The following sections describe the functions that you can use with algorithmic compression (ALC) to compress and uncompress column data of character or byte type. Compression of data reduces space usage and the size of disk I/Os.
If the compression and decompression functions described here are not optimal for your data, you can write your own user-defined functions (UDFs) to compress and uncompress table columns.
Using ALC together with block-level compression (BLC) may degrade performance, so this practice is not recommended.
Prerequisites
The functions described here are embedded services system functions. For information on activating and invoking embedded services functions, see "Embedded Services System Functions" in Teradata Vantage™ - SQL Functions, Expressions, and Predicates, B035-1145.
| FOR more information on... | SEE... |
|---|---|
| ALC |
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| writing UDFs for ALC |
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| compression methods supported by Teradata Database and a comparison of the various methods |
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