Informix C-ISAM performance on SCO

I was wondering if anyone knew of a serious downgrade with Informix C-ISAM performance once a program hit a certain point while building a database. I have a program running on SCO Openserver 3.2v4.2 and C-ISAM v4.00.UE1 . It was first created back in Feb. 1995, and ran well for quite a while. It used to take about 5 or 6 hours to create my database. Now, it takes 3 or 4 DAYS to create the database. There's LOTS of data, and the program is recursive. Basically, I used an unsigned char as well as the data to be displayed as the key to the database which contains a record consisting of the following: struct record{ unsigned char number[12]; // record number char data[6]; //the data to be displayed on the screen unsigned char answer; // the value to be put on the end of the key if the user chooses this choice. } All it basically is that the user chooses one of the choices on the screen, and once that choice is chosen, the value in 'answer' of tacked on the end of the 'number' field, and another lookup is done, which produces another set of choices, and so on until the end of the tree is reached, and the user has his answer. Well, I have a file with the following properties: 1 key length 18 key type is string no dups leading and trailing compression key is not segmented. The last time the program worked 'normally', I ended up with 1.2 million records. I now have over 1.3 million records, and has been running from 10/29 at 12:17pm , and it is now 10/30 9:23 am, and it still needs to run about 40,000 records and is still slowing down. I can understand the slow down in performance, but have I hit some type of upper boundary that the program begins to CRAWL in the database build? Any insights would be appreciated. Thanks, Joe Schofield joes@keycomp.net