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zX41ZdbW

2,845 karma · joined May 23, 2016

https://github.com/alexey-milovidov
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zX41ZdbW··on A map of every lighthouse
I have a similar project (which I created in 2024): https://adsb.exposed/

Among various datasets, it has OSM data (all of it): https://adsb.exposed/?dataset=OSM&zoom=4&lat=52.3756&lng=2.5...

And here are lighthouses: https://adsb.exposed/?dataset=OSM&zoom=3&lat=40.0444&lng=9.9...

zX41ZdbW··on Comparison of Malloc() Algorithms
lfalloc: https://github.com/ClickHouse/ClickHouse/pull/62826 hualloc: https://github.com/ClickHouse/ClickHouse/pull/31376
zX41ZdbW··on Comparison of Malloc() Algorithms
ClickHouse has been tested with jemalloc, mimalloc, tcmalloc (both variants), rpmalloc, lfalloc, hualloc, and ended up using jemalloc after a few patches and bug fixes.
zX41ZdbW··on GitHub is having trouble counting things
Some of the oldest PRs could no longer be found.

For example, when I decided to continue my eight-year-old PR https://github.com/ClickHouse/ClickHouse/pull/104948, I couldn't see it - neither in search nor while navigating through pages.

Direct links still work.

zX41ZdbW··on Vectorized and performance-portable Quicksort (2022)
Strange to see it here, the article is quite old.

Since pdqsort, vqsort, and glide sort, the current state-of-the-art are driftsort and ipnsort.

I've integrated them into ClickHouse: https://github.com/ClickHouse/ClickHouse/pull/106650

zX41ZdbW··on Ask HN: Anyone want my realtime-snapshots dataset of Hacker News?
I'm interested. milovidov@clickhouse.com
zX41ZdbW··on Haiku R1/beta6 has been released
Maybe share my old article with Haiku developers: https://clickhouse.com/blog/agentic-coding

Could be a small chance, but it has already made many engineers reconsider their AI stance.

zX41ZdbW··on Visual Analysis of Binary Files
I've also built a visualizer into ClickHouse, so we can analyze its binary: https://play.clickhouse.com/binary?user=binary - which code takes more space, what dependencies are too big, or what template instantiations are bloated.
zX41ZdbW··on Visualizing Binary Files
ClickHouse can read and visualize its own binary: https://play.clickhouse.com/binary?user=binary

It is useful to understand which dependencies, libraries, and template instantiations contribute to the size.

zX41ZdbW··on RayforceDB – a pure C analytics database with a Lisp-like syntax
Let's add it to ClickBench: https://github.com/ClickHouse/ClickBench/
zX41ZdbW··on 50k Boat Names
If you are interested in the AIS (ship telemetry) data, my team has created a visualization project: https://adsb.exposed/?dataset=Ships&zoom=5&lat=52.3890&lng=4...
zX41ZdbW··on When Compilers Disagree About UTF‑8
This is one of the optimizations from ClickHouse - detect ASCII and go a fast path: https://github.com/ClickHouse/ClickHouse/blob/6cde32de1a2463...
zX41ZdbW··on Show HN: ClickBench Playground – a playground for 110 database systems
All databases are hosted in VMs. Most of them only support amd64, so the host machine is also amd64 - this is the only limitation. It uses hardware virtualization, so nothing is emulated.
zX41ZdbW··on Show HN: ClickBench Playground – a playground for 110 database systems
Thanks! There is a write-up: https://clickhouse.com/blog/clickbench-playground A lot of interesting things around hosting it.
zX41ZdbW··on Faster Than Ninja
Thank you for Ninja!

The speed (reading the build.ninja file) was never a concern for us. If I could share a wish-list, it will be:

- Fix the possibility of a segmentation fault when the build file is damaged;

- Use a better order of execution: https://github.com/ninja-build/ninja/issues/2157

zX41ZdbW··on Don't stop early: Case-folding source code at memory speed
Interesting, how does it compare with StringZilla? It has highly optimized case-fold and case-insensitive Unicode search kernels as well: https://github.com/ashvardanian/Stringzilla
zX41ZdbW··on Pgrust v0.2: Now faster than Postgres and Clickhouse Latest
Thanks, merged!
zX41ZdbW··on Pgrust v0.2: Now faster than Postgres and Clickhouse Latest
You should submit it to ClickBench for verification.
zX41ZdbW··on PGSimCity – an explorable 3D model that shows how Postgres works
Someone ported it to ClickHouse: https://slach.github.io/CHSimCity/

Though it looks much simpler - fewer moving parts.

zX41ZdbW··on Cesium DevCon 2026 talks are up, including a keynote from SQLite's creator
As a coincidence, I've just integrated Cesium into my data analytics tool two days ago, https://adsb.exposed/ Though the 3D mode gives a little bit worse image quality, so I keep 2D with Leaflet as the default.
zX41ZdbW··on ALP: Adaptive lossless floating-point compression
ALP has been successfully integrated into ClickHouse: https://presentations.clickhouse.com/2026-release-26.3/, though the range of scenarios when it is reasonable to choose ALP over general-purpose compression is not so large.
zX41ZdbW··on Some combinatorial applications of spacefilling curves
Yes, for example, the datasets at this page: https://adsb.exposed/ are indexed by the Morton curve: https://github.com/ClickHouse/adsb.exposed/#database-and-que... and https://reversedns.space/ as well.

Also, a trivial application is image compression. Let's say you have a PNG image. PNG uses zlib, so if instead you take a raw bitmap and compress it with ZSTD, it typically will be better, but if you also sort pixels by the Hilbert curve first and then compress with ZSTD, it will be typically even better.

zX41ZdbW··on Pgrust was built: four attempts to rewrite Postgres in Rust with AI
I tried pgrust on ClickBench recently, but it didn't work at all: https://github.com/ClickHouse/ClickBench/pull/983#issuecomme...
zX41ZdbW··on Postgres in Rust: three dead ends before we passed 100% of the regression suite
I tried pgrust on ClickBench recently, but it didn't work at all: https://github.com/ClickHouse/ClickBench/pull/983#issuecomme...
zX41ZdbW··on GigaToken: ~1000x faster Language model tokenization
This is exactly what we need! Will try: https://github.com/ClickHouse/ClickHouse/issues/108247

It will be nicer if the README focuses more on per-core performance.

About the actual algorithm - will something like matching in a perfect hash table help?

zX41ZdbW··on Claude Is Not a Compiler
Why not a wildcard DNS pointing to a few Anycast IP addresses with proxies?
zX41ZdbW··on Postgres rewritten in Rust, now passing 100% of the Postgres regression tests
https://github.com/ClickHouse/ClickBench/pull/983
zX41ZdbW··on Show HN: misa77 - a codec that decodes 2x faster than LZ4 (at better ratios)
Yes, it was a typo. Thank you!
zX41ZdbW··on Show HN: misa77 - a codec that decodes 2x faster than LZ4 (at better ratios)
https://pastila.nl/?cafebabe/5763fb6ec6db85bf0f20fbd710a8c83...
zX41ZdbW··on Show HN: misa77 - a codec that decodes 2x faster than LZ4 (at better ratios)
Just tested a few minutes ago on the ClickBench dataset. Overall quite good, but, depending on particular columns, most of the time slower - e.g., ~2.0 vs ~2.8 GB/sec on Graviton 4 machine in AWS.
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