frontpage.
newsnewestaskshowjobs

Open Source @Github

fp.

The Death of Educational Content on YouTube [video]

https://www.youtube.com/watch?v=-Gnrp_caPvo
1•ferryth•3m ago•0 comments

How Not to Build a Shading Language – BCON26 [video]

https://www.youtube.com/watch?v=1kWmzitkmkA
1•matt_d•5m ago•0 comments

Problee – free play-money prediction markets (midterms, AI benchmarks, more)

https://problee.com
1•mehmetaliozmen•5m ago•0 comments

OpenAI axes next model citing safety issues

https://www.ft.com/content/488cb467-3cb7-4d06-9a5f-c0749c729d91
3•mcgin•10m ago•0 comments

Former PLA Officers Eavesdrop on South Korean, U.S. Military Bases

https://www.chosun.com/english/national-en/2026/09/29/TWI7IQUWZ5CJZAKTQWWJIR2ACI/
1•snarky-comments•13m ago•0 comments

Show HN: Jev Decision Layer: Save Frontier Tokens on Closed Decisions

https://github.com/qualixar/jev-decision-layer
1•vpbhardwaj•13m ago•0 comments

OpenAI models may get more reasoning budget through the API than through Codex

https://twitter.com/TokenGremlin/status/2104559277700510034
1•KingOfMyRoom•15m ago•0 comments

Show HN: AppMaker – a visual JavaScript app builder

https://appmaker.io/
1•codeguppy•16m ago•0 comments

Poincaré Conjecture Formalized in Lean4

https://twitter.com/ayushkhaitan343/status/2104289939840176167
2•korbonits•22m ago•0 comments

Show HN: TheSiftNow – a field guide and compatibility checker for The Sift

https://thesiftnow.com/
1•richardharmer•28m ago•0 comments

The Macroeconomic Effect of AI: Sizing the Software Engineering Channel (NBER)

https://www.nber.org/papers/w35793
1•imakwana•29m ago•1 comments

Japan holds first panel meeting on anti-espionage measures

https://mainichi.jp/english/articles/20260929/p2g/00m/0na/004000c
2•snarky-comments•31m ago•0 comments

Hamilton–Perelman's proof of Poincaré conjecture is claimed to be autoformalized

https://github.com/qinz1yang/differential-geometry
2•unexpectedtrap•33m ago•0 comments

Quake 2 on ESP32-P4

https://github.com/alexkid77/ESP32_QUAKE2
3•alexkid777•34m ago•1 comments

With iOS 27, Apple Is Quietly Setting the Stage to Paywall Your iPhone

https://www.pcmag.com/opinions/with-ios-27-apple-is-quietly-setting-the-stage-to-paywall-your-iphone
2•divbzero•36m ago•1 comments

Migrating from MinIO to Predastore

https://mulgadc.com/blog/migrate-minio-to-predastore
6•InsideStick•36m ago•1 comments

Tailmux – connect to multiple tailnets at once

https://github.com/growlyx/tailmux
1•subhamkts•37m ago•0 comments

Why Cheetahs Are Friendly (But Never Domesticated) [video]

https://www.youtube.com/watch?v=nXQD3nPaO-k
1•dataflow•42m ago•0 comments

Cantor's Diagonal Argument

https://en.wikipedia.org/wiki/Cantor%27s_diagonal_argument
1•CGMthrowaway•42m ago•0 comments

VPNs, Copyright Territoriality, and Why Borders Still Matter Online

https://legalblogs.wolterskluwer.com/copyright-blog/vpns-copyright-territoriality-and-why-borders...
2•bryanrasmussen•43m ago•1 comments

El Niño bursts through temperature record months before peak

https://www.theguardian.com/environment/2026/sep/21/super-el-nino-temperature-record
1•ijidak•43m ago•0 comments

