Julien Le Dem

parquet.apache.orgALP: Adaptive Lossless Floating-Point Encoding in Apache ParquetA technical overview of ALP's design, performance, and adoption across the Apache Parquet ecosystem.

Fresh off the press: ALP: Adaptive Lossless Floating-Point Encoding in Apache Parquet parquet.apache.org/blog/2026/09... Thank you Kosta Tarasov, @andrewlamb1111.bsky.social, Prateek Gaur

Julien Le Dem reposted

Gonéri Le Cozannet

@goneri76.bsky.social

29 Aug

Peut-on s'adapter au changement climatique sans l'atténuer? Bien sûr que non, et à supposer que cela soit possible, s'engager dans une telle voie equivaudrait à se tirer une balle dans le pied Mervi @lefigaro.fr d'avoir publié ma tribune www.lefigaro.fr/vox/societe/...

lefigaro.frGonéri Le Cozannet : «S’adapter au changement climatique sans réduire nos émissions de CO₂ relève de la gageure»FIGAROVOX/TRIBUNE - La France a renoncé à des politiques climatiques ambitieuses en se laissant convaincre par l’idée, chimérique, d’une adaptation au changement climatique sans tenter de l’atténuer, ...

Julien Le Dem reposted

The Berkeley Scanner

@berkeleyscanner.com

13 Aug

A magnitude 3.9 earthquake in Oakland shook Berkeley on Thursday morning, according to early reports.

berkeleyscanner.comOakland quake felt in BerkeleyThe epicenter was in Oakland but some felt it in Berkeley.

Earthquake!

earthquaketrack.com/quakes/2026-...

earthquaketrack.com4.0 Magnitude Earthquake Near San Leandro, California, United States - Earthquake Track4.0 magnitude earthquake near San Leandro, California, United States on 2026-08-13 15:30:04

youtube.comOpenLineage - A Common Observability Framework for Data PipelinesYouTube video by Datadog Community

26 June

I had a great time seating with Whitney Lee to chat about OpenLineage Datadog Illuminated is such a fun format! www.youtube.com/watch?v=uIuB...

youtube.comThe Deconstructed Database at DatadogYouTube video by AI Council

25 June

The recording of the talk "The Deconstructed Database at Datadog" that Pierre Lacave and I gave at AI Council this year now available. www.youtube.com/watch?v=Bh9O...

🌉🛫😴🛬🇫🇷🥖🥐

If you missed my talk "Column storage for the AI era", this is your chance to watch it live tomorrow in SF. thedive.motherduck.com#schedule

thedive.motherduck.comThe Dive — MotherDuck at Snowflake Summit 2026Your home base during Snowflake Summit.

docs.google.com[The Dive, MotherDuck 2026] Column Storage for the AI era

3 June

The slides: docs.google.com/presentation...

10 Apr

Thank you for letting me keynote day 2 of the Iceberg summit. I hope you all enjoyed it!

28 May

The recording of my Iceberg Summit keynote "Column Storage for the AI Era" is now available. www.youtube.com/watch?v=qWU3...

youtube.comyoutube.com

28 May

The recording of my Iceberg Summit keynote "Column Storage for the AI Era" is now available. www.youtube.com/watch?v=qWU3...

youtube.comyoutube.com

youtube.comSeattle Apache Parquet Meetup May 2026YouTube video by Xinli shang

20 May

Recording of the Seattle Parquet meetup. Thank you Xinli, Micah, Kenny and all the presenters. www.youtube.com/watch?v=69nT...

9 May

I’m in this picture and I don’t like it.

1 May

Last year, I gave a keynote at AI Council about The Deconstructed Database: a composable and extensible database design enabled by the cloud and a collection of standard open source formats and components. (Parquet, Arrow, Substrait, Iceberg, OpenLineage, Calcite, DataFusion).

1 May

After the talk I was asked how we apply those principles at Datadog. Well, thank you for your patience, this year, Pierre Lacave and I will go over the evolution of the data platform at Datadog from the very beginning to today and the challenges ahead. Come see our talk in San Francisco!

aicouncil.comThe Deconstructed Database and the Advent of the Open Data Lake

1 May

The keynote from last year: aicouncil.com/talks26/keyn... My blog on the deconstructed database: sympathetic.ink/2024/04/29/T... Our talk in two weeks: aicouncil.com/talks26/the-...

29 Apr

I'm speaking today at www.openxdata.ai You can watch my talk online.

pinkbike.com2022 YT Capra CF Core 3 Yellow - Large For Sale2022 YT Capra CF Core 3 Yellow - Large For sale on Pinkbike buysell

26 Apr

My son is selling his mountain bike. www.pinkbike.com/buysell/4171...

26 Apr

Weekend project . Designed and assembled in California.

10 Apr

And that’s a wrap! Thank you for a great Iceberg Summit! @thedanicafine.bsky.social, Matt and everyone involved in the organization.

19 Mar

I have LLM jokes, they write themselves.

This post is unavailable.

wired.comBluesky CEO Jay Graber Is Stepping DownVenture capitalist Toni Schneider will take over as interim CEO as Bluesky’s board of directors hunts for a permanent replacement.

