Memory problems with 7.12UC1 and Dec Unix 4.0a

I have a serious problem with On-line Dynamic Server 7.12UC1 running on Dec Unix 4.0a. The system has 128 megs of physical memory and Informix is running it into the ground after about 4 hours of operation. The scenario is as follows: I have an Alpha running the database server. There is one database on the system with 14 tables in it. One of the tables has about 500 records in it, the rest no more than about 20 or so records. The big table is static, the data in it virtually never changes. The other tables change constantly, with all the data turning over at least daily. The whole thing is running behind a Web server running Livewire/Netscape Enterprise Server on a seperate machine. The Web server establishes 3-4 connections to the database which remain open as long as the system is up. The problem is Informix just grows without bound. While a ps -Al will show perhaps 10-20 megs in use between the various oninits which are running, vmstat shows a system totally starved of virtual memory, as does the system log, and the online.log file. At this point Informix stops processing queries due to insufficient virtual memory and must be shut down. Downing and reupping Informix restores the system to normal operation. I just don't understand this. The system has only a very small amount of data in it, and the number of queries being made seems modest, probably on the order of a few hundred per hour. Some of the queries are 2 and 3 table joins, but I really can't see that this is in any way a demanding application. I have yet to see CPU use exceed 2%, and its only a 166mhz system, not a high-end machine. Obviously there is a bug or configuration problem here! I would really appreciate anything anyone could tell me about this problem. I'm a software guy, not a DBA, so maybe this problem has an obvious solution and I don't know it? Thanks in Advance. Tod Harter Director of Internet Development Rhombus Communications, Inc. tharter@intake.rhombus.net