The High_Group (HG) Index Type

The High_Group index is commonly used for join columns with integer data types. It is also more commonly used than High_Non_Group because it handles GROUP BY efficiently.

• Recommended Use
  HG indexes and multicolumn HG indexes offer different functionality that must be considered when choosing which to use.
• Advantages and Disadvantages of High_Group
  High_Group indexes have these advantages and disadvantages.
• Comparison with Other Indexes
  The following is a comparison of other indexes.
• Additional Indexes
  In some cases, a column that meets the criteria for a High_Group index may be used in queries where a different type of index may be faster. If this is the case, create additional indexes for that column.
• Automatic Creation of High_Group Index
  Sybase IQ creates a High_Group index by default whenever you issue a CREATE INDEX statement without specifying an index type.