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Instant database clones with PostgreSQL 18

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Re: Instant database clones with PostgreSQL 18

#111

Post by theturtletalks »

newusertoday wrote: post #105
elitan wrote: post #17

For those who can't wait for PG18 or need full instance isolation: I built Velo, which does instant branching using ZFS snapshots instead of reflinks. Works with any PG version today. Each branch is a fully isolated PostgreSQL container with its own port. ~2-5 seconds for a 100GB database. https://github.com/elitan/velo Main difference from PG18's approach: you get complete server isolation (useful for testing migrat…

thanks for sharing its interesting approach. I am not sure why people are complaining most of the software is written with the help of agents these days.

It’s rampant. Launch anything these days and it’s bombarded with “vibe-coded” comments.

The issue of quality makes sense since it’s so easy to build these days, but when the product is open-source, these vibe coded comments make no sense. Users can literally go read the code or my favorite? Repomix it, pop it into AI Studio, and ask Gemini what this person has built, what value it brings, and does it solve the problem I have?

For vibe coded proprietary apps, you can’t do that so the comments are sort of justified.

Re: Instant database clones with PostgreSQL 18

#112

Post by scottyah »

riskable wrote: post #85

PostgreSQL seems to have become the be-all, end-all SQL database that does everything and does it all well. And it's free! I'm wondering why anyone would want to use anything else at this point (for SQL).

It's heavy, I'd say sqlite3 close to the client and postgres back at the server farm is the combo to use.

Re: Instant database clones with PostgreSQL 18

#113

Post by cstrahan »

teiferer wrote: post #21
elitan wrote: post #17

For those who can't wait for PG18 or need full instance isolation: I built Velo, which does instant branching using ZFS snapshots instead of reflinks. Works with any PG version today. Each branch is a fully isolated PostgreSQL container with its own port. ~2-5 seconds for a 100GB database. https://github.com/elitan/velo Main difference from PG18's approach: you get complete server isolation (useful for testing migrat…

You mean you told Claude a bunch of details and it built it for you? Mind you, I'm not saying it's bad per se. But shouldn't we be open and honest about this? I wonder if this is the new normal. Somebody says "I built Xyz" but then you realize it's vibe coded.

Do you take issue with companies stating that they (the company) built something, instead of stating that their employees built something? Should the architects and senior developers disclaim any credit, because the majority of tickets were completed by junior and mid-level developers?

Do you take issue with a CNC machinist stating that they made something, rather than stating that they did the CAD and CAM work but that it was the CNC machine that made the part?

Non-zero delegation doesn’t mean that the person(s) doing the delegating have put zero effort into making something, so I don’t think that delegation makes it dishonest to say that you made something. But perhaps you disagree. Or, maybe you think the use of AI means that the person using AI isn’t putting any constructive effort into what was made — but then I’d say that you’re likely way overestimating the ability of LLMs.

Re: Instant database clones with PostgreSQL 18

#114

Post by fanf2 »

pak9rabid wrote: post #64
francislavoie wrote: post #23

Is anyone aware of something like this for MariaDB? Something we've been trying to solve for a long time is having instant DB resets between acceptance tests (in CI or locally) back to our known fixture state, but right now it takes decently long (like half a second to a couple seconds, I haven't benchmarked it in a while) and that's by far the slowest thing in our tests. I just want fast snapshotted resets/rewinds t…

I was able to accomplish this by doing each test within its own transaction session that gets rolled-back after each test. This way I'm allowed to modify the database to suit my needs for each test, then it gets magically reset back to its known state for the next test. Transaction rollbacks are very quick.

This doesn’t work for testing migrations because MySQL/MariaDB doesn’t support DDL inside transactions, unlike PostgreSQL.

Re: Instant database clones with PostgreSQL 18

#115

Post by teiferer »

cstrahan wrote: post #113
teiferer wrote: post #21

Earlier quoted context omitted.

You mean you told Claude a bunch of details and it built it for you? Mind you, I'm not saying it's bad per se. But shouldn't we be open and honest about this? I wonder if this is the new normal. Somebody says "I built Xyz" but then you realize it's vibe coded.

Do you take issue with companies stating that they (the company) built something, instead of stating that their employees built something? Should the architects and senior developers disclaim any credit, because the majority of tickets were completed by junior and mid-level developers? Do you take issue with a CNC machinist stating that they made something, rather than stating that they did the CAD and CAM work but t…

Could we please avoid the strawmen? Nowhere have I claimed that they didn't put work into this. Nowhere did I say that delegation is bad. I'd like to encourage a discussion, but then please counter the opinion that I gave, not a made-up one that I neither stated nor actually hold.

