Должен ли я использовать постоянство или изменить операцию groupBy?
def joinTests(measurements: DataFrame): DataFrame = {
val df_joined = df.join(measurements, Seq("part_id"))
logger.info(df_joined.count + " elements found!")
val df_keep = df_joined.groupBy(col("name"))
.agg(countDistinct(col("value")).as("count"))
.filter(col("count") > 1)
.select(col("name"))
.dropDuplicates
df_joined.join(broadcast(df_keep), Seq("name"))
}