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Klaus Aschenbrenner

@sqlpassion.at
687 followers 146 following 17K posts

Senior Database Administrator in the Online-Gambling industry. SQL Server & PostgreSQL specialist during the day. Astrophotographer during the night. Triathlete in between. Loves low-level system programming in Rust.

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Reposted by Klaus Aschenbrenner
Franck Pachot @franckpachot.bsky.social · 10/09/2026
PostgreSQL MVCC is often criticized for storing old versions in place. But the question is: does it have to traverse a chain of versions to find the correct row? A new blog post to answer that: dev.to/franckpachot...
dev.to
PostgreSQL MVCC: Why Bloat Doesn't Automatically Mean Expensive Reads
One of the most persistent misconceptions about PostgreSQL MVCC is that old row versions accumulate...
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Klaus Aschenbrenner @sqlpassion.at · 30/08/2026
I've burned down a huge amount of my weekly available tokens across multiple LLMs, but I have now for my own x64 OS a working Rust-based Intel NIC driver - for the Intel 82577LM (8086:10ea) and Intel I219-V (8086:15b8) #osdev #rust #rustlang
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Klaus Aschenbrenner @sqlpassion.at · 30/08/2026
Why do Java developer wear glasses? Because they don't C# ;-)
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Klaus Aschenbrenner @sqlpassion.at · 29/08/2026
My x84 OS implements now a fully working RTL8139 network driver. It can ping IP addresses on the internet, and also answers ping requests. #osdev #rust #rustlang
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Reposted by Klaus Aschenbrenner
Hannes Mühleisen @hannes.muehleisen.org · 26/08/2026
Some big news: @ducklabs.com is joining AWS, with the move expected to complete by early September. Our team will stay together in Amsterdam, with more resources to take DuckDB, DuckLake and Quack further - while the open-source Duck Stack remains free under MIT license ducklabs.com/news/2026/08...
ducklabs.com
DuckLabs to Join AWS, Projects to Remain Open Source
DuckLabs provides services around the DuckDB in-process OLAP data management system directly from its main developers.
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Reposted by Klaus Aschenbrenner
Armin Ronacher @mitsuhiko.at · 22/08/2026
Some weekend thoughts on how LLMs change the way we start new projects. lucumr.pocoo.org/2026/8/22/fa...
lucumr.pocoo.org
Fast and Hard Code
People pick languages differently with LLMs.
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Klaus Aschenbrenner @sqlpassion.at · 10/08/2026
Having some fun with orbital mechanics, and TLIs (trans lunar injections)... 😁
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Klaus Aschenbrenner @sqlpassion.at · 05/08/2026
Fighted against a SPID of -3. Won with 1:0 :-)
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Klaus Aschenbrenner @sqlpassion.at · 03/08/2026
Over the last 6-8 hours (spread across 3 days), I’ve vibe-coded a Home Assistant dashboard that displays data from our photovoltaic system, collected via Modbus over the local TCP/IP network. Home Assistent runs on my old Odriod-H2 Mini-PC from the year 2018...
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Klaus Aschenbrenner @sqlpassion.at · 25/07/2026
Working with multiple sub-agents across multiple GitHub issues in parallel - works like a charm :-)
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Reposted by Klaus Aschenbrenner
antirez @antirez.bsky.social · 25/07/2026
I tried to adapt the transcript of my video "Being Linus Torvalds" into an english language blog post here: antirez.com/news/171
antirez.com
Being Linux Torvalds - <antirez>
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Reposted by Klaus Aschenbrenner
Exoscale - The European Public Cloud @exoscale.com · 24/07/2026
What actually happens inside an LLM after you press enter? Our blog post maps out the mechanical journey of a prompt through the forward pass. 👉 www.exoscale.com/blog/llm-fro... . . . #AI #LLM #inference
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Klaus Aschenbrenner @sqlpassion.at · 17/07/2026
Hello Kimi K3 :-) #ai #llm #agenticcoding
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Reposted by Klaus Aschenbrenner
Chrissy LeMaire @funbucket.dev · 16/07/2026
Linus Torvalds, my man! *finger gun emoji*
per linus torvalds: I realize that some people really dislike AI, but this is an area where I'm willing to absolutely put my foot down as the top-level maintainer.

