When it is set at the default of TRUE, A_SYB_ADD_IDENTITY adds an extra column to any table created by the Acu4GL for Sybase product. The extra column has identity property and is included on all indexes that are not unique.
When A_SYB_ADD_IDENTITY is set to FALSE, an extra column is not added. While the default value is FALSE (OFF, NO), this configuration variable can also take values of TRUE (ON , YES).
On keys that allow duplicates, this variable has been found to vastly improve performance. Note that the default value is TRUE for a file that allows duplicates, and is FALSE for a file with no duplicate keys.