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Postgres rewritten in Rust, now passing 100% of the Postgres regression tests

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Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests

#31

Post by rustyhancock »

sshine wrote: post #14
gingersnap wrote: post #3

I start to see a lot of these re-writes that depend on tests to state that its working. But the things that make software like Postgres and SQLite reliable are not mostly the test, but the real world production scars. That's where the reliability comes from, years and years of running in production.

> not mostly the test, but the real world production scars Most extensive test suites are exactly production scars: every time you have a bug or a regression, you write a test that confirms correct behaviour. SQLite is a good example to bring up because its extensive closed-source tests are what’s often cited as being what keeps people from forking it. (Turso did it, though, but it takes a company to deliver some gua…

One issue is those are the bugs you get when you write it in C++.

They aren't the bugs you get when you write it in Rust.

The kind of bugs you get are usually a function of the problem, language, implementation approach.

Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests

#32

Post by flanked-evergl »

What is the future of this? Code is not the same as a viable open-source project with a community, contributors, advocates, users and funding, even if it's perfect code.

Even though I'm sure it won't be easy to convince the Postgres project to switch to Rust, I do think that trying would be time better spent.

Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests

#33

Post by ottavio »

Why should a developer use this for anything beyond a pet project? Just because it is written in Rust?

All these "rewritten in rust" projects only reinforce the idea that a significant part of the rust community consists of software talibans and not of engineers who must deliver something that works and is reliable over time.

Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests

#34

Post by kelnos »

sshine wrote: post #14
gingersnap wrote: post #3

I start to see a lot of these re-writes that depend on tests to state that its working. But the things that make software like Postgres and SQLite reliable are not mostly the test, but the real world production scars. That's where the reliability comes from, years and years of running in production.

> not mostly the test, but the real world production scars Most extensive test suites are exactly production scars: every time you have a bug or a regression, you write a test that confirms correct behaviour. SQLite is a good example to bring up because its extensive closed-source tests are what’s often cited as being what keeps people from forking it. (Turso did it, though, but it takes a company to deliver some gua…

Sure, but behaviors that never have a bug or regression don't get a test. Software of this kind of complexity has all kinds of behavior that has never been broken, and doesn't have a specific test written for it.

Getting an extensive test suite passing is certainly orders of magnitude better than having no test suite at all, but it still doesn't tell you as much as you need to know. I would absolutely never trust an LLM Postgres rewrite (in any language) in production based on "only" Postgres's test suite passing.

Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests

#35

Post by bozdemir »

juliangmp wrote: post #2

I feel like we need to heavily differentiate between a rewrite and an AI rewrite.

I'd %100 prefer an opus 4.8 rewrite over %99 of the time. Unless Fabrice Bellard is rewriting the stuff I need, I'd prefer AI over a human coder.

Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests

#36

Post by kelnos »

kstrauser wrote: post #7
gingersnap wrote: post #3

I start to see a lot of these re-writes that depend on tests to state that its working. But the things that make software like Postgres and SQLite reliable are not mostly the test, but the real world production scars. That's where the reliability comes from, years and years of running in production.

In a project like PostgreSQL, those scars are reflected in unit tests demonstrating that they’re fixed. It’d be hard to pass its test suite and not be as robust as the original.

Passing a regression test suite only proves that those particular regressions aren't present. It proves nothing about robustness beyond that.

Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests

#37

Post by raincole »

bozdemir wrote: post #35
juliangmp wrote: post #2

I feel like we need to heavily differentiate between a rewrite and an AI rewrite.

I'd %100 prefer an opus 4.8 rewrite over %99 of the time. Unless Fabrice Bellard is rewriting the stuff I need, I'd prefer AI over a human coder.

Or, you know, you can use Postgres. It's right there for you.

Re: Postgres rewritten in Rust, now passing 100% of the Postgres regression tests

#40

Post by alex_duf »

ottavio wrote: post #33

Why should a developer use this for anything beyond a pet project? Just because it is written in Rust? All these "rewritten in rust" projects only reinforce the idea that a significant part of the rust community consists of software talibans and not of engineers who must deliver something that works and is reliable over time.

I think this shouldn't be taken too seriously, from what I understand it's an exploration of what's possible with today's LLMs.

You're right to talk about the trend though, because what it shows is how the cost of re-writing well covered project has completely crashed, so that in itself is a learning.

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