Filling Indexes
When you create an index, you can specify how densely or sparsely filled you want the index. The index fill factor is a percentage of each index page that will be filled during the index build. Use the FILLFACTOR option of the CREATE INDEX statement or the FILLFACTOR configuration parameter to set the fill factor. This option is particularly useful for indexes that you do not expect to grow after they are built. For additional information about the FILLFACTOR option of the CREATE INDEX statement, see the Informix® Guide to SQL: Syntax.