Author: Robert Sample
Posted: Thu Oct 06, 2016 10:18 pm (GMT 5.5)
I've seen plenty of VSAM KSDS with 4K data CI size and less than 3584 index CI size that did not waste space -- I think the manual is being very conservative in its recommendation.
For a data set with growth, a balanced set of values for the primary and secondary space makes sense -- you'll be doing splits anyway. However, for a fixed-size data set which is NOT going to grow, allocating all the space in one extent makes sense -- why have multiple extents if not needed?
_________________
TANSTAAFL
The first rule of code reuse is that the code needs to be worth re-using.
"We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil." -- Donald Knuth
Posted: Thu Oct 06, 2016 10:18 pm (GMT 5.5)
I've seen plenty of VSAM KSDS with 4K data CI size and less than 3584 index CI size that did not waste space -- I think the manual is being very conservative in its recommendation.
For a data set with growth, a balanced set of values for the primary and secondary space makes sense -- you'll be doing splits anyway. However, for a fixed-size data set which is NOT going to grow, allocating all the space in one extent makes sense -- why have multiple extents if not needed?
_________________
TANSTAAFL
The first rule of code reuse is that the code needs to be worth re-using.
"We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil." -- Donald Knuth