The CheckTable utility verifies the structure of the Teradata Database system tables and user tables. CheckTable provides four levels of internal data structure checking. Prior to starting an upgrade, run the CheckTable utility at level two for DBC, then run CheckTable again at level one for all user tables.
Level two checking does the following:
- Determines whether row IDs on any given subtable are consistent with row IDs on other subtables by comparing lists of these IDs in those objects
- Compares the checksum of primary and fallback rows
- Verifies that hash codes reflect correct row distribution in each subtable
On systems with a large number of objects, running the CheckTable utility may take a considerable length of time.
If CheckTable reports any problems, they must be corrected before the Teradata Database upgrade is performed.