The previous responders certainly know alot more about this stuff than I and I they mentioned all of the things to do. However, if I had to do just ONE thing, I would certainly pick the separation expansion to 4. The way I read it, the average group contains 1/3 of a logical record, so expanding the separation should reduce the reads even if they are cached. You'd also of course have to choose a modulus that would allow enough overall space.
On 10/17/07, Ross Ferris <[EMAIL PROTECTED]> wrote: > Sounds like the file may be V E R Y poorly sized, as Jeff F suggested > > Was this process "fast" previously? What has happened on the system > around the time it started to get slow? Are there any triggers on the > file > > Ross Ferris > Stamina Software > Visage > Better by Design! > > > >-----Original Message----- > >From: [EMAIL PROTECTED] [mailto:owner-u2- > >[EMAIL PROTECTED] On Behalf Of roy > >Sent: Wednesday, 17 October 2007 3:45 AM > >To: [email protected] > >Subject: RE: [U2] Size of Key Question > > > >Random reads and updates on a file with ~2 million records. I > separated > >the > >reads and writes to a separate program that only does this processing > to > >no > >avail. > > > >Topas shows 100% disk usage during this process and all other users are > >affected. > > > >-----Original Message----- > >From: [EMAIL PROTECTED] > >[mailto:[EMAIL PROTECTED] On Behalf Of Jeff > Fitzgerald > >Sent: Tuesday, October 16, 2007 1:14 PM > >To: [email protected] > >Subject: RE: [U2] Size of Key Question > > > >I wouldn't expect much difference in file access speed with long record > >keys versus short keys. What are you doing with the file that seems > >slow? -- i.e. random reads of individual records, updates, sequential > >selects and processing, etc. If the slowness is seen in an application > >program, are there other possibilities? Does the file have alternate > >keys or associated files that might be causing the slowness? Could > >locking be a bottleneck? Just for grins it would be interesting to see > >a FILE.STAT on the file. > > > >Jeff Fitzgerald > >Fitzgerald & Long, Inc. > >www.fitzlong.com > > > >-----Original Message----- > >From: Roy Beard [mailto:[EMAIL PROTECTED] > >Sent: Tuesday, October 16, 2007 12:17 PM > >To: '[email protected]' > >Subject: Size of Key Question > > > > > > > >Can someone comment on what effect if any the length of the key has on > >the speed of disk access? The software I am working with has one file > >with a complex key of 64 alpha-numeric characters and that file seems > >to be very slow no matter the modulo and sep or even file type I > choose. > >This is in UV > >10.2 Pick Flavor on AIX 5.3 > > > > > > > >Any insight would be appreciated. > > > > > > > >Thanks, > > > > > > > > > > > >Roy C. Beard > > > >Distributor Solutions Inc > > > >P.O. Box 110520 > > > >Palm Bay, FL 32911-0520 > > > > > > > >321-956-6500 > > > >501-642-8698 Fax > >------- > >u2-users mailing list > >[email protected] > >To unsubscribe please visit http://listserver.u2ug.org/ > >------- > >u2-users mailing list > >[email protected] > >To unsubscribe please visit http://listserver.u2ug.org/ > >------- > >u2-users mailing list > >[email protected] > >To unsubscribe please visit http://listserver.u2ug.org/ > ------- > u2-users mailing list > [email protected] > To unsubscribe please visit http://listserver.u2ug.org/ > -- john ------- u2-users mailing list [email protected] To unsubscribe please visit http://listserver.u2ug.org/
