We recently migrated arcsde 10.6.1 on oracle 11g to oracle 12c on #exadata.
Exadata outperforms oracle 11g on normal queries but any queries with st_functions are very slow. We noticed that its due to extproc calls for shape lib.
How could we avoid this or improve?
I would highly recommend that you contact Technical Support to investigate this in more detail. There could be multiple factors involved in this.
Have you performed a trace to compare the times between Oracle 11.2.x.x and Exadata 12c?