISPATCHERS dispatchers = “(PROTOCOL=TCP)(DISPATCHERS=2)\ (PROTOCOL=IPC)(DISPATCHERS=1)” Dispatcher D002 TCP/IP Init.ora file Dispatcher D003 IPC Dispatcher D001 TCP/IP Specifies the number of dispatchers initially started for a given protocol

SHARED_SERVERS shared_servers = 6 Init.ora file S001 S002 S003 S004 S005 S006 Specifies the number of server processes created when an instance is started up

MAX_DISPATCHERS max_dispatchers = 5 Init.ora file Dispatcher D002 TCP/IP Dispatcher D003 IPC Dispatcher D001 TCP/IP Dispatcher D004 Dispatcher D005 Specifies the maximum number of dispatcher processes that can run simultaneously Issue ALTER SYSTEM command to add more dispatchers than initially started

MAX_SHARED_SERVERS max_shared_servers = 10 Init.ora file S001 S002 S003 S004 S005 S006 S007 S008 S009 S010 Specifies the maximum number of shared servers that can be started Allows shared servers to be allocated dynamically based on the length of the request queue

CIRCUITS Instance: TST8i CIRCUITS = 100 Init.ora file Specifies the total number of virtual circuits that are available for inbound and outbound network sessions Contributes to total SGA size

SHARED_SERVER_SESSIONS SHARED_SERVER_SESSIONS = 100 Init.ora file Specifies the total number of Oracle Shared Server user sessions to allow. Setting this parameter enables you to reserve user sessions for dedicated servers.

Related Parameters Other initialization parameters affected by Oracle Shared Server that may require adjustment: LARGE_POOL_SIZE SESSIONS

Verifying Setup $ lsnrctl services Verify that the dispatcher has registered with the listener when the database was started by issuing: Verify that you are connected using shared servers by making a single connection then query V$CIRCUIT view to show one entry per shared server connection

Data Dictionary Views V$CIRCUIT V$SHARED_SERVER V$DISPATCHER V$SHARED_SERVER_MONITOR V$QUEUE V$SESSION

Summary In this lesson, you should have learned how to: Identify the components of the Oracle Shared Server Describe the Oracle Shared Server architecture Configure the Oracle Shared Server Identify and explain usefulness of related data dictionary views

Practice 5 Overview This practice covers the following topics: Configuring Oracle Shared Server Defining LOCAL_LISTENER for instance registration Using LSNRCTL utility to verify services Verifying shared server configuration and performance using V$ views Verifying instance registration