If you see rpmdb errors during package management (during yum/rpm operations), like this,
rpmdb: Thread/process 277623/140429100390144 failed: Thread died in Berkeley DB library error: db3 error(-30974) from dbenv->failchk: DB_RUNRECOVERY: Fatal error, run database recovery error: cannot open Packages index using db3 - (-30974) error: cannot open Packages database in /var/lib/rpm CRITICAL:yum.verbose.cli.yumcompletets:Yum Error: Error: rpmdb open failed
From above error, It means that the RPM database is corrupted.
Please follow the below steps to backup and rebuild the rpmdb database,
mkdir /var/lib/rpm/backup cp -a /var/lib/rpm/__db* /var/lib/rpm/backup/ rm -f /var/lib/rpm/__db.[0-9][0-9]* rpm --quiet -qa rpm --rebuilddb yum clean all