Carrot

Carrot is a Redis-like key-value database that supports both basic KV operations and sorted sets. It implements a subset of Redis commands with a focus on simplicity and efficiency.

Prerequisites

Before building Carrot, ensure you have the following installed:

• CMake (version 3.0 or higher)
• Make
• GCC or Clang compiler
• Unix-like operating system

Building from Source

1. Clone the repository:

git clone git@github.com:devansh-srv/carrot.git
cd carrot

2. Give execution permission to the build script:

chmod +x build.sh

3. Build the project:

./build.sh

This will initialize CMake and build both the server and client binaries.

Running the Server

Start the server by specifying a port number:

cd build
./bin <port>

Example:

cd build
./bin 6379

Using the Client

The client can be used to send commands to the server:

cd build
./client <hostname> <port> <command>

Example:

./client localhost 6379 get mykey

Supported Commands

Basic Key-Value Operations

1. GET - Retrieve a value by key

./client localhost 6379 get mykey

2. SET - Set a value for a key

./client localhost 6379 set mykey myvalue

3. DEL - Delete a key-value pair

./client localhost 6379 del mykey

4. KEYS - List all stored keys

./client localhost 6379 keys

Sorted Set Operations

1. ZADD - Add a scored element to a sorted set

./client localhost 6379 zadd myset 1.5 element1

2. ZREM - Remove an element from a sorted set

./client localhost 6379 zrem myset element1

3. ZSCORE - Get the score of an element

./client localhost 6379 zscore myset element1

4. ZRANK - Get the rank of an element

./client localhost 6379 zrank myset element1

5. ZQUERY - Query elements in a sorted set

./client localhost 6379 zquery myset 1.0 "" 0 10

Parameters:

• key: The sorted set key
• score: Minimum score to start from
• name: Minimum element name to start from
• offset: Number of elements to skip
• limit: Maximum number of elements to return

Cache Evinction Operations

1. PEXPIRE - Set the ttl value for any key in msec

./client localhost 6379 pexpire myset 1000 

2. PTTL - Get the ttl for any key

./client localhost 6379 pttl myset

Technical Details

• Written in C
• Uses non-blocking I/O
• Implements an event loop using poll()
• Supports concurrent client connections
• Uses FNV hash for key hashing
• Implements AVL trees for sorted sets

Acknowledgement

• Thank you Vansh Jangir and Amritanshu Darbari for coming up with this amazing name.
• Thank you to Erik Demaine for this amazing lecture on data structure augmentation that helped me in understanding AVL trees and range queries.
• MITOCW Lecture
• Also big thanks to 0xAX for the amazing repo that taught me about intrinsic data structures
• linux-insiders

Contributing

Feel free to submit issues and pull requests.