in externals/kyuubi-flink-sql-engine/src/main/scala/org/apache/kyuubi/engine/flink/operation/GetColumns.scala [174:187]
private def getColumnSize(flinkType: LogicalType): Integer = flinkType.getClass match {
case c: Class[_] if c == classOf[TinyIntType] => 3
case c: Class[_] if c == classOf[SmallIntType] => 5
case c: Class[_] if c == classOf[IntType] => 10
case c: Class[_] if c == classOf[DateType] => 10
case c: Class[_] if c == classOf[BigIntType] => 19
case c: Class[_] if c == classOf[FloatType] => 7
case c: Class[_] if c == classOf[DoubleType] => 15
case c: Class[_] if c == classOf[DecimalType] => flinkType.asInstanceOf[DecimalType].getScale
case c: Class[_] if c == classOf[VarCharType] => Integer.MAX_VALUE
case c: Class[_] if c == classOf[BinaryType] => Integer.MAX_VALUE
case c: Class[_] if c == classOf[TimestampType] => 29
case _ => null
}