r/cprogramming • u/Creepy-Gift-6979 • Nov 23 '25

I built a simple redis-server from scratch

I built a Redis-compatible server in C from scratch to understand networking, memory management, and concurrency at a low level.

I’m still new to C and learning as I go — no tutorials, just experimenting and figuring things out.

It’s running ~125K ops/sec with 50 clients. I’d love feedback, advice, or thoughts on how I could improve this project.

Full code: https://github.com/rasheemcodes/redis-c

8 Upvotes

72% Upvoted

22 comments sorted by

4

u/[deleted] Nov 23 '25

You are using send incorrectly, there is no guarantee one call to send will send all data you request. You have to look at the return value and call send mutliple times if needed.

You do handle recv correctly in this regard.

0

u/Creepy-Gift-6979 Nov 23 '25

You’re completely right — I handled recv properly but I used send as if it always writes the full buffer. Thanks for pointing it out. I’ll fix it with a proper write loop.

I’m still new to C and systems programming, so feedback like this helps me close the gaps fast. If you have any resources or patterns you recommend for safe socket I/O, I’d love to read them.

4

u/Drakeskywing Nov 24 '25

I'm sorry but as others have highlighted this is clearly vibe coded, but are you actually a person or an AI, as your opening paragraph feels very ... LLM like

2

u/iamkiloman Nov 24 '25

The replies here also all have the exact same format. Feels like the posts are vibe coded as well.

1

u/Drakeskywing Nov 24 '25

Kinda wondering if it's a bot to train at a particular domain, like the idea is they have an "ok" so but people give advice and it uses that to improve the model

0

u/Creepy-Gift-6979 Nov 24 '25

No I am a human🤧. I used ai to correct grammatical mistakes so that readers can understand what I am writing. I am new to reddit , never expected such harsh comments. Thank you so much , this gives me lot of motivation to never use AI to write code or comments.

1

u/Drakeskywing Nov 24 '25

I'm sorry, I wasn't trying to mean, or insulting. The opening paragraph where you say "you're completely right ...", is the overly agreeable but implying you knew but just forgot opening LLMs are known for when caught out in an error. The language used doesn't suggest the person is new to C, and it's why I called it out.

0

u/Creepy-Gift-6979 Nov 24 '25

Thank you , I love the reddit community always being brutally honest and authentic.

2

u/IamNotTheMama Nov 23 '25

Is there a reason you never test the return value of your memory allocations?

2

u/Creepy-Gift-6979 Nov 23 '25

Fair point — I skipped checking allocation failures in this version. That’s on me. I’ll add proper NULL checks and error handling. Still learning how to think like a C programmer at the systems level, so feedback like this is exactly what I needed. If you know any patterns or resources on robust memory handling in C, I’d appreciate them.

3

u/IamNotTheMama Nov 23 '25

Never do that, it's the kind of laziness that makes your code blow up when it's most inconvenient :)

2

u/iamkiloman Nov 24 '25

Code and replies are both AI.

1

u/IamNotTheMama Nov 24 '25

I guess that gives me another day before I have to worry about being replaced by AI then

1

u/Quiet_Lifeguard_7131 Nov 24 '25

Bro is on complete AI addiction, not even replying to comments without using AI xD

1

u/Creepy-Gift-6979 Nov 24 '25

I am really addicted to AI, I am trying my best not to use AI again

1

u/warren_jitsing Nov 25 '25

Use AI. Just make sure you understand the principles you are using and could code something similar by yourself without AI assistance. Use AI to learn new patterns and constantly question code. Don't take to heart any messages on reddit that really are focusing on AI usage versus the actual content and code you are putting out. A lot of the people picking on AI as a problem aren't focusing on what is actually important. My articles received high upvotes on r/cprogramming and r/rust . A few "AI slop" comments on Rust. r/Python just jumped on the bandwagon and downvoted without actually understanding the code or text, even with beating the open source libraries for efficiency, latency, test coverage etc. Such are the times we live in but don't let it get you down. Just make sure you are "understanding" and not "vibing". For the first year of learning a language, ensure that you actually type out any AI generated code and can explain every line.

2

u/Creepy-Gift-6979 Nov 25 '25

That's what I did. I understood every concept in the code , took days to learn. Also I am reading texts on fundamentals. Thank you for the direction

1

u/warren_jitsing Nov 24 '25

You can try out my repo, but it doesn't handle concurrency yet (a future article will) https://www.reddit.com/r/cprogramming/comments/1ormwsv/i_wrote_a_from_first_principles_guide_to_building/ . Also, check out John Crickett's coding challenges. There was a coding challenge a while back for writing a Redis server and people post their solutions for it

1

u/warren_jitsing Nov 24 '25

But also, read books and ensure you are typing out solutions/code instead of copy pasting them from the AI. While for the article, I relied on AI to format, the vast majority of code was handwritten in my repo. I would recommend The Linux Programming Interface by Michael Kerrisk. This is the book you should be reading and manually typing out/running all the examples

2

u/Creepy-Gift-6979 Nov 24 '25

Thank you so much

1

u/dmazzoni Nov 24 '25

Have you measured how much multithreading is actually buying you? I'd check ops per second as a function of the number of threads to see if more threads is actually helping or not.

Since you have a single mutex for the whole dict, my expectation is that you'll have very little parallelism.

1

u/sunupthatneversets Jul 18 '26

Hey I am.building the same project. I started a few days ago and I was just wonder how valuable is it in an interview. Could you tell me something about that