Managing DBC space
A system user named DBC (database computer) is the owner of all disk space on a system. When the system is initially set up, spaces for child databases are derived from DBC itself. DBC's space includes dictionary tables, databases, views, and all the child databases:
**DBC database space** Select sum(MaxPerm) from DBC.DiskSpace where DatabaseName = 'DBC';
It is very important to understand space in DBC itself. Why is it important and what it is used for?
Once you allocate space from DBC to other databases, it is important that you keep adequate space in the DBC database to accommodate the growth of system tables and logs, and the transient journal. Also, if you are not using a separate database for the spool, space in DBC can also be used for spool purposes (all the empty space in the system is used as the spool).
The main reason to keep an eye on DBC is because of TJÂ (transient journal). It maintains snapshots of rows that are going to be processed or are getting processed...
