ERROR ORA-01455 AFTER UPGRADED ARCGIS SERVER TO 10.3.1

You just upgraded your ArcGIS Server and Desktop to 10.3.1 and when you tried to connect to Oracle DB from SDE connection, it threw error:

Underlying DBMS error[ORA-01455: converting column overflows integer datatypeNo extended error.]

Actually this error is not related to your new ArcGIS 10.3.1. it is due to your Oracle client that does not meet the minimum requirement. Try update your Oracle client to latest one. It should solve the issue.

Good Luck!!!