Making Postgres 300x faster for analytics: batching, operator fusion, and SIMD (malisper.me)

264 points by poly2it 17 hours ago

malisper 13 hours ago

Author here. Let me know if you have any questions about the post or about pgrust.

Let me take a shot at answering what I think will be the most common question: how can I trust pgrust? Our #1 priority right now is correctness. Over the past two weeks, I've done a mix of formal verification and differential fuzz testing. We've been able to prove over 1000 user facing functions have the exact same logic in both pgrust and postgres (see the proofs directory if you're curious). For cases where formal verification is not easy, we've taken the c implementation of a function and the rust implementation of a function and ran millions of inputs through each of them and confirmed they gave the same results every time.

We've only covered about 15% of the surface area so far, but in the process, we've discovered ~100 bugs in pgrust and ~20 bugs in Postgres itself. My favorite postgres bug we found is this one[0]. Postgres has a quadtree implementation. Due to floating point rounding, it was possible for a point to be neither above, nor below, nor even with the center point of the quadtree.

We've also entered engagements with Antithesis[1] to do Jepsen style fault testing and Aretta[2] to do more serious formal verification.

If you want to support the project, the easiest way is to give us a star on GitHub[3]

[0] https://www.postgresql.org/message-id/19597-39c532e61d78dff6...

[1] https://antithesis.com/

[2] https://aretta.ai/

[3] https://github.com/malisper/pgrust

marginalia_nu 11 hours ago

How do you know if you're making the right optimizations?

I struggle with this a lot with Marginalia's index. Where I identify a hot method in a prod profiler run, try to replicate it on a test machine where I can never get the same cache characteristics because everything in this space is like an onion of caching layers that you affect the real performance of the system. I may get it to run significantly faster, but that only sometimes makes the production profiler sample move its needle.

e.g. I've recently been experimenting with using a cursed hybrid model in Marginalia's index, where based on a mincore probe, I switch between mmap and io_uring for reading a cluster of pseudoadjacent data. There are real tanglible benefits both in the test machine and in prod with this, but the numbers do not agree at all about how the needle moves :P

malisper 11 hours ago

I would probably dig into the reasons for the differences in the benefit on the test machine and in prod

I had an issue like this for optimizing pgrust. I had an optimization that showed no impact on my test machine (c8g.4xl) and showed a 20% improvement when ran on my mac. It turns out the issue was the instruction cache on the c8g.4xl was being saturated on the test machine but not on my laptop, moving the bottleneck to a different place

If you can consistently reproduce the performance difference, you're already half way there

marginalia_nu 10 hours ago

postgresperf 3 hours ago

Optimizing a multi-layer cache system is a Complex System task with no subset you can reduce to a simpler version of the problem. PG has a 3 layer cache--database, OS, storage--and when you combine that with concurrency and locality, you have a giant 5 dimensional space to map out. Building the right set of benchmarks for PG with guidance for the most important parts to navigate fro that space has kept me busy for 20 years now.

jnwatson 12 hours ago

The floating point comparison bug is nightmare fuel. I could look at that for years and never spot the mistake.

bee_rider 12 hours ago

On the bright side it could probably run for years without hitting the mistake as well. But it is nice to get it out of there.

wffurr 11 hours ago

Fuzzers are brilliant at this and produce all kinds of insane floating point inputs.

btown 12 hours ago

If someone wanted to use this as a real-time WAL-tracking read-only mirror of a live production database, for analytics work, is it ready for that use case yet?

postgresperf 3 hours ago

When I got early access to pgrust my first question was whether it had been tested for building read-only standby analytics questions. The problem has goals beyond that, but having a real analytics node available just by playing WAL data from your primary makes pgrust a low risk eval for your data. Just have to build confidence the results are connection, which is being applied by all the PG infrastructure regression tests the code has been trained on,

malisper 12 hours ago

You can try it. We're happy to help you with it, but expect there to be issues to work through. You would want to do it for something non-critical

wkoszek 4 hours ago

I really hope your project succeeds so that you can sit, sip delicious coffee with your legs on a high desk, and laugh really loud, like a gorilla, at all the haters from this and previous HN threads.

malisper 3 hours ago

Thanks!

throwaway7783 11 hours ago

This is a great project. Thank you!

