n is either 1 or 0. The default value is 1.
When DDLDefineBitmapExtent is enabled (n = 1), a table created by a DDL CREATE TABLE statement defines a bitmap extent index. The index improves the performance of COUNT(*), a function that returns the number of rows in the table.
Changing This Parameter
To set the desired value for DDLDefineBitmapExtent from the Terminal, use the SetOption(“DDLDefineBitmapExtent”) method of the %SYSTEM.SQL.Util class. See the class reference for details.
You can also change DDLDefineBitmapExtent with the Config.SQL class (as described in the class reference) or by editing the CPF in a text editor (as described in the Editing the Active CPF section of the “Introduction to the Configuration Parameter File” chapter in this book).