Oracle - What TNS Names file am I using?

Sometimes I get Oracle connection problems because I can't figure out which tnsnames.ora file my database client is using.

What's the best way to figure this out? ++happy for various platform solutions.

Solution 1:

Oracle provides a utility called tnsping:

R:\>tnsping someconnection

TNS Ping Utility for 32-bit Windows: Version 9.0.1.3.1 - Production on 27-AUG-20
08 10:38:07

Copyright (c) 1997 Oracle Corporation.  All rights reserved.

Used parameter files:
C:\Oracle92\network\ADMIN\sqlnet.ora
C:\Oracle92\network\ADMIN\tnsnames.ora

TNS-03505: Failed to resolve name

R:\>


R:\>tnsping entpr01

TNS Ping Utility for 32-bit Windows: Version 9.0.1.3.1 - Production on 27-AUG-20
08 10:39:22

Copyright (c) 1997 Oracle Corporation.  All rights reserved.

Used parameter files:
C:\Oracle92\network\ADMIN\sqlnet.ora
C:\Oracle92\network\ADMIN\tnsnames.ora

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (COMMUNITY = **)
 (PROTOCOL = TCP) (Host = ****) (Port = 1521))) (CONNECT_DATA = (SID = ENTPR0
1)))
OK (40 msec)

R:\>

This should show what file you're using. The utility sits in the Oracle bin directory.

Solution 2:

For linux:

$ strace sqlplus -L scott/tiger@orcl 2>&1| grep -i 'open.*tnsnames.ora'

shows something like this:

open("/opt/oracle/product/10.2.0/db_1/network/admin/tnsnames.ora",O_RDONLY)=7

Changing to

$ strace sqlplus -L scott/tiger@orcl 2>&1| grep -i 'tnsnames.ora'

will show all the file paths that are failing.

Solution 3:

There is another place where the TNS location is stored: If you're using Windows, open regedit and navigate to My HKEY Local Machine/Software/ORACLE/KEY_OraClient10_home1 where KEY_OraClient10_home1 is your Oracle home. If there is a string entry called TNS_ADMIN, then the value of that entry will point to the TNS file that Oracle is using on your computer.

Solution 4:

On my development machine I have three different versions of Oracle client software. I manage the tnsnames.ora file in one of them. In the other two, I have entered in the tnsnames.ora file:

ifile=path_to_tnsnames.ora_file/tnsnames.ora

This way, if for some reason the wrong tnsnames.ora file is used by a client, it will always end up at the up-to-date version.

Solution 5:

Codeslave asks "Shouldn't it always be "$ORACLE_ HOME/network/admin/tnsnames.ora"? The answer is no, it isn't. Consider these two invocations of tnsping on the same machine:

C:\Documents and Settings\me>D:\Oracle\10.2.0_DB\BIN\tnsping orcl

TNS Ping Utility for 32-bit Windows: Version 10.2.0.4.0 - Production on 09-OCT-2
008 14:30:12

Copyright (c) 1997,  2007, Oracle.  All rights reserved.

Used parameter files:
D:\Oracle\10.2.0_DB\network\admin\sqlnet.ora


Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = xxxx
)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = ORCL)))

OK (40 msec)

C:\Documents and Settings\me>tnsping orcl

TNS Ping Utility for 32-bit Windows: Version 10.2.0.1.0 - Production on 09-OCT-2
008 14:30:21

Copyright (c) 1997, 2005, Oracle.  All rights reserved.

Used parameter files:
D:\oracle\10.2.0_Client\network\admin\sqlnet.ora


Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)
(HOST = XXXX)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = ORCL)))
OK (20 msec)

C:\Documents and Settings\me>

Note the two different parameter file locations, that are dependent on which tnsping executable you're running (and perhaps where it's being run from). For tnsnames-based oracle networking, using the TNS_ADMIN variable is the only way to ensure you're getting a consistent tnsnames.ora file. (NOTE: Windows-centric answer)