15.00 - Multicolumn Column Partition Values for a Container - Teradata Database

Teradata Database Design

Teradata Database
User Guide

Multicolumn Column Partition Values for a Container

A series of one or more multicolumn column partition values is stored as a container for a multicolumn partition.

The following diagram shows the layout of a multicolumn column partition value.

The fixed‑length, compressible, and variable‑length sets of columns are each stored in the order of their field IDs in their respective sets which is the order in which they are specified in the database object defining DDL text.

If there are no columns with user-specified compression and the columns are all fixed length, a multicolumn partition has fixed‑length column partition values unless autocompression causes the column partition values to have variable length. Otherwise, the multicolumn partition has variable‑length values, which could either be all variable‑length columns or a mix of fixed‑length and one or more variable‑length columns.

The presence bits array is omitted from the container if there are no nullable columns or columns with user‑specified compression.

A fixed‑length column, whether nullable or not, fixed-length column is not user-specified to be compressed, space is consumed in the row for a fixed‑length column in the fixed‑length columns area.