Machine will eventually solve face powder, in theory.. (2021)

https://www.reddit.com/r/opus_magnum/s/vNe9IWl3pq
2•112233•48m ago•0 comments

Is this the Future of Gaming? [video]

https://www.youtube.com/watch?v=FyBL8atiZSE
1•sb057•49m ago•0 comments

InputConfig: Free Controller Mapper for Mac

https://inputconfig.com/
1•jonbaer•49m ago•0 comments

TraceOn – best DevTools extension that explains why your page loaded slow

https://chromewebstore.google.com/detail/traceon/nodnccgfalinelngbdkkhkhbeialnljb
2•Solomon_mh•55m ago•0 comments

Google Assistant won't be available soon

https://www.androidpolice.com/google-assistants-death-officially-weeks-away/
2•auaauaaaaua•57m ago•0 comments

AG of Florida files for temporary injunction against OpenAI [pdf]

https://www.myfloridalegal.com/sites/default/files/plaintiffs_motion_for_temporary_injunction.pdf
2•theahura•58m ago•0 comments

Anthropic warns AI may pose 'existential risks to humanity' in IPO filing

https://www.cnbc.com/2026/09/29/anthropic-warns-ai-existential-risks-ipo-filing-reuters.html
3•magoghm•58m ago•1 comments

Show HN: Error in official Swiss weather forecasts, recorded since September '25

https://forecasterror.xlit.app/
1•ghasemi•59m ago•1 comments

Egg producers reach federal and state settlement over price-fixing allegations

https://www.cbsnews.com/news/doj-states-secure-proposed-settlement-with-egg-producers-over-price-...
3•dataflow•1h ago•0 comments
Open in hackernews

Ask HN: How can I load test PostgreSQL but avoid changing actual data?

1•LawZiL•1y ago
I'm running a load test on my Node.js application and want to simulate realistic write-heavy scenarios to stress test the system — especially the PostgreSQL database.

There's a part of the code that performs UPDATE queries, but during load testing, I don't want these updates to actually change the state of the database. However, I still want the database to experience the full impact of the update — query planning, locking, I/O, WAL writes, etc. — so I can measure how it affects performance under peak load.

Is there a best-practice approach to achieve this?

So far, the most viable option I’ve found is to wrap the UPDATE queries in a transaction and then roll it back — that way, the queries still execute, but the state doesn’t change. Is this the right way to go? Does rollback introduce any performance overhead that would skew my results? Are there better or more realistic alternatives that simulate the full write path without persisting changes?

Thanks in advance!

Comments

sargstuff•1y ago
pgbench[2] / pgreplay-go[0] / python locust[1]

very old school approach:

Misuse sql VIEW[3][4] to generate a temporary parallel table setup. Testing database separate from production database would be 'better', IMHO.

-----

[0] pgreplay-go : https://github.com/gocardless/pgreplay-go

[1] python locust : https://miguel-codes.medium.com/unconventional-load-testing-...

[2] pgbench load testing :

   a) https://medium.com/@c.ucanefe/pgbench-load-test-166bdfb5c75a

   b) https://neon.tech/blog/autoscaling-in-action-postgres-load-testing-with-pgbench

   c) https://hackernoon.com/how-to-create-and-load-test-data-in-postgresql-i41e353m
----------------------------

[3] : a) https://hashrocket.com/blog/posts/materialized-view-strategi...

      b) https://tech.jonathangardner.net/wiki/PostgreSQL/Materialized_Views

      c) https://stackoverflow.com/questions/77603705/what-is-the-use-of-materialized-view-in-postgresql
[4] : https://en.wikipedia.org/wiki/View_(SQL)
LawZiL•1y ago
but again, how can i perform the query, but not actually change the state, i really need the state to keep untouched, but be able to perform the query itself.
MatthiasPortzel•1y ago
> Does rollback introduce any performance overhead that would skew my results?

I would expect it to be the other way around—since the transactions are rolled back and not committed, they would have significantly less performance impact. But I’m working from an academic model of the database.

apothegm•1y ago
Load test against a clone instead of a DB whose contents you care about?