Insert 2 million rows into SQL Server quickly

1. I think its better you read data of text file in DataSet

2. Try out SqlBulkCopy – Bulk Insert into SQL from C# App

   // connect to SQL
   using (SqlConnection connection = new SqlConnection(connString))
   {
       // make sure to enable triggers
       // more on triggers in next post
       SqlBulkCopy bulkCopy = new SqlBulkCopy(
           connection, 
           SqlBulkCopyOptions.TableLock | 
           SqlBulkCopyOptions.FireTriggers | 
           SqlBulkCopyOptions.UseInternalTransaction,
           null
           );
   
       // set the destination table name
       bulkCopy.DestinationTableName = this.tableName;
       connection.Open();
   
       // write the data in the "dataTable"
       bulkCopy.WriteToServer(dataTable);
       connection.Close();
   }
   // reset
   this.dataTable.Clear();
   

or

after doing step 1 at the top

2. Create XML from DataSet
3. Pass XML to database and do bulk insert

you can check this article for detail : Bulk Insertion of Data Using C# DataTable and SQL server OpenXML function

But its not tested with 2 million record, it will do but consume memory on machine as you have to load 2 million record and insert it.