Extended checkpoint times

Hi, We are trying to investigate a series of overly long checkpoints on one of our informix databases, here is a snippet of the online.log file detailing the events: 21:16:55 Checkpoint Completed: duration was 76 seconds. 21:22:04 Checkpoint Completed: duration was 6 seconds. 21:27:16 Checkpoint Completed: duration was 8 seconds. 21:40:15 Checkpoint Completed: duration was 476 seconds. 21:45:29 Checkpoint Completed: duration was 10 seconds. 21:50:36 Checkpoint Completed: duration was 2 seconds. 21:55:42 Checkpoint Completed: duration was 3 seconds. 22:03:22 Checkpoint Completed: duration was 155 seconds. In general we have checkpoint times around the 6-7 second region, but recently we've seen several occurances were informix goes catatonic on us whilst doing a 400 second checkpoint! Are there commands available to analyze the log files to see which sql statements were running upto when the checkpoint took place - or if you know of anything that could cause these kinds of checkpoint times that would be useful. From the informix manual it states checkpoints wait for critical code sections to complete before it can complete so in theory if an application hung for whatever reason inside a critical code section it could hold up a checkpoint - forever? or until informix decided the application was not responding? Thanks in advance, Mark