hung process

Hello, I am using informix online 7.2 over SCO Unix. I frequently notice that there are a lot of hung process. Specifically, I saw that two process were eating up nearly 100 % cpu time (a pentium biprocessor) as seen with vmstat or cpusar. Both of them had huge ammounts of cpu time as by ps. The two processes turned out to be dbaccess sessions, which had 1 as parent process, but did not belong to root, just to normal users. They could be seen from onstat also. Killing them solved the cpu usage problem. However, such process tend to appear frequently. Any suggestions? TIA Oscar Goldes