Portal | Manuals | References | Downloads | Info | Programs | JCLs | Mainframe wiki | Quick Ref
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Profile Log in to check your private messages Log in
 
Query on BLSR

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM
View previous topic :: :: View next topic  
Author Message
Nileshkul

New User


Joined: 09 May 2016
Posts: 16
Location: India

PostPosted: Sat Aug 13, 2016 5:18 am    Post subject: Query on BLSR
Reply with quote

Please help with a query on BLSR:
I have a 20 threads for a job running paralally. A VSAM file which has 20 copies used by 20 threads. That means each thread has dedicated copy file of VSAM.
NOW the same VSAM is using BLSR in all threads which I doubt why. Because each thread has it's own copy, there us no sharing of vsam copy file across threads or any other job. Will BLSR degrade performance in this case, Please suggest.
Back to top
View user's profile Send private message

Robert Sample

Global Moderator


Joined: 06 Jun 2008
Posts: 8188
Location: East Dubuque, Illinois, USA

PostPosted: Sat Aug 13, 2016 8:05 am    Post subject:
Reply with quote

BLSR improves performances for random access of VSAM data sets (you do NOT have a "VSAM file" -- you have a VSAM data set; the only "files" on z/OS are on tape or in Unix System Services and neither of these can be VSAM). If the data set is being read sequentially, then BLSR won't improve performance (and may make it worse). Notice that the number of threads does NOT factor into whether or not BLSR can improve performance -- only the amount of sequential versus random processing.
Back to top
View user's profile Send private message
Nileshkul

New User


Joined: 09 May 2016
Posts: 16
Location: India

PostPosted: Sun Aug 14, 2016 12:48 am    Post subject: Thanks
Reply with quote

Got it now, thanks
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
No new posts Query on IEFBR14 with GDG Ashishpanpaliya JCL & VSAM 3 Tue Nov 07, 2017 8:34 pm
No new posts Query on XMITIP abdulrafi All Other Mainframe Topics 1 Wed Oct 25, 2017 6:54 pm
No new posts HEX value search in a DB2 query maxsubrat DB2 2 Wed Oct 04, 2017 3:04 pm
No new posts Create procedure issues -628 when add... chandraBE DB2 1 Mon Sep 18, 2017 12:16 pm
No new posts Can we limit length in concatenation ... balaji81_k DB2 7 Tue Aug 22, 2017 2:50 am

Facebook
Back to Top
 
Job Vacancies | Forum Rules | Bookmarks | Subscriptions | FAQ | Polls | Contact Us