presto-main/src/main/java/io/prestosql/connector/system/jdbc/ColumnJdbcTable.java/ColumnJdbcTable/decimalDigits
class ColumnJdbcTable:    private static Integer decimalDigits(Type type)
    {
        if (type instanceof DecimalType) {
            return ((DecimalType) type).getScale();
        }
        return null;
    }