Whenever you have to analyze a huge Teradata table regarding Multivalue compression, this is a costly operation from a workload point of view.

Unfortunately, Teradata (the company) does not offer any tool which would allow automatizing this task.

Usually, analysis requires counting the number of distinct values per table column. Counting is resource and time intensive for huge tables.

Luckily, with Teradata 14.10, we have a less costly method available:

SHOW STATISTICS VALUES COLUMN <column> ON <table>;

The above statement outputs the most biased column values and many other useful statistics about a column. Usually, the biased values are great candidates for Teradata Multivalue compression.

This approach’s advantage is that no costly table analysis is required (compare this against the approach of counting the distinct column values for each column of a huge table). Nevertheless, it delivers astoundingly good compression suggestions.

By additionally using the number of NULL values per column, you should have a great starting point for a quick win regarding space reduction.

Nevertheless, as good as this method is for achieving quick results, it comes with some drawbacks: