Build Your Own Redis in C/C++

This repository is my implementation of a Redis-like server from scratch, inspired by the "Build Your Own Redis with C/C++" guide. It focuses on network programming (TCP/IP) and fundamental data structures (hashtables, balanced trees, etc.), aiming to deepen understanding of systems programming by doing.

Features

• TCP Server & Request-Response Protocol
  Basic socket programming for handling multiple client connections, plus a custom request/response format.

• Data Structures

  • Hashtables for O(1) key lookups
  • AVL-tree-based Sorted Set implementation (like Redis ZSET)
  • Heap-based TTL timers for automatic key expiration

• Thread Pool
  Thread pool for asynchronous tasks (such as large data deallocation), improving responsiveness under heavy load.

• Performance Tweaks

  • Receive Buffer Offset: Minimize `memmove` calls by tracking data offset in the buffer.
  • `std::string` Reserve: Avoid repeated small allocations when generating responses.
  • Preallocated Vectors: Reserve capacity for `std::vector` to reduce reallocations in the event loop.

Why Build Redis from Scratch?

1. Learn Low-Level Fundamentals
   Gain hands-on experience in C/C++ network programming (sockets, non-blocking I/O, concurrency) and in data structure design (hashtable, balanced trees).

2. Deeper Understanding
   As Richard Feynman once said, “What I cannot create, I do not understand.” Building key components yourself reinforces how things work under the hood.

3. Practical System Skills
   C/C++ remain prevalent in systems and infrastructure development. Mastering memory management, concurrency, and performance tuning in C/C++ is valuable.

Building & Running

cd redis/src

# Example build
clang++ -std=c++17 -O2 redis_server.cpp avl.cpp hashtable.cpp heap.cpp thread_pool.cpp zset.cpp memory_pool.cpp -o redis_server

# Run server (listens on port 1234)
./redis_server &

# In another terminal, use the included client to test commands
./redis_client set key1 value1
./redis_client get key1
./redis_client zadd zset 1 n1
./redis_client zscore zset n1

Reference

Guide: Build Your Own Redis with C/C++
Why from scratch? Quoting from the guide:

“Reading about things often just gives an illusion of knowledge. Learn deeper by doing!”