Incorrect Index Selection on Informix 5.08 / HP-UX 10.20

We have had a problem on a system where a major table needs to be updated when creating orders. Informix seems to get confused, and selects an incorrect index resulting in 2 hour update times and excess resource usage. We investigate the problem using explain, and are unable to confirm what starts the problem although the user suspects it occurs after an update statistics. This is run daily now so that may not be correct. The system ran fine on friday but the problem occured today. Any Ideas Shaun -- ----------------------------------------------------------------------- | Shaun Mumford | P O Box UA 325 | Phone + 263 4 739944 | | Systems Consultant | Union Avenue | Fax + 263 4 704946 | | C F Tulley Associates | Harare, Zimbabwe | Cell + 263 4 11 600 920 | -----------------------------------------------------------------------