Child logic app with split on does not communicate to parent logic app?

Question

Child logic app with split on does not communicate to parent logic app?

Divya venkatakrishnan 1

The child logic app with split on works as expected. But how does it pass the array to the parent logic app without the response step?. Because of this ,the parent logic app does not wait for the child to complete.

Please help.

Answer 1

MikeUrnun 5,761

Per the Note section here, SplitOn is not synchronous. So behind scenes, it'll create a separate Logic Apps instance per iteration of the array, and as each iteration starts processing, they will immediately send a response with 202 success code which is probably what's starting your parent workflow too soon.

If that appears to be the problem, I'd recommend adjusting the workflow steps just a bit to incorporate the use of For Loop with the sequential looping turned on: "Foreach" loop: Sequential

If you don't care about the order of sequence, on the parent Logic Apps side, you can try turning on the Asynchronous Pattern setting: Asynchronous request-response behavior

Divya venkatakrishnan 1 Reputation point

2021-02-22T23:06:47.143+00:00

Hi MikeUrnun ,

Thanks for the answer. However the main aim to create a child workflow is to reduce the processing time at the for each step.
So i think m approach to have a spliton at the child logic app to collect all the details in micro seconds and pass on to the parent logic app will not work.

My logic app has to processes several items at a time and hence the for each loop takes a good 12-13 secs . Do you suggest any other way to reduce it.

FYI. for each step accepts the array and formats it as xml to be accepted at the API step.
Divya venkatakrishnan 1 Reputation point

2021-02-22T23:32:15.523+00:00

Also Mike , If i dont want it to run sequentially ( because that takes time) , and if the setting is off, does it mean that it does parallel runs?
MikeUrnun 5,761 Reputation points

2021-02-23T00:20:01.247+00:00

Hi, @Divya venkatakrishnan - Oh I see, nesting is more for organizing large and complex workflows. With performance being the priority for your particular workflow, I definitely recommend using the For Loop as-is for processing your array iterations asynchronously. The key is to make your LA workflow aware that it is dealing with Asynchronous workflow (and how it has to wait for each iteration to complete their work) by turning on the Asynchronous Pattern setting for the Action/step that is processing the response from each iteration. I hope this helps. Feel free to let me know if you have any further questions, I'd be happy to help!
Divya venkatakrishnan 1 Reputation point

2021-02-23T01:00:37.567+00:00

@MikeUrnun yes, That is my major question.
When my child LA had a 200 response , it was able to return the array (looped) to the parent. But still took a long time. When i made the child as split on and ( removed the response step) as you said the parent completed before waiting for the child to complete.

Now how will i pass on the child LA's response to parent. Both the LA has " When HTTP request is received " as the first step. Should the child have HTTP Trigger?
Divya venkatakrishnan 1 Reputation point

2021-02-23T01:10:37.177+00:00

This is how it looks like now,
MikeUrnun 5,761 Reputation points

2021-02-24T04:05:16.833+00:00

@Divya venkatakrishnan Can you check if the Asynchronous Pattern setting (screenshot below) is turned on for your child workflow action? If you hit the 3 dots on the right (of the BBG API ORDER CREATE child action), a menu will appear and you'll want to go to the Settings to turn on the Asynchronous Pattern setting. Once that's done, your parent workflow should start waiting for all of the iterations that your child workflow may be running before moving onto the next action.

Asynchronous Pattern setting:
MikeUrnun 5,761 Reputation points

2021-02-26T22:21:13.893+00:00

Hi @Divya venkatakrishnan - I wanted to check in to see if you were able to get your Logic Apps workflow working?

Child logic app with split on does not communicate to parent logic app?

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