A question on 20s postgresql time - It does not look like you are accounting for reading data from disk? Wouldn't the aggregation query have to load data from disk first? Or is it somewhat guaranteed that the table is already in memory? The Rust version is clearly in memory (I am no rust expert, so that may not even be actually in memory, if its a generator).

malisper 11 hours ago

> A question on 20s postgresql time - It does not look like you are accounting for reading data from disk

I choose the data size so that it would fit in memory on the machine I was testing on. fwiw, there's still a ton of overhead Postgres has that the toy example does not. For example Postgres will serialize the numbers into tuples and need to deserialize them to execute the query. That's why it's not an apples-to-apples comparison

lizimo 12 hours ago

Is `pgrcolumnar` the default storage layout for tables? It would be cool if the same storage engine outperforms vanilla Postgres under both OLTP and OLAP workloads.

AlloyDB from Google Cloud uses columnar storage like a secondary index, while the relations are still stored in TOAST.

malisper 12 hours ago

pgrcolumnar is not the default storage method. Right now, it's exposed as a table access method. There's lots of design space for how to do this so I want to avoid pre-committing to anything

andriy_koval 12 hours ago

what is your vision of this project? Do you think pgrust will eventually be prod ready?

malisper 12 hours ago

I want to build the best database possible. While Postgres is great, there are a lot of core issues that have been around for over a decade. We're working hard to get pgrust production-ready, and it will definitely be production-ready in the near future. I wouldn't be putting hundreds of thousands of dollars into this project if I didn't think we could build a production-ready database.

timacles an hour ago

theplumber 5 hours ago

doctorpangloss 13 hours ago

“Show me the prompt.”

sgt 11 hours ago

Cool project but .. reality is that people will generally not choose pgrust over Postgres, even 5-10 years from now. The problem is not that it may be technically superior and faster by then, it's that it's not built by the trusted Postgres team. There's a lot more to trust than development velocity or performance. It's also about the longevity and continuity of a critical piece of technology.

andriy_koval 11 hours ago

People will use it if it really delivers gain and can solve problems PG can't.

f311a 8 hours ago

It takes years to test it thoroughly in real environments. You don't want your data to be silently corrupted.

ozgrakkurt 2 hours ago

People are very willing to use new things when something they are using can't do what they want to do.

Dogma is more effective than reliability concerns in my experience. It just happens that the dogma prefers Postgres in this case.

It is just difficult to make these decisions in a more informed way because it requires actual manual testing with the concrete use case and also a decent understanding of databases in question. Chances are you won't have people that understand these things or those people won't have much of a say in decisions.

59nadir 6 hours ago

There's also the fact that it's basically vibecoded.

whateveracct 5 hours ago

potemkin industry. jeez.

quadrifoliate 4 hours ago

We still have companies that use COBOL and mainframes due to their longevity and continuity. There is no reason Postgres and pgrust cannot both flourish. I can pick and choose which one to use according to its use case.

yieldcrv 11 hours ago

Their ai agents will if we keep writing about it

Project managers and Human Resources rolling out overengineered projects will outnumber current software engineers 10 to 1

sgt 10 hours ago

That's a pretty gloomy view

yieldcrv 10 hours ago

hmokiguess 2 hours ago

I don’t understand. It’s not like we don’t already have faster alternatives, don’t we have things like k and kdb that are many orders of magnitude faster even than this?

We use Postgres because it’s fantastic at the scale and problems it solve, if you have an extremely critical system where raw speed is at the core of everything and you’re dealing with petascale then maybe you’re bringing a solution you like to a problem it doesn’t fit?

AsyncBanana 11 hours ago

You have no idea how long I have been waiting for adaptive planning. One of my biggest annoyances with the Postgres core team has been their reluctance to implement any sort of adaptive planning despite it, at this point, being a well-established technique that has been implemented in multiple production databases. I hope this, at the very least, proves the viability of this model outside of academic/niche contexts.

rastignack 12 hours ago

I would be interested about a more detailed architecture overview of the io scheduler (like this: https://www.scylladb.com/2021/04/06/scyllas-new-io-scheduler...) and the thread scheduler.

