Unique Tool Outputting Zero Records to U-Anchor

[kelsey_kincaid]

Hi Everyone,

I ran into a problem recently that I cannot figure out. I have approximately 500 records that flow into a Unique tool that is configured to find unique values in all columns. When this workflow ran on Gallery it was writing zero records. I pulled it down to investigate the issue and the Unique tool was outputting zero records to the U (Unique) anchor, which theoretically should never happen. I tried replacing the Unique tool with a Summarize tool configured to 'Group By' every column and it output zero records also. 

The workflow runs correctly if we copy the whole thing into a new empty workflow but I would like to understand what happened so that we can take steps to prevent it from recurring. Does anyone know what might have been the issue?

Unfortunately, I am unable to share the exact workflow or data and cannot recreate the issue using dummy data.

[BrandonB]

Is it possible that a workflow file asset was packaged up with the workflow to the server that didn't have any records? This would result in the server referencing the packaged file rather than reaching out to the network location on runtime. 

[kelsey_kincaid]

@BrandonB No, I don't think so. I can see in the workflow that there are 500 records going directly into the Unique/Summarize tools and then zero records from the U anchor, so I do not think it is an issue with any of the data sources

Example: 

[BrandonB]

Were you using the AMP engine by chance? Can you send an email to support@alteryx.com? I wouldn't expect this behavior either, but it isn't something I have ever come across.