15.00 - Using the NO AUTO COMPRESS Option - Teradata Database

Teradata Database Design

Teradata Database
User Guide

Using the NO AUTO COMPRESS Option

You can override the autocompression default by specifying the NO AUTO COMPRESS option. This option ensures that Teradata Database uses the specified null compression, multi-value compression, or algorithmic compression for the column partition when you create the column‑partitioned table or join index.

If you specify NO AUTO COMPRESS for a column partition, or if the column partition has ROW format, Teradata Database always applies any compression techniques that you specify to every container or subrow of the column partition. For column partitions with COLUMN format, Teradata Database applies row header compression, which is applied to column partitions that have COLUMN format. To disable row header compression, specify ROW format when you create a column‑partitioned table or join index.

There is some overhead in determining whether or not a physical row should be compressed and, if so, what compression techniques to use. If Teradata Database determines that there is no appropriate technique to compress the physical rows of the column partition, or if you determine that the compression techniques used do not effectively compress the column partition, you can eliminate this overhead by specifying the NO AUTO COMPRESS option for the column partition.