1838-test.cs

gistfile1.txt

using System;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
using System.IO;
using System.Linq;
using ClosedXML.Excel;

namespace ClosedXML.Sandbox
{
    internal static class Program
    {
        private static DataTable GetTable()
        {
            DataTable table = new DataTable();

            // add columns
            for (var col = 1; col <= 245; col++)
            {
                table.Columns.Add("col_" + col.ToString(), typeof(string));
            }

            List<string> valuesList = new List<String>();
            foreach (DataColumn dc in table.Columns)
            {
                valuesList.Add("testing 101.001000000000 test");
            }

            for (var row = 1; row <= 50000; row++)
            {
                table.Rows.Add(valuesList.ToArray<string>());
            }

            return table;
        }


        private static void Main(string[] args)
        {
            var table = GetTable();


            var stopwatch = Stopwatch.StartNew();
            XLWorkbook workbook = new XLWorkbook();


            var worksheet = workbook.Worksheets.Add("fgtesting");

            worksheet.Cell(1, 1).InsertData(table);

            Console.WriteLine($"Create workbook: {stopwatch.Elapsed}");

            // average 1.06min 245 columns 50k rows (no styles)
            var memoryStream = new MemoryStream();

            stopwatch.Restart();

            workbook.SaveAs(memoryStream);

            Console.WriteLine($"Save workbook: {stopwatch.Elapsed}");

            stopwatch.Restart();

            workbook.Dispose();

            Console.WriteLine($"Dispose of workbook : {stopwatch.Elapsed}");

            stopwatch.Restart();

            GC.Collect();
            GC.WaitForPendingFinalizers();
            GC.Collect();

            Console.WriteLine($"GC cleanup: {stopwatch.Elapsed}");
        }
    }
}