Block-Level Compression | Database Design | Teradata Vantage - Block-Level Compression - Teradata Vantage - Analytics Database

Database Design
Deployment
VantageCloud
VantageCore
Edition
VMware
Enterprise
IntelliFlex
Product
Analytics Database
Teradata Vantage
Release Number
17.20
Published
June 2022
ft:locale
en-US
ft:lastEdition
2025-11-21
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zqc1472244571611
lifecycle
lifecycle
Product Category
Teradata Vantage™
A data block is a physical unit of I/O that defines how Vantage handles data. When you specify block-level compression (BLC), Vantage stores data blocks in compressed format to save storage space. BLC can be enabled or disabled system-wide or for specific types of tables only. BLC can be applied to these objects:
  • Journal tables
  • Join indexes
  • Hash indexes
  • Spool tables
  • Global temporary tables
  • Primary subtables
  • Fallback subtables
  • LOB subtables (JSON, XML, and character)
Block-level compression is independent of any other type of compression applied to the same data.

The goals of block-level compression are to save storage space and to reduce disk I/O bandwidth. Block-level compression can use significantly more CPU to compress and decompress data dynamically, so whether query performance is enhanced with block-level compression depends on whether performance is more limited by disk I/O bandwidth or CPU usage.

Teradata offers software-based and hardware-based BLC. You select the BLC method when you specify the compression algorithm in the CompressionAlgorithm field in DBS Control. See Controlling BLC at the System Level Using the DBS Control Utility.

The following site provides guidelines for evaluating the impact of block-level compression on performance and on disk space: https://downloads.teradata.com/extensibility/articles/block-level-compression-evaluation-with-the-blc-utility. The site also provides a link to download the Block Level Compression Evaluation utility.