PostgreSQL has historically been bad at managing the noisy neighbor problem, but with thread pools, and io priorities, it can be solved.

Has this been tackled here ?

malisper 12 hours ago

I'll need to write up how the scheduler works at some point, but it's heavily based on these papers[0][1]. It solves two different problems. First, it lets us throttle resource-intensive queries. Second, it enables work stealing. If you have idle cores on your machine, we'll assign those cores to running queries to help speed them up. That means if you have an over-provisioned machine, we'll make use of the extra capacity to speed your queries up.

[0] https://15721.courses.cs.cmu.edu/spring2016/papers/p743-leis...

[1] https://db.in.tum.de/~kohn/papers/query-scheduling-sigmod21....

ZiiS 9 hours ago

Surly AI could also write a clearer headline. For the millions running it in production for decades, using a great echosystem of help support, books, consultants, and managed hosting providers; the is a noteworthy difference between the official release and a partially compatable rewrite.

3dedb728-3f77 6 hours ago

So one trick you can do is make a ramfs/tmpfs and start Postgres on it.

You need a server with enough ram to fit it all.

But it kind of make the database fly.

shdnx 5 hours ago

You can certainly do that, but it'll perform much worse than properly tuning your Postgresql to take advantage of requiring no durability and having lots of RAM. Source: I do this kind of thing for a living.

lossolo 5 hours ago

Or you can also just place one or more tables on tmpfs, we are doing that in production.

kopirgan 4 hours ago

Can some of these optimization get back propagated to Postgres?

refulgentis 11 hours ago

The project has 2 commits.

2.

Commit #1's message is "hey claude, do a breakthrough" from a week ago and is 1.5M lines. Commit #2 is "blog post" from 4 days ago.

My head is spinning. I don't mind AI stuff or AI enabled stuff but there's gotta be some bar for ending up on HN, and also personal accountability: the lack of humility and honesty sets a new low for me. There is no "we" who "released pgrust 0.2". It's one person cosplaying a serious engineering team doing a mountain of work. The bus factor is 1, and its one you can't trust on the basics.

ex. the first 1/3 of the blog post is bloviating about how a rust for loop is faster at summing 500M numbers on the heap than loading the numbers from a table and summing them.

It leaves me in quite some anguish. This site kept me well-informed and growing for 16 years. It is no longer reliable for that as long as things like this can be the #1 post with 60 comments, with the author here, and no one mentioned any of this.

wffurr 10 hours ago

The second line of commit #2's message is "You can find the actual git history at the v0.2 github tag." which in turn has almost 6000 commits.

I think it's a weird way to handle git history versus squashing feature branches into single commits, but it's not just one Claude session slapped up on GitHub. The OP also has a post above about their exhaustive testing which has uncovered a goodly number of bugs in Postgres itself, too. I think it's fair to say they're putting in a good amount of work on this.

refulgentis 10 hours ago

I cloned it. The 6000 commits are the problem, not the defense.

5,940 commits, one author, 29 days. 5,067 of them, 85%, have a `Co-Authored-By: Claude` trailer. Busiest day is 1,393 commits, running 60-105/hour for ~20 hours straight. Commit messages reference .claude/skills/fleet/ and agent worktree "lanes". That's an unattended agent fleet committing once a minute around the clock. Commit count used to mean review time. Here it means GPU time.

Also: the v0.2 tag shares no common ancestor with main. git merge-base fails. "The actual git history" is an orphan branch grafted in after the fact.

And the testing rigor we're crediting them for should be weighed against the headline claim: 300x faster than Postgres, ahead of ClickHouse: fastest analytical DB on earth, one guy, one month.

Most damning: the Postgres baseline ran with *max_parallel_workers_per_gather = 0*. Parallel engine vs. deliberately-hobbled single-core Postgres, headline says 300x.

