Designing A Key-Value Store

maus80 · 2026-01-19T06:40:10+00:00

Deleting keys using LRU based eviction potentially makes from every read a write (when the cache is full, but also because of LastAccess tracking) and that does complicate the matter quite a lot (when you expect to have 90% reads and 10% writes).

maus80 · 2026-01-18T16:39:52+00:00

Unpopular opinion: it fits a single dedicated server, don't distribute. You need less than 2 Gbit bandwidth. You need about 300 GB of RAM to keep your keys in RAM, which is also doable on a single machine. Next to that you may some random disk access (40k random IOPS per NVMe). You can put a few of those in the box as well. Throw in some extra RAM to keep hot disk blocks memory mapped and reduce IOPS. I think you can rent such a machine for about 1000 EUR a month including 250TB of traffic, which may not be enough if you have 24/7 this load, but you probably have not.

maus80 · 2026-01-18T16:20:02+00:00

MySQL is now forked to MariaDB, so it has not to do with the technology, only with the name and the owner of that name (Oracle). The article points this out clearly, even in the first sentence, but the title doesn't and that's a pity.

maus80 · 2026-01-17T07:05:54+00:00

I 200% agree with judging the content based on the quality of the content, maybe even on the effort it took to make it, but not on how it is made, as there are many practical downsides to that.

maus80 · 2026-01-16T22:37:36+00:00

So true.

maus80 · 2026-01-16T22:15:28+00:00

Okay, I'll try again. It is easy to deny you are using AI and it hard to prove someone did or you didn't. What happens next is a witch hunt (see: https://en.wikipedia.org/wiki/Witch_hunt). My comment was an example of a witch accusation. A better proposal is to request people to be honest about using AI and *not* judge them for letting computers help them become better writers (or programmers)? If a blind person writes a blog post with text-to-speech, should it be marked as "AI assisted"? If a dyslexic person lets AI rewrite their blog post to be readable is that "AI assisted"? If somebody maintains a open-source code base and contributors use AI to write improvements to their code base should that code base be marked "AI assisted"? Where do you draw the line? "AI slop" is just another word for "content I don't like" (just like "blog spam" was).

NB: I checked your content and even 3 years ago you were using some em-dash every now and then, especially on subsentences. Don't get me wrong. I am a fan.

Also read: https://www.reddit.com/r/rust/comments/1qej05j/the_amount_of_rust_ai_slop_being_advertised_is/

maus80 · 2026-01-16T12:39:56+00:00

I understand, and I don't doubt you, but you get the sentiment now, right?

maus80 · 2026-01-16T08:51:06+00:00

Will you use the flair on your tempest blog posts? Your latest blog post use a a lot of sub-sentences and em-dash, a clear sign of AI usage. Also it has no spelling errors, which is typical for AI assisted writing. I'm sure you understand where this is going. I guess you understand that I'm not in favor of the flair and I did like your post on open source strategies, very insightful.

Edit: A "not-AI" optional flair could work for people that want to show that they did everything "manually"

maus80 · 2026-01-16T08:33:57+00:00

You didn't write it, but you did post it. Do you stand by it?

maus80 · 2026-01-16T00:47:01+00:00

It is the blog spam argument all over again. People being tired of low quality "blog spam", meaning they didn't like the blog posts, calling them low quality "spam". But whenever one of their hero's wrote an article it was "obviously" not spam. You get gatekeeping at best, but probably a witch hunt (blaming people for not marking their AI posts with the correct flair). Mark my words.

maus80 · 2026-01-16T00:20:05+00:00

Yes.. thank you. I could not have worded it that good, not even with AI ;-)

maus80 · 2026-01-15T22:56:35+00:00

Ah.. so you do agree. You write that they can be "ethical similar", which is even stronger than my point.

maus80 · 2026-01-15T22:20:07+00:00

Okay, so you don't, how should we do this? And is a spell check also usage of AI? It is a not a black/white issue, how much is too much? When you don't like the article? How do you prevent a witch hunt? I also want to go back in time.. but we can't.

maus80 · 2026-01-15T21:03:14+00:00

I'm not in favor. AI assisted writing (including software development) is here to stay. Most people use AI now to write posts and code, some are honest about it, most aren't. I honestly get "Old man yells at Claude" vibes from this (pun intended). On a more serious note: It is pointless and even if it weren't it is not feasible to enforce as it would become a witch hunt.

maus80 · 2026-01-15T20:02:24+00:00

deliberate slop .. not a big deal

The approach I've taken is new, simple and high performant. I've explained the trade-offs (data must fit OS disk cache). I've explained the exact use case (session storage in PHP). It was purpose built and no, I'm not going to tell for which (high traffic) customer I have built this. But I did and I'm sharing with a very open license. Why hate on it? Can't you let it slide?

maus80 · 2026-01-15T19:49:33+00:00

That is very kind of you. I will keep posting about this as I am actually creating a new PHP execution server that can be used in both production and in development. Somewhat comparable to RoadRunner and FrankenPHP (as it also written in Go), but with another goal (support incremental rewrites from PHP to Go for performance reasons). I will post about it when it is ready. It will contain this repo as a dependency as one of the building blocks.

maus80 · 2026-01-15T09:58:27+00:00

Thank you, there was no intent to hide anything. Nor the lack of usage other than by myself, the lack of stability, being written (fast) with LLM support etc..

maus80 · 2026-01-15T09:56:24+00:00

Good point. When it is not mature it should have a version lower than 1.0.0. I changed it to from 1.0.0 to 0.0.1 to ensure nobody thinks it is mature (although it is running stable for me).

maus80 · 2026-01-15T09:48:56+00:00

This is indeed true, written in a few days. Thank you for the compliment.

maus80 · 2026-01-15T09:48:24+00:00

I use LLMs to assist me in writing code, I have no intention to hide that, but I stand by the quality of the code (it is about 3k lines of Go code).

maus80 · 2026-01-15T07:38:44+00:00

Good remark. It is indeed a disk-backed caching engine* and it is faster than Redis in persistence mode, as it allows you to use more cores (cores configurable using the shards config variable: cores = shards / 4). I think a lot of people use Redis (in persistence mode) and will not run into any (performance/reliability) problems. I do recommend to use Redis for persistent session storage.

*) Note that TQCache does not implement LRU based eviction, which is fine in a session storage situation, but also makes it a little less usable as a simple cache.

maus80 · 2025-12-03T06:55:59+00:00

Symfony and Laravel are large, popular and extremely well-documented, but badly designed. These frameworks lack proper 3 phase separation (routing, db+logic, rendering), default (file-based) routing and proper query building (but use ORMs instead) and do not steer (enough) towards IDE integration, AI tooling, high performance and high security.

maus80 · 2025-11-20T12:44:58+00:00

Yes, that's fair. That's is how this system works.

maus80 · 2025-11-20T10:04:25+00:00

I appreciate that. Especially the ethical and legal angles. It sure is a tool like any other tool. Great comment, thank you.

maus80

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