Upgrades to release 12.x are not supported using Oracle RAC.

Using Oracle RAC causes a significant performance issue for any data set that has high volumes of insert/update/delete’s due to cluster locks for block comparisons. It is required, for performance reasons, that upgrade not be done with RAC enabled. Use the same RAC connection string, but narrow it down to just a single node or use the standard JDBC short syntax. On the Oracle side you must disable all of the RAC nodes in the cluster with the exception of the one that Windchill is pointing at. Failure to properly disable the RAC cluster will result in RAC node evictions.