RE: PDQ Advice Please

For a OLTP instance and doing large queries and update's, setting PSORT_NPROC and PSORT_DBTEMP are a better way to use the parallel processing features in Informix IDS or even 5.x instances. Check that out, before doing down the PDQ path. Wayne E. Martin Informix Database Administrator Kmart Corp. -----Original Message----- From: Obnoxio The Clown [mailto:obnoxio@hotmail.com] Sent: Tuesday, March 07, 2000 4:25 AM To: aef@mfs.misys.co.uk; informix-list@iiug.org Subject: Re: PDQ Advice Please From: "Tony Flaherty" <aef@mfs.misys.co.uk> > >Hp-Ux 10.20 >IDS 7.30.UC7 > >We have a OLTP set-up with occasional large queries/updates running during >the day. I've not paid that much attention to the PDQ settings previously >:o/ I thought it was disabled. However I've started reading up on it in >the >hopes that I can use it to reduce the impact of the bigger update programs >that are run. > >My current ONCONFIG params for PDQ are; > >MAX_PDQPRIORITY 100 # Maximum allowed pdqpriority >DS_MAX_QUERIES # Maximum number of decision support>queries >DS_TOTAL_MEMORY # Decision support memory (Kbytes) >DS_MAX_SCANS 1048576 # Maximum number of decision support scans> >NOTE that there is no entry for PDQPRIORITY, TFM indicates that there >should be an entry for this and it should be zero. Is this the default >since there isn't one, is my manual out of date or is my instance >configured >incorrectly? PDQPRIORITY is now controlled with an SQL statement or an environment variable. >A MAX_PDQPRIORITY of 100 appears to be bad! is it? From my understanding >of >TFM I would of thought if PDQ was active on my machine I would be having >real problems with the above settings. Nope, it means that you are prepared to allocate 100 % of PDQPRIORITY % of PDQ resources to any given PDQ query. >If I set PDQPRIORITY to zero in the ONCONFIG and then assign values to the >other PDQ parameters, do they have any effect? I think it will ignore PDQPRIORITY in the onconfig. >Also, am I correct in saying that I can modify my heavy process >(Informix-4GL) so that it issues a SET PDQPRIORITY stmnt to reduce its >impact on the system. If so can you recommend a % to use? or indeed any >other methods of reducing its impact, I was toying with the rather >inelegant >idea of placing a SLEEP 1 in an appropriate place :o(. I don't think 4GL supports that syntax, I'd go for setting the PDQPRIORITY environment variable. But there is a fundamental problem here: if your 4GL is a record-oriented, line-at-a-time kind of program, PDQ probably won't help. :) ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com

Ok, thanks for the info, I've had a quick look at my manuals, don't CD based manuals suck! I take it that these env. variables are for the process running the SQL not the process running the oninit -- --------------------------------------- Tony Flaherty aef@mfs.misys.co.uk Analyst Programmer Misys Financial Systems All statements and opinions are my own, Misys don't pay me enough to have opinions on their behalf . Martin, Wayne E. wrote in message <8a387c$l9t$1@news.xmission.com>... > > >For a OLTP instance and doing large queries and update's, >setting PSORT_NPROC and PSORT_DBTEMP are a better way >to use the parallel processing features in Informix IDS or >even 5.x instances. Check that out, before doing down >the PDQ path. > >Wayne E. Martin >Informix Database Administrator >Kmart Corp. > > > > > >-----Original Message----- >From: Obnoxio The Clown [mailto:obnoxio@hotmail.com] >Sent: Tuesday, March 07, 2000 4:25 AM >To: aef@mfs.misys.co.uk; informix-list@iiug.org >Subject: Re: PDQ Advice Please > > >From: "Tony Flaherty" <aef@mfs.misys.co.uk> >> >>Hp-Ux 10.20 >>IDS 7.30.UC7 >> >>We have a OLTP set-up with occasional large queries/updates running during >>the day. I've not paid that much attention to the PDQ settings previously >>:o/ I thought it was disabled. However I've started reading up on it in >>the >>hopes that I can use it to reduce the impact of the bigger update programs >>that are run. >> >>My current ONCONFIG params for PDQ are; >> >>MAX_PDQPRIORITY 100 # Maximum allowed pdqpriority >>DS_MAX_QUERIES # Maximum number of decision support>>queries >>DS_TOTAL_MEMORY # Decision support memory (Kbytes) >>DS_MAX_SCANS 1048576 # Maximum number of decision support scans>> >>NOTE that there is no entry for PDQPRIORITY, TFM indicates that there >>should be an entry for this and it should be zero. Is this the default >>since there isn't one, is my manual out of date or is my instance >>configured >>incorrectly? > >PDQPRIORITY is now controlled with an SQL statement or an environment >variable. > >>A MAX_PDQPRIORITY of 100 appears to be bad! is it? From my understanding >>of >>TFM I would of thought if PDQ was active on my machine I would be having >>real problems with the above settings. > >Nope, it means that you are prepared to allocate 100 % of PDQPRIORITY % of >PDQ resources to any given PDQ query. > >>If I set PDQPRIORITY to zero in the ONCONFIG and then assign values to the >>other PDQ parameters, do they have any effect? > >I think it will ignore PDQPRIORITY in the onconfig. > >>Also, am I correct in saying that I can modify my heavy process >>(Informix-4GL) so that it issues a SET PDQPRIORITY stmnt to reduce its >>impact on the system. If so can you recommend a % to use? or indeed any >>other methods of reducing its impact, I was toying with the rather >>inelegant >>idea of placing a SLEEP 1 in an appropriate place :o(. > >I don't think 4GL supports that syntax, I'd go for setting the PDQPRIORITY >environment variable. > >But there is a fundamental problem here: if your 4GL is a record-oriented, >line-at-a-time kind of program, PDQ probably won't help. :) >______________________________________________________ >Get Your Private, Free Email at http://www.hotmail.com