Upgrade adds columns to the following backup and restore history tables: backupfile, backupmediafamily, backupmediaset, backupset, ...

Upgrade adds columns to the following backup and restore history tables: backupfile, backupmediafamily, backupmediaset, backupset, restorefile, restorefilegroup, and restorehistory. If a server instance has a very large number of rows in any of these tables, when upgrade runs ALTER TABLE statements on that table, the upgrade will stall and can appear to hang.