NULL columns are also due for compression in a table. For every nullable column, a presence bit is set to a 1 if that row has a null value in that column for that particular row. Presence bit(s) are also defined for any column with null values. Teradata automatically compresses the NULL values if COMPRESS is defined on that column.
Let's check how MVC improves performance:
- Improves performance of the table where the full scan is happening
- Physical row gets small, which reduces the data blocks, hence less I/O operation
Multivalue compression analysis requires tools, which can execute on the system and generate the DDL of tables which can be compressed. But users can be educated to compress regular values in their tables. ...