Using AI is fine. But "look how many commits" is precisely the signal this workflow is built to fake.

sunzhousz 7 hours ago

I am very disappointed to see the direction: It is moving from a "interesting attempt to recreate system software" to "building flashy but useless demo"

Everyone who knows a bit about databases knows the difference between execution models and what kind of optimization it brings.

malisper 6 hours ago

> I am very disappointed to see the direction: It is moving from a "interesting attempt to recreate system software" to "building flashy but useless demo"

What makes you say this is a useless demo? I can't count the number of people who've struggled to do analytics inside of Postgres. Almost always they end up setting up a separate system such as Clickhouse and replicating the data between the two systems. Now they can have one system that's Postgres-compatible, and it's faster than either of the original systems.

> Everyone who knows a bit about databases knows the difference between execution models and what kind of optimization it brings.

In our last post[0], when we mentioned we were getting close to Clickhouse level performance (now faster than Clickhouse), we were met with disbelief. This post is meant to explain part of how we closed the 300x gap between Postgres and Clickhouse. The execution model being 10x of it.

[0] https://news.ycombinator.com/item?id=48841676

patkepa 7 hours ago

Question, does having it in pure rust, opens possibility of embedding pgrust directly into binary, making it an alternative to SQLite/turso?

malisper 5 hours ago

It absolutely can be embedded. The bigger enabler is replacing the process-per-connection model with a thread-per-connection model. Projects like pglite[0] had to give up concurrency because of it. We also support compiling to wasm so you can embed it in the browser too, which is what powers pgrust.com

[0] https://github.com/electric-sql/pglite

[1] https://pgrust.com/

ComputerGuru an hour ago

Look into tursodb for this.

wkoszek 4 hours ago

I'd help with testing if you helped them add this. I'd be interested in this.

luciana1u 8 hours ago

300x faster is nice, but I mostly clicked to see if operator fusion finally explains why my GROUP BY still feels like it is doing the work by hand.

Lucasoato 12 hours ago

I’m curious to see how this compares to pgColumnar or other OLAP extensions.

malisper 12 hours ago

At least in terms of speed, we're much faster on clickbench: https://benchmark.clickhouse.com/#system=+_b|pnc|pgrs|gQ|saB...

wiradikusuma 10 hours ago

I think in addition to making it faster, it would be useful if it could be made "leaner," e.g. can run better on lower-spec hardware than PG.

claytonjy 10 hours ago

does one not imply the other? if it can run faster in the same hardware, it should also run as fast on lower spec hardware

smolder 9 hours ago

No, it doesn't. Different algorithms can vary pretty wildly in performance based on the design of the hardware they run on. For instance cache sizes can make one implementation of a sort on a certain sized dataset faster or slower than another. You can have a theoretically fast algorithm that just isn't as cache efficient as a theoretically slower one in big-O terms. All levels of the memory hierarchy as well as storage have specific bandwidths and latencies that inform the real world performance results. Parallelism is another issue. Many cores can do work very fast when you're careful about how you split up work between them, taking into consideration the synchronization latency and individual cache sizes and so on. The best approach for doing work on 64 cores can be dramatically different from what works best on 1 or even 2.

Tuna-Fish 9 hours ago

That is not a given. A database server can run faster on better hardware because it more effectively and aggressively caches things in memory, which can hurt it on lower-spec systems. Or it can better utilize SIMD instructions that are not present on the low end. Or it is more effective at utilizing more threads, but is slower when run at a low threadcount, etc etc etc.

wiradikusuma 10 hours ago

If I'm not mistaken ClickHouse's min spec is quite steep.

KolmogorovComp 11 hours ago

Thanks to the authors for choosing a license that respect users freedom, on top of being an awesome technical project.

jjice 9 hours ago

While I do like pgrust's license, I do feel like it's kind of wrong to port in such a direct way and change the license. I guess this isn't a fork, but it kind of is? It looks like according to this post [0], they did a Claude Fable + Opus re-write. I know that legally this is seemingly a valid way to do things and avoid copyright, but it feels wrong to me. I don't even necessarily think that my feelings are correct, but standing on the backs of giants and using an LLM to "reimplement" the code (not a clean room implementation) feels like it's it _shouldn't_ be a valid way to avoid copyright or allow for license changes.

Now, I don't know how MIT -> AGPL re-licensing specifics work, but still.

