System Error while querying Dremio in Power BI


I’m trying to query Dremio with Power BI, I managed to setup a working connection and to see the list of available schemas/tables but I can’t see the content of a table.
Power BI says that it can’t establish a secure connection even though I have deactivated this in the data source options.

In Dremio jobs I can see the query that was executed with a Failed status and the following error message :
SYSTEM ERROR: CompileException: Line 97, Column 30: No applicable constructor/method found for actual parameters "org.apache.arrow.vector.holders.UnionHolder"; candidates are: "public void com.dremio.exec.vector.complex.fn.JsonWriter.write(org.apache.arrow.vector.complex.reader.FieldReader) throws com.fasterxml.jackson.core.JsonGenerationException,"

Any help would be appreciated !

Best regards,

Hi @damiencoueron

This looks like a known issue. This may be caused because multiple files . Are you have different datatypes for columns with the same name. Are you trying to query a folder of Parquet files?

There are couple of workarounds you can do now

  1. Convert the heterogeneous data types on the parquet side to the same data type
  2. Cast the column to the desired data type and create a VDS and query the VDS from PowerBI

Note: This is only a ODBC/JDBC specific issue and this query would work when tried from Dremio UI