13 Copyright © 2004, Oracle. All rights reserved. Oracle Shared Servers

13-2 Copyright © 2004, Oracle. All rights reserved. Objectives After completing this lesson you should be able to do the following: Identify when to use Oracle Shared Servers Configure Oracle Shared Servers Monitor Shared Servers

13-3 Copyright © 2004, Oracle. All rights reserved. Listener Establishing a Connection Incoming connection request

13-4 Copyright © 2004, Oracle. All rights reserved. Dedicated Server Process Listener Server process User process

13-5 Copyright © 2004, Oracle. All rights reserved. Server process User Sessions PGA Listener User Session User process

13-6 Copyright © 2004, Oracle. All rights reserved. User Sessions: Dedicated Server User sessions Server process User session

13-7 Copyright © 2004, Oracle. All rights reserved. User Sessions: Shared Server Listener Dispatcher Server process

13-8 Copyright © 2004, Oracle. All rights reserved. Response queue for D001 Response queue for D002 Instance SGA Shared server processes Database server Client or middle tier S001 S002 User process Dispatcher D001 Dispatcher D002 S000 Dispatcher D000 Response queue for D000 Processing a Request User process Common request queue for all dispatchers

13-9 Copyright © 2004, Oracle. All rights reserved. SGA Oracle Shared Server: User session data is held in the SGA. SGA Shared pool and other memory structures 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 The SGA and PGA User session data

13-10 Copyright © 2004, Oracle. All rights reserved. Configuring Oracle Shared Server Required parameter DISPATCHERS Optional parameters SHARED_SERVERS MAX_SHARED_SERVERS CIRCUITS SHARED_SERVER_SESSIONS

13-11 Copyright © 2004, Oracle. All rights reserved. DISPATCHERS = “(PROTOCOL=TCP)(DISPATCHERS=2)\ (PROTOCOL=IPC)(DISPATCHERS=1)” Dispatcher D001 TCP/IP Dispatcher D002 IPC Dispatcher D000 TCP/IP DISPATCHERS Specifies the number of dispatchers that are initially started for a given protocol.

13-12 Copyright © 2004, Oracle. All rights reserved. DISPATCHERS Full Notes Page

13-13 Copyright © 2004, Oracle. All rights reserved. SHARED_SERVERS = 6 S000 S001 S002 S003 S004 S005 SHARED_SERVERS Specifies the number of shared server processes created when an instance is started up, and retained during instance operation.

13-14 Copyright © 2004, Oracle. All rights reserved. MAX_SHARED_SERVERS = 10 S000 S001 S002 S003 S004 S005 S006 S007 S008 S009 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

13-15 Copyright © 2004, Oracle. All rights reserved. CIRCUITS = 100 CIRCUITS Specifies the total number of virtual circuits that are available for inbound and outbound network sessions Contributes to total SGA size

13-16 Copyright © 2004, Oracle. All rights reserved. SHARED_SERVER_SESSIONS = 100 SHARED_SERVER_SESSIONS Specifies the total number of Oracle Shared Server user sessions to allow Enables you to reserve user sessions for dedicated servers

13-17 Copyright © 2004, Oracle. All rights reserved. Related Parameters Other initialization parameters affected by Oracle Shared Server that may require adjustment: LARGE_POOL_SIZE SESSIONS PROCESSES LOCAL_LISTENER

13-18 Copyright © 2004, Oracle. All rights reserved. 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 connection and then query V$CIRCUIT view to show one entry per shared server connection. $ lsnrctl SERVICES Verifying Shared Server Setup

13-19 Copyright © 2004, Oracle. All rights reserved. Verifying Shared Server Setup Full Notes Page

13-20 Copyright © 2004, Oracle. All rights reserved. Data Dictionary Views V$CIRCUIT V$SHARED_SERVER V$DISPATCHER V$SHARED_SERVER_MONITOR V$QUEUE V$SESSION

13-21 Copyright © 2004, Oracle. All rights reserved. Choosing a Connection Type Unless otherwise configured, Oracle Net connections will use: Shared server if one is available Dedicated server if a shared server connection is not available Using local or directory naming, the connection type can be specified as part of the Net service alias.

13-22 Copyright © 2004, Oracle. All rights reserved. When Not to Use Shared Server Certain types of database work should not be performed using shared servers: Database administration Backup and recovery operations Batch processing and bulk load operations Data warehouse operations Dispatcher Server process

13-23 Copyright © 2004, Oracle. All rights reserved. Summary In this lesson you should have learned how to: Identify when to use Oracle Shared Servers Configure Oracle Shared Servers Monitor Shared Servers

13-24 Copyright © 2004, Oracle. All rights reserved. Practice 13 Overview: Oracle Shared Servers This practice covers the following topics: Investigating the impact of dedicated server connections on your system Configuring your system to use shared servers Investigating the impact of shared server connections on your system

13-25 Copyright © 2004, Oracle. All rights reserved. Practice Lesson 13

13-26 Copyright © 2004, Oracle. All rights reserved.