Can a query be sent from within a workflow to another workflow?

Community Support
1

Hi Temporal Community,

TLDR
Can a query be sent from within a workflow to another workflow just like signal?

Details
I am working on a service which has 1 parent workflow and multiple child workflows. The parent workflow needs to fetch the intermediate progress (as a float number) from each child workflow and update the value accordingly.

We tried to use query handler at first, but from the temporal doc and google search, it seems a query can only be sent from a temporal client (aka outside of workflow). In our use case, we want the query to be sent from parent workflow so that a child workflow can receive it and return its progress.

We make it work via signal. But we still wonder if it’s possible to use query as it will be more straightforward and good to learn.

Any thoughts?

Thanks,
Shi

2

It is not cleanly supported at this point. I would love to add some sort of global CRDT counter to Temporal service in the future.

As a workaround I would recommend a query that returns the list of child workflow ids and then query all these children for the progress independently from the external client.

3

Thank you @maxim !

Just took note that it’s not supported as of now. For the workaround, we are able to use signal to implement this feature and it’s working well so far.