GROUPED Clause

Groups two or more columns into a single disk file. This minimizes file I/O for work loads that:

If you have data that is always accessed together and it is not used in predicates, you can increase query performance by grouping these columns. Once grouped, queries can no longer independently retrieve from disk all records for an individual column independent of the other columns within the group.

Note: RLE encoding is reduced when an RLE column is grouped with one or more non-RLE columns.

When grouping columns you can:

Note: Vertica performs dynamic column grouping. For example, to provide better read and write efficiency for small loads, Vertica ignores any projection-defined column grouping (or lack thereof) and groups all columns together by default.