Re: How does the i handle programs in memory using different methods?

On 7/20/2015 5:18 PM, Kurt Anderson wrote:

I was trying to go a best practices route with a consideration of procedures being called on the high end of 40 million times in a job run. I can add it to my list to test, although I'm always concerned about other active jobs impacting a test run.

I have processes like that, and all of them are I/O bound. In my
experience, IBM i is really good at handling memory, and it's got much
better with newer machines, where the base, minimum memory is greater
than it used to be.

Alan's concern about static variables comes from the need for IBM i to
preserve static storage when another process wants that physical memory.
At that moment, IBM i needs to write that page to DASD, and at some
future time, read it back. Imagine the same exact program running in a
dedicated pool where IBM i never needs to swap it out. No performance
penalty. Then there's the real life machine which isn't dedicated, but
does partial paging.

This is why measuring is so important. What runs poorly on my
constrained memory pool may run great on your big, dedicated pool.
Generic advice is... well, generic.