15.00 - Space Considerations - Teradata Database

Teradata Database Design

prodname
Teradata Database
vrm_release
15.00
category
User Guide
featnum
B035-1094-015K

Space Considerations

Creating a secondary index causes the system to build a subtable to contain its index rows, thus adding another set of rows that requires updating each time a table row is inserted, deleted, or updated.

Secondary index subtables are also duplicated whenever a table is defined with FALLBACK, so the maintenance overhead is effectively doubled.

When compression at the data block level is enabled for their primary table, secondary index subtables are not compressed See “Data Block” on page 248 and “Compression Types Supported by Teradata Database” on page 695 for more information about data block compression.