Performance problems in Informix 7.11

Hi all We have a large Informix application with primarily 4GL (and some ESQL/C = code) running on a HP-T500 2 processor machine. The Online engine = version is 7.13 and the operating system is HP-UX 10.10. The database is = replicated onto a similar box. The replication is HDR and synchronous. The system performs well for upto 50 users, but begins to slow down = drastically for 90-100 users. There is very little disk i/o and network = i/o. What we see is a large number of lock requests, lock waits and some = deadlocks (13 in 4 hours). We think it is a concurrency problem, so we have tried to scan our = sqexplain.out files and have tried to reduce sequential scans wherever = possible. We have also tried bumping up the oninit priority with rtprio = which I suspect works the same at the Unix level as NOAGE in Informix. = System performance has improved but not dramatically. We now perform = adequately with around 70-80 users. We are targeting at around 500-600 = simultaneous users.=20 We would appreciate any suggestions that will help us wring more = performance out of the system. Thanks in advance Sujit Pal DBA, CSC Intellicom