RE: PDQ

The number of scan threads to be used during the index build and the amount of memory used are affected by PDQ parameters,Aren't they ? Sathish Sadagopan -----Original Message----- From: Yerli, Gursoy [mailto:gursoy.yerli@tmssc.brooks.af.mil] Sent: Monday, March 22, 1999 9:53 AM To: 'wisse'; informix-list@iiug.org Subject: RE: PDQ Albert, PDQ has nothing to do with index creation. You can not optimize these kind of tasks with PDQ resources. Performance degration during index creation is a consequence of allacation of PDQ resources that is supposed to used by that process. You can de-allocate PDQ resources (while index creation) dynamically by onmode -D 0 that is onmode <max PDQ priority allowed> Gursoy YERLI TMSSC, Informix DBA Brooks AFB, TX > -----Original Message----- > From: wisse [SMTP:wisse@kabelfoon.nl] > Sent: Monday, March 22, 1999 3:22 PM > To: informix-list@iiug.org > Subject: PDQ > > > --------------89105C2EC6E19702FDEFD42E > Content-Type: text/plain; charset=us-ascii > Content-Transfer-Encoding: 7bit > > I noticed a performance decrease instead of a performance increase > when > using PDQ with creating indexes. > > The create indexes are done one/with: > > * Informix 7.23.UC6 on Solaria 2.5.1. > * System: SUN E4000 with 6 CPU's and 5.3 GB internal memory. > * Informix has four CPU, NOAGE is set, AFFINITY is set for all 4 > Informix CPU's. > * Tables are fragmented round robbin on two dbspaces. > * Indexes has their own dbspace and disk/diskchannel > * All dbspaces are on raw devices > > During the creations of indexes nobody is using the system. When using > PDQ the index creation takes around 10% longer. That is not what I > want. > > Monitoring onstat -g mgm tells me hat I have PDQ resources enough. And > other measurements show me that the system has plenty of resources > left. > > The question is this a feature of Informix 7.23.UC6 or do I something > wrong. > > > Regards, > > Albert Wisse > > --------------89105C2EC6E19702FDEFD42E > Content-Type: text/html; charset=us-ascii > Content-Transfer-Encoding: 7bit > > <!doctype html public "-//w3c//dtd html 4.0 transitional//en"> > <html> > I noticed a performance decrease instead of a performance increase > when > using PDQ with creating indexes. > <p>The create indexes are done one/with: > <ul> > <li> > Informix 7.23.UC6 on Solaria 2.5.1.</li> > > <li> > System: SUN E4000 with 6 CPU's and 5.3 GB internal memory.</li> > > <li> > Informix has four CPU, NOAGE is set, AFFINITY is set for all 4 > Informix > CPU's.</li> > > <li> > Tables are fragmented round robbin on two dbspaces.</li> > > <li> > Indexes has their own dbspace and disk/diskchannel</li> > > <li> > All dbspaces are on raw devices</li> > </ul> > During the creations of indexes nobody is using the system. When using > PDQ the index creation takes around 10% longer. That is not what I > want. > <br>Monitoring onstat -g mgm tells me hat I have PDQ resources enough. > And other measurements show me that the system has plenty of resources > left. > <p>The question is this a feature of Informix 7.23.UC6 or do I > something > wrong. > <br>&nbsp; > <p>Regards, > <p>Albert Wisse</html> > > --------------89105C2EC6E19702FDEFD42E--