Except that IBM COBOL only provides us with the ability to give a record to the SORT during INPUT PROCEDURE processing, requiring us to use COBOL I/O to read the records to be massaged and then sorted, whereas a true E15 exit gets the records read from SORTIN by the sort itself passed to it, and then decides what to do with each record -- use the one given, insert another in its place, or delete it. Similar logic is required in the COBOL OUTPUT PROCEDURE, which only gets records back from the SORT, and must write them out using only COBOL I/O facilities, whereas a true E35 exit can give the record back to the SORT and let SORT use its own I/O facilities to write out the sorted and massaged record.
There may be some potential for decrease in CPU time for true E15/E35 exits which would come from taking advantage of the SORT's own optimized I/O facilities, but that is just a theory which I have not tested. Other replacements for COBOL SORT processing discussed in this thread do certainly seem to be almost guaranteed to increase rather than decrease CPU consumption, if only from the increase in the number of passes that must be made over the data. And paying attention to optimizing SORT's control parameters both on a shop-wide and particular-application level seems likely to produce some benefits without any program restructuring at all. Thanks to all who participated in this discussion. I appreciate the help. Peter -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Staller, Allan Sent: Monday, December 02, 2013 9:16 AM To: [email protected] Subject: Re: Has anyone measured CPU savings using external SORT's vs. internal (COBOL) SORT's? Sorry about the late reply. The last time I seriously looked, the COBOL sort verb invoked the installation sort (DFsort, SYNCSORT,....). The COBOL program effectively became the E15/E35 sort exits. On that basis, I would not expect any significant difference in CPU time consumed, *AND* as someone previously noted, a possible significant increase in elapsed time. HTH, <snip> It has been suggested to management here that there could be potentially significant CPU savings from re-engineering application programs such that any SORT's are done in a separate step, so that a program with a single internal SORT would be broken up into a pre-SORT process followed by an external SORT of the massaged data followed by a post-process of the SORTed data. </snip> -- This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
