SqlBulkCopy.cs

        private void Copy(string sourceCommandText, string destinationTableName, IEnumerable<SqlBulkCopyColumnMapping> columnMappings)
        {
            using (var sqlBulkCopy = new SqlBulkCopy(_destinationConnectionString, SqlBulkCopyOptions.Default))
            {
                const int timeout = 1200;

                sqlBulkCopy.BulkCopyTimeout = timeout;
                sqlBulkCopy.BatchSize = 50000;
                sqlBulkCopy.DestinationTableName = destinationTableName;
                sqlBulkCopy.NotifyAfter = 1000000;
                sqlBulkCopy.SqlRowsCopied += SqlBulkCopy_SqlRowsCopied;

                foreach (var columnMapping in columnMappings)
                {
                    sqlBulkCopy.ColumnMappings.Add(columnMapping);
                }

                using (var sourceConnection = new SqlConnection(_sourceConnectionString))
                {
                    sourceConnection.Open();

                    using (var sqlCommand = new SqlCommand(sourceCommandText, sourceConnection))
                    {
                        sqlCommand.CommandType = CommandType.Text;
                        sqlCommand.CommandTimeout = timeout;

                        using (var sqlDataReader = sqlCommand.ExecuteReader(CommandBehavior.CloseConnection))
                        {
                            sqlBulkCopy.WriteToServer(sqlDataReader);
                        }
                    }
                }
            }
        }