> -----Ursprungligt meddelande----- > Från: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] För Paul > Gilmartin > Skickat: den 2 juli 2010 15:40 > Till: IBM-MAIN@bama.ua.edu > Ämne: Re: SV: Delete all members of a PDS that is allocated > > On Fri, 2 Jul 2010 13:26:41 +0200, Thomas Berg wrote: > >> > > >> >How ? The "shut the door" job is *waiting* for EXCL ENQ (OLD). > >> > > >> As I read it, "shut the door" never completes its wait. So > >> you don't know how many other jobs may have previously > >> allocated the data set SHR, opened it, done BLDLs, and not > >> yet closed it. They are holding TTRs which will point to > >> unpredictable content once you compress (w DISP=SHR). > > > >(The "STD" job is cancelled by the compress job when it's finished.) > >Yes, a couple of other jobs has opened the pds and if they haven't > >finished their update it may theoretically cause local corruption > >in the pds. But I have never experienced that, maybe because of the > >30 seconds wait I do before beginning the compress. > > > I was concerned less with directory corruption than with the harmful > effect on other DISP=SHR jobs already running. > > >And of course, this is in a test environment. > > > Ah! So you don't care if a few jobs fail. I, also, often operate > in that mode.
Well, I do care, but it's not a very big problem if it happens and, as mentioned, in practice it very seldom do. > >BTW, the "STD" is not a problem in this case, the only potential > >problem is the compress (job). > >And if You are worried You can always wait until all jobs that may > >have opened the pds are finished before You start the compress. Then > >there is no problem anymore regarding the risk ds corruption. > > > IOW, simply submit a compress job with DISP=OLD. I sometimes do > that, too. Then the operators telephone me to complain about the > flood of MIM ENQ messages on the console, and to relay complaints > from other testers attempting to allocate the data set. The problem with the DISP=OLD compress job is that some jobs that enques the pds could be running VERY long time after the access to the pds due to unrelated (but valid/correct) causes. (And with DISP=OLD You are placed behind all other jobs that are *waiting* for the enq.) Regards, Thomas Berg _________________________________________ Thomas Berg Specialist A M SWEDBANK ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
