A while back we added this slide to our big slide deck:
The story behind this slide
A large and important customer in the US tested a patch set upgrade – but when they approached the production upgrade from 188.8.131.52 to 184.108.40.206 on a large RAC cluster they’ve had to cancel the attempt and revert to the previous state.
They’ve hit a dictionary corruption somewhere silently sleeping in the database causing no trouble at all so far – until the upgrade touched the broken structures
They’ve asked us:
“How could we ensure the database is really healthy and …