19 Mar

Paging @dickc

WIRED@wired.com

Exclusive: Jay Graber is stepping down as head of Bluesky. Venture capitalist Toni Schneider will be the interim CEO until a permanent replacement is found.

parquet.apache.orgVariant Type in Apache Parquet for Semi-Structured DataIntroducing Native Variant Type in Apache Parquet

5 Mar

If you want to learn more about the Variant type in Parquet, Aihua Xu and @andrewlamb1111.bsky.social wrote a great blog post on the project blog. parquet.apache.org/blog/2026/02...

parquet.apache.orgNative Geospatial Types in Apache ParquetNative Geospatial Types in Apache Parquet

14 Feb

Great inaugural post about the geospatial types on the Parquet blog. Thank you Jia Yu, Dewey Dunnington , Kristin Cowalcijk, Feng Zhang. More posts coming ! parquet.apache.org/blog/2026/02...

arrow.apache.orgApache Arrow is 10 years old 🎉The Apache Arrow project was officially established and had its first git commit on February 5th 2016, and we are therefore enthusiastic to announce its 10-year anniversary! Looking back over these 10...

13 Feb

Apache Arrow is ten years old! I can't believe that Apache board meeting when the project was instated was 10 years ago! This went fast! arrow.apache.org/blog/2026/02...

21 Jan

Congratulations to @andrewlamb1111.bsky.social on becoming the latest Parquet PMC member! Thank you, Andrew, for your leadership in the community. I look forward to our continued collaboration!

cs.cmu.eduDatabases in 2025: A Year in ReviewThe world tried to kill Andy off but he had to stay alive to to talk about what happened with databases in 2025.

8 Jan

File formats! Great references 😎

Andy Pavlo@andypavlo.bsky.social

I've posted my latest recap of the world of databases: www.cs.cmu.edu/~pavlo/blog/... All the hot topics from the last year: • More Postgres action! • MCP for everyone! • MongoDB gets litigious with FerretDB! • File formats! • Market movements! • The richest person in the history of the world!

Happy new year

Bonne année!

And that applies to sparkling wine as well ;)

WIRED@wired.com

Don't just party on New Year's Eve, think about the cool physics that you can see around you.

wrd.cmThe Physics Behind Popping Champagne BottlesDon't just party on New Year's Eve, think about the cool physics that you can see around you.

29 Dec 2025

I always dip the fries in the tartar sauce with my fish and chips.

doggsul@doggsul.bsky.social

ketchup isn’t available, what are you putting on your fries?

sympathetic.inkColumn Storage for the AI EraIn the past few years, we’ve seen a cambrian explosion of new columnar formats, challenging the hegemony of Parquet: Lance, Fastlanes, Nimble, Vortex, AnyBlox, F3 (File Format for the Future). The thi...

11 Dec 2025

In the past few years, we’ve seen a cambrian explosion of new columnar formats, challenging the hegemony of Parquet. Presumably, the design of yore is not going to cut it moving forward. I spent some time to understand a bit better how things actually changed. sympathetic.ink/2025/12/11/C...

docs.google.comColumn Storage for the AI era(illustration hand generated in 1958) “Column Storage for the AI era” © 2025 by Julien Le Dem is licensed under CC BY-NC-SA 4.0. To view a copy of this license, visit https://creativecommons.org/licen...

11 Dec 2025

I also gave a talk on this topic. Slides: docs.google.com/presentation... Recording here: www.youtube.com/watch?v=S_ao...

youtube.comThe advent of the open data lake | Julien Le Dem, AI By the Bay 2025YouTube video by FunctionalTV

9 Dec 2025

If you missed my talk "The advent of the open data lake" at AI By the Bay, the recording is now available. ai.bythebay.io/talks/the-ad... www.youtube.com/watch?v=xHGV...

Earthquake!

It turns out that Friday’s NYT’s mini crosswords was written by my 13-year-old.

youtube.comIntroducing DuckLakeYouTube video by DuckDB

1 Dec 2025

Parquet praise in the wild :) Nice chatting with you at Datacouncil Hannes! www.youtube.com/watch?v=zeon...

ai.bythebay.ioThe advent of the open data lake | AI By the Bay

Come say hi, Wednesday at 10am. I'll be speaking at the AI By the Bay Conference about "The Advent of The Open Data Lake". ai.bythebay.io/talks/the-ad...

In this talk I’ll discuss the impact of the cloud and the advent of the Open Data Lake breaking silos to form the foundation of this ecosystem.

ai.bythebay.ioThe advent of the open data lake | AI By the Bay

As compute and storage can be efficiently decoupled, a common storage layer enables a vibrant ecosystem of on-demand tools specialized to specific use cases that avoids vendor lock-in. ai.bythebay.io/talks/the-ad...

ai.bythebay.ioThe advent of the open data lake | AI By the Bay

Come say hi, Wednesday at 10am. I'll be speaking at the AI By the Bay Conference about "The Advent of The Open Data Lake". ai.bythebay.io/talks/the-ad...

The components of databases, distributed or not, have been commoditized as individual parts that anyone can compose into use-case specific engines. Define your constraints and build a query engine that solves your problem.

It’s been incredible to see the adoption of key components like Parquet, Arrow, Iceberg, and DataFusion. They provide an interoperability layer that enables using data without creating silos and duplication.

ai.bythebay.ioThe advent of the open data lake | AI By the Bay

Come say hi, Wednesday at 10am. I'll be speaking at the AI By the Bay Conference about "The Advent of The Open Data Lake". ai.bythebay.io/talks/the-ad...

Over the past decade, the big data ecosystem has matured and evolved from a melting pot of competing projects into a composable ecosystem organized around a few open source standards.

14 Nov 2025

If you missed me giving it live, the slides of my talk, "Column Storage for the AI era" are available here: docs.google.com/presentation...