Long transaction and checkpoints

To any On-Line guru's We are currently running Online 5.05 on an NCR box and an AIX box, and we had both databases lock up under seemingly identical circumstances. A user started a long transaction, and the logs hit the threshold level(set at 60%), and the transaction starts to rollback. As the transaction is rolling back, the systems tries to write a checkpoint, is unable to, and the database basically stops with no activity. The tbstat -m looks like: RSAM Version 5.05.UC1 -- On-Line (CKPT REQ) (LONGTX) -- Up 10:05:46 -- 58304 Kbytes Message Log File: /usr/informix/log.ellie 05:28:53 Checkpoint Completed 05:34:14 Checkpoint Completed 05:37:51 Logical Log 548 Complete <<INFORMIX-OnLine>>> Logical Log 548 Complete 05:39:33 Checkpoint Completed 05:44:09 Logical Log 549 Complete <<INFORMIX-OnLine>>> Logical Log 549 Complete 05:44:54 Checkpoint Completed 05:50:13 Checkpoint Completed 05:50:53 Logical Log 550 Complete <<INFORMIX-OnLine>>> Logical Log 550 Complete 05:50:58 Checkpoint Completed 05:50:58 Aborting Long Transaction: tx 0x4000bad4 uid = 349 Informix's answer has been to re-boot the engine(standard fix). Has anyone else had this problem, or have any ideas that might shed some light on the issue? All answers are throughly appreciated. ===================================================================== Paul Watje Database Something or Another watjep@hasting.com Hastings Books, Music, & Video