Xpath node failing with error: Encountered duplicate row ID "Row0_1_4_1_1"

I am parsing a XML which has complex and inconsistent hierarchy. So in my Knime workflow I am using multiple Xpath nodes, concatenate nodes and so on.

Workflow was running fine until I added additional two additional xpath nodes to further parse two xml columns from previous output one followed by other. Second node is failing with following error:
ERROR XPath 0:64 Execute failed: Encountered duplicate row ID “Row0_1_4_1_1”

I checked in output of previous xpath node and there is only one row with Row0_1_4_1_1 id. It has however ? in the column which I have used as xml source column in a xpath node which is failing. Could that be the reason? How can I avoid this error? What is the purpose of row id? Why would duplicates matter for xpath?

Sharing snapshot of node configuration below:

Hi @ddnyaneshwar,

Is it possible for you to provide a workflow with a sample data set which reproduces the error?


Hi Armingrud,

Please find the workflow and sample xml attached.

Use the RowID node and the problem is solved.



That helped Armin. Thank you! What is the purpose of RowID?

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Creating Row IDs?!.. :sweat_smile:

You can create new row IDs, use the values of a column as the row IDs or copy the current row IDs to a new column.


Sorry for not being specific. I meant to ask what is the purpose of rowID which is generated by concatenate node. In my case it was not required and causing error so I was curious why would knime create it in the first place.

The nodes are working fine. I think the problem is that you had a row ID “row0_1_4_1” and a row ID: “row0_1_4_1_1” and operating on the former row creates a row ID with the same ID as the latter one. So the node throws an error.

I’m not 100% sure about this but I’m pretty sure the Concatenate node is working fine.


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Okay, thanks Armin! :slight_smile:

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