IBM Mainframe Forum

Hello,

Can anybody please let me know where do i can find any document for improving the syncsort performance. I have been browsing thru forums i did find some
post that helped me, but can anybody throw me a light where do i start frist.

I ran a job with B message , this is what i found


6,904K BYTES OF VIRTUAL STORAGE AVAILABLE, MAX REQUESTED,
0 BYTES RESERVE REQUESTED, 6,096K BYTES USED
12K BYTES OF EMERGENCY SPACE ALLOCATED
SORTIN : RECFM=VB ; LRECL= 504; BLKSIZE= 32760
5,876K BYTES OF VIRTUAL STORAGE AVAILABLE ABOVE THE 16MEG LINE,
0 BYTES RESERVE REQUESTED, 5,860K BYTES USED

Thanks
Anand

There is nothing useful there. Can you post the full sysout from the step? Why do you think it needs tuning?

In general, you will be able to impact sort performance only slightly no matter what you do. The sort products are already highly optimized. Ensure you have plenty of memory (the short snippet you posted implied a lack of memory), plenty of sort work space, and your sort performance will be pretty much as good as you're going to get.

Mmmm

This section is for DFSORT, not SYNCSORT. In any event, Mr. Sample's observations are probably as good as you're going to get, regardless of whether you're running DFSORT or SYNCSORT. I'm far from a sorting expert, but

1. Keep the number of keys to a minimum.
2. Do not, if possible, specify packed decimal keys.
3. Specify the number of records as close to the actual number of records as possible.

Hello,

One way to reduce the runtime is to make sure that only needed data fields are being sorted. Many times an entire file is sorted when only a few fields from each record and only some of the records need to be sorted.

You may not have control over the input, but possibly improving the input blksize can help. Same with the output - make sure that a proper blksize is used.

Hello,

What version of Syncsort ? Whats the Z/OS version ? MFX manual for programmers has lots of pointers related to Performance like passing BMSG or GMSG, Usage of Virtual Storage etc..

Jaggz