Parallel branches are wrongly displayed in the Tracing UI and one step keeps running forevever

[fniu]

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Dify version

0.9.2

Cloud or Self Hosted

Cloud

Steps to reproduce

A set of parallel branches (1-B, 1-C and 1-D) comes at a Template node. Everythings works fine except for the UI, e.g., the Template node is missing for Branch-1-B, the steps for the Template node keeps running forever.

✔️ Expected Behavior

Every branch should end with the node "TEMPLATE", and should stop showing "Running" when the workflow is ended.

❌ Actual Behavior

Explained above and with a screenshot.

[dosubot[bot]]

I found a similar unsolved discussion regarding issues with parallel execution in the workflow. In version 0.8.0, there was a problem where the issue classifier was treated as a parallel execution branch, which might be related to the problem you're experiencing ^[1].

Regarding the Tracing UI, the structure and logic for displaying parallel branches are managed by the TracingPanel component. It uses a function buildLogTree to construct a tree of nodes from a list of NodeTracing objects. This tree structure is used to render the UI, and parallel nodes are displayed with a collapsible UI element ^[2].

For the issue of a node remaining in the 'Running' state indefinitely, I couldn't find specific conditions or errors that cause this. However, it might be related to how the platform handles the execution and termination of parallel branches, using events and a queue system to manage execution and status updates ^[3].

If the problem persists, it might be worth checking if there are any updates or patches available for version 0.9.2 that address these issues.

To continue talking to Dosu, mention @dosu.

[crazywoola]

Can you provide a minimal DSL for us to reproduce this issue.

[fniu]

After upgraded to 0.10.0, the same workflows run into another error:

Variable ans0 not found in variable pool

I suspect it has been fixed, by #9646. Could you confirm? (or I can re-check this issue when 0.10.1 is avaiable)

[fniu]

With 0.10.1, the error "Variable ans0 not found in variable pool" still exists. Could it be a synchronization issue at node "TEMPLATE", where ans0 and ans2 are not yet available (still running at the previous LLM steps) when ans1 has arrived? If this is the case, this issue could be closed because the UI seems OK.

[laipz8200]

I can't reproduce this problem. Can you try again to see if it can work properly?

[fniu]

@laipz8200

I can't reproduce this problem. Can you try again to see if it can work properly?

The error would show if you add knowledge retrieval for each branch before the LLM step. At least this is what happened to me. FYI, I see someone else has reproted the same issue in #9844.

[laipz8200]

Currently, the situation shown in the image is not supported. Deleting this branch can resolve the issue.