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Configuring the
Oracle Network Environment
Copyright © 2008, Oracle. All rights reserved.
Objectives
After completing this lesson, you should be able to:
• Use Enterprise Manager to:
–
–
–
–
Create additional listeners
Create Oracle Net Service aliases
Configure connect-time failover
Control the Oracle Net Listener
• Use tnsping to test Oracle Net connectivity
• Identify when to use shared servers and when to use
dedicated servers
5-2
Copyright © 2008, Oracle. All rights reserved.
Oracle Net Services
Application
Oracle Net
Client or
middle tier
RDBMS
TCP/IP
network
Oracle Net
configuration files
5-3
Oracle Net
Listener
Database server
Oracle Net
configuration files
Copyright © 2008, Oracle. All rights reserved.
Listener
(DESCRIPTION=
(ADDRESS=(PROTOCOL=tcp)(HOST=dbhost.example.com)
(PORT=1521)))
Connection descriptor
DESCRIPTION= (ADDRESS=(PROTOCOL=tcp)(HOST=myserver) PORT=1521))
(CONNECT_DATA=
(SERVICE_NAME=mydb.us.example.com))
5-4
Copyright © 2008, Oracle. All rights reserved.
Oracle Net Listener
Enterprise
Manager
Database
Control
Listener
Oracle databases
Oracle Net
configuration files
<oracle_home>/network/admin/listener.ora
sqlnet.ora
5-5
Copyright © 2008, Oracle. All rights reserved.
Establishing Net Connections
To make a client or middle-tier connection, Oracle Net
requires the client to know the:
• Host where the listener is running
• Port that the listener is monitoring
• Protocol that the listener is using
• Name of the service that the listener is handling
Names resolution
5-6
Copyright © 2008, Oracle. All rights reserved.
Establishing a Connection
Incoming
connection request
Listener
5-7
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User Sessions
Server
process
User session
PGA
User process
Listener
5-8
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User session: Dedicated server process
•
Dedicated server process: With the session established, the server
process now acts as the user’s agent on the server. The server process
is responsible for:
–
–
–
–
–
–
5-9
Parsing and running any SQL statements issued through the application
Checking the database buffer cache for data blocks required to perform SQL
statements
Reading necessary data blocks from data files on the disk into the database
buffer cache portion of the System Global Area (SGA), if the blocks are not
already present in the SGA
Managing all sorting activity. The Sort Area is a memory area that is used to
work with sorting; it is contained in a portion of memory that is associated
with the Program Global Area (PGA).
Returning results to the user process in such a way that the application can
process the information
Reading auditing options and reporting user processes to the audit
destination
Copyright © 2008, Oracle. All rights reserved.
Tools for Configuring and Managing
the Oracle Network
•
•
•
•
5 - 10
Enterprise Manager Net Services Administration page
Oracle Net Manager
Oracle Net Configuration Assistant
Command line
Copyright © 2008, Oracle. All rights reserved.
Listener Control Utility
Oracle Net listeners can be controlled with the lsnrctl
command-line utility (or from EM).
$ lsnrctl
LSNRCTL for Linux: Version 11.1.0.6.0 - Production on 05-AUG-2008 11:58:01
Copyright (c) 1991, 2007, Oracle. All rights reserved.
Welcome to LSNRCTL, type "help" for information.
LSNRCTL> help
The following operations are available
An asterisk (*) denotes a modifier or extended command:
start
stop
status
services
version
reload
save_config
trace
spawn
change_password
quit
exit
set*
show*
5 - 11
Copyright © 2008, Oracle. All rights reserved.
Listener Control Utility Syntax
Commands from the listener control utility can be issued
from the command line or from the LSNRCTL prompt.
• UNIX or Linux command-line syntax:
$ lsnrctl <command name>
$ lsnrctl start
$ lsnrctl status
• Windows Prompt syntax:
LSNRCTL> <command name>
LSNRCTL> start
LSNRCTL> status
5 - 12
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Listener Home Page
5 - 13
Copyright © 2008, Oracle. All rights reserved.
Creating a Listener
2
1
3
4
5 - 15
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Adding Listener Addresses
5
8
6
7
10
9
5 - 16
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Database Service Registration
5 - 17
Copyright © 2008, Oracle. All rights reserved.
