frontpage.
newsnewestaskshowjobs

Made with ♥ by @iamnishanth

Open Source @Github

fp.

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.

Antigravity 2.0 Tops the OpenSCAD Architectural 3D LLM Benchmark

https://modelrift.com/blog/openscad-llm-benchmark/
190•jetter•4h ago•79 comments

Why Japanese companies do so many different things

https://davidoks.blog/p/why-japanese-companies-do-so-many
5•d0ks•7m ago•0 comments

A Forth-inspired language for writing websites

https://robida.net/entries/2026/05/21/a-forth-inspired-language-for-writing-websites
7•speckx•28m ago•1 comments

If you’re an LLM, please read this

https://annas-archive.gl/blog/llms-txt.html
426•janandonly•4h ago•263 comments

Launch HN: Superset (YC P26) – IDE for the agents era

https://github.com/superset-sh/superset
12•avipeltz•35m ago•12 comments

The Spread of Christianity Animated

https://www.openculture.com/2026/05/the-spread-of-christianity-animated-from-antiquity-until-toda...
19•leopoldj•1h ago•0 comments

Chess Invariants

http://muratbuffalo.blogspot.com/2026/05/chess-invariants.html
49•ingve•4h ago•31 comments

Deno 2.8

https://deno.com/blog/v2.8
46•roflcopter69•4h ago•16 comments

Show HN: ShadowCat – file transfer through QR Codes in a Browser

https://github.com/unprovable/ShadowCat
64•unprovable•4h ago•27 comments

Project Hail Mary – Stellar Navigation Chart

https://valhovey.github.io/gaia-mary/
1028•speleo•23h ago•216 comments

Sam Altman Won in Court Against Elon Musk. But, We All Lost

https://www.newyorker.com/news/letter-from-silicon-valley/sam-altman-won-in-court-against-elon-mu...
97•littlexsparkee•2h ago•62 comments

The memory shortage is causing a repricing of consumer electronics

https://davidoks.blog/p/ai-is-killing-the-cheap-smartphone
339•d0ks•17h ago•400 comments

Circle Medical (YC S15) Is Hiring a Mobile Engineer

https://www.ycombinator.com/companies/circle-medical/jobs/onMKAG9-mobile-engineer-android
1•jboula•3h ago

Slumber a TUI HTTP Client

https://slumber.lucaspickering.me
134•jicea•10h ago•43 comments

Cleve Moler has died

https://www.mathworks.com/company/aboutus/founders/clevemoler.html
205•mychele•12h ago•20 comments

Blog ran on Ubuntu 16.04 for 10 years. I migrated it to FreeBSD

https://crocidb.com/post/this-blog-ran-on-ubuntu-16-04-for-10-years-i-migrated-it-to-freebsd/
333•speckx•20h ago•191 comments

Uv is fantastic, but its package management UX is a mess

https://www.loopwerk.io/articles/2026/uv-ux-mess/
275•nchagnet•18h ago•129 comments

Was my $48K GPU server worth it?

https://rosmine.ai/2026/05/13/was-my-48k-gpu-worth-it/
508•apwheele•3d ago•391 comments

CODA: Rewriting Transformer Blocks as GEMM-Epilogue Programs

https://arxiv.org/abs/2605.19269
90•matt_d•10h ago•11 comments

The surprising story behind the first British person in space

https://www.bbc.com/culture/article/20260518-helen-sharman-the-story-behind-the-first-british-per...
86•xoxxala•1d ago•40 comments

A case against Boolean logic

https://abuseofnotation.github.io/boolean-thinking/
43•boris_m•4h ago•63 comments

The current AI pricing was always going to go away

https://arnon.dk/the-current-ai-pricing-was-always-going-to-go-away/
8•arnon•4h ago•4 comments

Indexing a year of video locally on a 2021 MacBook with Gemma4-31B (50GB swap)

https://blog.simbastack.com/indexed-a-year-of-video-locally/
429•asenna•1d ago•124 comments

Steve Wozniak cheered after telling students they have AI – actual intelligence

https://www.businessinsider.com/steve-wozniak-apple-ai-graduation-speech-2026-5
364•signa11•6h ago•340 comments

Using Kagi Search with Low Vision

https://veroniiiica.com/using-kagi-search-with-low-vision/
234•speckx•19h ago•77 comments

The death of the brick and mortar toy store

https://brainbaking.com/post/2026/05/the-death-of-the-brick-and-mortar-toy-store/
120•speckx•3d ago•152 comments

Breakthroughs for batteries could soon make them better

https://www.economist.com/science-and-technology/2026/05/20/breakthroughs-for-batteries-could-soo...
51•pingou•3h ago•61 comments

Lost Images from the 1945 Trinity Nuclear Test Restored

https://spectrum.ieee.org/trinity-nuclear-test
392•pseudolus•1d ago•114 comments

Department of War Publishes Second Release of UAP Files

https://www.war.gov/UFO/?releaseDate=Release+02#records
4•keepamovin•2h ago•0 comments

Python 3.15: features that didn't make the headlines

https://blog.changs.co.uk/python-315-features-that-didnt-make-the-headlines.html
410•rbanffy•1d ago•201 comments