Oracle - What TNS Names file am I using?

Question

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

For Windows: Filemon from SysInternals will show you what files are being accessed.

Remember to set your filters so you are not overwhelmed by the chatty file system traffic.

Added: Filemon does not work with newer Windows versions, so you might have to use Process Monitor.

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