The virtual data disks controlled by the AMPs include reserved space and permanent space.
Reserved Space
Reserved space is used for the TVS map, DeviceTag, and statistics areas that are located at the beginning of each pdisk.
Permanent Space
| Content | Use |
|---|---|
| CRASHDUMPS user | Temporary storage of diagnostic information and crash dumps generated by the database and Open PDE. |
| SYSTEMFE user | Special macros and objects used by Teradata field support personnel. |
| SYSADMIN user | Special views and macros used by Teradata Support personnel. |
| TDStats | Contains all of the tables, views, macros, UDFs, and external stored procedures used by the Teradata statistics management system. TDStats is the repository for statistics management data. |
| Data dictionary | Maintains Vantage user, database, table, index, trigger, permanent journal, view, stored procedure, and macro definitions. |
| WAL log (transient journal) space | Stores Redo and Undo records that enable data to be brought to a consistent state as well as before-image records that enable uncommitted transactions to be rolled back. |
| Depot area space | Stores cylinders reserved by the File System as a staging area to temporarily contain modified-in-place data blocks before they are written to their home disk destinations. |
| Spool | Stores intermediate and response results of SQL requests. |
| Temporary space | Stores data inserted into materialized global temporary tables. Note that each materialized global temporary table also requires a minimum of 512 bytes from the PERM space of its containing database or user for its table header. |
| Top-level hierarchical ownership of PERM and TEMP spaces |
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