Is this combination supported?
The company uses a financial package that I know nothing about and have no say on, either. The company recently decided to upgrade it, and got the supplier in to perform a test upgrade run for us. For this test upgrade, I was asked to install and create a new 11.1.0.7 64-bit Windows 2008 database, which I did and everything worked smoothly.
Then they came to do the test upgrade. This involved them installing their accounting application onto the database server itself. Their application uses .NET and is strictly a 32-bit application. When it tried to connect to the database, their own error messages warned that 64-bit libraries were being used, and that only 32-bit ones should be. So they asked me to install a 32-bit client version of 11.1.0.7 onto the same box (different ORACLE_HOME, of course) as the 64-bit database was running on. No problems: installation went without a problem and the suppliers were happy with their upgrade testing.
I am not so sure, however! For a start, when I create a database link from production to the testing server, whenever I try to use it, I get told the username or password are invalid, when I know for an absolute, multiple-times-checked-and-certified, fact that they are both fine. What's more, if I connect to the test database server using Windows Remote Desktop, open a command window and immediately type set ORACLE_SID=fintest and then sqlplus / as sysdba, I get told there's a tns protocol adapter error. But if I open a command window, cd to the original 64-bit home's BIN directory, and then sqlplus / as sysdba, it works fine. That suggests to me that the 32-bit client binary (which is first in the PATH and therefore used by default when invoking sqlplus) is having trouble reading the environment variables on a 64-bit server, whereas the 64-bit binary does not.
So my question (finally!) is: is it actually supported to have a 32-bit client and a 64-bit database installed on the one server? And if it is, anyone else have experience of the 32-bit client having problems reading things like ORACLE_SID on a 64-bit Windows server?