Software-Based Block-Level Compression
Software-based BLC is designed for use on large volumes of seldom-accessed data. This is because access requires CPU-intensive decompression. BLC can also achieve relatively good compression on unknown/unclassified data across different column types, including the internal data structures and the row header. Teradata recommends that you do not load or access tables that use software-based BLC during peak hours (except on CPU-rich platforms).
There are two types of software-based block-level compression: manual and automatic temperature-based. They can be enabled at the system level using the DBS Control utility and at the table level using SQL DDL.