sofastack/sofa-jraft

RFC: multi-generation log cache

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#854 创建于 2022年6月23日

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 (9 评论) (1 反应) (0 负责人)Java (3,406 star) (1,125 fork)batch import
enhancementhelp wanted

描述

RFC: multi-generation log cache

As discussion in #840 , jraft keeps a cache for latest log entries, it's unlimited and may consume too much memory under write-heavy workload or catching up replication when node restarts.

I think we can abstracts a cache interface and provide a multi-generation cache to replace current one:

  • Gen-1: totaly in memory with limited capacity.
  • Gen-2: Off-heap cache.When Gen-1 overflows, move the LRU(least recently used) item into off-heap cache such as OHC.

Main goals:

  • Abstracts log cache interface.
  • Provide a multi-generation cache implementation.

贡献者指南

技术栈
java
领域
backendperformance
议题类型
feature
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
4
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
over 1 week
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
needs maintainer response
清晰度议题是否清楚说明期望改动、验收标准和下一步。
mostly clear
前置要求
JavaRaft consensusCaching concepts
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
15
研究方向
Review the existing log cache implementation in the codebase and the discussion in issue #840. Understand the current unlimited cache behavior and design a cache interface with multi generation support. Consider using OHC for off heap cache. Propose a detailed design before implementation.