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PGSimCity - How PostgreSQL Works

https://nikolays.github.io/PGSimCity/
217•jonbaer•3h ago•32 comments

Show HN: Physically accurate black hole you can put in your room

https://blackhole.plav.in
104•aplavin•3d ago•23 comments

Decker, a platform that builds on the legacy of Hypercard and classic macOS

https://beyondloom.com/decker/
252•tosh•9h ago•63 comments

French firefighters face 'pyrocumulonimbus' for first time

https://www.france24.com/en/live-news/20260726-french-firefighters-face-pyrocumulonimbus-for-firs...
215•saaaaaam•10h ago•124 comments

Scriptc by Vercel: TypeScript-to-Native compiler, no JavaScript engine in binary

https://github.com/vercel-labs/scriptc
50•maxloh•5h ago•23 comments

We have proof automation now

https://www.imperialviolet.org/2026/07/26/zstd-lean.html
107•zdw•6h ago•16 comments

US citizen charged after GrapheneOS phone wipes during airport search

https://www.techspot.com/news/113236-us-prosecutors-charge-atlanta-man-after-grapheneos-phone.html
337•eecc•5h ago•213 comments

Jacobian Conjecture for Baby

https://muchmirul.github.io/jacobian-conjecture/
17•porphyra•4d ago•1 comments

Introduction to Data-Oriented Design [pdf]

https://www.gamedevs.org/uploads/introduction-to-data-oriented-design.pdf
131•tosh•9h ago•38 comments

Htmx 4.0, the first JavaScript library to release exclusively on the Game Boy

https://swag.htmx.org/en-cad/products/htmx-4-the-game
379•rcy•15h ago•127 comments

Fonts In Use – Find out where a font is used

https://fontsinuse.com/
29•open_•4h ago•1 comments

Design is compromise

https://stephango.com/design-is-compromise
207•ankitg12•11h ago•76 comments

Simulate cassette tape audio profiles using FFmpeg

https://github.com/AARomanov1985/Audio-Cassette-Simulation
92•xterminal•7h ago•42 comments

Teaching Kids Forth

https://gracefulliberty.com/articles/teaching-kids-forth/
65•rbanffy•6h ago•20 comments

Show HN: CheapSecurity – Lightweight, Self-Hosted CCTV for Linux SBCs

https://github.com/gmrandazzo/CheapSecurity
116•zeldone•11h ago•22 comments

How to Write English Prose

https://thelampmagazine.com/blog/how-to-write-english-prose
90•geneticdrifts•10h ago•47 comments

Plasma Tunnels Reveal How Dying Satellites Fall to Earth

https://spectrum.ieee.org/space-debris-atmosphere-burn-up
50•marc__1•7h ago•26 comments

Go Analysis Framework: modular static analysis by go team

https://pkg.go.dev/golang.org/x/tools/go/analysis
187•AbuAssar•15h ago•44 comments

History of John Backus's functional programming project [draft]

https://softwarepreservation.computerhistory.org/FP/
16•cwbuilds•2d ago•1 comments

The Usefulness of Useless Knowledge (1939) [pdf]

https://faculty.lsu.edu/kharms/files/flexner_1939.pdf
34•jxmorris12•3d ago•2 comments

The relay market powering token resellers and fraud

https://vectoral.com/blog/token-relay-market
167•mlenhard•12h ago•99 comments

How to Block Some of the Bots

https://nochan.net/b/Internet-Crap/20260606-How-To-Block-Some-Of-The-Bots/
88•Bender•9h ago•99 comments

The New AI Superpowers: Focus and Followthrough

https://www.rickmanelius.com/p/the-new-ai-superpowers-focus-and
167•mooreds•14h ago•49 comments

I learned PCB design, 3D printing and C just to listen to music

https://pentaton.app/blog/2026-07-12-introducing-pentaton-lp/
187•interfeco•3d ago•35 comments

Show HN: Port Zero – how I learned to stop worrying and love PORT=0

https://portzero.net/
14•octopoc•3h ago•6 comments

Kill The Cookie Banner

https://killthecookiebanner.eu/
863•rapnie•15h ago•424 comments

Show HN: Reverse Minesweeper

https://sunflowersgame.com/
164•pompomsheep•14h ago•54 comments

Some more things about Django I've been enjoying

https://jvns.ca/blog/2026/07/21/more-nice-django-things/
138•surprisetalk•5d ago•85 comments

Using sed to make indexes for books (1997)

https://www.pement.org/sed/make_indexes.txt
53•TMWNN•3d ago•9 comments

What's Under Your Feet in New York City?

https://practical.engineering/blog/2026/7/21/whats-under-your-feet-in-new-york-city
170•sohkamyung•4d ago•36 comments
Open in hackernews

Pglocks.org

https://pglocks.org/
80•hnasr•1y ago

Comments

whilenot-dev•1y ago
I'm a bit lost here.

