What version you are using in tableau server.
The Windows 64-bit Oracle driver is installed by default with Tableau Server.
The Oracle docs note this on the ora-12547 error:
- ORA-12547: TNS: lost contact
- Cause: Partner has unexpectedly gone away, usually during process startup.
Action: Investigate partner application for abnormal termination. On an Interchange, this can happen if the machine is overloaded.
Tableau Desktop ----->Oracle ---Working Fine
You need to check this network ---Tableau Server ------- > Oracle DB ?????
The "TNS lost contact error is most commonly a network error, and you can diagnose it by following my notes on troubleshooting sql*net connectivity errors.
Useful links above.
Lets do some experimentation. Please do the following:
1. Disable the Oracle servers Windows Firewall.
2. Disable Any Anti-virus realtime-scanning and/or services.
3. Do the same for your Tableau Servers host operating system.
Please give feedback after trying,