Alex Tough asked:

> If you have all or most of the cluster allocated to a DLF data 
> object, why would BLSR be faster ?

It might depend on what you mean by "faster"...

Note that nowadays a DLF (or any) hiperspace would be backed by central 
but would still require a more distant data movement. And, in principle, 
VSAM LSR (whether via BLSR or not) ought to be in the job's own address 
space. So, in CPU terms I'd speculate that BLSR might cost less CPU. That 
probably wouldn't turn into elapsed time differences that were measurable 
- but it just MIGHT.

Another thing to remember, though, is that Hiperbatch keeps the memory 
"pro bono publico" whereas BLSR doesn't. The affordability of Hiperbatch 
may be much greater for CONCURRENT jobs. In the same vein with multiple 
BLSR jobs each job would have to populate the buffer pool itself. So 
initially you might get a lot of misses.

All a long-winded way of saying "YMMV". :-)

Cheers, Martin

Martin Packer
Performance Consultant
IBM United Kingdom Ltd
+44-20-8832-5167
+44-7802-245-584
[EMAIL PROTECTED]










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