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One of the new compression features in Teradata 13.10 is Block Level Compression (BLC), which provides the capability to perform compression on whole data blocks at the file system level before the data blocks are actually written to storage. Like any compression features, BLC helps save space and reduce I/O. 

There is a CPU cost to perform compression on inserting data. And there is a CPU cost to perform decompression on whole data blocks whenever the compressed data blocks are accessed. Even when only one column of a single row is needed, the whole data block must be decompressed. For updates, the compressed data blocks have to be decompressed first and then recompressed. Careful evaluations shall be done before applying BLC in your production systems.

Teradata 13.10 provides Algorithmic Compression (ALC) feature that allows  users to apply compression / decompression functions on a specific column of character or byte type. The compression / decompression functions may be Teradata built-in functions provided along with ALC or user provided compression / decompression algorithm registered as UDFs.

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