Role of tnsnames. ora in Oracle

The role of tnsnames. ora in listener. When the database is started, it will only read the content in tnsnames. ora to parse LOCAL_LISTENER, and then change tnsnames.

The role of tnsnames. ora in listener. When the database is started, it will only read the content in tnsnames. ora to parse LOCAL_LISTENER, and then change tnsnames.

1. Role of tnsnames. ora in listener
The database only reads the content in tnsnames. ora during the startup process to parse LOCAL_LISTENER. After that, tnsnames changes have nothing to do with listening.

--- Set LOCAL_LISTENER, port 1522
SQL> show parameter list

NAME TYPE VALUE
-----------------------------------------------------------------------------
Listener_networks string
Local_listener string LISTENER_1
Remote_listener string

--- Contents in listener. ora
[Oracle @ node1 admin] $ more listener. ora
# Listener. ora Network Configuration File:/oracle/app/oracle/db/network/admin/listener. ora
# Generated by Oracle configuration tools.

LISTENER_1 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP) (HOST = 1.1.1.10) (PORT = 1522 ))
)

ADR_BASE_LISTENER_1 =/oracle/app/oracle

--- Content in tnsnames. ora
LISTENER_1 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP) (HOST = 1.1.1.10) (PORT = 1522 ))
)
)
The current database status is normal.

Delete tnsnames. Ora, start the database
SQL> ORA-00119: invalid specification for system parameter LOCAL_LISTENER
ORA-00132: syntax error or unresolved network name 'listener _ 1
The database reports an error, indicating that the database uses tnsnames. ora to parse LOCAL_LISTENER at startup.

Step 2: Modify tnsnames. The ora content gives him an incorrect IP address.
[Oracle @ node1 admin] $ vi tnsnames. ora

LISTENER_1 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP) (HOST = 1.1.1.17) (PORT = 1522 ))
)
)
1.1.1.17 is an incorrect IP address.
SQL> startup
ORACLE instance started.

Total System Global Area 1054593024 bytes
Fixed Size 1349616 bytes
Variable Size 507512848 bytes
Database Buffers 541065216 bytes
Redo Buffers 4665344 bytes
Database mounted.
Database opened.
SQL>
The database can be started normally.

SQL>! Ps-ef | grep tns
Oracle 3219 1 0? 00:00:00/oracle/app/oracle/db/bin/tnslsnr LISTENER_1-inherit
Oracle 4125 3881 0 00:00:00 pts/1/bin/bash-c ps-ef | grep tns
Oracle 4127 4125 0 00:00:00 pts/1/bin/bash-c ps-ef | grep tns

SQL>! Lsnrctl status LISTENER_1

LSNRCTL for Linux: Version 11.2.0.3.0-Production on 30-SEP-2013 21:40:25

Copyright (c) 1991,201 1, Oracle. All rights reserved.

Connecting to (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP) (HOST = 1.1.1.10) (PORT = 1522 )))
STATUS of the LISTENER
------------------------
Alias LISTENER_1
Version TNSLSNR for Linux: Version 11.2.0.3.0-Production
Start Date 30-SEP-2013 21:26:50
Uptime 0 days 0 hr. 13 min. 34 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File/oracle/app/oracle/db/network/admin/listener. ora
Listener Log File/oracle/app/oracle/diag/tnslsnr/node1/listener_1/alert/log. xml
Listening Endpoints Summary...
(DESCRIPTION = (ADDRESS = (PROTOCOL = tcp) (HOST = 1.1.1.10) (PORT = 1522 )))
The listener supports no services
The command completed successfully

SQL>

No service registered to listener

Step 3: Modify tnsnames. ora to the correct IP address.

Restart listener
[Oracle @ node1 admin] $ lsnrctl stop LISTENER_1
[Oracle @ node1 admin] $ lsnrctl start LISTENER_1

SQL> alter system register;

System altered.

SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0-Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
[Oracle @ node1 admin] $ lsnrctl status LISTENER_1

LSNRCTL for Linux: Version 11.2.0.3.0-Production on 30-SEP-2013 21:43:03

Copyright (c) 1991,201 1, Oracle. All rights reserved.

Connecting to (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP) (HOST = 1.1.1.10) (PORT = 1522 )))
STATUS of the LISTENER
------------------------
Alias LISTENER_1
Version TNSLSNR for Linux: Version 11.2.0.3.0-Production
Start Date 30-SEP-2013 21:42:30
Uptime 0 days 0 hr. 0 min. 32 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File/oracle/app/oracle/db/network/admin/listener. ora
Listener Log File/oracle/app/oracle/diag/tnslsnr/node1/listener_1/alert/log. xml
Listening Endpoints Summary...
(DESCRIPTION = (ADDRESS = (PROTOCOL = tcp) (HOST = 1.1.1.10) (PORT = 1522 )))
The listener supports no services
The command completed successfully

Still not good
[Oracle @ node2 admin] $ sqlplus vic @ vic2

SQL * Plus: Release 11.2.0.3.0 Production on Mon Sep 30 21:43:32 2013

Copyright (c) 1982,201 1, Oracle. All rights reserved.

Enter password:
ERROR:
ORA-12514: TNS: listener does not currently know of service requested in connect
Descriptor

The client cannot be connected either. Therefore, restarting listner will not read tnsnames. Ora content.

Next, let's take a look at the highlights of page 2nd:

Related reading:

Differences between listener. ora sqlnet. ora tnsnames. ora in Oracle databases

Non-Default port listening configuration in Oracle RAC (listener. ora tnsnames. ora)

Oracle RAC listener Configuration (listener. ora tnsnames. ora)

Oracle: listener. ora, sqlnet. ora, tnsnames. ora configuration and example

Configure tnsnames. ora in the local Naming Service of Oracle

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