Mini-Redis

A lightweight, Redis-inspired in-memory key-value store written in C++ for Windows.

Features

• TCP Server: Thread-per-client or IOCP (I/O Completion Ports) modes
• RESP Protocol: Full Redis Serialization Protocol with pipelining support
• Thread-Safe Store: Key-value operations with expiration and LRU eviction
• Persistence: RDB snapshots and AOF logging
• Replication: Basic primary-replica support
• Benchmarking: Python and C++ benchmark tools

Supported Commands

Command	Description
PING	Test server connection
ECHO msg	Return message
SET key value	Set key to value
GET key	Get value of key
DEL key	Delete key
EXISTS key	Check if key exists
KEYS pattern	List all keys
EXPIRE key secs	Set expiration
TTL key	Get time-to-live
MGET key1 key2...	Get multiple keys
INCR key	Increment integer value
DECR key	Decrement integer value
INCRBY key n	Increment by n
DECRBY key n	Decrement by n
APPEND key value	Append to string
STRLEN key	Get string length
SAVE	Save to RDB file
LOAD	Load from RDB file
INFO	Server information
QUIT	Close connection

Building

Prerequisites

• Windows 10/11
• CMake 3.10+
• C++17 compiler (VS 2019+ or MinGW-w64)

Quick Build

From Developer Command Prompt:

mkdir build && cd build
cmake .. -G "NMake Makefiles" -DCMAKE_BUILD_TYPE=Release
nmake

Or use the build script:

.\build.ps1 -Force

Running

Server Options

.\mini_redis.exe [options]

Options:
  -p, --port PORT      Server port (default: 6379)
  -m, --max-keys N     Max keys before LRU eviction (default: 10000)
  -a, --aof PATH       AOF file path
  -r, --rdb PATH       RDB file path
  -c, --config PATH    Load config file
      --iocp           Use IOCP server (high performance)
  -h, --help           Show help

Config File Format

# mini_redis.conf
port = 6379
max_keys = 10000
use_iocp = true
aof_path = mini_redis.aof
rdb_path = mini_redis_dump.rdb

Example Session

> PING
+PONG

> SET user alice
+OK

> GET user
$5
alice

> INCR counter
:1

> INCRBY counter 10
:11

> APPEND msg "Hello"
:5

> STRLEN msg
:5

Benchmarking

Python Benchmark

python mini_redis_benchmark.py [options]

Options:
  --host HOST           Server host (default: localhost)
  --port PORT           Server port (default: 6379)
  --single-ops N        Single-client operations (default: 50000)
  --multi-clients N     Concurrent clients (default: 5)
  --multi-ops N         Ops per client (default: 20000)
  --correctness-only    Run only correctness tests
  --compare-modes       Help compare thread vs IOCP modes

C++ Load Generator

.\loadgen.exe --host localhost --port 6379 --requests 10000 --threads 4

Testing

# Build and run tests
cd build
nmake mini_redis_tests
.\mini_redis_tests.exe

Tests include:

• Parser tests
• RESP parser tests
• KVStore tests
• Atomic command tests (INCR/DECR/INCRBY/DECRBY/APPEND/STRLEN)
• Configuration tests

Project Structure

mini-redis/
├── src/
│   ├── main.cpp                  # Entry point with CLI
│   ├── server/
│   │   ├── tcp_server.cpp/hpp    # Thread-per-client server
│   │   ├── iocp_server.cpp       # IOCP async server
│   │   └── replication.cpp/hpp   # Replication manager
│   ├── storage/
│   │   ├── kv_store.cpp/hpp      # Key-value store
│   │   └── aof_logger.cpp/hpp    # AOF logging
│   ├── protocol/
│   │   ├── parser.cpp/hpp        # Command parser
│   │   ├── resp_parser.cpp/hpp   # RESP protocol parser
│   │   └── resp_utils.cpp/hpp    # RESP serialization helpers
│   └── utils/
│       ├── config.cpp/hpp        # Configuration parsing
│       └── logger.hpp            # Thread-safe logging
├── tests/
│   ├── test_protocol.cpp         # Main test runner
│   ├── test_atomic_commands.cpp  # Atomic op tests
│   └── test_config.cpp           # Config tests
├── bench/
│   └── loadgen.cpp               # C++ load generator
├── CMakeLists.txt
├── mini_redis_benchmark.py       # Python benchmark
└── build.ps1                     # Build script

Implementation Notes

Thread Safety

• KVStore: mutex-protected operations
• Atomic counters for server statistics
• AOF: background writer thread with queue
• Replication: mutex-protected replica list

Memory Management

• LRU eviction at 10,000 keys (configurable)
• Lazy expiration on key access
• Binary RDB format for persistence

Server Modes

• Thread-per-client: Simple, one thread per connection
• IOCP: Windows async I/O, better for high concurrency

License

See LICENSE file.

Author

Sritej Bommaraju
EECS + Applied Math, UC Berkeley