Normally, check_ducc -k sends -9 signal to those process it aims to kill, including the database. This may leave the database in a bad (unusable?) state.
1. Change check_ducc -k to issue signal -9 to all daemons except database which will get -3.
2. Change check_ducc to accept the --db-9 option that indicates that the database should get signal -9. The db-9 option only applies if the -k option is also specified, and should be used only as a last resort.