Gedis

Purpose

Here I have created an in memory database inspired by Redis. This program also contains a tcp client to connect to the database. The database allows for O(1) lookup, adds and deletes on average. Gedis also suppports transactions.

Please read Reasoning as to why the program was separated into a 2 parts (server, client).

Installation

To install Gedis, you first most have (Go)[https://go.dev/] installed and in your PATH. In the root directory run the following command

go build

Now you have a binary of gedis that you can run on your system.

(for Unix) For server Database

./gedis

After you have the server running, you can use any tcp client you want to communicate with the server at address localhost:8080. I personally recommend nc/netcat on mac/linux. If you do not have a these programs, or want to use the client that comes bundled with gedis, use thee flag -cli.

For tcp client

./gedis -cli

Reasoning

When deciding how to build this in memory database, I had a few objectives:

1. High performance
2. Low resource usage
3. Scalable

After establishing my goals, I concluded that I wouldn't use Python to build this database. While Python is a great language and my go to when it comes to scripting, it isn't great at performance. Next I looked at using Nodejs. Nodejs is great for I/O intensive task but it has one glaring weakness, it loves ram. It would seem counterintuitive to build an in memory database, with a tech stack that loves to eat memory.

Finally I landed on Golang. Go offers high performance with low memory usage. On top of that Go scales really well, allowing concurrency natively with channels and goroutine. On the subject of scalability, I decided to seperate the database from the client.

Since one of our focuses is scalability, I did not want our client to be the only one to connect to the database. I would like multiple on going streams to the same database, so I went with a tcp approach. I decided to go with tcp for my first version of Gedis.

Usage

./gedis
nc localhost 8080

After starting the server and connecting to server with a TCP client. You can use the following commands to interact with the Database server.

Commands

SET [key] [value]

Stores key value pair

GET [key]

Responds with value associated with key

DELETE [key]

Deletes key, value pair

COUNT [value]

Returns amount of times value is located in database

END

Exits Database

BEGIN

Begins a transaction

ROLLBACK

Discards transactions without committing

COMMIT

Commits transactions

Todos

• HTTP interface to allow for a web facing interface.
• Due to the time constraint, I was not able to add testing.
• Persistant backup to a json file or a different database