My first job in IT had me working on a fairly new application that was designed around an ISAM master file. Shortly before going live, it was discovered that the data center billed application business units for I/O but not for memory usage. So a quick change was instituted to read the entire ISAM file into virtual storage at startup and process it there. I don't know what the savings amounted to, but it was certainly an example of nudging people in an unexpected--and probably unwanted--direction.
. . J.O.Skip Robinson Southern California Edison Company Electric Dragon Team Paddler SHARE MVS Program Co-Manager 323-715-0595 Mobile 626-543-6132 Office ⇐=== NEW [email protected] -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Cameron Conacher Sent: Friday, October 26, 2018 9:01 AM To: [email protected] Subject: (External):Re: SORT not behaving consistently About a hundred years ago I ran into a similar sort issue. Parallel runs in our pre-production environment did not have sequence matched sort outputs. I chased several threads. EQUALS made things match but there is a cost. Apparently it was related to sort work DASD. Knowing I could make it right with EQUALS was good enough. It was the only way to guarantee a sequence of records with matching sort keys. Since I considered the final matching key sequence random I just did not care enough to use EQUALS to force a matching sequence. Sent from my iPhone > On Oct 26, 2018, at 11:35 AM, Seymour J Metz <[email protected]> wrote: > > Be careful what you measure; people will optimize in ways that you didn't > anticipate and don't want. What affects perfolrmance is the working set, and > a large region is not synonymous with a large working set. > > > -- > Shmuel (Seymour J.) Metz > http://mason.gmu.edu/~smetz3 > > ________________________________________ > From: IBM Mainframe Discussion List <[email protected]> on > behalf of Paul Gilmartin > <[email protected]> > Sent: Thursday, October 25, 2018 5:06 PM > To: [email protected] > Subject: Re: SORT not behaving consistently > >> On Thu, 25 Oct 2018 20:36:58 +0000, Jesse 1 Robinson wrote: >> >> OK, I'm simmering down. Here's my concern: I own the SORT product; I own the >> CEC; I own the DASD. If I change any of those things and the user's output >> differs, then I'm on the spot to explain why. The explanation may not be >> difficult, but if a user presses with 'why didn't you tell us this would >> happen', I'm on the defensive for an outcome I can't control or even >> anticipate. I don't like being on the defensive. You don't score points on >> defense even if you survive to battle another day. OK, I'm done. >> > I was once a user of a site that had a chargeback policy and tried > (desperately) to make the charge for any job repeatable, regardless of > background system load, to avoid "Why didn't you tell us this would > happen?" Impossible. For example, who pays for paging I/O? If you > don't charge for it, you're motivating prodigal REGION use. They > seemed to have the misguided idea that making the formula complicated > enough would make it repeatable. > > -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
