google/leveldb

Make background thread stoppable

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#863 opened on Dec 18, 2020

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 (2 comments) (0 reactions) (0 assignees)C++ (39,075 stars) (8,199 forks)batch import
enhancementhelp wanted

Description

Hi,

Current version of LevelDB has detached background thread that can't be stopped and each environment calls std::abort() in destructor. This behavior prevents using of LevelDB in plugin dlls that can be started and stopped when main application still runs.

I think it is better to allow background thread to finish tasks in queue and then exit, when environment is being destroyed. That will make database loadable and unloadable.

Contributor guide

Tech stack
cpp
Domain
database
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C++ threadingLevelDB environment API
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the current environment destructor and background thread implementation in LevelDB. Look at files such as util/env posix.cc and include/leveldb/env.h to understand how the background thread is created and managed. Identify where std::abort() is called and design a mechanism to allow the thread to finish its current tasks and exit gracefully when the environment is destroyed. Review any existing discussions in the issue comments for additional insights or constraints.