Naming Methods
Oracle Net supports several methods of resolving
connection information:
• Easy connect naming: Uses a TCP/IP connect string
• Local naming: Uses a local configuration file
• Directory naming: Uses a centralized
LDAP-compliant directory server
• External naming: Uses a supported non-Oracle naming
service
Client/application server
Oracle Net
Oracle Net configuration files
5 - 19
Copyright © 2008, Oracle. All rights reserved.
Easy Connect
•
•
•
•
Is enabled by default
Requires no client-side configuration
Supports only TCP/IP (no SSL)
Offers no support for advanced connection options
such as:
– Connect-time failover
– Source routing
– Load balancing
SQL> CONNECT hr/[email protected]:1521/dba11g
No Oracle Net configuration files
5 - 20
Copyright © 2008, Oracle. All rights reserved.
Local Naming
• Requires a client-side Names Resolution file
• Supports all Oracle Net protocols
• Supports advanced connection options such as:
– Connect-time failover
– Source routing
– Load balancing
SQL> CONNECT hr/hr@orcl
Oracle Net
configuration files
5 - 21
Copyright © 2008, Oracle. All rights reserved.
Directory Naming
• Requires LDAP with Oracle Net Names Resolution
information loaded:
– Oracle Internet Directory
– Microsoft Active Directory Services
• Supports all Oracle Net protocols
• Supports advanced connection options
LDAP directory
SQL> CONNECT hr/hr@orcl
Oracle Net
configuration files
5 - 22
Copyright © 2008, Oracle. All rights reserved.
External Naming Method
• Uses a supported non-Oracle naming service
• Includes:
– Network Information Service (NIS) External Naming
– Distributed Computing Environment (DCE) Cell Directory
Services (CDS)
Non-Oracle
naming
service
Oracle Net
5 - 23
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Configuring Service Aliases(net service name)
5 - 24
Copyright © 2008, Oracle. All rights reserved.
Advanced Connection Options
Oracle Net supports the following advanced connection
options with local and directory naming:
• Connect-time failover
• Load balancing
• Source routing
5 - 25
Copyright © 2008, Oracle. All rights reserved.
Testing Oracle Net Connectivity
The tnsping utility that tests Oracle Net service aliases:
• Ensures connectivity between the client and the Oracle
Net Listener
• Does not verify that the requested service is available
• Supports Easy Connect Names Resolution:
tnsping db.us.oracle.com:1521/dba11g
• Supports local and directory naming:
tnsping orcl
5 - 27
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User Sessions: Dedicated Server
User sessions
Server process
Server process
Server process
Listener
5 - 28
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User Sessions: Shared Servers
Server process
Server process
Server process
User sessions
Dispatchers
Listener
5 - 29
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SGA and PGA
Oracle Shared Server: User session data is held
in the SGA.
SGA
User
Cursor
session
state
data
PGA
Sort
data
Large pool and
other memory
structures
Remember to consider shared server memory
requirements when sizing the SGA.
5 - 30
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Stack
space
Shared Server: Connection Pooling
Idle
client
The client application has been idle
past the specified time, and an
incoming client requests a
connection.
Active
client
New
client
Database
server
This client connection is the 256th
connection into the server. Connection
pooling is turned on so that this
connection can be accepted.
5 - 31
Copyright © 2008, Oracle. All rights reserved.
The maximum
number of
connections is
configured to 255.
When Not to Use a Shared Server
Certain types of database work must not be performed
using shared servers:
• Database administration
• Backup and recovery operations
• Batch processing and bulk load operations
• Data warehouse operations
Dispatcher
5 - 32
Dedicated
server process
Copyright © 2008, Oracle. All rights reserved.
Summary
In this lesson, you should have learned how to:
• Use Enterprise Manager to:
–
–
–
–
Create additional listeners
Create Oracle Net Service aliases
Configure connect-time failover
Control the Oracle Net Listener
• Use tnsping to test Oracle Net connectivity
• Identify when to use shared servers and when to use
dedicated servers
5 - 33
Copyright © 2008, Oracle. All rights reserved.
Practice 5 Overview:
Working with Oracle Network Components
This practice covers the following topics:
• Configuring local Names Resolution to connect to
another database
• Creating a second listener for connect-time failover
5 - 34
Copyright © 2008, Oracle. All rights reserved.