[0] https://malisper.me/postgres-in-rust-regression-suite/

nz 7 hours ago

My understanding is that they used c2rust, and then told the LLM/Agents to make the code more idiomatic rust, while also using the PG test suite as a feedback mechanism. This is almost certainly a derived work (and thus a fork, and should thus have the original license and copyright preserved).

For example, if I compiled PG into x86-64 assembly, and then decompiled it into C (via, say, IDA), and then polished that decompiled C code into very readable C code, it is still a derived work. For some reason, people think that if you include an LLM or Agent, copyright can be ignored, and plagiarism is now no longer possible.

It is similar to the crypto-folks thinking that if you use crypto, you no longer have to pay taxes, because the internet/computers make all inconvenient realities go away.

Honestly, such flagrant and arrogant copyright violations make it hard for me to take the project seriously, because it seems like a desperate stunt for attention (which itself may be a solid business move, but that is besides the point).

Put differently, if one were to fork pgrust, strip away the new license and copyright, and restore the original PG license and copyright (while also adding malisper+team to that copyright), they would face no legal consequences at all. In fact, they would probably be a less legal risk than the pgrust team.

malisper 5 hours ago

imhoguy 8 hours ago

Does that license protect anything legally? This is written by AI under some initial guidance. Prompts may be protected but the output of unlicensed knowledge model corpus?

up2isomorphism 5 hours ago

300x if it is true you will be just busy dealing with you customers rather than pitching here. Also since it is a vibe coded project, if you are really that good , you should even need to related yourself with Postgres. Who will want related itself to something that is 300x slower than itself?

wkoszek 4 hours ago

You use stability of PostgreSQL to open a pitch. Also most people use PostgreSQL because someone out there was a fan, proponent and champion of Postgres. Otherwise they'd be on MySQL or Oracle.

And your sales folks would call and say: "No need to change anything, we still run PostgreSQL, and ours is just called pgrust, but it's N times as fast".

jiggawatts 5 hours ago

Batch mode execution has been in Microsoft SQL Server for a while and just recently gained AVX-512 support.

I’ve done some experiments replacing spatial SQL queries with custom vectorised batch mode code in C# and the speed up was astonishing.

The people dubious about these claims have no idea what their computers are really capable of.

Seattle3503 8 hours ago

pgrust looks interesting. Could it be used as a library by someone who wants a new DB for each integration test in their Rust test suite?

malisper 8 hours ago

One of the new features we recently built is "test mode". This brings cloning a template db from 100ms down to <10ms making it much better for tests.

If you're interested in trying it out, please reach out to me at malis@pgrust.com

cognitiveinline 15 hours ago

pgrust seems to have good momentum. AGPL is an odd license for a non web project. Postgres is MIT-like, and that drove it's adoption.

Have pgrust folks reconsidered this? Else, IMO we can have an independant rust port of pgrust, which can be MIT, which will garner more attention.

malisper 13 hours ago

Author here. At least for databases, AGPL (or stricter) has become standard. The issue is it's so easy for megacorps (Amazon, Google, etc) to take a permissively licensed product and monetize it at the expense of the original standard.

For instance, Mongo, Cockroach, and Materialize have all gone source available. We picked AGPL because it's the best balance between open source and prevents Amazon from just repackaging it and selling it.

If AGPL is an issue for anyone, we would be happy to dual-license under a commercial license.

mey 13 hours ago

There is nothing wrong with wanting to be compensated for your work, but for people like myself which use a cloud managed DB solution (GCP CloudSQL PostgreSQL) it means something like this would never be available.

I consider AGPL a poison pill in my work. That is not true with a suitable commercial license, although I expect a lot more commercial product (support/features/etc). As you note, your objective is to prevent commercialization of your software, but radically speeding up analytics is primarily a concern of large organizations so it seems like a mismatch in purpose.

JamesSwift 10 hours ago

hobofan 11 hours ago

andriy_koval 11 hours ago

ForHackernews 11 hours ago

hobofan 10 hours ago

> If AGPL is an issue for anyone, we would be happy to dual-license under a commercial license.

