How to Take advantage of a multi-processor system using informix?

How to Take advantage of a multi-processor system using informix? Do I have to make some special configuration in the Informix Database Engine to achieve the best performance from a dual processor system? Thanks, NSM (Portugal)

"S. Martins" wrote: > > How to Take advantage of a multi-processor system using informix? > Do I have to make some special configuration in the Informix Database Engine > to achieve the best performance from a dual processor system? If you only have two processors then IDS does not take good advantage of the second processor. IDS works best with three or more CPUs. HOWEVER, that does not mean it takes NO advantage of the second CPU or that IDS does not have to be tuned for this environment. The main tuning needed is to make sure that processor affinity is NOT used (AFF_NPROCS and AFF_SPROCS should be zero), MULTIPROCESSOR is 1, NUMCPUVPS is 1, and set SINGLE_CPU_VP appropriately (if you want to experiment with adding a second or third CPU VP on faster {>400MHZ (for SPARC or PA/RISC) or >500MHZ for ix86} CPUs dynamically using onmode -p leave it set to zero otherwise performance will be a bit better with SINGLE_CPU_VP set to 1). Art S. Kagel