RE: PDQ
PDQ makes a BIG difference on my sysytems when building indexes.
> ----------
> From: Sadagopan, Sathish, CFCTR[SMTP:sadagop0458@att.com]
> Sent: Monday, March 22, 1999 10:06 AM
> To: informix-list@iiug.org
> Subject: 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
> >
> >
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> > 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
> >
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> > <!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>
> > <p>Regards,
> > <p>Albert Wisse</html>
> >
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>