> -----Ursprungligt meddelande----- > Från: IBM Mainframe Discussion List [mailto:[email protected]] För Paul > Gilmartin > Skickat: den 1 juli 2010 21:59 > Till: [email protected] > Ämne: Re: Delete all members of a PDS that is allocated > > On Thu, 1 Jul 2010 19:38:40 +0200, Thomas Berg wrote: > > >> -----Ursprungligt meddelande----- > >> Från: IBM Mainframe Discussion List [mailto:[email protected]] För > Paul > >> Gilmartin > >> Skickat: den 1 juli 2010 18:26 > >> > >> On Wed, 30 Jun 2010 17:51:40 +0200, Thomas Berg wrote: > >> > >> >When I have needed to compress a PDS that was in frequent/continuous > use, > >> >e g a target load library in test env, I use a command/rexx that > submits > >> >a job which begins with submitting another job that has the pds > allocated > >> >with DISP=OLD. This as a way to "shut the door" behind. Then it > waits > >> >typically 30 seconds where after it starts the compress (w DISP=SHR). > >> >And in the last step cancels the "shut the door" job and ends. > >> >Something along this could be used as a way to minimize problems when > >> >deleting members. > >> >I have never had any problems with this approach. > >> > > >> You're lucky. It will also "shut the door" on jobs that have the > >> data set open, and have done BLDLs, and may subsequently use TTRs > >> that point to trash. > > > >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. And of course, this is in a test environment. 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. Regards, Thomas Berg _________________________________________ Thomas Berg Specialist A M SWEDBANK ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
