Thank you, Bret. A mistake. the column is varchar(600). The pagesize of ase is 2K.
Here is the output from my ase:
| 56 | Item dependent on page size : 2048 4096 8192 16384 | |
| 85 | Max index row-size, including row-overheads : 650 1300 2700 5400 | |
| 86 | Max user-visible index row-size : 600 1250 2600 5300 |