pypa/pip

Performance Issue: Too many hashes in RequirementPreparer

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#12,589 建立於 2024年3月23日

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help wantedtype: performance

描述

Description

RequirementPreparer hashes more than necessary. This leads to poor performance on large wheels in the GB size range.

A call to prepare_linked_requirement calls down to _checked_download_dir. https://github.com/pypa/pip/blob/f5e4ee104e7b171a7cfb2843c9c602abf7a4e346/src/pip/_internal/operations/prepare.py#L501

If the file exists in the download_dir, hashing is triggered. The file is marked as downloaded. https://github.com/pypa/pip/blob/f5e4ee104e7b171a7cfb2843c9c602abf7a4e346/src/pip/_internal/operations/prepare.py#L516

Then we head into _prepare_linked_requirement and eventually hash again. https://github.com/pypa/pip/blob/main/src/pip/_internal/operations/prepare.py#L612

Potential Fix

Files which have passed the hash check can be marked as such, to prevent rehashing.

Expected behavior

RequirementPreparer hashes each file at most once.

pip version

24.0

Python version

3.11

OS

Windows 10

How to Reproduce

Construct a RequirementPreparer supplied with a download_dir. Run prepare_linked_requirement() for a link available as a wheel in the download_dir.

Output

No response

Code of Conduct

貢獻者指南

技術棧
python
領域
performancetooling
議題類型
performance
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
half day
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
fresh
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
Pythonfamiliarity with pip's source code
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
40
研究方向
Investigate the double hashing in pip's RequirementPreparer. Focus on the ` checked download dir` and ` prepare linked requirement` methods in `src/pip/ internal/operations/prepare.py`. The issue suggests marking files that have passed the hash check to avoid rehashing. Implement a mechanism to track hashed files, possibly using a set or flag. Ensure the change does not affect downstream logic.
Performance Issue: Too many hashes in RequirementPreparer · pypa/pip#12589 | Good First Issue