Performance issues at extracting 7z file to a directory c#

Question

I'm using SharpCompress library for extracting .7z files but it takes about 35 mins to extract 60mb .7z file. Is this normal or am I doing something wrong in terms of performance? .7z file is compressed in high compress mode and LZMA type.

 using (var archive2 = ArchiveFactory.Open(source))
 {
     foreach (var entry in archive2.Entries)
     {
         if (!entry.IsDirectory)
         {
             entry.WriteToDirectory(destination, ExtractOptions.ExtractFullPath | ExtractOptions.Overwrite);
             }
         }
      }
  }

Asking about normality in computing stuff is based on so many parameters that it won't be much value to answer that question. Maybe you could rephrase this to "In my opinion this is taking too long. Is it possible to speed it up?" which I think will be easier to answer — default, Jan 13 '17 at 12:55
How long big is the *resulting* file? How high is the CPU load? How long does it take to unzip the file with a program like 7-zip in *single-threaded* mode? You may simply have a slow computer, or the resulting files are too big. — Panagiotis Kanavos, Jan 13 '17 at 12:55
@PanagiotisKanavos resulting file is 60.5 mb and Cpu load is around %15 — Miral, Jan 13 '17 at 12:59
No sorry. 60Mb is the uncompressed data. 11.7Mb is compressed data — Miral, Jan 13 '17 at 13:17

score 1 · Answer 1 · answered Jun 06 '17 at 00:16

This is an old post, but I just had the same problem.

This line is the problem

foreach (var entry in archive2.Entries)

The problem is described here (ie. If there are 100 files, it decompresses the 1st file 100 times, 2nd file 99 times, and so on)

The solution is to use reader (forward-only). See the API.
But the sample code there doesn't support 7z.

For 7z you can use archive.ExtractAllEntries(), eg.

using (var archive = ArchiveFactory.Open(movedZipFile))
{
    var reader = archive.ExtractAllEntries();
    while (reader.MoveToNextEntry())
    {
        if (!reader.Entry.IsDirectory)
            reader.WriteEntryToDirectory(extractDir, new ExtractionOptions() { ExtractFullPath = false, Overwrite = true });
    }
}

It will be much faster.

Performance issues at extracting 7z file to a directory c#

1 Answers1