Re: Weird one

Hello Art, may be you see a lot of unnessary physical logging??? you could try to create a dbspace called mydbs1 create the table and load. then drop the table, drop the dbs mydbs1. then zero the device used by mudbs1 (dd if=/dev/zero of=.... ) so there are no initialized pages. then add the dbspace again, create the table, dotheload.. Superboer. On 25 sep, 02:51, "Art Kagel" <art.ka...@gmail.com> wrote: > <Cross posted to CDI & IDS Forum> > > OK, an oddity for you. I'm doing some performance and tuning testing using > multiple copies of dbload. > > I'll tell you what I'm dealing with. Anyone with any idea as to why the > engine is behaving as it is please pipe in. > > Platform: Linux 2.6.9-67.ELsmp, x86-32 with 2 single core 3.4GHZ processors, > single disk spindle for IDS another for the OS > IDS Vers: 10.00.UC8 > > OK, so I'm getting reasonable timings running various numbers of load > clients against the engine with 1, 2, 4, 6, & 8 CPU VPs truncating the table > between runs. > > I notice in TOP that at some point in the run IO Wait goes way up and CPU > consumption way down for 10-30 seconds then back to 'normal'. I figure, > "Oh! Extends are being added." So after completing the set of timing runs > I change the script to drop and recreate the table with an extent size > sufficient for the loaded data in the initial load instead of the truncate > and run the tests again expecting to see that the runtimes have decrease by > 10-20 seconds per run. NO! the runtimes INCREASED by 16 to 64 seconds! > > Yes, I checked that there was indeed still a single extent the size of the > initial extent size allocation after each load. > > Any ideas as to why this should be? > > -- > Art S. Kagel > Oninit (www.oninit.com) > IIUG Board of Directors (a...@iiug.org) > > Disclaimer: Please keep in mind that my own opinions are my own opinions and > do not reflect on my employer, Oninit, the IIUG, nor any other organization > with which I am associated either explicitly or implicitly. Neither do those > opinions reflect those of other individuals affiliated with any entity with > which I am affiliated nor those of the entities themselves.