frontpage.
newsnewestaskshowjobs

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.

Atomarine: Nuclear Data Centers at Sea

https://atomarine.co/
21•ndr•34m ago•14 comments

Google will expand age checks on Android worldwide till the end of the year

https://android-developers.googleblog.com/2026/07/google-play-age-signals-api-safer-experiences.html
63•dmantis•52m ago•62 comments

Gpiozero Flow

https://bennuttall.com/blog/2026/07/gpiozero-flow/
12•benn_88•33m ago•1 comments

AI's top startups are barely publishing their research

https://www.science.org/content/article/ai-s-top-startups-are-barely-publishing-their-research
493•YeGoblynQueenne•13h ago•253 comments

Azulejo

https://en.wikipedia.org/wiki/Azulejo
21•Amorymeltzer•1d ago•2 comments

The coolest use for the Vision Pro

https://christianselig.com/2026/07/vision-pro-house/
697•robbiet480•14h ago•268 comments

Show HN: Open-source engine running Gemma 4 26B in 2 GB RAM on any M-series Mac

https://github.com/drumih/turbo-fieldfare
821•gitpusher42•20h ago•287 comments

Superlogical

https://www.superlogical.com/
712•yan•19h ago•421 comments

The first watch featuring computer functions

https://by.seiko-design.com/140th/en/topic/58.html
24•stefanv•3d ago•0 comments

LLM Honeypot

https://llm2human.pages.dev/
270•8thom•12h ago•80 comments

Concurrency, interactivity, mutability, choose two

https://www.n16f.net/blog/concurrency-interactivity-mutability-choose-two/
34•billiob•3d ago•17 comments

Keychron announces first open-source firmware for gaming mice

https://www.digitalfoundry.net/news/2026/07/keychron-announces-first-open-source-firmware-for-gam...
390•JLO64•18h ago•158 comments

The Productivity Mirage

https://frantic.im/mirage/
262•msephton•11h ago•108 comments

The Cold Email

https://zachholman.com/posts/cold-email
231•holman•13h ago•88 comments

Anatomy of a Frontier Lab Agent Intrusion: A Timeline of the July 2026 Incident

https://huggingface.co/blog/agent-intrusion-technical-timeline
394•artninja1988•1d ago•220 comments

Logic for Programmers

https://logicforprogrammers.com/
141•_doctor_love•10h ago•27 comments

ESP32-C6 Power Consumption: Arduino vs. Zephyr vs. ESP-IDF Comparison

https://www.qoitech.com/blog/esp32-c6-power-consumption-comparison/
36•hasheddan•4d ago•7 comments

A.I. companies are recruiting electricians and carpenters by the thousands

https://www.nytimes.com/2026/07/29/business/economy/data-center-electricians-training.html
293•thm•20h ago•362 comments

Kuna: Decompiler Development in the Age of Coding Agents

https://noelo.org/blog/kuna-release/
48•matt_d•8h ago•10 comments

Kimi K3-256k

https://www.kimi.com/code/docs/en/kimi-code/models
448•monneyboi•15h ago•130 comments

Show HN: CheapFoodMap – A map of good meals under $10

https://cheapfoodmap.com/
219•jaep1•18h ago•196 comments

Turning a dumb AC unit smart (without losing my security deposit)

https://prilik.com/blog/post/automating-ac-nyc/
173•austinallegro•16h ago•140 comments

Angels in Coptic Magic I: Introduction

https://www.coptic-magic.phil.uni-wuerzburg.de/index.php/2026/01/16/angels-in-coptic-magic-i-intr...
48•jruohonen•3d ago•6 comments

Some thoughts about Anthropic's new cryptanalysis results

https://blog.cryptographyengineering.com/2026/07/29/some-notes-about-anthropics-new-results/
162•supermatou•18h ago•86 comments

SalesPatriot (YC W25) Is Hiring FDEs

https://www.ycombinator.com/companies/salespatriot/jobs/M46X6YX-forward-deployed-engineer
1•maciejSz•14h ago

London’s most equidistant pub

https://equidistance.io/londons-most-equidistant-pub/
46•lambfruit•4d ago•25 comments

The Rust on ESP Book

https://docs.espressif.com/projects/rust/book/
165•AlexeyBrin•4d ago•19 comments

Hamburg's Stadtpark: A Park Built to Be Used

https://alsterrunde.com/hamburgs-stadtpark-a-park-built-to-be-used/
162•mertbio•3d ago•48 comments

Launch HN: Tokenless (YC S26) – Automatic model switching to save money

https://usetokenless.com/
64•rohaga•19h ago•57 comments

Recursive Filters: SMA, EMA, Low‑Pass, and a Tiny Kalman

https://www.staszewski.xyz/blog/recursive-filters/
48•kamilstaszewski•2d ago•10 comments