EPPlus使用200列以上的数据表将200万行保存到多个Excel文件 [英] EPPlus save two million rows with 200+ columns datatable to multiple excel files
问题描述
我具有使用EPPlus将SQL表中的所有记录保存到excel工作表的功能。
如果我导出少量数据，则一切正常，但是具有200+列和500000+行时，出现OutOfMemory异常。
I have function that saves all records from SQL table to excel worksheet using EPPlus. If I export small amount of data everything works fine, but with 200+ columns and 500 000+ rows I get OutOfMemory exception.
我想修改我的代码，使其每个文件可以保存5万条记录。
I'd like to modify my code in a way to be able to save 50 000 records per file.
这是我的适用于小数据的代码：
Here is my code that works for small data:
private Task SaveAsync(string tableName)
{
return Task.Run(() =>
{
try
{
using (var conn = new SqlConnection(_connectionString))
{
using (var cmd = new SqlCommand(string.Format(DataQuery, tableName), conn))
{
cmd.CommandType = CommandType.Text;
cmd.CommandTimeout = 360;
conn.Open();
using (SqlDataReader sdr = cmd.ExecuteReader())
{
var fileName = string.Format(TargetFile, tableName);
if (File.Exists(fileName))
{
File.Delete(fileName);
}
sdr.Read();
var numberOfRecordsInTable = sdr.GetInt32(0);
sdr.NextResult();
using (ExcelPackage pck = new ExcelPackage(new FileInfo(fileName)))
{
ExcelWorksheet ws = pck.Workbook.Worksheets.Add("Results");
int count = sdr.FieldCount;
int col = 1, row = 1;
for (int i = 0; i < count; i++)
{
ws.SetValue(row, col++, sdr.GetName(i));
}
row++;
col = 1;
while (sdr.Read())
{
for (int i = 0; i < count; i++)
{
var val = sdr.GetValue(i);
ws.SetValue(row, col++, val);
}
row++;
col = 1;
}
//autosize
ws.Cells[ws.Dimension.Address].AutoFitColumns();
//autofiltr
ws.Cells[1, 1, 1, count].AutoFilter = true;
}
}
conn.Close();
}
}
}
catch (Exception e)
{
Debug.WriteLine("Error at: " + Thread.CurrentThread.ManagedThreadId);
Debug.WriteLine(e);
}
});
}
和我修改过的代码，每个文件分割记录50000：
and my modified code that splits records 50 000 per file:
private Task SaveAsync2(string tableName)
{
return Task.Run(() =>
{
try
{
using (var conn = new SqlConnection(_connectionString))
{
using (var cmd = new SqlCommand(string.Format(DataQuery, tableName), conn))
{
cmd.CommandType = CommandType.Text;
cmd.CommandTimeout = 360;
conn.Open();
using (SqlDataReader sdr = cmd.ExecuteReader())
{
var fileName = string.Format(TargetFile, tableName,"");
if (File.Exists(fileName))
{
File.Delete(fileName);
}
sdr.Read();
var max = sdr.GetInt32(0);
int filesCount = 1;
if (max > 50000)
{
fileName = string.Format(TargetFile, tableName, filesCount);
}
sdr.NextResult();
ExcelPackage pck = new ExcelPackage(new FileInfo(fileName));
ExcelWorksheet ws = pck.Workbook.Worksheets.Add("RESULTS");
int count = sdr.FieldCount;
int col = 1, row = 1;
for (int i = 0; i < count; i++)
{
ws.SetValue(row, col++, sdr.GetName(i));
}
row++;
col = 1;
while (sdr.Read())
{
for (int i = 0; i < count; i++)
{
var val = sdr.GetValue(i);
ws.SetValue(row, col++, val);
}
row++;
col = 1;
if (row > 50000)
{
pck.Save();
filesCount++;
fileName = string.Format(TargetFile, tableName, filesCount);
pck = new ExcelPackage(new FileInfo(fileName));
ws = pck.Workbook.Worksheets.Add("RESULTS");
count = sdr.FieldCount;
col = 1;
row = 1;
for (int i = 0; i < count; i++)
{
ws.SetValue(row, col++, sdr.GetName(i));
}
row++;
col = 1;
}
}
//autosize
ws.Cells[ws.Dimension.Address].AutoFitColumns();
//autofiltr
ws.Cells[1, 1, 1, count].AutoFilter = true;
pck.Save();
}
}
conn.Close();
}
}
catch (Exception e)
{
Debug.WriteLine("Error at: " + Thread.CurrentThread.ManagedThreadId);
Debug.WriteLine(e);
}
});
}
基本上可以正常工作，但是在我的代码的第一个版本中，我使用了所有功能在 using 语句中，在第二个版本中，我两次调用相同的代码。
basically this works fine, but in first version of my code I was using everything inside using statement, when in second version I'm calling same code twice.