Linux is not one of those anti-AI projects, and if somebody has issues with that, they can do the open-source thing and fork it.

Or just walk away.

AI is a tool, just like other tools we use. And it's clearly a useful one.

It may not have been that "clearly" even just a year ago, but it's no longer in question today.

There are other questions around AI (like what the economy of it will actually look like in the end), but "is it useful" is no longer one of those questions. Anybody who doubts that clearly hasn't actually used it.

Yes, it can also be a somewhat painful tool, both for maintainer workloads and just from a "it keeps finding embarrassing bugs" standpoint.

But the solution is not to put your head in the sand and sing "La La La, I can't hear you" at the top of your voice like some people seem to do.
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Reposted by Klaus Aschenbrenner
Franck Pachot @franckpachot.bsky.social · 01/07/2026
Can PostgreSQL perform multi-block reads to reduce system calls? Yes, it's coming in PG19 with IO combine prefetching. What about TOASTed documents? Here's a new blog post: dev.to/franckpachot...
dev.to
Multi-block buffered reads in PostgreSQL 19 (IO combine & prefetch)
PostgreSQL scans operate at the page level: the buffer manager fetches one 8 KB page (BLCKSZ) at a...
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Klaus Aschenbrenner @sqlpassion.at · 28/06/2026
I have now a full-blown working UEFI boot path in my OS - incl. a simple AHCI driver to access the SATA based SSD drive with its FAT32 ESP partition. 100% pure Rust code (not a single asm file!), without any dependencies to other crates! #rust #rustlang #x64 #computerscience
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Klaus Aschenbrenner @sqlpassion.at · 28/06/2026
How to escape the heat wave? Starting a 100K “red eye” bike ride at 05:00am in the morning… 😴😴😴
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Klaus Aschenbrenner @sqlpassion.at · 26/06/2026
Running my own OS in Proxmox - booted via UEFI :-)
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Klaus Aschenbrenner @sqlpassion.at · 23/06/2026
I can boot now my x64 kernel on native UEFI hardware - like my AMD Ryzen system with 128 GB RAM. It uses the provided GOP framebuffer to draw a pseudo console to the screen. The legacy BIOS boot path (on older hardware) supports now also the VBE-based graphics mode for the console. #osdev #rust
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Klaus Aschenbrenner @sqlpassion.at · 23/06/2026
My prediction: when you don't incorporate AI into your daily workflow, you will not be needed anymore in the software industry within the next 12 - 24 month.
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Klaus Aschenbrenner @sqlpassion.at · 18/06/2026
It's the 1st time in my life that I've implemented my own UEFI loader - entirely in Rust - without any external dependencies. #Rust #rustlang #computerscience
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Klaus Aschenbrenner @sqlpassion.at · 17/06/2026
I have migrated now my whole x64-based OS entirely to Rust. There is NO single line of C code anymore - just a few pure assembly files! In addition, I'm also providing a VScode based Dev-Container, with which you can even build and run the OS in your browser! #rust #rustlang #osdev #computerscience
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Klaus Aschenbrenner @sqlpassion.at · 14/06/2026
Finished the first bicycle race of my life: the „Dolomitenradrundfahrt“ in East-Tyrol. 110km with 1700m ascent! 🥵 4:19h, and the 96th place (out of 153 participants) within my age group! 💪
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Klaus Aschenbrenner @sqlpassion.at · 09/06/2026
What could go wrong, if you have to safeguard a new LLM (Claude Fable 5) for cybersecurity, biology and chemistry related prompts... www.anthropic.com/news/claude-...
anthropic.com
Claude Fable 5 and Claude Mythos 5
Today we’re launching Claude Fable 5: a Mythos-class model that we’ve made safe for general use.
