Recommended Use of HG

HG indexes and multicolumn HG indexes offer different functionality that must be considered when choosing which to use.

Use an HG index when:

The column will be used in a join predicate
A column has more than 1000 unique values

Use multicolumn HG indexes to enhance the performance of ORDER BY queries with references to multiple columns. This change is transparent to users, but improves query performance.

Note: Foreign key columns require their own, individual HG index.