apavlo

For those that are unaware, the instructor of this is on the board of OpenAI:

https://openai.com/index/zico-kolter-joins-openais-board-of-...

I'd love to hear about semantic layer developments in this space (e.g. Malloy etc.)

We also hosted Llyod to give a talk about Malloy in March 2025:

https://db.cs.cmu.edu/events/sql-death-malloy-a-modern-open-...

How is SpacetimeDB not mentioned here?

https://www.cs.cmu.edu/~pavlo/blog/2026/01/2025-databases-re...

none of the reviews of the last few years mention immutable and/or bi-temporal databases.

We hosted XTDB to give a tech talk five weeks ago:

https://db.cs.cmu.edu/events/futuredata-reconstructing-histo...

Which looks more like a blind spot to me honestly.

What do you want me to say about them? Just that they exist?

Am I living in a bubble?

There are rumblings that the MySQL project is rudderless after Oracle fired the team working on the open-source project in September 2025. Oracle is putting all its energy in its closed-source MySQL Heatwave product. There is a new company that is looking to take over leadership of open-source MySQL but I can't talk about them yet.

The MariaDB Corporation financial problems have also spooked companies and so more of them are looking to switch to Postgres.

Nothing about time series-oriented databases?

https://www.cs.cmu.edu/~pavlo/blog/2026/01/2025-databases-re...

I can't believe that article has no mention of SQLite ??

https://www.cs.cmu.edu/~pavlo/blog/2026/01/2025-databases-re...

Thanks for catching this. Updated: https://www.cs.cmu.edu/~pavlo/blog/2026/01/2025-databases-re...

I need to figure out an automatic way to track these.

If the org behind it ever decides to rugpull/elastic you

I love it that you use "elastic" as a verb here.

so... you take 10%-30% performance hit _right away_, and you perpetually give up any opportunities to improve the decoder in the future.

The WASM is meant as a backup. If you have the native decoder installed (e.g., as a crate), then a system will prefer to use that. Otherwise, fallback to WASM. A 10-30% performance hit is worth it over not being able to read a file at all.

The backstory is complicated. The plan was to establish a consortium between CMU, Tsinghua, Meta, CWI, VoltronData, Nvidia, and SpiralDB to unify behind a single file format. But that fell through after CMU's lawyers freaked out over Meta's NDA stuff to get access to a preview of Velox Nimble. IANAL, but Meta's NDA seemed reasonable to me. So the plan fell through after about a year, and then everyone released their own format:

→ Meta's Nimble: https://github.com/facebookincubator/nimble

→ CWI's FastLanes: https://github.com/cwida/FastLanes

→ SpiralDB's Vortex: https://vortex.dev

→ CMU + Tsinghua F3: https://github.com/future-file-format/f3

On the research side, we (CMU + Tsinghua) weren't interested in developing new encoders and instead wanted to focus on the WASM embedding part. The original idea came as a suggestion from Hannes@DuckDB to Wes McKinney (a co-author with us). We just used Vortex's implementations since they were in Rust and with some tweaks we could get most of them to compile to WASM. Vortex is orthogonal to the F3 project and has the engineering energy necessary to support it. F3 is an academic prototype right now.

I note that the Germans also released their own fileformat this year that also uses WASM. But they WASM-ify the entire file and not individual column groups:

→ Germans: https://github.com/AnyBlox

• Memory-Mapping (mmap): We treat the database file as if it’s already in memory, eliminating the distinction between disk and RAM.

Ugh, not another one...

You are conflating MySQL and InnoDB. The latter does a lot of good things, much more than the former.

They double dip. You pay them to review your company. Other companies pay them to read those reviews.

Dude fix your DBMS implementation before you start losing people's data. Or switch to something vetted like SQLite.

This schedule is not finalized yet.

I'm gonna have to implement my own buffer pool and manage my reads directly like that vexatious paper[1] said all along.

You make it sound like I was trying to troll everyone when we wrote that paper. We were warning you.

"Bridged Indexes" is a non-standard term. These are just secondary indexes using logical pointers with a mapping index. IIRC, Oracle, Hana, and HyPer do the same thing.

Source: https://db.cs.cmu.edu/papers/2017/p781-wu.pdf (see Table 1 + Section 6.1)

It's quite amazing how a db like this shows that all of those row-based dbs are doing something wrong

They're not "doing something wrong". They are designed differently for different target workloads.

Row-based -> OLTP -> "Fetch the entire records from order table where user_id = XYZ"

Column-based -> OLAP -> "Compute the total amount of orders from the order table grouped by month/year"

Any opensource libraries in that satellite's tech stack will now get to brag about "our code running on the moon" :)

A safe bet would be that SQLite is on there. It's already in airplanes / satellites.

our new query language, HelixQL

But why? Why increase the barrier of entry for your system?

Is there an SVG version of your logo?

I teach any entire lecture on this topic:

https://15445.courses.cs.cmu.edu/fall2024/schedule.html#sep-...

Thomas is the greatest database systems researcher in the world. He is an incredible human.

Wrt Andy, here are [1] somehow interesting views from (presumably) previous employees.

I am only seeing this now and I take the complaints about being "slightly racist and offensive" very seriously. I am checking with investors, former HR people, and co-founders. I was not made aware of any issues. If anything, I was overly cautious at the company.

I was openly transparent with our employees about every direction the company was pursuing up until the very end. The complaint that "He thinks he knows everything about business" makes me believe this person is just trolling because I was always the first to admit in meetings that I was not an expert in how to run a business. We had to fire people because of inappropriate behavior, but not because I had strong disagreements with how to run the company.

Wow, the reasons why Redis commands API suck in Andy's video (linked in the post) are the weakest ever.

In my example, the API on a key changes based on its value type. And the same collection can have different value types mixed together. You've recreated the worst parts of IBM IMS from the 1960s. However, the original version of IMS only changed the API when a collection's backing data structure changed. Redis can change it on every key!

We didn't get into the semantics of Redis' MULTI...EXEC, which the documentation mischaracterizes as "Transactions". I'm happy that at least you didn't use BEGIN...COMMIT.

Instead of emailing me to ask if you can translate my end-of-year blog article to Chinese like you did last year, this year you decided to just copy my format? I will be sure to mention that when I release mine next week.

If all table pages exist in memory and you are using cooperative GC, then O2N can be preferable. As workers scan version chains, they can clean up dead tuples without taking additional locks.

This is what Microsoft Hekaton does.

EloqKV brings significant innovations to database design

What is the novel part? I read your "Introduction to Data Substrate" blog article and the architecture you are describing sounds like NuoDB from the early 2010s. The only difference is that NuoDB scales out the in-memory cache by adding more of what they call "Transaction Engine" nodes whereas you are scaling up the "TxMap" node?

See also Viktor Leis' CIDR 2023 paper with the Great Phil Bernstein:

* https://www.cidrdb.org/cidr2023/papers/p50-ziegler.pdf

* https://youtu.be/tiMvcqIfWyA

This is from me. I didn't realize the connection to Lutris + Enhydra. It should be listed as a "Acquired Company" + "Abandoned Project". Wikipedia also says that it lasted until 2001. Usage is different from development/maintenance. I will update the entry for the old InstantDB and add an entry for this new InstantDB.

I think given that the original InstantDB died over two decades okay and is not widely known/remembered, reusing the name is fine.

Can you try to use a memory-mapped file

Definitely do *not* use MMAP for this.