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Klaus Aschenbrenner @sqlpassion.at · 31/05/2026
What a day: finished my 1st Aqua Bike competition. 53th out-of-water (the last one!), and finished after the bike split at the 26th place - in 3:48h! 💪
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Klaus Aschenbrenner @sqlpassion.at · 09/04/2026
What a day! mMy longest bike ride of my life! 😎 #mallorca
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Reposted by Klaus Aschenbrenner
Mathias Lafeldt @mathias.blog · 14/03/2026
This is one of the most balanced critiques of AI I've read so far. "Reviewing AI output all day without the dopamine of creation is not a sustainable job description." tomwojcik.com/posts/2026-0...
tomwojcik.com
What AI coding costs you | Tom Wojcik
What's the effect of the prolonged AI usage among coders and is it tracked correctly, if it all?
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Reposted by Klaus Aschenbrenner
Florian Aigner @florianaigner.at · 11/03/2026
Max Schrems ist ein Jurist, der mit seinem Einsatz für Datenschutz- und Grundrechte international höchst erfolgreich war. Peter Steinberger reitet eine Bubble, die uns derzeit alle mit einem ganzen Bündel gefährlicher Probleme konfrontiert. Österreichische Medienpolitik so:
Screenshot aus der Presse:
Pröll: "Österreich braucht mehr Steinberger und weniger Schrems"
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Reposted by Klaus Aschenbrenner
DuckDB @duckdb.org · 09/03/2026
We released DuckDB v1.5! This release comes with a “friendly CLI” client, a new (opt-in) PEG parser, support for VARIANT types and many lakehouse features. It also ships a new network stack, a reworked geospatial extension, Azure writes and an ODBC scanner. Read more at duckdb.org/2026/03/09/a...
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Reposted by Klaus Aschenbrenner
Alex Miller @alexmillerdb.bsky.social · 09/03/2026
[VLDB '25] MD-MVCC: Multi-version Concurrency Control for Schema Changes in Azure SQL Database www.vldb.org/pvldb/v... A great discussion of the end-to-end impact of allowing multiple versions of schema metadata information to be live concurrently, in a real, production system.
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Reposted by Klaus Aschenbrenner
antirez @antirez.bsky.social · 08/03/2026
New blog post: "GNU and the AI reimplementations" antirez.com/news/162
antirez.com
GNU and the AI reimplementations - <antirez>
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Klaus Aschenbrenner @sqlpassion.at · 06/03/2026
It's so "funny" when #ChatGPT hallucinates about SQL Server 2025 feature internals, which are not documented anywhere. And then it says "sorry", because it delivered garbage to you... #StrangeNewWorld
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Klaus Aschenbrenner @sqlpassion.at · 04/03/2026
CoPilot in SSMS reads from my database/sql server instance, but doesn't show me any executed queries. This is *so* dangerous for your production data - CoPilot could just pass some of your sensitive data to the LLM provider... #ai #llm #datasecurity #gdpr
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Klaus Aschenbrenner @sqlpassion.at · 02/03/2026
[Blog] Don’t Miss Out – SQL Server 2025 Unleashed Training Starts Next Monday! www.sqlpassion.at/archive/2026... #sqlserver #performance #ai #vector #hadr
sqlpassion.at
Don’t Miss Out – SQL Server 2025 Unleashed Training Starts Next Monday! – SQLpassion
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Reposted by Klaus Aschenbrenner
Darling Data @erikdarling.com · 28/02/2026
The new Ballmer Curve: tomwojcik.com/posts/2026-0...
tomwojcik.com
What AI coding costs you | Tom Wojcik
What's the effect of the prolonged AI usage among coders and is it tracked correctly, if it all?
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Klaus Aschenbrenner @sqlpassion.at · 28/02/2026
When my MacBook Air M3 24 GB outperforms my AMD Ryzen system (128 GB RAM) with a RTX 3080Ti GPU for local LLM inference. The Unified Memory architecture rocks! 💪
