Mainframe, MVS and zOS Discussion

Hi,

For a test SORT job I need to format a numeric field to make it negative. For that, I can think of two options, one is to multiply yhr fied with "-1" or subtractit from 0. In both the case which one is more efficeint and why, please let me know.

If I have to test such scenario my own what can I do to get a fair estimate on this?

how many billions of records do You have to process that would make any difference ?

Not billions of records are there but I shall have considerable amount of records, at least in millions. This job would be a daily job.

Even if you are processing 10 million records per day, that is only 3.65 billion per year. With the cycle time of the system Z machines, you might (and I stress MIGHT) make a few CPU seconds difference over the course of the entire year. You have already spent more time worrying about this than you could possibly save in several years or more.

...I can think of two options, one is to multiply the field by -1 or subtract it from 0.

You are not making a field negative You are just switching the sign

enrico-sorichetti wrote: ↑Thu Nov 09, 2017 9:02 pmYou are not making a field negative You are just switching the sign

But are not both mean same?

Sorry for a late reply.

But are not both mean same?

Not at all -- if the value is +10 and you multiply by -1 you have a -10; if the value is -10 and you multiply by -1 you have a +10. This is switching the sign. Making the field negative would be testing the value and if it is positive then multiply by -1; if the value is negative then don't do anything to it.

Robert Sample wrote: ↑Tue Feb 27, 2018 6:32 pmNot at all -- if the value is +10 and you multiply by -1 you have a -10; if the value is -10 and you multiply by -1 you have a +10. This is switching the sign. Making the field negative would be testing the value and if it is positive then multiply by -1; if the value is negative then don't do anything to it.

, never thought it that way. Thanks.