17.10 - CheckTable General Checks - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - Database Utilities

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Configuration
Publication ID
B035-1102-171K
Language
English (United States)

CheckTable checks certain aspects of tables regardless of the level of checking that is specified. These general checks include things like checking the table headers, checking for obsolete subtables, and checking the Data Dictionary.

Check Type Description
Data Dictionary Two special checks involve the Data Dictionary:
  • Table List Validation

    This check compares the table IDs found in the DBC.TVM and DBC.TempTables with the table IDs on each AMP. It looks for missing tables (tables found in the dictionary but not found on one or more AMPs), extra tables (tables found on one or more AMPs that are not found in the dictionary), and table data that resides on one or more AMPs where those AMPs are not in the defined map for the table.

  • Contiguous Map Info Validation

    This check compares contiguous map information stored in the DBC.Maps table with the corresponding information stored in the MapInfo GDO. The MapInfo GDO is a memory-resident data structure that stores information about all contiguous maps on the system. For more information about contiguous and sparse maps, see Teradata Vantage™ - Database Design, B035-1094, Teradata Vantage™ - Database Administration, B035-1093, and Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.

These special checks are only performed when the user issues a CHECK DBC or CHECK ALL TABLES command and the system has logons disabled and is quiescent.

Table headers Compares table header components on all AMPs with the table header from the AMP with the lowest virtual processor (vproc) number of all online AMPs.
Table structure Compares the table structure version stored in DBC.TVM to the table structure version stored in the header.
Obsolete subtables checks for extraneous subtables of a given table.
Parent/Child count Verifies if the ParentCount and ChildCount in DBC.TVM match the ParentCount and ChildCount in the table header.
Table Map Info Verifies that the map information stored in DBC.TVM and DBC.MAPS match the map information stored in table headers.
Pending operations Checks the table header to determine if any table has any pending operations. This check works for global temporary tables as well as base tables.
Tables with online archive active logs are checked by CheckTable, however their online archive log subtables are not checked.