When you create a column-partitioned table, Vantage compresses the data that you insert into the physical table rows unless you specify the NO AUTO COMPRESS option for the table or for specific column partitions.
- Considers the cost of decompressing the data and determines whether autocompression is worthwhile
- Selects a compression method
- Automatically compresses values and decompresses them when you need to retrieve them
Autocompression is most effective for a column partition with a single column and COLUMN format.
Vantage determines whether to apply both autocompression and user-specified multivalue and algorithmic compression to a column, and if the user-specified methods do not help to compress a container, the system only applies autocompression.