Mini Redis Server

A lightweight, high-performance, in-memory key–value store inspired by Redis, implemented in C++. It supports a subset of Redis-style commands (strings, sorted sets, TTL) and is portable across Windows and Linux. Deployment options include local builds, Docker containers, and Render.

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Table of Contents

• Features
• Supported Commands
• Quick Start
  • Windows (Visual Studio Code)
  • Linux Build
  • Docker
  • Deploy on Render
• Connecting With redis-cli
• Benchmarks
• Project Structure
• Architecture Overview
• Configuration Notes
• Limitations and Future Work
• Contributing
• License

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Features

• Key–Value string storage.
• Sorted sets backed by an AVL tree for efficient score-ordered lookups and range-style queries.
• TTL support (PEXPIRE, PTTL) with automatic expiration.
• Background thread pool used for asynchronous clean-up of large data structures.
• Cross-platform networking layer: builds on Windows (MSVC / Visual Studio Code) and Linux (g++).
• Event-driven I/O uses select() for multiplexing multiple client connections.

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Supported Commands

Command	Description	Example
SET key value	Set string value.	SET foo bar
GET key	Get string value.	GET foo
DEL key	Delete key.	DEL foo
PEXPIRE key ms	Set TTL in milliseconds.	PEXPIRE foo 5000
PTTL key	Return remaining TTL in ms.	PTTL foo
KEYS pattern	Return keys matching glob-like pattern (*, ?).	KEYS *
ZADD zset score member	Add/update sorted-set member.	ZADD ranks 1.0 alice
ZREM zset member	Remove member from sorted set.	ZREM ranks alice
ZSCORE zset member	Get score of member.	ZSCORE ranks alice
ZQUERY zset min max	Range query by score (inclusive).	ZQUERY ranks 0 100

Notes:

• Command grammar is simplified; multi-bulk protocol coverage is limited.
• Numeric ranges in ZQUERY are parsed as doubles.

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Quick Start

Windows (Visual Studio Code)

git clone https://github.com/VikingForcee/Redis.git
cd Redis/RedisMain
mkdir build
cd build
cmake ..
cmake --build . --config Release

Run the Server

server.exe By default the server listens on localhost:1234.

Docker

A Dockerfile is provided in RedisMain/

cd Redis/RedisMain
docker build -t mini-redis-server .
docker run --rm -p 1234:1234 mini-redis-server

Connecting with Redis CLI

redis-cli -h <host> -p 1234

Examples: SET key value GET key ZADD zset 1.0 member ZSCORE zset member

Benchmarks

Benchmarks were run on Windows using testing/bench.py unless noted. Times include network overhead on localhost.

Summary Metrics

Scenario	Operations	Threads	Total Time (s)	Throughput (ops/s)	Avg Latency (ms)	P50	P95	P99	P99.9	Max (ms)
Default	100,000 SET	1	3.044	32,846.70	0.290	0.254	0.602	0.857	1.320	8.409
High Load	1,000,000 SET	50	36.744	27,215.01	1.822	1.561	4.250	6.075	8.865	68.679
Mixed (80% GET, 15% SET, 5% DEL)	100,000 ops	multi	3.123	32,019.48	0.300	0.269	0.598	0.813	1.155	7.680
Large Values (512B)	100,000 SET	1	3.213	31,123.64	0.306	0.270	0.638	0.890	1.274	8.684
Latency Sample (sample every 5 ops)	100,000 SET	1	2.865	34,898.79	0.277	0.247	0.569	0.787	1.163	6.382

Raw benchmark scripts live in testing/bench.py and testing/bench2.py.

Project Structure

Redis/
├── RedisMain/
│   ├── avl.cpp
│   ├── avl.h
│   ├── common.h
│   ├── hashtable.cpp
│   ├── hashtable.h
│   ├── heap.cpp
│   ├── heap.h
│   ├── list.h
│   ├── server.cpp
│   ├── thread_pool.cpp
│   ├── thread_pool.h
│   ├── zset.cpp
│   ├── zset.h
│   ├── CMakeLists.txt
│   ├── Dockerfile
│
├── testing/
│   ├── bench.py
│   ├── bench2.py
│
└── README.md

Architecture Overview

Networking / Event Loop

Uses select() to multiplex client sockets. Simple line-based or space-delimited command parsing (see server.cpp).

Data Structures

String keys stored in a hash table (hashtable.). TTL metadata tracked via a min-heap (heap.) keyed by expiration timestamps; expired keys lazily removed. Sorted sets implemented using an AVL tree (avl.* + zset.*) keyed by score; supports score lookups and score-range scans.

TTL & Expiration Flow

PEXPIRE registers expiration time in the heap. Periodic or on-access checks clear expired keys. Large deletions may be delegated to the thread pool.

Thread Pool

C++11 std::thread based. Tasks queued for background cleanup/non-blocking operations. Size configurable at compile time or via a constant (see thread_pool.*).

Configuration Notes

Default listen port is 1234. Update in source or through a command-line flag if implemented (check server.cpp).

Ensure port 1234 is open in local firewall, container runtime, and cloud security groups.

For large-scale deployments, consider replacing select() with:

epoll (Linux)

IOCP (Windows)

Persistence is not implemented; all data is in-memory and lost on restart.

Authentication and ACLs are not implemented; run behind trusted network boundaries.

Limitations and Future Work

Full Redis protocol (RESP) parsing is partial; multiline values and binary-safe payloads need work.

select() scales poorly to thousands of concurrent sockets; move to epoll/kqueue/IOCP for higher concurrency.

No replication, clustering, or persistence (AOF/RDB-style snapshots).

Metrics / monitoring endpoints would be helpful.

Add CI builds for Windows + Linux.

Add fuzz + stress tests for parser and data structures.

Expand ZSET API: ZRANGE, ZRANGEBYSCORE, ZCARD, etc.

Contributing

Contributions are welcome. Please:

Fork the repository.

Create a feature branch.

Follow existing coding style (see headers/sources).

Add tests (benchmark or unit) when possible.

Open a pull request describing the change and performance impact.

Bug reports are also welcome—open an issue with reproducible steps, environment details, and expected vs. actual behavior.

Acknowledgments

Inspired by Redis data structures and semantics. Not a drop-in replacement. The project could'nt have been possible without Build Your Own X : Mini Redis Server (Book)