Mats Kindahl

Docker containers for Postgres servers are convenient and is easy to configure using environment variables. But is that a good security practice? If not, what should you do instead? Let's look at this. #docker #postgres #security dbmsdrops.kindahl.net/2026/05/22/don…

Tillväxtprognoser för 2026 just nu: EU: 1% USA: 2% Sverige: 2,3% Det spelar roll vem som regerar.

@ssougou @muratdemirbas @mkindahl TLA+ catches silent divergence in protocols. Empirical complement, Vortex DSE run today: 3-node KV under partition, isolated node applied 15,382 mutations vs 27,048 on the others, different order.

@svgmzr @ssougou I'm curious. WAL is written for each change, so not sure in what way it was out of order and what problem using timestamps solved it?

@ssougou @mkindahl I’ve actually had weird bugs when WAL records were out of order. Don’t know how it’s possible but we switched to just using timestamps

Did you know that the metadata in the Postgres wal is insufficient to uniquely identify timelines? @mkindahl uses TLA+ to prove this. multigres.com/blog/2026/05/0…

@gwenshap True, but this is what makes distributed systems so fun! You find a new amazing way things can break every day! 😉

Design discussions on distributed systems are essentially endless rounds of: "What if W fails after X and Y happened, but Z didn't happen yet?".

Model-checking is a very good method to find subtle bugs in complex systems, but can be challenging to use. Here we modeled failover in TLA+ to find a bug in pg_rewind. multigres.com/blog/2026/05/0…

I have been publishing and discussing internals about PostgreSQL, but I had one itch I needed to scratch, so here is a PostgreSQL InfluxDB API with HTTP endpoint, UDP endpoint, TLS/HTTPS support, basic authentication, and a few more things. dbmsdrops.kindahl.net/2026/05/02/int…

@rene_cannao @YashHustle_22 It depends on what you want to scale. Replicas can scale reads, but the only way to scale writes is to do partitioning / sharding. Read scalability can be dealt with using a connection-based proxy (so fast), but sharding require either a smart proxy or application awareness.

@YashHustle_22 Both have their place. Read replicas for most read-heavy workloads (with proper routing). Sharding only when you truly outgrow vertical scaling + replicas. The routing/observability layer (proxy) often determines how painless either approach actually is.

Which database scaling approach are you using? Read replicas or Sharding

Even though this book is about 20 years old, it's still a good starting point for anyone who wants to learn how to build databases. It just took me a couple of weeks to go through it. For the interested folks, the link is here: dsf.berkeley.edu/papers/fntdb07…

@neogoose_btw Well... PostgreSQL has a binary format for the protocol. Did you have anything else in mind apart from transferring data in binary? #PROTOCOL-FORMAT-CODES" target="_blank" rel="nofollow noopener">postgresql.org/docs/current/p…

I never liked databases as an idea. You literally send a string query over TCP to postgres and it returns you data over tcp as strings. There is so much potential to make this whole thing better …. but everyone seems to be just fine with it.

I could not find a utility to restart processes inside Docker containers, so tossed one together and am sharing it with others. Kubernetes normally restart containers automatically, but there are situations where you cannot do that. dbmsdrops.kindahl.net/2026/04/09/reb…

the @multigres operator is now open source progress so far: ◆ Direct pod management ◆ Zero-downtime rolling upgrades ◆ pgBackRest PITR backups ◆ Observability with OTel tracing link to repo in thread

You can now run a full Linux operating system inside a 6mb PDF. Someone embedded a RISC-V emulator inside a standard document. You don't need a virtual machine, just a PDF reader. → Runs interactively inside the file. → Powered by a tiny RISC-V emulator. → The entire OS fits in just 6MB.

Grattis SVT som fick Guldspaden för ett gräv de tog av mig. Jag publicerade i september 2023 och avslöjade att AP-fonderna köpt in sig i Northvolt via nytt bolag utan verksamhet. I maj 2025 kom SVTs identiska gräv…… 👇👇👇 uvell.se/2023/09/20/pen…

Took the Gripen out for a ride yesterday. Strong, smart and at supersonic speed - Sweden! X – won’t you help me? Send this to someone who also should get themselves a piece of world class engineering and innovative adaptable software. Welcome to Sweden, we are open for business.

@h_ingo @Mishi_2210 Shouldn't 51181 be possible?

@Mishi_2210 5118

Tell me the number that is biggest then this Only 1 percent will succeed

@sunbains "Clippy" checks this. Just use it and don't ignore the warnings.

Rust shops all over the world today: grep -rnw . -e 'unwrap'

@sunbains Same here. Same copy I used is still in my shelf. :)

@mkindahl SICP

When I first encountered LISP, I only knew one type of equality “==“. Been a very long time since I’ve written LISP in anger. I should try my hand at it again, I found the LISP books to be of more value than programming in it. Lots to learn from them. “Common Lisp has various equality functions: =, eq, eql, equal, equalp, string-equal, char-equal… but what are the differences??” lispcookbook.github.io/cl-cookbook/eq…