Re: 'Multi-threading' and RPG

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

Stephen,

I haven't tested threadsafety in YAJLINTO.   Skimming over the code very 
quickly, I don't see anything that wouldn't be threadsafe... but, 
without thorough testing, its hard to be certain.

Its also hard to tell whether making it multi-threaded would have any 
impact on performance.   Your description didn't mention multiple 
consumers, so I assume you're looking to reduce the total time of 
processing all of your documents.  With that in mind, whether 
multi-threaded access would be faster or not would depend on your 
hardware.  So this is really hard to predict.

I did write an article on multi-threaded programming in RPG back in 
2012.  I think it was published in System iNEWS or iPro Developer.  I 
don't remember the specifics, and that stuff isn't online anymore.

I believe the ILE RPG Programmer's Guide has a multi-threaded example, 
though.

I want to add...   multi-threaded programming is complicated and 
requires a great deal of expertise.  The reason you see so little in 
terms of examples is because its very unusual for it to offer any 
benefits in a business application.  There's very little reason to write 
examples.  If you want to spend a month studying it, plus an extra month 
in debugging your application for threadsafety...  you might get 
something out of this.  But, why would you do that when you can simply 
submit multiple jobs?

Really the place where it has added benefit is when you have a single 
program that needs to have multiple simultaneous consumers that need to 
share resources between them.  But, who does that in RPG?  Indeed, its 
unusual in ANY environment unless you're writing something like a web 
server or other network application server.



On 8/20/2020 11:51 AM, Stephen Piland wrote:
> Does anyone have a real world example of this?  A link or anything?
>
> I'm trying to decode a very large number of element JSON using DATA-INTO and it using YAJLINTO as the %parser.  Each file on the IFS is one transaction/message and can have over 3k individual elements.  Each message has 2 big blocks of elements split about 50/50.  Each half of the message end up writing out to separate group of PFs.  Can I process each half simultaneously and not have to submit a ton of separate jobs?  Just trying to speed the process.
>
> Any thoughts would be appreciated!  Thanks!