You're getting a "logic assert" error meaning that an internal process is failing an expected logic check and doesn't necessarily mean you are running out of memory or other system resources.
That Java error likely isn't enough info to determine what's wrong. You likely would find additional details in the Tableau Prep logs.
- Close out all instances of Tableau
- Navigate to the My Tableau Prep Repository in your Documents folder
- Rename the "Logs" folder to "Logs.old"
- Launch Tableau Prep and perform the desired functions
- When Tableau Prep throws an error, note the time and steps went through to get the error
- Review Tableau Prep logs from that time period to see what additional info is available
If you cannot determine the issue, these logs can be useful when engaging Tableau tech support.
Thanks reaching out with your question! Tableau Prep doesn't allow you to copy and past steps or flows across files. From your description it seems you are trying to replace the tables that are included in your union. Try this:
- Right click on the branch that leads to the union for the input step you are trying to remove
- Click 'Remove'
- Take the new table and drag it to the Union Step. Drop it on the 'Add' target.
Let me know if this helps! If copying and pasting steps or diagrams across files is something that is important for your workflow, we would love to hear more about it in the ideas forum.
I will need to try your approach to removing the existing inputs. Right now, if I click on the existing inputs and select "remove", Tableau Prep hangs on me. As I mentioned in my original email, after a few minutes, Tableau Prep goes to a white screen and effectively hangs. Compared to OpenRefine, the open source tool I used, Tableau Prep is wonderful. But I tend to crash fairly frequently with Tableau Prep. Next time it occurs, I will send the log files via the support channel.
As for copying nodes, I had already placed this in the Idea forum. I can not imagine not wanting to copy nodes. Right now, I am building my flow using multiple clean nodes that each have a specific purpose. I can easily see wanting to copy nodes that you have created to be used in another flow. It may not be the way you look at the software, but I think of Tableau Prep as a form of "object oriented programming" with the nodes being designed for "reusability". I think it would be great if eventually users could upload their own specialized nodes for others to use.