- 如何修复代码以删除重复的代码并将所有内容放入其中。
- 是否可以将下一组（50,000条记录）添加为新工作表，而不是创建新文件？ >
- 将数据保存到文件时，EPPlus的限制是多少？
行x列？我发现，EPPlus应该处理超过一百万行，但没有那么多列。我认为我可以单列导出一百万行，但是对于我来说200+列是5万行的限制。我想知道是否有数量（行x列）将限制我的导出正常运行。我希望该导出功能具有通用性，因此当我传递具有50列的数据表时，它将导出例如每个文件100000行，而对于2列则将导出每个文件50万行。
- How can I fix my code to remove duplicate code and put everything inside using.
- Can I add next set (50 000 records) as new worksheet instead of creating new file?
- What would be EPPlus limit when saving data to file?
rows x columns? I found information that EPPlus should handle more than million rows, but not so much columns as I have. I thinks that I can export million rows with single column, but for 200+ columns for me 50 000 rows is limit. I'm wondering if there is number (rows x columns) that will be limit to which my export will work fine. I want that export function to be universal, so when I pass datatable with 50 columns it will export for example 100 000 rows per file and for 2 columns it will export half million per file.
推荐答案
不幸的是，没有简单的方法可以将大量数据与Epplus合并到一个文件中。基本上，整个文件在打开时都会加载到内存中-全部或全部不加载。从理论上讲，您可以生成XLSX包含的XML文件（它们是重命名的zip文件），然后手动插入它，因为它具有较小的内存占用空间，但这并不容易。
Unfortunately, there is no easy way to merge that much data with Epplus in a single file. Basically, the entire file is loaded into memory when open - its either all or nothing. In theory, you could generate the XML files that XLSX contains (they are zip files renamed) and manually insert it since it would have a smaller memory footprint but that is no small feat.
对于您当前的代码，如果要避免使用using语句，总是可以手动调用 .dispose（）。但我知道您要避免重复的代码。这样的事情怎么样（但是在复制所有对象数据时要注意内存使用情况）：
For you current code, you could always just call .dispose() manually if you want to avoid the using statement. But I understand you wanting to avoid duplicate code. What about something like this (but watch for memory usage when copying all the object data):
const int max = 10;
var loop = 0;
using (var sdr = cmd.ExecuteReader())
{
var fieldcount = sdr.FieldCount;
var getfi = new Func<int, FileInfo>(i =>
{
var fi = new FileInfo(String.Format(@"c:\temp\Multi_Files{0}.xlsx", i));
if (fi.Exists) fi.Delete();
return fi;
});
var savefile = new Action<FileInfo, List<Object[]>>((info, rows) =>
{
using (var pck = new ExcelPackage(info))
{
var wb = pck.Workbook;
var ws = wb.Worksheets.Add("RESULTS");
for (var row = 0; row < rows.Count; row++)
for (var col = 0; col < fieldcount; col++)
ws.SetValue(row + 1, col + 1, rows[row][col]);
pck.Save();
}
});
var rowlist = new List<Object[]>();
while (sdr.Read())
{
var rowdata = new Object[sdr.FieldCount];
sdr.GetValues(rowdata);
rowlist.Add(rowdata);
if (rowlist.Count == max)
{
savefile(getfi(++loop), rowlist);
rowlist.Clear();
}
}
if (rowlist.Count > 0)
savefile(getfi(++loop), rowlist);
}
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