Troubleshoot issues with registering Oracle databases with ArcGIS for Server

Scenario 1: Is the ArcGIS for Server installation file an old file from the product initial release?

If it is an old installation file, it is possible that ArcGIS for Server is not patched for Oracle services. Download and install the patch service for Oracle. For more information, refer to the following web help page, ArcGIS 'Oracle Critical Patch Update - October 2014' Connection Issue Patch.

Scenario 2: Install the required bit version of the Oracle client.

ArcGIS for Server runs on a 64-bit system and requires the same bit version of an Oracle client on the server. The absence of a 64-bit installation also results in the Oracle client libraries being non-existent. A 64-bit Oracle client installation fixes this issue. Download and install the Oracle Instant Client from the following download site, Oracle Instant Client.

Scenario 3: Ensure the Windows environment is reading the right installation path.

If there are two bit versions installed on the same machine, the Windows environment acknowledges the latest installed bit version first since this is the directory listed first in the PATH environmental variable. Thus, if a 32-bit client is installed after the 64-bit client, the 32-bit client is read first. To fix this issue, repair the 64-bit Oracle client installation to allow the Windows environment variable to read the 64-bit version of Oracle client before the 32-bit version. Alternatively, edit the PATH environmental variable to place the 64-bit client directory before the 32-bit client directory.
 

Note:
 If the installation of the Oracle library is done beforehand, restart the machine. Upon installation of the Oracle library, a new path is set in the Windows environment variables. The new path variable is only read at the startup of the machine.

Scenario 4: Test the login credentials in the Oracle database.

Invalid login credentials can result in failure of registering Oracle databases. Test the connection from ArcCatalog, or run the Oracle Net Service Configuration Assistant to identify and input valid credentials. For more information, refer to the following web page, Oracle: Configuring the Network Environment.

Scenario 5: Check the syntax in the connection properties for the ArcSDE connection file.

Before ArcGIS 10.1, it was necessary to type "sde:oracle11g:" before the Oracle service name to connect to the database successfully. This is no longer necessary, as that string is added automatically when using tnsname connection in the sde connection file. For more information, refer to the following article, KB40576. If tnsname syntax is resulting in an error, try using EZCONNECT syntax. For more information on these different connection options, refer to the following article, KB42269.
For more information on correct syntax for SDE connections, refer to the following web help document, ArcGIS Help: Database connections in ArcGIS for Desktop.