Re: Instant database clones with PostgreSQL 18

#116

Post by aftbit »

riskable wrote: post #85

PostgreSQL seems to have become the be-all, end-all SQL database that does everything and does it all well. And it's free! I'm wondering why anyone would want to use anything else at this point (for SQL).

Once upon a time, MySQL/InnoDB was a better performance choice for UPDATE-heavy workloads. There was a somewhat famous blog post about this from Uber[1]. I'm not sure to what extent this persists today. The other big competitor is sqlite3, which fills a totally different niche for running databases on the edge and in-product.

Personally, I wouldn't use any SQL DB other that PostgreSQL for the typical "database in the cloud" use case, but I have years of experience both developing for and administering production PostgreSQL DBs, going back to 9.5 days at least. It has its warts, but I've grown to trust and understand it.

1: https://www.uber.com/blog/postgres-to-mysql-migration/

Re: Instant database clones with PostgreSQL 18

#117

Post by francislavoie »

pak9rabid wrote: post #64
francislavoie wrote: post #23

Is anyone aware of something like this for MariaDB? Something we've been trying to solve for a long time is having instant DB resets between acceptance tests (in CI or locally) back to our known fixture state, but right now it takes decently long (like half a second to a couple seconds, I haven't benchmarked it in a while) and that's by far the slowest thing in our tests. I just want fast snapshotted resets/rewinds t…

I was able to accomplish this by doing each test within its own transaction session that gets rolled-back after each test. This way I'm allowed to modify the database to suit my needs for each test, then it gets magically reset back to its known state for the next test. Transaction rollbacks are very quick.

Unfortunately a lot of our tests use transactions themselves because we lock the user row when we do anything to ensure consistency, and I'm pretty sure nested transactions are still not a thing.

Re: Instant database clones with PostgreSQL 18

#118

Post by teiferer »

fauigerzigerk wrote: post #101
pritambarhate wrote: post #80

Earlier quoted context omitted.

Even with LLMs delivering software that consistently works requires quite a bit of work and in most cases requires certain level of expertise. Humans also write quite a bit of garbage code. People using LLMs to code these days is similar to how majority people stopped using assembly and moved to C and C++, then to garbage collected languages and dynamically typed languages. People were always looking for ways to make…

I'm not opposed to AI generated code in principle. I'm just saying that we don't know how much effort was put into making this and we don't know whether it works. The existence of a repository containing hundereds of files, thousands of SLOCs and a folder full of tests tells us less today than it used to. There's one thing in particular that I find quite astonishing sometimes. I don't know about this particular proje…

I fully agree with your overall message and sentiment. But let me be nit-picky for a moment.

> The test cases are supposed to be the formal specification of our requirements

Formal methods folks would strongly disagree with this statement. Tests are informal specifications in the sense that they don't provide a formal (mathematically rigorous) description of the full expected behavior of the system. Instead, they offer a mere glimpse into what we hope the system would do.

And that's an important part, which is where your main point stands. The test is what confirms that the thing the LLM built conforms to the cases the human expected to behave in a certain way. That's why the human needs to provide them.

(The human could take help of an LLM to write the tests, as in they give an even-more-informal natural language description of what the test should do. But the human then needs to make sure that the test really does that and maybe fill in some gaps.)

Re: Instant database clones with PostgreSQL 18

#119

Post by teiferer »

dpedu wrote: post #32
teiferer wrote: post #21

Earlier quoted context omitted.

You mean you told Claude a bunch of details and it built it for you? Mind you, I'm not saying it's bad per se. But shouldn't we be open and honest about this? I wonder if this is the new normal. Somebody says "I built Xyz" but then you realize it's vibe coded.

Huh? It says so right in the README. https://github.com/elitan/velo/blame/12712e26b18d0935bfb6c6e... And are we really doing this? Do we need to admit how every line of code was produced? Why? Are you expecting to see "built with the influence of Stackoverflow answers" or "google searches" on every single piece of software ever? It's an exercise of pointlessness.

Indeed. There is a difference between "I have learnes by reading a lot of SO" and "I have copied the contents of this file verbatim from SO". Using Claude is very close to the latter without saying it.

Re: Instant database clones with PostgreSQL 18

#120

Post by victorbjorklund »

risyachka wrote: post #67
pritambarhate wrote: post #38

Earlier quoted context omitted.

Let's say there is an architect and he also owns a construction company. This architect, then designs a building and gets it built from of his employees and contractors. In such cases the person says, I have built this building. People who found companies, say they have built companies. It's commonly accepted in our society. So even if Claude built for it for GP, as long as GP designed it, paid for tools (Claude) to…

Asking someone to build a house - and then saying I built it - is "very misleading" to put it nicely. When you order a website on upwork - you didn't build it. You bought it.

Plenty of architects claim ”this is my building” even if they didn’t pour all the concrete
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