libgit2 / libgit2/libgit2sharp

Fetching history for a file VERY slow using libgit2sharp

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主要語言
C#
星號
3.5k
分支
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PR 合併指標
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描述

I am attempting to use libgit2sharp to get the list of commits for a specific file in a repository. The code works, but it is VERY slow. How can I get git command line like performance from libgit2sharp?

Reproduction steps

Run the following code:

using System;
using System.Collections.Generic;
using System.Diagnostics;
using LibGit2Sharp;

namespace GitHistoryTime
{
class Program
{
static void Main(string[] args)
{
if (args.Length < 2)
{
Console.WriteLine("Format is GitHistoryTime ");
}
else
{
string repoName = args[0];
string fileName = args[1];
Stopwatch stopwatch = System.Diagnostics.Stopwatch.StartNew();
Repository repo = new Repository(repoName);
if (repo == null)
{
Console.WriteLine("Could not find git repository for " + repoName);
}
else
{
CommitFilter filter = new CommitFilter
{
SortBy = CommitSortStrategies.Topological
};
IEnumerable log = repo.Commits.QueryBy(fileName, filter);
if (log != null)
{
foreach (LogEntry entry in log)
{
Console.WriteLine(entry.Commit.Sha);
}
}
Console.WriteLine("Time to get the log: {0}", stopwatch.Elapsed.ToString());
}
}
}
}
}

Expected behavior

I would expect to get times similar to doing git --no-pager log --fileName. On my system, git took 0.43 seconds to return the full history

Actual behavior

On my machine, the above code took 6 minutes and 45 seconds! That is roughly 800 times slower than the git command line.

Due to the comments in https://github.com/libgit2/libgit2/issues/4428, I first tried to use a sort strategy of None, but LibGit2Sharp threw an exception that None was not valid. Why?

Version of LibGit2Sharp (release number or SHA1)

7fc4be5193dbdd08538b4b150332b5a73770e0f6

Operating system(s) tested; .NET runtime tested

Windows 10 2004 .NET 4.6.1

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  4. 送出 Pull Request,並在描述裡引用這個 Issue 編號。

研究方向

先使用 Repository.Commits.QueryBy(fileName, filter) 及其 CommitFilter.SortBy 設定進行 C# 重現,然後將其與報告中的 git --no-pager log 耗時進行比較。調查效能差距以及 SortBy = None 被拒絕的原因,並以相關的 libgit2 issue 4428 作為背景。確立檔案歷程效能問題的原因和可執行的解決方案後,即視為完成。

由索引模型根據 Issue 內容生成。

評估

技術堆疊
csharp, git
領域
devtools, performance
Issue 類型
缺陷
難度
4/5
預估耗時
3-5 天
活躍度
停滯
描述清晰度
基本清楚
新手友好度
38/100

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