Summary of Hash Index Functions - Teradata Database

Summary of Hash Index Functions

A hash index always has at least one of the following functions.

Replicates all, or a vertical subset, of a single base table and partitions its rows with a user‑specified partition key column set, such as a foreign key column to facilitate joins of very large tables by hashing them to the same AMP.

Provides an access path to base table rows to complete partial covers.

The AMP software updates hash indexes automatically, so the only task a DBA must perform is to keep the statistics on hash index or base table columns current (see “Collecting Statistics on Hash Index Columns” on page 560).