attempting to map Dataset[Row]

[Stephen Fletcher]

I'm attempting to perform a map on a Dataset[Row] but getting an error on
decode when attempting to pass a custom encoder.
 My code looks similar to the following:


val source =
spark.read.format("parquet").load("/emrdata/sources/very_large_ds")



source.map{ row => {
      val key = row(0)

   }
}