The right answer is to log a case with Cisco support to get official steps.
What we do here (an Oracle DB):
- bring down CM
- make an export of TES schema (optional)
- run the clearcache.sql script (in the ../cache/tes6.0.0.0/cachesql.zip) to drop schema objects.
- verify that sql ran correctly and scheme is indeed empty
- restart the CM - in our case it takes 2 - 2.5 hrs for cache to be rebuilt (the secondary sync completed to show up)