Oracle: Does a 10g oracle client work with an 11g server?

Question

This is the reciprocal to this question. Currently, I am trying to use the instant client for Mac, version 10.2. There\'s no 11g version for Mac, as of now, based on this page(y

Answer 1

It should work. I have never had problems with upwards compatiblity of Oracle Client. Test:

myclient{oracle}# sqlplus system@rac11g

SQL*Plus: Release 10.2.0.3.0 - Production on Thu Jun 25 08:44:09 2009

Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.

Enter password:

Connected to:
Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - Production
With the Partitioning, Real Application Clusters, OLAP, Data Mining
and Real Application Testing options

SQL> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - Production
PL/SQL Release 11.1.0.7.0 - Production
CORE    11.1.0.7.0      Production
TNS for Linux: Version 11.1.0.7.0 - Production
NLSRTL Version 11.1.0.7.0 - Production

Answer 2

Normally this should just work. Here I sometimes have to connect to a 10g DB with a 9er client. Works flawless.

Answer 3

There can be problems when a lower version client is used to access a higher version database, particularly when using links where you might get some erroneous results.

See Document ID 207303.1 on My Oracle Support for more details (if you have access).

Answer 4

I would certainly say it should. The SQL*Net protocol it uses is essentially unchanged. Here's an example of me connecting an Oracle 9 to an Oracle 10 server.

oracle@cammi:~$ sqlplus "urs/urs@THANOS_URS"

SQL*Plus: Release 9.2.0.8.0 - Production on Thu Jun 25 05:55:57 2009

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.

Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production With the Partitioning, Data Mining and Real Application Testing options

According to the guys at "http://www.experts-exchange.com/"...

11 can talk to 11,10,9
10 can talk to 11,10,9,8
9 can talk to 11,10,9,8,7
8 can talk to 10,9,8,7
7 can talk to 9,8,7

According to Oracle forums, this is defined in Metalink DocID 207303.1, which provides a comprehensive client/ server compatibility matrix. I don't have Metalink access sadly, so I can't confirm this.

If you are having connection troubles, I suggest you start with the Oracle alert log on your server machine. To find the location of your oracle alert log:

SQL> select value from v$parameter where name = 'background_dump_dest';

Also, you'll probably get something useful out of enabling listener tracing:

$ lsnrctl
LSNRCTL> set trc_level ADMIN

The trace file on my Solaris Oracle 10 install is found in:

$ORACLE_HOME/network/trace/listener.trc

You can view it directly or use the trcasst program to "format" it. Note that ALL of this is on the server, not your client side.

Hope this helps.