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Klaus Aschenbrenner @sqlpassion.at · 27/02/2026
Anthropic has style and responsibility! 👍
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Reposted by Klaus Aschenbrenner
LaurieWired @lauriewired.bsky.social · 27/02/2026
Most programmers are taught that L1 is the “top level” cache on x86.
 It’s not quite true anymore! 
Intel calls it the Decoded Stream Buffer (DSB), AMD the OpCache. Only enough room for ~4,000 micro-ops, but there are interesting ways to take advantage of it.
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Klaus Aschenbrenner @sqlpassion.at · 27/02/2026
I have never thought that software engineers will be substituted by endless loops... #AgenticAI
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Klaus Aschenbrenner @sqlpassion.at · 27/02/2026
"new consulting pipeline almost shut off starting in December" -> same here! 😪
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Klaus Aschenbrenner @sqlpassion.at · 24/02/2026
AI destroys now almost every company on earth: IBM stock Drops 13.5% After Anthropic COBOL Warning: www.filmogaz.com/165789
filmogaz.com
Ibm Stock: ibm stock Drops 13.5% After Anthropic COBOL Warning
ibm stock sold off steeply on Monday, dropping 13. 5% after Anthropic renewed fears that AI code assistants could disrupt legacy COBOL workloads. The rout erased $31 billion in market value, and share...
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Klaus Aschenbrenner @sqlpassion.at · 24/02/2026
WTF! 🫣
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Klaus Aschenbrenner @sqlpassion.at · 23/02/2026
Never, ever trust an LLM *blindly*: Claude Code generated me frontend code that stores a bearer token (used for authentication against the REST API backend) in local storage. That's the perfect use case for XSS attacks... #fail #llm
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Klaus Aschenbrenner @sqlpassion.at · 23/02/2026
[Blog] PostgreSQL Quickie #2: Installation in Virtual Machines: www.sqlpassion.at/archive/2026... #PostgreSQL #postgres #quickie #youtube
sqlpassion.at
PostgreSQL Quickie #2: Installation in Virtual Machines – SQLpassion
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Klaus Aschenbrenner @sqlpassion.at · 23/02/2026
Nobody needs you anymore…
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Klaus Aschenbrenner @sqlpassion.at · 22/02/2026
Using various LLMs to design and implement a web app. The results are amazing.
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Reposted by Klaus Aschenbrenner
bernd @berndberger.eu · 21/02/2026
I’m not really surprised, but still…
thelocalstack.eu
I Verified My LinkedIn Identity. Here's What I Actually Handed Over.
I wanted a blue badge on LinkedIn. To get it, I gave a US company my passport, my face, and my biometric data. Then I read the fine print.
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Klaus Aschenbrenner @sqlpassion.at · 20/02/2026
Yesterday I built a full end-to-end PoC stack with OpenAI Codex 🚀, from frontend to backend to database, and then added load testing and observability across the entire flow 📈 Current architecture: Vite web frontend 🖥️ -> Rust backend service 🦀 -> PostgreSQL 🐘
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Klaus Aschenbrenner @sqlpassion.at · 18/02/2026
Working in VScode with the @continue.dev extension against the model "meta-llama-3.1-8b-instruct" that runs locally in LM Studio on my MacBook Air (M3, with 24 GB unified memory).
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Klaus Aschenbrenner @sqlpassion.at · 18/02/2026
Over the past two months, I’ve been diving deep into agentic coding with tools like Claude Code and OpenAI Codex. It’s incredible to witness how rapidly software development is evolving - and just how much leverage you can gain when you use these tools intentionally.
lnkd.in
LinkedIn
This link will take you to a page that’s not on LinkedIn
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