Basic Question on SOA

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osuru75
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Basic Question on SOA

Post by osuru75 »

I have a Fully RTI enabled job.I deployed my job successfully to WISD. After the successful deployment, i see a new job in director always running.But i am wondering what is happening with this job and what is it doing while always running ? Because unless and until i invoke my web service, i don't see anything happening.
Thanks for your help//Subra
Subra Osuru
chulett
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Post by chulett »

It is "running" waiting for input, for the service to be called / invoked. Think of it like you in your car, sitting at a red light with your foot on the brake. Invocation is the green light and the road is the data it was sent to process... until you are done and stuck idling at the next red light. :wink:

I'm sure Ernie will be along with a better explanation shortly.
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ray.wurlod
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Post by ray.wurlod »

There are other analogies. I like that of the toll collector. Most of the time doing nothing but, when something comes along performs a small amount of processing (collecting the toll, maybe issuing a receipt) then, once that transaction has ended, going back to doing nothing till the next one comes along. Sure there are times when things are busy, which means that the "do nothing" times are fewer and/or briefer, and there are times when things are not busy. The model doesn't change, and the toll collector's base state of being is "do nothing".

Interestingly, and to extend the analogy, the toll collector does periodically have other things to do, such as reconciling the takings, taking mandatory breaks, and so on. Your WISD-enabled DataStage job can also periodically do other things (such as maintaining a log).
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eostic
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Post by eostic »

Keep in mind that being "always on" is a way to reconcile the start up overhead of ETL in the real-time space. ETL tools do a lot of work for you....they initialize connnections, they preload lookup tables into memory, they prepare and validate SQL, they authenticate connections, they initialize buffers....etc etc. etc. Important work that can take 1 second, or a minute or more. In batch, who cares, if that overhead allows you to process a few hundred gigabytes in a shorter window. In real-time, even 1 second is far too long. "Always on" allows the set-up to occur only once, so that each individual request, or message, is independently processed.

What happens while it is waiting? Not much, which is what you want.

However, that being said, you need to weigh the impact of that "always on" job on your machine. If you have a service that is only going to be called at the start of each day, and only for 10 clients (perhaps to initialize a price list), then having it "Always on" is a waste. "Always on" Jobs as Services are best when you are looking at 24 by 7 requirements and many requests per second.......

Ernie
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