If I'm not mistaken, FDR has an ENQ/NOENQ option. You decide which you can tolerate in your situation.
-----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Clark Morris Sent: Monday, February 15, 2021 7:24 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: [EXTERNAL] Re: question on enqueues CAUTION! This email originated outside of the organization. Please do not open attachments or click links from an unknown or suspicious origin. ====================================================================== [Default] On 15 Feb 2021 15:37:38 -0800, in bit.listserv.ibm-main rpomm...@sfgmembers.com (Pommier, Rex) wrote: >I have one that's puzzling me and I'm sure there's a simple solution/answer. >I'm seeing 2 jobs running on a single system that are hitting an enqueue >problem on a parmlib. The JCL in both jobs has DISP=SHR, yet one of the jobs >has an exclusive ENQ on the library. Here's the scenario: > I suspect the flash process does an exclusive ENQ on all data sets being flashed. Clark Morris >Job A is a system backup job. It does a bit of early processing, then runs an >FDRFlash of most of our disk, then runs FDR to back up the offline volumes >created in the flash as well as some volumes that weren't flashed. Once the >backup step is done (3 hours later) it does some more post backup processing. >There are 3 steps in the post processing that allocate this parmlib, all >allocating the same member - call it A.B.C.PARM(MEMB), all with DISP=SHR. > >Job B is a cyclical job that runs in a matter of a few seconds and runs every >5 minutes. It also has A.B.C.PARM(MEMB) DISP=SHR as well as A.B.C.PARM(MEMZ) >DISP=SHR in a different step. > >Timing: > >Job A started and was doing its preliminary work. >Job B started and ended successfully. >Job A does the flash step and starts the full volume dumps. >Job B comes along again and can't start because job A has an exclusive ENQ on >A.B.C.PARM. Job B does not start until job A has completed the last step with >A.B.C.PARM in the JCL. > >A couple other points are that A.B.C.PARM is on a volume that was flashed, so >the source volume wasn't part of the backup. The job steps in both jobs with >A.B.C.PARM in them are all conditional steps that actually didn't execute. > >So my question is what could have caused an ENQ change from SHR to OLD when >the JCL explicitly has SHR? > >TIA, > >Rex > >The information contained in this message is confidential, protected from >disclosure and may be legally privileged. If the reader of this message is >not the intended recipient or an employee or agent responsible for delivering >this message to the intended recipient, you are hereby notified that any >disclosure, distribution, copying, or any action taken or action omitted in >reliance on it, is strictly prohibited and may be unlawful. If you have >received this communication in error, please notify us immediately by replying >to this message and destroy the material in its entirety, whether in >electronic or hard copy format. Thank you. > > >---------------------------------------------------------------------- >For IBM-MAIN subscribe / signoff / archive access instructions, send >email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
