When you first install Teradata Database, it has only one user. This user is called DBC, and from it all other future databases and users in the system are created.
User DBC also initially owns all the space in the entire system. As you create new databases and users, any permanent space you grant them is subtracted from available permanent space in user DBC. Because all space ultimately comes from user DBC, user DBC owns all database objects.
User DBC contains data like a database, but unlike a database it has a password. The usable (PERM) disk space in DBC initially reflects the entire system hardware capacity, minus space for the following system users, databases, and objects:
- All the space available for your databases, users, journals, data tables, indexes, stored procedures, functions, and temporary tables. DBC owns all unallocated space.
- Crashdumps user
- SysAdmin user
- Sys_Calendar database
- TD_SYSFNLIB database
- SQLJ, SYSLIB, and SYSUDTLIB databases for external routines and user-defined types. For details, see SQL External Routine Programming.
- SYSSPATIAL database for geospatial data types. For details, see SQL Geospatial Types.
- DBCExtension database for Global and Persistent (GLOP) sets. For details, see “DBCExtension Tables” in Data Dictionary.
- SystemFE user for field engineers
- TDPUSER user
- The system Transient Journal (TJ) which stores the before-change image of every data row involved in a transaction, the row ID of every inserted row, and other control records used by the system to automatically recover data from transaction aborts or to complete transactions.
- The system catalog tables of the Data Dictionary and the suite of user-accessible views defined on those tables (for details, see Data Dictionary).
This also includes a suite of special system query logging tables used to store query logging rules and data when you enable the DBQL feature. See Tracking Query Behavior with Database Query Logging: Operational DBAs.