> DFSORT has the capability of using memory (real and auxiliary storage) and if > it runs out of it, it will then use disk workspace.
Hi Sri, I understand you can't share the inner workings any more than what's documented in docs. >From the few tests I've seen, it seems that DFSORT prefers hiperspaces over >memory objects or real memory. MEMLIMIT and REGION are decent enough, size-wise, but DFSORT doesn't seem to touch MO at all; goes directly to Hiperspace. Assume I have MOSIZE=MAX already.. - KB ------- Original Message ------- On Monday, July 3rd, 2023 at 9:58 PM, Sri h Kolusu <skol...@us.ibm.com> wrote: > > > I will only get the primary space of 5000 cylinders, and the other > > > 14x2000 cylinders is never used. Is that right? > > > Billy, > > No. Incorrect. DFSORT will make use of BOTH primary and secondary space > allocations ( 1 primary + 15 Secondary) for a total of 16 extents. So if you > allocated 1 sortwk dataset with (CYL,(5000,2000)), then DFSORT would use 5000 > + 15* 2000 = 5000 + 30000 = 35,000 cylinders. Also note that the secondary > extents will only come into picture ONLY when needed. > > > > Is there a written explanation I can forward to the programmers so they > > > understand this? > > > Also (since I know it will come), is there any good way to calculate how > > > much DASD sortwork would be used? I know this depends on what is in > > > memory at the time, but want to get a better handle on how Sort > > > determines what it needs. > > > I would suggest that you use DFSORT's Dynamic Allocation as it will allocate > the required workspace optimally rather than programmers calculating it. The > reason is you don't want to change the allocation every time there is an > increase/decrease in the number of records to be sorted. > > Having said that, here is a general formula that you want to use. > > The amount of sortwk space required depends on the size of the file. It > usually ranges from 1.3X to 1.8X of the size of the file to be sorted > depending on the sorting path that DFSORT chose. > > Filesize = Number of records * Avg length of the record ( for Fixed length > RECFM=F or FB , it is the LRECL value, or RECFM=V or RECFM=VB is the average > length of the record) > > However, that range is applicable ONLY when the entire file is being sorted > using Disk workspace. DFSORT has the capability of using memory (real and > auxiliary storage) and if it runs out of it, it will then use disk workspace. > > > Thanks, > Kolusu > > ---------------------------------------------------------------------- > 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
