Re: Performance problems

In article <7j5kpc$kan$1@news.xmission.com>, Willaert Doris <doris.willaert@suzuki.be> wrote: > > System : IBM RS6000 model suz580 AIX v 4.2.1 (Single processor) (73.3 > Specint92 134.6 Specfp92) > Informix : Version 7.3 UD6 > > We upgraded 2 weeks ago from Online Version 5.05 to version 7.3. With > version 5.05 the performance was ok, but since the upgrade we have big > performance problems. We see that the CPU is heavely overloaded. (onstat -p) > When we run onstat -g rea we almost always see jobs waiting with vp- class > cpu. > > After reading the performance manual, we adjusted some of the ONCONFIG > parameters. We had some approvement, but we still have serious performance > problems. > > Our question now is if our system too small for IDS version 7.3 or do we > overlook something in the ONCONFIG parameters. > Oops ! Is this configuration of your production system ? It's poor. Here are some advises that definetily improve situation : 1.Have you issued UPDATE STATISTICS on your new system after upgrade ? This is critical to the query performance. Without this statement optimizer doesn't know where he must use index, and where he must scan table sequentially. 2. Add another CPU VP.You can do it by changing NUMCPUVPS to the desired value. To run with multiple CPU vp's you have to change SINGLE_CPU_VP to 0. To dynamically add another CPU VP enter this : onmode -p +1 CPU 3.Add more buffers. 2000 is too small. You need at least 10000. 4.Use forced residency if this feature is enabled in your platform and if you have enough memory available. This helps your system to avoid paging of resident segment. 5.Looks like poll thread runs on the CPU VP. Remove poll thread to NET VP. For example, if you're using soctcp, insert into ONCONFIG string like this NETTYPE soctcp,,NET6.Set OPTCOMPIND to 2. This will help optimizer to choose correct query pathes. Good luck ! Tell us if this help. -- With best regards, Yuri Dovgart, SAP R/3, Informix consultant, "Telecominvest" company. E-mail y_dovgart@tci.ukrtel.net Sent via Deja.com http://www.deja.com/ Share what you know. Learn what you don't.