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Usage and Configuration of the Oracle Shared Server. 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
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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
Instance SGA SMON DBWn PMON CKPT LGWR ARCn Dedicated Server Processes Client Server Userprocess Serverprocess
Oracle Shared Server Shared serverprocesses Instance SGA Snnn Snnn Snnn DispatcherD001 DispatcherD002 DispatcherD003 Database server Client Userprocess Userprocess
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
Using a Dedicated Server with Oracle Shared Server TEST.world = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP) (HOST = stc-sun02) (PORT = 1521) ) (CONNECT_DATA=(SERVICE_NAME=TEST.us.oracle.com) (SERVER=DEDICATED) ) )
Connecting Dispatcherprocess D001 Dispatcherprocess D002 Listener Database server 3 2 Client 1 Userprocess Userprocess
Processing a Request Shared serverprocesses Instance SGA 4 Snnn Response queue for (D001) RequestQueue Snnn Response queue for (D002) 3 Snnn 5 Response queue for (D003) 2 DBWn PMON CKPT LGWR ARCn SMON DispatcherD001 DispatcherD002 DispatcherD003 6 Database server Listener 1 Userprocess Userprocess client
PGA • SGA User session data Stack space Cursor state • Shared pool and other memory structures • PGA • SGA • Shared pool and other memory structures Cursor state Usersession data Stack space The SGA and PGA Dedicated Server: User session data is kept in the PGA Oracle Shared Server: User session data is held in the SGA
Configuring Oracle Shared Server • Required initialization parameters • DISPATCHERS • SHARED_SERVERS • Optional initialization parameters • MAX_DISPATCHERS • MAX_SHARED_SERVERS • CIRCUITS • SHARED_SERVER_SESSIONS
DISPATCHERS • Specifies the number of dispatchers initially started for a given protocol DISPATCHERS = "(PROTOCOL=TCP)(DISPATCHERS=2)\ (PROTOCOL=IPC)(DISPATCHERS=1)" DispatcherD003 IPC DispatcherD001 TCP/IP DispatcherD002 TCP/IP
MAX_DISPATCHERS • Specifies the maximum number of dispatcher processes that can run simultaneously • Issues the ALTERSYSTEM command to add more dispatchers than initially started MAX_DISPATCHERS = 5 DispatcherD004 DispatcherD001 TCP/IP DispatcherD002 TCP/IP DispatcherD003 IPC DispatcherD005
S001 S003 S005 S002 S004 S006 SHARED_SERVERS • Specifies the number of server processes created when an instance is started up SHARED_SERVERS = 6
MAX_SHARED_SERVERS • 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 MAX_SHARED_SERVERS = 10 S007 S001 S003 S005 S009 S008 S002 S004 S006 S010
CIRCUITS • Specifies the total number of virtual circuits that are available for inbound and outbound network sessions • Contributes to total SGA size CIRCUITS = 100
SHARED_SERVER_SESSIONS • Specifies the total number of Oracle Shared Server user sessions to allow • Setting this parameter enables you to reserve user sessions for dedicated servers SHARED_SERVER_SESSIONS = 100
Related Parameters • Other initialization parameters affected by Oracle Shared Server that may require adjustment: • LARGE_POOL_SIZE • SESSIONS
Verifying Setup • Verify that the dispatcher has registered with the listener when the instance 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. $ lsnrctl services
Dynamic 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 the Listener Control utility to verify services • Verifying shared server configuration and performance using V$ views • Verifying instance registration