快速测试显示 EF 核心与 ADO.Net 相比存在很大差异

Question

I am reading that the EF core performance is improved and is almost as fast as ADO.NET and decided to create a simple test. The results I got, show huge difference. ADO.NET was 10 times faster.

I am posting here the code I used to test. Is there something wrong with my test? Steps taken:

Reverse engineer a database using Scaffold-DbContext. Get one record from one table:

using (var db = new TestFECore.Models.AchieveDB_EncryptContext())
{
    var watch = System.Diagnostics.Stopwatch.StartNew();
    var disbursement = db.Disbursement
                         .Where(c => c.CashOutid > 999 && c.CashOutid < 2001)
                         .First();

    Console.WriteLine(disbursement.DisbursementId.ToString()); 

    watch.Stop();
    var elapsedMs = watch.ElapsedMilliseconds;
    Console.WriteLine("Time elapsed:" + elapsedMs.ToString());

    var dis = new TestFECore.Models.Disbursement();
    var ds = new DataService();

    watch = System.Diagnostics.Stopwatch.StartNew();
    dis = ds.GetDisbursements();

    Console.WriteLine("Cashoutid from regular ado.net " + dis.DisbursementId.ToString());
    watch.Stop();

    elapsedMs = watch.ElapsedMilliseconds; 
 }

Here is the GetDisbursements code

 public  Models.Disbursement GetDisbursements()
      //   public List<Models.Disbursement> GetDisbursements()
      {

         Models.Disbursement disbursement = new Models.Disbursement();
         using (System.Data.SqlClient.SqlConnection connection = new System.Data.SqlClient.SqlConnection("Data Source=*******; etc"))
         {
            string commandString = @" The exact SQL created by the EF ";
            SqlCommand command =
                new SqlCommand(commandString, connection);
            connection.Open();

            SqlDataReader reader = command.ExecuteReader();


            while (reader.Read())
            {

               disbursement.DisbursementId = (int)reader["DisbursementId"];

            }


            reader.Close();

         }
            return disbursement;
      }

Here are the results:

Core 3.0 Testing!
Querying Disbursments
1498
Time elapsed:2138
Using regular ado.net
Cashoutid from regular ado.net 1498
Time elapsed:144
Press enter to continue...

Where am I wrong in my comparison? Thanks

Answer 1

Following the remarks of TheGenral "first call to dbContext", I added a query to another table before the comparison and now I am getting close enough results. Thanks