how "hour" function in Spark SQL is supposed to work?

[Serega Sheypak]

hi, desperately trying to extract hour from unix seconds

year, month, dayofmonth functions work as expected.
hour function always returns 0.

val ds  = dataset
  .withColumn("year", year(to_date(from_unixtime(dataset.col("ts") / 1000))))
  .withColumn("month", month(to_date(from_unixtime(dataset.col("ts") / 1000))))
  .withColumn("day",
dayofmonth(to_date(from_unixtime(dataset.col("ts") / 1000))))
  .withColumn("hour", hour(from_utc_timestamp(dataset.col("ts") / 1000, "UTC")))

  //.withColumn("hour", hour(dataset.col("ts") / 1000))
  //.withColumn("hour1", hour(dataset.col("ts")))
  //.withColumn("hour", hour(dataset.col("ts")))
  //.withColumn("hour", hour("2009-07-30 12:58:59"))

I took a look at source code

year, month, dayofmonth expect to get

override def inputTypes: Seq[AbstractDataType] = Seq(DateType)

hour function expects something different

override def inputTypes: Seq[AbstractDataType] = Seq(TimestampType)

from_utc_timestamp returns Timestamp

override def dataType: DataType = TimestampType

but It didn't help

What do I do wrong? how can I get hour from unix seconds?
Thanks!