One Star

Passing data flow to tRunjob

Hi,
I'm new to Talend and I have a couple of questions regarding tRunjob.
I'd like to know if it's possible to pass a data flow to a tRunjob to compute, and if it is, what's the component used as an input in the child job.
Regards,
ml
15 REPLIES
One Star

Re: Passing data flow to tRunjob

Passing data to a client job is usually done with a context.
If you look at the component properties you can see that you can set context variables of your sub job. Before you do so you need to declare a context in your sub job.
You can for example dump your data into a file, communicate the file name to the sub job as context variable, open the file in your sub-job and process the data, store the output in a tBufferOutput, return the buffer to the parent job and continue the processing in your parent job with a flow from the job icon (the data comes from your buffer).
I think there is no interactive communication between parent and sub job. Does passing down the data fulfil your requirement?
One Star

Re: Passing data flow to tRunjob

Actually, I don't want to generate any temporary file. I've already thought about the context variables, but I want to use some components like tAggregate on the input flow in the subjob. So the link between the father and the child must be a data flow, it's like using a main row that will be between a component in the father job and the tRunjob.
One Star

Re: Passing data flow to tRunjob

Here is a little screenshot of what I want to do:

I want to split one huge Job into 2 jobs, with the upper part working as a father job and the lower one as a child Job. The splitting must be at the data flow coming from the filter.
Thanks for your time.
One Star

Re: Passing data flow to tRunjob

I can?t see your picture.
The parent job is not running when TOS is executing the sub-job (at least that?s my understanding) therefore I don?t see how you could establish a flow between them.
Sometimes I?m complicating things because I like to have them well organized. Are you sure it?s the best approach to split your work in two parts if the different parts need to talk to each other? Seeing your picture would probably answer my question. My firewall is very restrictive on displaying images, would it be possible for you to use the forum picture attachment functionality instead of in-text linkage?
One Star

Re: Passing data flow to tRunjob

One Star

Re: Passing data flow to tRunjob

My problem is that my firewall is blocking common image provider. I will not see your picture if it is hosted outside of the forum. Do you have seen the functionality to direct upload the image with your post?
One Star

Re: Passing data flow to tRunjob

Now that I'm logged-in, I have the option Smiley Tongue.
Here it is:
Community Manager

Re: Passing data flow to tRunjob

Hi All
The parent job is not running when TOS is executing the sub-job (at least that?s my understanding) therefore I don?t see how you could establish a flow between them.

Yes, Vaiko is right. The father job is not running when you execute the child job. Generally speacking, one job is created for one function and use servel tRunJob to run father job and all the chird jobs continuity. Spliting the function in different jobs is not stable and readable.
Best regards
shong
----------------------------------------------------------
Talend | Data Agility for Modern Business
One Star

Re: Passing data flow to tRunjob

Thanks for these answers. I was thinking about using a child job because I want to reuse the lower part of the job in other jobs, Is it possible by any means other than the unreliable copy/paste?
One Star

Re: Passing data flow to tRunjob

Your job looks quite complex.
What I did in the past was a data modification tracking job which is comparing data, line by line, for several databases and schemas. But I?m not sure it relates to your situation.
I stored the differences (mainly the sql queries) in a configuration file. I dumped the output of the queries into temporary files. After this generalisation I was able to code the job with only few components because the differences where encapsulated in the files. The processing sub-job was run as a loop for every line in the configuration file.
My personal feeling is that TOS jobs should use temporary files a lot. In some cases it really simplifies the job design and I think file processing is so fast that it may not worth to try to keep the data in memory.
Employee

Re: Passing data flow to tRunjob

Hello,
Since 2.3.0 and tBufferOutput, the son job can share data with his father.
You can also use tSocketInput/ tSocketOutput.
Regards,
One Star

Re: Passing data flow to tRunjob

You can use tSocketInput/ tSocketOutput for parent ? child communication?
My understanding was that when the child process is running the parent process can not process data at the same time.
Employee

Re: Passing data flow to tRunjob

tSocketInput/Output can be used for parent chid communication if used in addition of Multithreading.
These components are probably one of the major new functionality of TOS 2.3
Regards,
One Star

Re: Passing data flow to tRunjob

I'think some more advertising on new versions is needed :-)
One Star

Re: Passing data flow to tRunjob

Actually I took the context variables solution, I use a tFlowToIterate to transform the flow into and iteration and I store it into a context variable that I process into a child job that I call 2 times: one for each branch from the filter.
Thank you for your answers.
Regards.