You should be setting up a CLA process then ASAP if you are looking to take outside contributions.

cognitiveinline 13 hours ago

Sure, that's your prerogative, and kudos for not talking up open source. I'm not amazon size so can't use it, and AGPL is a no go for DB, don't want to be forced to open source my app because I use this!

Will await a MIT based fork myself.

jnwatson 12 hours ago

appplication 14 hours ago

Oh bummer. I was really excited about pgrust but AGPL is a dealbreaker. Not for me personally, but it will never see wide adoption because it’s a banned license in most corporate environments. Lack of path to wide adoption means it’s dead in the water.

It’s weird because those who actually care about optimized pg gains are most likely large corporate customers. Why make a product targeting them and license it in such a way they’ll never use it?

This also hard blocks upstreaming any beneficial features into core Postgres.

ForHackernews 11 hours ago

> It’s weird because those who actually care about optimized pg gains are most likely large corporate customers. Why make a product targeting them and license it in such a way they’ll never use it?

Wait, sorry, you're asking why make something enterprise customers might pay for, and then not give it away to them for free?

guenthert 12 hours ago

If it is indeed 300* faster, I'm sure more rational corporations will rethink their license policy or be left in the dust.

hunterpayne 12 hours ago

jacquesm 12 hours ago

xyzzy_plugh 12 hours ago

kornelijus 11 hours ago

karlmush 11 hours ago

AGPL seems like the right choice to me. I’m tired of companies like PlanetScale taking PostgreSQL, building a business on top of it, and then acting like PostgreSQL is theirs to control.

samlambert 11 hours ago

wrs 10 hours ago

Good news, we now know up front what an independent port would cost, and it’s not much. So no reason AWS, Google, and friends couldn’t bang out their own port if they want, binary-compatible with this one.

What we don’t know for sure is whether there is any copyright for LLM-generated code. The license might be irrelevant!

ognarb 15 hours ago

2 commits in the repo both generated by claude. This is AI slop, I wonder where you see good momentum?

Whitespace 14 hours ago

main indeed has two commits, but it clearly states the location of the rest of the commits, so I wouldn't be critical of main itself.

  hey claude, do a breakthrough
  You can find the actual git history at the v0.2 github tag.
  
  Co-Authored-By: Fable <noreply@anthropic.com>
Now we see https://github.com/malisper/pgrust/tree/v0.2 has almost 6000 commits in it, with the very first one on 2026-07-02. That's a lot of token momentum!

It's easy to claim AI slop nowadays, but you should still mistrust-but-verify.

f311a 12 hours ago

refulgentis 10 hours ago

esafak 14 hours ago

4K stargazers in a week.

busterarm 14 hours ago

Everything around Rust is political, so the license choices are also about political statement.

johnsonjo 14 hours ago

Most official Rust projects are dual MIT/Apache licensed by convention [1] (and most Rust libraries from third parties I've seen that are open source MIT follow the MIT/Apache dual license), so seems like this library shouldn't just be AGPL for a typical political choice of a Rustacean?

[1]: https://rust-lang.org/policies/licenses/

busterarm 14 hours ago

borplk 10 hours ago

I'll take the 300x slower non-vibe-coded pg, thanks!

refulgentis 10 hours ago

They disabled Postgres parallelism to benchmark too. Sigh.

malisper 10 hours ago

We disabled parallelism in the blog post for demonstration purposes. The 300x slower refers to the clickbench numbers[0] where parallelism is enabled

[0] https://benchmark.clickhouse.com/#system=+liH|pgrs|gQ&type=-...

refulgentis 10 hours ago

wkoszek 3 hours ago

I'm really happy seeing this project. Not sure if this helps you gain $$$ customers, but stupid thing that turns out very difficult in PG is making this fast:

SELECT COUNT(*) FROM large_text_db WHERE X

Where X is something that must be matched exactly. X can be FTS query on FTS-indexed table, but the way COUNT() works in PG is that it's impossible to make it fast. Over large tables, lets say 1B+ rows, it can be very very slow.

Example use case is: searching through a hospital DB of reports that have "pancreatic cancer" in them. This is trivial in SQLite, but in PG it's hard.