David, The use of DD DUMMY in a concatenation ends the processing of input data. The following is from the JCL Reference Manual:
Data sets concatenated to dummy data sets: The system treats data sets concatenated to a DUMMY data set as dummy data sets in that I/O operations are bypassed. However, the system performs disposition processing and allocates devices and storage for any concatenated data sets. So, in your example you only read the file once. Without the DD DUMMY it would read the file twice. Chris Blaicher Principal Software Engineer, Software Development Syncsort Incorporated 50 Tice Boulevard, Woodcliff Lake, NJ 07677 P: 201-930-8260 | M: 512-627-3803 E: [email protected] -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Jousma, David Sent: Tuesday, February 04, 2014 8:45 AM To: [email protected] Subject: Re: Dummy dataset No, we have users sorting data with path names as input. Just ran a test. Single path input, concatenated, all work fine, unless they add a DD DUMMY between them. As a side note, DFSORT doesn’t do a good job with dynamic sortwk allocations with PATH input because it cannot accurately determine the input filesize. I had opened a ticket with IBM on this, and all I got was "this is the way it is". My only option was to tell my developers to hardcode sorkwk datasets in their job. //DFSORT EXEC PGM=SORT //SORTIN DD PATHDISP=KEEP, // PATHOPTS=ORDONLY, // FILEDATA=TEXT, // RECFM=VB,LRECL=255,BLKSIZE=25496, // PATH='/etc/httpd1443.conf' // DD DUMMY // DD PATHDISP=KEEP, // PATHOPTS=ORDONLY, // FILEDATA=TEXT, // RECFM=VB,LRECL=255,BLKSIZE=25496, // PATH='/etc/httpd1443.conf' -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Paul Gilmartin Sent: Tuesday, February 04, 2014 8:37 AM To: [email protected] Subject: Re: Dummy dataset On Thu, 30 Jan 2014 20:18:05 +0000, Jousma, David wrote: >We have an exit for DFSORT that scans TIOT to see if someone concatenated a >DUMMY dataset as input. Here is what I believe to be the relevant snippet of >code: > ... >* CHECK FOR DUMMY DD STATEMENT >* NOTE: COULD ALSO BE DD * >DDCHK CLC TIOEFSRT,=AL3(0) Q. REAL UCB ADDRESS ? > BE DDBAD A. NO, BAD DD > ... > How does this behave for DD PATH=...? Is the UCB address nonzero for zFS files? Are you unwittingly prohibiting use of zFS in the SORTIN concatenation? That would be imprisoning your users in the twentieth century. Prohibiting "DD *" is also unduly harsh. A similar question applies to Shmuel's suggestion of DEVTYPE. The definitive test should be for DSNAME='NULLFILE'. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN This e-mail transmission contains information that is confidential and may be privileged. It is intended only for the addressee(s) named above. If you receive this e-mail in error, please do not read, copy or disseminate it in any manner. If you are not the intended recipient, any disclosure, copying, distribution or use of the contents of this information is prohibited. Please reply to the message immediately by informing the sender that the message was misdirected. After replying, please erase it from your computer system. Your assistance in correcting this error is appreciated. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ________________________________ ATTENTION: ----- The information contained in this message (including any files transmitted with this message) may contain proprietary, trade secret or other confidential and/or legally privileged information. Any pricing information contained in this message or in any files transmitted with this message is always confidential and cannot be shared with any third parties without prior written approval from Syncsort. This message is intended to be read only by the individual or entity to whom it is addressed or by their designee. If the reader of this message is not the intended recipient, you are on notice that any use, disclosure, copying or distribution of this message, in any form, is strictly prohibited. If you have received this message in error, please immediately notify the sender and/or Syncsort and destroy all copies of this message in your possession, custody or control. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
