How can I optimize my code so as to run faster

Question

I am writing a code that can fetch some data Via API but it needs a Parameter called Item id which is stored in my database. Code is working fine I am getting what type of output I want but the issue is it is taking more time(it is not fast).

there are two functions

1. Function Item_id to fetch Item_Id from the database which I have already in my SQL server.

2. Main function which calls Item_id function to fetch Item_id's from the database. these Item Id's are used as a parameter in API query to fetch serial numbers for the serial numbers for that particular Item_id.

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Data;
using System.Data.SqlClient;
using System.Net;
using Newtonsoft.Json;


namespace ConsoleApp2
{
    class serial_connected_to_Database
    {
    /**************************************************
     * Properties to convert Json output to C# objects
     * ***********************************************/
       #region Properties
       public class SerialNumber
       {
           public string serialnumber_id { get; set; }
           public string serialnumber { get; set; }
           public string status { get; set; }
       }

       public class PageContext
       {
            public int page { get; set; }
            public int per_page { get; set; }
            public bool has_more_page { get; set; }
            public string sort_column { get; set; }
            public string sort_order { get; set; }
       }

       public class RootObject
       {
            public int code { get; set; }
            public string message { get; set; }
            public List<SerialNumber> serial_numbers { get; set; }
            public PageContext page_context { get; set; }
       }
       #endregion

    /***********************************************************
     * Main program to fecth serial Numbers based on the Item_id
     * specified in the API
     ***********************************************************/
       public static void Main()
       {
            string strResponse = string.Empty;  //to collect json Data
            DataTable dataTable = Item_Id();    //fetching item id from function Item_id
            foreach (DataRow dr in dataTable.Rows) 
            {
                Console.WriteLine(dr["col_item_id"]+"Serial numbers for particular Item id are given below");
                int k = 1; //variable to navigate to different pages
                while (1 > 0)
                {
                /****************************************************************
                 * Requesting API with item id as parameter
                 * *************************************************************/
                    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(@"https://books.zoho.com/api/v3/items/serialnumbers?per_page=200&item_id=" + dr["col_item_id"] + "&organization_id=***********&page=" + k);
                    request.Method = "GET";
                    request.Headers.Add("Authorization", "*************************");

                    using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
                    {
                        if (response.StatusCode != HttpStatusCode.OK)
                        {
                            throw new ApplicationException("Error code in response recieved: " + response.StatusCode.ToString());
                        }

                        using (Stream resStream = response.GetResponseStream())
                        {
                            if (resStream != null)
                            {
                                using (StreamReader streamReader = new StreamReader(resStream))
                                {
                                    strResponse = streamReader.ReadToEnd();
                                }
                            }
                       }
                   }
                   string Jsoncontent = strResponse;

                /***************************************************************
                 * Deserializing Json Data into C# objects
                 * ************************************************************/
                    RootObject root = JsonConvert.DeserializeObject<RootObject>(Jsoncontent);
                    if (root.serial_numbers.Count != 0)
                    {
                        for(int i = 0; i < root.serial_numbers.Count; i++)
                        {                           
Console.WriteLine(root.serial_numbers[i].serialnumber);
                        }
                    }
                    else
                    {
                        break;
                    }
                    k = k + 1;
                    Console.WriteLine("Page= " + k);
                }
            }
        }

    /******************************************************************************
     * Function to return Item id which is stored in Database 
     * ***************************************************************************/
        public static DataTable Item_Id()
        {
            SqlConnection cnn = new SqlConnection(@"Data Source=************;Initial Catalog=*************;User ID=*******************;Password=*************");
            cnn.Open();
            DataTable dataTable = new DataTable();

            string Query = "select col_item_id from tbl_Zoho_Items_data";

            SqlDataAdapter DA = new SqlDataAdapter(Query, cnn);
            DA.Fill(dataTable);
            return dataTable;
        }
    }
}

It takes a lot of time while executing please help me with some best way use write or any best practices.

Answer 1

A lot of the work is being done by external services - both HTTP requests and database queries. You cannot meaningfully optimise your code until you understand where the time is being spent - it may be that you cannot improve things because the bottlenecks are outside your application, but you cannot know that unless you profile your application, and/or mock out the external services. Get yourself a trial of a profiler and find out what your application is really doing - you'll learn a lot more that way.

Answer 2

I think it would be better to use DataReader other tan DataTable and to use Async methods for connections and for posting or you can get a list of items and you parallel.for method inside an async method I think this would more faster

I think like this one would be better and faster please test it and tell me

        /******************************************************************************
 * Function to return Item id which is stored in Database 
 * ***************************************************************************/
    public static async Task<IEnumerable<string>> Item_Id()
    {
        var items = new List<string>();

        using (var cnn = new SqlConnection(@"Data Source=************;Initial Catalog=*************;User ID=*******************;Password=*************"))
        {
            await cnn.OpenAsync().ConfigureAwait(false);
            var Query = "select col_item_id from tbl_Zoho_Items_data";

            using (var command = new SqlCommand(Query, cnn))
            {
                using (SqlDataReader reader = await command.ExecuteReaderAsync().ConfigureAwait(false))
                {
                    while (await reader.ReadAsync().ConfigureAwait(false)) items.Add(reader["col_item_id"].ToString());
                }
            }

            return items;
        }
    }

    /***********************************************************
 * Main program to fecth serial Numbers based on the Item_id
 * specified in the API
 ***********************************************************/
    public static async Task Main()
    {
        string strResponse = string.Empty; //to collect json Data
        IEnumerable<string> items = await Item_Id().ConfigureAwait(false); //fetching item id from function Item_id

        Parallel.ForEach(items, async item =>
        {
            Console.WriteLine(item + "Serial numbers for particular Item id are given below");

            var k = 1; //variable to navigate to different pages
            while (1 > 0)
            {
                /****************************************************************
                 * Requesting API with item id as parameter
                 * *************************************************************/
                var request = (HttpWebRequest) WebRequest.Create(@"https://books.zoho.com/api/v3/items/serialnumbers?per_page=200&item_id=" + item + "&organization_id=***********&page=" + k);
                request.Method = "GET";
                request.Headers.Add("Authorization", "*************************");

                using (var response = (HttpWebResponse) await request.GetResponseAsync().ConfigureAwait(false))
                {
                    if (response.StatusCode != HttpStatusCode.OK) throw new ApplicationException("Error code in response recieved: " + response.StatusCode.ToString());

                    using (Stream resStream = response.GetResponseStream())
                    {
                        if (resStream != null)
                            using (var streamReader = new StreamReader(resStream))
                            {
                                strResponse = await streamReader.ReadToEndAsync().ConfigureAwait(false);
                            }
                    }
                }

                string Jsoncontent = strResponse;

                /***************************************************************
                 * Deserializing Json Data into C# objects
                 * ************************************************************/
                var root = JsonConvert.DeserializeObject<RootObject>(Jsoncontent);
                if (root.serial_numbers.Count != 0)
                    foreach (SerialNumber serial in root.serial_numbers)
                        Console.WriteLine(serial.serialnumber);
                else
                    break;

                k++;
                Console.WriteLine("Page= " + k);
            }
        });
    }

Answer 3

you can try Applying cache technique in web api code. meaning, You will have to call db only if cache will not be available. you will get sample everywhere.