The fix for
DERBY-5680 currently requires hard upgrade. A soft upgrade database with an orphaned stat row, that can be caused by something like DERBY-5681, will cause DERBY to spin eating up 100% of a cpu and possibly all the disk bandwith of the disk where the database is located.
We should implement a fix that can be applied to soft upgraded databases if at all possible.
In soft upgraded databases we can no use the work around of dropping the statistics as it is not available
to soft upgraded db's with version < 10.9. The only current workaround is to disable background stats
completely. Dropping and recreating the suspect table may also work.