Problem asynchronous call activity in multi instance loop

Camunda 7 Topics Discussion & Questions
1

Hello,

It seems I have a problem. I don’t know if it’s a bug or a misunderstanding on my part.

I have a process in which I have a parallel multi instance loop fixed at 3 iterations (via loop cardinality).
in this loop I use a call activity. (see picture bellow)

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The process that is called has only one service task in asynchronous before. (see bellow)

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The problem is the loop is set to 3, my sub process is called 6 times (sometimes 4).

This problem is solved if the service task is either synchronous or the parallel multi instance is sequential.

Do you know what’s wrong?

Thanks!

2

So this is very likely due to the way that the multi-instance is re-synchronized with the process.
So - it’s possible that more than one thread want to complete it’s subprosses at the same time. Camunda will only let one thread be active on a single process instance in order to ensure consistency of state.
So - one of the threads is successful but he other one will be rolled back and then retry.

This can be fixed if you put an async before on the end-event. It will still rollback the transaction but it won’t re-run the code in the service task.

3

Thanks for the reactivity!
It works

4