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(you have to click into each link to find out the actual version for each platform...lame).

I tried connecting to our Oracle 11g server, and it just hangs there forever. Are they simply incompatible, or is something else fishy going on?

Answer 1

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.