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Cloud Repatriation Calculator to Oxide

https://github.com/jplock/precipitate
1•jplock•25s ago•0 comments

Supercomputer for sale with 9,600 A100 GPUs and 4,200 EPYC CPUs, free shipping

https://www.tomshardware.com/desktops/servers/it-vendor-lists-massive-usd60-million-ai-cluster-on...
1•jonah•28s ago•0 comments

Mac Studio M5 Ultra 512GB Officially Released

https://www.apple.com/shop/buy-mac/mac-studio
1•nsagent•45s ago•0 comments

Apple Mac Studio M5 Ultra with 512GB of Memory, ~$23k

https://www.apple.com/shop/buy-mac/mac-studio/m5-ultra-chip-36-core-cpu-80-core-gpu-512gb-memory-...
1•zf00002•1m ago•1 comments

Apple Teases Touchscreen MacBooks

https://www.macrumors.com/2026/10/28/apple-ceo-john-ternus-teases-touchscreen-macbook/
1•bigwheels•1m ago•0 comments

Security incident at Amplitude resulted in Coinbase customer contact info leak

https://twitter.com/CoinbaseSupport/status/2115274731310002356
1•bilalq•2m ago•0 comments

TTS-1 from AssemblyAI – Frontier voice at $15/M chars

https://www.assemblyai.com/blog/text-to-speech-api
1•dylanbfox•2m ago•0 comments

Waymo scaling service area in 5 cities

https://waymo.com/blog/shorts/more-places/
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Show HN: Native gnome markdown viewer with mermaid support

https://github.com/jefersondaniel/markdown-viewer
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AI at Whitman: Curiosity, Connection and Critique

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From academia to Hollywood: Blazing a trail for computer-animated hair

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1•mooreds•6m ago•0 comments

The regular investor gets in on Wall Street's record stock borrowing binge

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1•mooreds•7m ago•1 comments

AI financing driving private credit growth as refinancing risks rise – Moodys

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1•angry_impala•7m ago•0 comments

Farmed Out: How Detroit Ceded Control

https://www.worseonpurpose.com/p/automotive-supply-chain
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Why Is This Fingerprinting Script Creating Bioweapons?

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Optimizing voice activity detection hyperparameters

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The assistant I want isn't a chat box

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Buy MacBook Pro with Proled XDR Display

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3•htk•10m ago•0 comments

MacBook Pro with Touch Enabled Proled XDR Display

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Apple Introduces MacBook Pro PRLED XDR with Touchscreen

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Generative Overload Is Killing Your Productivity

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Why Nancy Cartwright Says Science Has No Fundamental Laws

https://www.thecollector.com/nancy-cartwright-universal-laws/
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Wasmtime Ported to Motor OS

https://github.com/moturus/motor-os/blob/dev/docs/wasm.md
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The mathematics behind why you find things beautiful

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2•mathattack•17m ago•1 comments

The Invisible Cost of Digital Infrastructure

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2•Aldus551•19m 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?