Hi Eddie, This is actually some SAS JCL generated by a REXX, with "millions" of datasets allocated to the SAS input file and which can change "at the drop of a hat".
I'll give your suggestion some thought, it sounds interesting but I'm not sure how it will fit just yet. Best regards Peter Peter Bishop HP Enterprise Services Asia Pacific South Mainframe Capability & Engineering +61 2 9012 5147 office | +61 2 9012 6620 fax | peter.bis...@hp.com 36-46 George St | Burwood | NSW 2134 Australia -----Original Message----- From: Linux on 390 Port [mailto:linux-...@vm.marist.edu] On Behalf Of Eddie Chen Sent: Tuesday, 3 November 2009 3:57 AM To: LINUX-390@VM.MARIST.EDU Subject: Re: emulating a z/OS DDNAME dataset concatenation in Linux I don't know the program/applications is being used or you are running. what you can do in use the DDNAME as an environmental variable that points to the file name(dataset name)... You need to keep a list of dataset as the it complete the first it will update the environmental variable to point to the second dataset name. i.e MYDSN=/opt/data/dataset.name.one then change it to "two" From: John Summerfield <deb...@herakles.homelinux.org> To: LINUX-390@VM.MARIST.EDU Date: 11/02/2009 11:19 AM Subject: Re: emulating a z/OS DDNAME dataset concatenation in Linux Sent by: Linux on 390 Port <LINUX-390@VM.MARIST.EDU> Rob van der Heij wrote: > On Mon, Nov 2, 2009 at 5:02 AM, BISHOP, Peter <peter.bis...@hp.com> wrote: > >> To John M - yes, I was thinking in "z/OS" terms, where a single open of the DDNAME is sufficient for all the datasets in that DDNAME. >> >> To David, Ed and John S - the annoying thing about pipes here is that they incur extra I/O for the "cat" command, and since these files are very large (approx 20GB daily) this extra I/O will be very costly, probably excessively so here. >> Looks like I'm out of luck here, more thinking required. > > What extra I/O do you mean? When "cat" has multiple arguments, it will > open one file after the other, read them to end-of-file and write the > output to stdout. You can pipe that into your processing. If it's your > own application, you could make the application process a list of file > names. As far as I know this is similar to how MVS does extents. > You would have extra I/O when you had to compose the input file on > disk by appending all your input files. But in a lot of cases you can > make the program use stdin and take the data from the pipe. > > Rob I expect Peter's referring to writing and reading the pipes. In OS, the data goes from disk to buffers to program. Here, it would be going disk to buffers to cat to buffers(?) to pipe to buffers(?) to program. I think Peter should measure the performance, but I'm inclined to think he's right. When I suggested it, I didn't expect it to be "as good." If there's some useful preprocessing that could be done before the program, he could replace cat with a program that does that processing and reduce the overhead. -- Cheers John -- spambait 1aaaa...@coco.merseine.nu z1aaaa...@coco.merseine.nu -- Advice http://webfoot.com/advice/email.top.php http://www.catb.org/~esr/faqs/smart-questions.html http://support.microsoft.com/kb/555375 You cannot reply off-list:-) ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 Visit our website at http://www.nyse.com **************************************************** Note: The information contained in this message and any attachment to it is privileged, confidential and protected from disclosure. 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 dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify the sender immediately by replying to the message, and please delete it from your system. Thank you. NYSE Euronext, Inc. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
