Blink-DB

Overview

Blink-DB is a high-performance, write-optimized database system implemented in C++. It consists of two core components integrated into a single codebase:

• Database Engine – Uses Log-Structured Merge-Trees (LSM-Trees) for fast writes and efficient data retrieval
• Server – A non-blocking, event-driven server leveraging kqueue for high-performance RESP command processing

Project Structure

.
├── benchmark.sh
├── Design Document.pdf
├── Doxyfile
├── html
├── images
│   └── LSM Tree.png
├── Makefile
├── README.md
├── report
│   ├── main.tex
│   └── pictures
└── src
    ├── cli.cpp
    ├── command_parser.hpp
    ├── engine
    ├── kqueue_server.hpp
    ├── main.cpp
    ├── resp
    └── resp_encoder.hpp

Documentation

Complete documentation is available at https://ganajayant.github.io/Blink-DB/html/index.html

For local documentation generation:

make docs

• Generates documentation using Doxygen
• Output will be available in the html/ directory

DB Architecture

Features

• Write-Major Architecture: Optimized for fast writes, ensuring quick insert operations
• LSM-Tree Based Storage: Efficiently manages and compacts data for optimized read and write performance
• Thread-Safe Execution: Supports concurrent operations using internal synchronization mechanisms
• Non-blocking kqueue-based server for high throughput
• RESP command processing (GET, SET, DEL)
• Multiple interfaces:
  • Command-line interface for direct interaction
  • Server interface for networked applications

Compilation and Execution

Build and Run the Server

make run

• Compiles src/main.cpp with C++17 standard
• Executes the database server

Build and Run the CLI

make cli

• Compiles src/cli.cpp with C++17 standard
• Executes the command-line interface

Benchmarking

make benchmark

This runs redis-benchmark with different loads and stores results in the result/ directory. The benchmarking script tests with:

Data Size	Key Size	Concurrent Requests	Parallel Connections
512 bytes	1024	10,000, 100,000, 1,000,000	10, 100, 1000

Generate Documentation

make docs

• Generates documentation using Doxygen

Clean Up Binaries

make prune

• Removes compiled binaries and data files

Usage Instructions

CLI Mode

Supported Commands

Data Operations

Set a key-value pair

SET <key> <value>

Stores the key-value pair in the database.

Retrieve a value

GET <key>

Fetches the value associated with the given key.

Delete a key

DEL <key>

Removes the key-value pair from the database.

Utility Commands

Show available commands

help

Displays the list of supported commands.

Clear the screen

clear

Clears the CLI screen.

Exit the application

exit

Terminates the Blink-DB CLI session.

Example CLI Usage

SET name "BlinkDB"
GET name
DEL name
GET name  # Returns NULL

Server Mode

The server listens on port 9001 by default and uses the Redis Serialization Protocol (RESP) for communication.

Telnet Testing

You can interact with the server using telnet on port 9001.

Store a key-value pair (SET)

telnet 127.0.0.1 9001
*3
$3
SET
$3
foo
$3
bar

Retrieve a value (GET)

telnet 127.0.0.1 9001
*2
$3
GET
$3
foo

Delete a key (DEL)

telnet 127.0.0.1 9001
*2
$3
DEL
$3
foo

Benchmark Results

The benchmark is run with the following parameters:

• Number of requests: 10000, 100000, 1000000
• Number of parallel connections: 10, 100, 1000
• Data size: 512 bytes
• Random key range: 1024 keys
• Operations: SET and GET

Performance Results

Concurrent Requests	Parallel Connections	Operation	Throughput (requests/s)	Avg. Latency (ms)
10000	10	SET	71942.45	0.132
10000	10	GET	86956.52	0.103
10000	100	SET	75187.97	1.311
10000	100	GET	103092.78	0.899
10000	1000	SET	73529.41	12.478
10000	1000	GET	90909.09	9.853
100000	10	SET	74460.16	0.128
100000	10	GET	91157.70	0.095
100000	100	SET	76923.08	1.293
100000	100	GET	94517.96	1.000
100000	1000	SET	76687.12	12.899
100000	1000	GET	91659.03	10.739
1000000	10	SET	73735.44	0.129
1000000	10	GET	80250.38	0.109
1000000	100	SET	70766.40	1.400
1000000	100	GET	86933.84	1.084
1000000	1000	SET	68465.02	14.572
1000000	1000	GET	84118.45	11.790

Additional Notes

• Blink-DB is designed for high-speed writes, making it ideal for write-heavy workloads
• Reads are optimized through efficient indexing and LSM-Tree compaction
• The server implementation is optimized for high-throughput network operations
• Future versions will include additional features such as range queries, snapshots, and replication

For more details, refer to the documentation in the docs/ directory.

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Author: Gana Jayant Sigadam Date: March 2025 Version: 1.0