Locking is a challenging problem in complex systems. Is this list to be interpreted as a "TODO: get rid of locking conflicts in future releases" or more a "NOTE: be aware there are known conflicts that will not change - find ways to work around them"?

EDIT: Also, is the creation of this list an automated or a manual effort?

tux3•1y ago
I think this is intended as educational material, not a list of things to fix.

The locks are here by necessity, it is not so easy at all to get rid of them. And even in special cases where it is possible, the complexity you have to introduce is not to be taken lightly...

If even a tenth of these disapppeared, it would be incredible, in a very surprising way.

atombender•1y ago
The creator looks like a developer and teacher, not a Postgres core team member. So I assume this is for documentation purposes.

I actually like this a lot, as there isn't a single place in the Postgres documentation that lists all the possible locks; it's spread out all over. Having a quick reference for what kinds of commands you'd be blocking with your transaction is valuable.

It's pretty evident that the pages have been programmatically generated, but I'd love know what it's generated from. I think you can derive this information from the documentation, but not sure if you can do it in an automated way without an LLM.

braiamp•1y ago
> there isn't a single place in the Postgres documentation that lists all the possible locks

Did you read this page? https://www.postgresql.org/docs/current/explicit-locking.htm...

atombender•1y ago
That's a great page, but it has several issues.

First, it isn't complete; as I said, the locking behaviour is spread out all over the Postgres documentation. For example, that page doesn't list what locks DROP INDEX takes. To find that out, you have to go to the documentation page for that command and read it carefully. In fact, really carefully — the locking behaviour is only documented under the section about CONCURRENTLY.

The page also doesn't list what possible commands are then blocked. Locks interact in subtle (and incorrectly named!) ways that are explained in the tables on that page ("Conflicting lock modes"), so to understand if something will block something else you have to look at the two commands you are curious about and then look at how their locks interact.

gulcin_xata•1y ago
I agree, it is not so straightforward to find out.
braiamp•1y ago
These are database locks, which means that depending which arrives first, the later transaction has to wait till the first one finishes to complete. These locks are about SQL commands and which commands can run concurrently with the others. There's a graph here of how that looks like https://pankrat.github.io/2015/django-migrations-without-dow...

Usually for maximum performance (minimum latency, maximum throughput) you want to have operations not lock each other, unless absolutely necessary, in which case you want them to be short.

whilenot-dev•1y ago
You make it sound like the conflict is just affecting performance and won't result in a deadlock. So it's for performance aware postgres clients/users, and not for postgres developers?
andyferris•1y ago
It is a guide for developers using postgres as a client, who need to write systems that don't deadlock, are performant and are correct. These are the (rather sharp) tools that postgres provides for doing so (or else you can use e.g. serializable isolation and optimistic concurrency, but in my experience that has too many false positives and bail out rather eagerly, whereas these tools let you be very precise and granular).
mebcitto•1y ago
Other relevant talks/blogs that I found really useful for understanding Postgres locks are:

* Unlocking the Postgres Lock Manager by Bruce Momjian: https://momjian.us/main/writings/pgsql/locking.pdf

* Anatomy of table-level locks by Gulcin Yildirim Jelinek: https://xata.io/blog/anatomy-of-locks

pasxizeis•1y ago
Shameless plug: I wrote a tool[1] that executes a given migration against a test database (e.g. in your CI) and reports back what locks it acquired.

The rationale being to have a "lock diagnostics report" commented in your PR's migration file.

It's a prototype and has a few rough edges and missing functionality, but feedback is more than welcome.

[1] https://github.com/agis/pglockanalyze

jononor•1y ago
Very practical! Locking is one of the things that can really bite when doing migrations.