Jordan Isaacs

tangled.orgsnowytrees.dev/project-managerIntegrated repository, worktree, git stacker, and project manager

17 May

trying out tangled.sh and what better way to start than to introduce a new project not on my gh. introducing project-manager, an integrated repo, worktree, git stacker, and project manager designed for multi-repo projects tangled.org/snowytrees.d... I daily drive all my work with it now!

Jordan Isaacs reposted

Phil Eaton

@eatonphil.bsky.social

22 Feb

You're probably right to pick a modern extension to support vector similarity search in Postgres. But did you know Postgres already has one built in? I took a look at the cube extension in Postgres, pgvector, and model2vec for some impressively fast embeddings generation.

14 Dec 2025

Just felt the earthquake in sf, got a short little ride on my couch 🎢

github.comGitHub - jordanisaacs/kernel-development-flake: Nix flake for linux kernel development (formerly kernel-module-flake)Nix flake for linux kernel development (formerly kernel-module-flake) - jordanisaacs/kernel-development-flake

28 Nov 2025

Finished the overhaul of kernel-development-flake ✨ inspired by virtme-ng which didn’t support NixOS. kdf is also a rust-based /init using virtiofs. You can now do fast live dev of kernel modules/in-tree, no more waiting for nix rebuilds github.com/jordanisaacs...

28 Nov 2025

TIL rust's spawn implementation uses a unix socket for communication between child & parent (github.com/rust-lang/ru...). Only happens when it can't use posix spawn (e.g. using pre_exec callback). Hit this when running a kernel without unix sockets in qemu and got function not implemented 🫠

gist.github.comtest_spawn.rsGitHub Gist: instantly share code, notes, and snippets.

28 Nov 2025

Little script to see for yourself gist.github.com/jordanisaacs...

db.cs.cmu.edu[Future Data] Storage Metadata for Modern Cloud Databases - Carnegie Mellon Database GroupIn modern database architecture, separating compute from storage unlocks powerful capabilities. Our... Read More +

27 Nov 2025

Entering my Postgres era 🐘

Jordan Isaacs reposted

CMU Database Group

@db.cs.cmu.edu

27 Oct 2025

Today's Future Data Systems Seminar Speaker: Joyo Victor will present @singlestore.com's "Bottle Service" meta-data system that supports database branching, change-data-capture, and Apache Iceberg. Zoom talk open to public at 4:30pm ET. YouTube video available after: db.cs.cmu.edu/events/futur...

github.comGitHub - backtrace-labs/dynamic_flag: A C library for runtime-flippable feature flags on Linux/x86-64, with negligible overhead in the common caseA C library for runtime-flippable feature flags on Linux/x86-64, with negligible overhead in the common case - backtrace-labs/dynamic_flag

Been working on using github.com/backtrace-la... which does cross modifying code for negligible overhead flags. But when I tried to use it I got dreaded linker errors with the '__start' and '__stop' symbols for the custom sections that were supposed to be generated at link time missing...

Of course this is where I ended up at maskray’s blog doing deep reads of linker GC (maskray.me/blog/2021-02... ) and metadata sections (maskray.me/blog/2021-01...). I realized the main flag list should always exist and the view should only be kept if in use.

So after a day of work I had my 3 line fix :) Add 'SHF_GNU_RETAIN' flag to the inline asm for the main flag list. And a dummy variable in the macro that uses the view sections to force a GC reference: `__attribute__((retain,used,section("view-section"))) static const char dummy[0];`

Luckily I had two build flavors with one passing and the other failing. I manually went through every linker flag difference to guess which one was causing issues. And '—gc-sections' looked suspicious. The linker has some crazy complexity to how it decides to GC sections.

There has actually been a ton of consideration to handling these sort of “meta” sections that have no direct access and thus do not participate in general GC references. But upon further looking the dynamic flag didn’t use any of the special flags. So I found my bug, the linker was GCing it

But the sections existed in the object files leaving me flummoxed. Why wasn’t the linker using the sections? So I went down one of the most interesting systems rabbit holes I’ve had recently.

So dynamic flag automatically generates sections using inline assembly. One section has the list of all flags. Then there are arbitrarily many other sections that are a “view” into that list of flags for more efficient lookups. There is no access of any sections beyond using '__start' and '__stop'

31 July 2025

This is really cool, TUM has a course on transaction systems theory (taught by Thomas Neumann), with open access slides in English. Stumbled upon it when one of the slides showed up in a search for commutative serializability theory. db.in.tum.de/teaching/ss2...

db.in.tum.dedb.in.tum.de

snowytrees.devBounding retries of write-write conflicts in MVCC+2PL | snowytrees.dev

25 July 2025

I wrote up on bounding retries of write-write conflicts in MVCC+2PL. There is surprisingly little publicly written on how databases can retry, so doing my part to fill that gap in :) snowytrees.dev/blog/boundin...