使用EPPlus Excel库时巨大的内存分配 [英] Huge memory Allocation when using EPPlus Excel Library

问题描述

我已经使用，这是它的更改日志：

 新单元格存储
 *减少内存消耗
 *插入列（不在范围级别）
 *更快的行插入
  

在更新Nuget之后，我仍然有同样的异常，这是在第一行之后抛出的，而不是在第二行被引发。

解决方案

现代Excel文件，即Xlsx文件是zip压缩的，经常实现压缩降低到10％。我刚解压缩了我使用类似工具生成的1.6MB文件，并将其解压到18.8 MB的数据。

您有一个0.138 GB的文件，使用1.370 GB的内存，几乎正好是10％。记忆中的未压缩的表现是什么在吃你的记忆。

如果你好奇，你可以使用一个像7-Zip这样的工具来提取Xlsx文件，或者你可以将文件重命名为.zip结尾并在Windows中浏览。

Context

I have been using EPPLUS as my tool to automate excel report generation, using C# as the client language of the library.

Problem:

After trying to write a really big report (response of a SQL Query), with pivot tables, charts and so forth, i end up having a Out of Memory Exception.

TroubleShooting

In order to troubleshoot, i decided to open an existing report that has 138MB, and use the GC object to try to take a peek on what's happening with my memory, and here are the results.

ExcelPackage pkg = new ExcelPackage (new FileInfo (@"PATH TO THE REPORT.xlsx"));
ExcelWorkbook wb = pkg.Workbook;

Garbage Collection Results, before the second line of code, and after.

So, i have no idea what to do from now on. All i am doing is opening the report, which is consuming roughtly 10 (9.98 actually) times the report size itself, on memory.

The ~138MB of the excel file, takes up 1.370.817.264 bytes of RAM.

Update One:

There's a fairly recent beta version of EPPlus that's out that has on it's changelog:

New Cell store
* Less memory consumtion
* Insert columns (not on the range level)
* Faster row inserts

After updating the Nuget, i still have the same exception, that is thrown after the first line, instead of being raised on the second line.

解决方案

Modern Excel files, ie, Xlsx files are zip-compressed, and often achieve compression down to 10%. I just uncompressed a 1.6MB file I generated using a similar tool and found it extracted to 18.8 MB of data.

You've got a 0.138 GB file that is using 1.370 GB of memory, which is almost exactly 10%. The uncompressed representation in memory is what is eating your memory.

If you're curious, you can use a tool like 7-Zip to extract the Xlsx files, or you can rename the file to end in .zip and browse it in Windows.

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