15.00 - CHECKSUM Integrity Checking and Physical Database Integrity - Teradata Database

Teradata Database Design

Product
Teradata Database
Release Number
15.00
Content Type
User Guide
Publication ID
B035-1094-015K
Language
English (United States)

CHECKSUM Integrity Checking and Physical Database Integrity

Unfortunately, not all hardware devices have end‑to‑end error detection and correction schemes in place, and it is possible for corrupted data to be written to the database. To minimize this problem, Teradata Database provides a mechanism for DBAs to selectively enforce physical data integrity at the level of disk I/O. When implemented, the feature checksums everything from system memory to disk, thus enforcing true end‑to‑end data integrity checking (see “Disk I/O Integrity Checking” on page 666 and “Integrity Checking Using a Checksum” on page 668).

You can specify various levels of corruption detection rigor by selecting among mechanisms that use various degrees of sampled checksums, including full checksums, to detect disk I/O corruption. Teradata Database controls the levels of physical integrity enforcement in two complimentary ways:

  • The default sampled checksum rigor is user‑definable at the system‑level by means of the DBS Control utility.
  • The specification of the checksum rigor at the level of individual base tables is user‑definable in DDL by means of the ALTER TABLE, CREATE HASH INDEX, CREATE JOIN INDEX, and CREATE TABLE statements.