GLS functionality costs

Sorting or indexing certain data sets can degrade performance.

For information about the performance degradation that occurs from indexing some data sets, see Searching for NCHAR or NVARCHAR columns in an index.

If you do not need a non-ASCII collation sequence, use the CHAR and VARCHAR data types for character columns whenever possible. Because CHAR and VARCHAR data require simple value-based comparison, sorting and indexing these columns is less expensive than for non-ASCII data types (NCHAR or NVARCHAR, for example).

For more information about other character data types, see the IBM® Informix® GLS User's Guide.