On Sun, Apr 3, 2016 at 6:28 PM, Andrew Rowley <[email protected]> wrote:
> The reason I like Java on Z so much is I got used to using Hashtable in > C#, then tried to use Rexx stems to do the same thing. (It was semi > successful but I always felt like it was very fragile due to the potential > for unexpected values etc. for the stems.) Then I found Java had real hash > tables. They make so many different problems so much easier. > > A million 1500 byte entries should be about 1.5 GB I think, and I would > expect a hashmap to handle it without difficulty as long as the real > storage was available. But typically a hashtable would hold an object with > the specific items you're interested in rather than the whole 1500 byte > item. > Yeah, my arithmetic is really bad. > As for sorting a List of a million 1500 byte items - again I would expect > Java to do this without difficulty as long as real storage is available. > Java is actually pretty efficient at this because you're actually sorting a > list of pointers - you go all over memory to do the compares Hum, just a concern or mine (it may be obsolete), would be the working set in memory of doing that. z/OS, even on our small shop, is probably running 8 other batch jobs, 5 TSO users (we're small), and 7 CICS regions. I'd worry about sizing the real memory on the LPAR if all 8 jobs were "going all over memory". But, again, I have a very small z9BC system, so I worry about things that the big boy would sneer at. > , but should be only shuffling 8MB of data in storage if you have a > million 64 bit pointers. I regularly test EasySMF (written in C#) > displaying lists of 1,000,000+ items on the PC. It has column click > sorting, and it copes just fine with 1,000,000+ lists. Sorting a column > takes a few seconds at most on a not particularly fast PC. > > DFSORT seems to be most useful where you need to sort more data than can > be processed in storage - but I'm wondering how often that really needs to > be done. I'm not so interested in utilities and databases calling it under > the covers - more in applications that require records in a particular > order. Nor am I saying that's wrong - I'm really just asking whether > languages like Java provide opportunities to eliminate some sorting. > You have a good point about using SORT directly. Let the thing in the infrastructure use sort, like SQL "ORDER BY" or other things. Of course, it would be easier in our shop to do this if the COBOL language had a hashing facility built into it. Most of our code is COBOL and a CA product called EasyTrieve. We don't have any "fancy" or "up to date" languages like Java, Python, Ruby, Go, ... insert others ... . Took me a while to write and I had to rewrite a number of times when my current bitterness about things at work got to be too much. I'm going to go watch some ALF and "Get Smart" episodes to cheer up. > > > -- > Andrew Rowley > Black Hill Software > +61 413 302 386 > -- How many surrealists does it take to screw in a lightbulb? One to hold the giraffe and one to fill the bathtub with brightly colored power tools. Maranatha! <>< John McKown ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
