We recently had a few customers where a connection to Oracle on a 64 bit machine was necessary. A quick search on the internet showed that this could be a big problem. I found all kind of blog and forum posts of developers complaining about this. A lot of developers will recognize the following error message:

Test connection failed because of an error in initializing provider. Oracle client and networking components were not found. These components are supplied by Oracle Corporation and are part of the Oracle Version 7.3.3 or later client software installation.
Provider is unable to function until these components are installed.

After a lot of searching, trying and debugging I think I found the right way to do it!

Problems

Because BIDS is a 32 bit application, as well on 32 as on 64 bit machines, it cannot see the 64 bit driver for Oracle. Because of this, connecting to Oracle from BIDS on a 64 bit machine will never work when you install the 64 bit Oracle client.

Another problem is the "Microsoft Provider for Oracle", this driver only exists in a 32 bit version and Microsoft has no plans to create a 64 bit one in the near future.

The last problem I know of is in the Oracle client itself, it seems that a connection will never work with the instant client, so always use the full client.
There are also a lot of problems with the 10G client, one of it is the fact that this driver can't handle the "(x86)" in the path of SQL Server. So using the 10G client is no option!

Solution

• Download the Oracle 11G full client.
• Install the 32 AND the 64 bit version of the 11G full client (Installation Type: Administrator) and reboot the server afterwards. The 32 bit version is needed for development from BIDS with is 32 bit, the 64 bit version is needed for production with the SQLAgent, which is 64 bit.
• Configure the Oracle clients (both 32 and 64 bits) by editing  the files tnsnames.ora and sqlnet.ora. Try to do this with an Oracle DBA or, even better, let him/her do this.
• Use the "Oracle provider for OLE DB" from SSIS, don't use the "Microsoft Provider for Oracle" because a 64 bit version of it does not exist.
• Schedule your packages with the SQLAgent.

Background information

• Visual Studio (BI Dev Studio)is a 32bit application.
• SQL Server Management Studio is a 32bit application.
• dtexecui.exe is a 32bit application.
• dtexec.exe has both 32bit and 64bit versions.
• There are x64 and x86 versions of the Oracle provider available.
• SQLAgent is a 64bit process.

My advice to BI consultants is to get an Oracle DBA or professional for the installation and configuration of the 2 full clients (32 and 64 bit). Tell the DBA to download the biggest client available, this way you are sure that they pick the right one ;-)

Testing if the clients have been installed and configured in the right way can be done with Windows ODBC Data Source Administrator:
Start...
Programs...
Administrative tools...
Data Sources (ODBC)

It seems that, unfortunately, some additional steps are necessary for SQL Server 2008 R2 installations:

1. Open REGEDIT (Start… Run… REGEDIT) on the server and search for the following entry (for the 32 bits driver): HKEY_LOCAL_MACHINE\Software\Microsoft\MSDTC\MTxOCI
Make sure the following values are entered:

2. Next, search for (for the 64 bits driver): HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\MSDTC\MTxOCI
Make sure the same values as above are entered.

3. Reboot your server.