Re: 7.x performance issue on DEC Alpha

Rakesh Mishra <rmishra@delphi.com> wrote: > >We are currently having some serious performance problems when using >7.x on DEC Alpha running Dec Unix 3.12B. > >We have two alphas. Alpha I runs the Informix database engine and >about 30 users and Alpha II runs about 150 users during peak time. >Both alphas have two CPUs each and about 1 GB of main memory and >2GB of swap space. The Alphas are 2100 model 4/275. > >Alpha II which basically runs our application for about 150 users works >fine. The load average hardly goes above 1 during peak times. > >Alpha I which runs similar 30 users and informix server has serious >performace problems and keeps on running out of CPU cycles. The load >average shoots up to 20-30 and them comes back quickly to 2-3 etc. Sometimes >it even goes upto 40-50 within seconds. > Are you running the same application on both Alpha 1 and Alpha 2 ? Have you checked to see if swapping is taking place on the unix side? (if so you may have the buffers set to high) Are you running update stats on Alpha 2 on a regular basis? What does your onconfig file look like? Check to make sure the temp dbspaces have the temp flag turned on? (onstat -d and look for the T flag on the tempdbspaces) Are the users accessing the database the same? Run the queries with set explain on to see what path they are taking. Make sure your update stats follows the guidelines in the performance and tuning manual. -- Tolly Brumbelow, Informix DBA email:tolly.brumbelow@bridge.bellsouth.com