Re: Database tuning.. any hints?

In article <jockcD07p3y.D0q@netcom.com>, jockc <jockc@netcom.com> wrote: >I'm very new to Informix and I'm trying to improve performance >for an Informix application we are running. The application is >Quintus and each process is consuming about 10 megs of virtual >memory on an HP 9000 server. Of the 10 megs about 6meg is private >data. Also the tbstat -p program reports about a 95-97% cache >hit rate on reads but less than 20% on writes.. I have BUFFERS >set at 1000, LOCKS is about the same, and the clean MIN/MAX values >(can't remember the parameter names) are 70 and 80.. I've made a >few changes as suggested by the ref manual tuning section and gotten >some improvement. Can anyone suggest anything I can do. Do I >need to provide more info about my tbconfig settings? ahh, Quintus... I cannot claim great expertise with either Quintus or Informix, but I can provide a few clues from my tuning experience. For Informix, you'll want to tune BUFFERS to be the amount of physical memory to devote to Informix. On our machine, I set it to about 60% of user memory as reported by Unix. All the other parameters are basically second-order effects after BUFFERS, except that you may also need to need to increase LOCKS also. Don't worry much about the poor performance on writes; they're noise compared to the number of reads Quintus does. For the Quintus X app, there's really only one answer: enough physical memory for everybody. We have perhaps 90 Quintus users, and 3 machines with 256M or more just to handle the X apps. If you have the X app on the same machine as Informix, you might need to configure Informix to be non-swappable so paging on the X apps doesn't drag Informix into the mud. I've not dealt with the Windows app. --john hood