Lili Cosic

After a few years focusing on cloud platforms, I’ve moved back to core database engineering in January! I wanted to move to our InfluxDB 3 team because I missed working on DBs. It’s been an intense start to 2026, but the team gave me a warm welcome and I was able to start contributing quickly. 🦀

The long-serving strongman leader of Serbia, Aleksandar Vucic, has conceded defeat in an election that pitted him and his right-wing party against a diverse student-led opposition movement that spent two years protesting his government.

I am not rage quitting Open Source reviews, but I am changing: andrew.nerdnetworks.org/blog/2026/10...

This is wild - somebody did a deep dive into the real stories behind this famous XKCD: sheets.works/data-viz/hol...

If anyone is interesting in signing up for the next DataFusion community showcase to describe their project, we have openings on Oct 29 -- let me know if you are interested

I ground the beans, refilled the water, put in a new filter into the coffee machine. I come back when it makes the beep and the water is clear… turns out ai left the beans out on the countertop. How is your day going?

I thought there was rain again outside, nope was just cargo build on my MacBook. Gets me everytime.

DataFusion 55 Release: datafusion.apache.org/blog/output/... Possibly includes a humble brag

Dash0 welcomes Polar Signals to the team. They built the leading continuous profiler for cloud native workloads, with GPU and CUDA support, and created Parca, the open source profiling project behind it. Profiling will live natively in Dash0, next to traces, metrics and logs. eu1.hubs.ly/H0xG-d70

So proud of everyone at Polar Signals! 🧊 congrats to Dash0! An unstoppable observability combination!👏

🚀 Incredibly excited to share: Polar Signals is joining Dash0! 🧊 www.polarsignals.com/blog/posts/2...

Can you accelerate queries when your data is *partially* sorted (and e.g. you don't want to have to resort it). Yes. Qi Zhu and I explain how in: datafusion.apache.org/blog/2026/07...

DataFusion is now a real thing -- en.wikipedia.org/wiki/Apache_...

I recently joined Rich Bowen of the ASF to talk about Apache DataFusion's origins and increasing popularity YouTube is at youtu.be/6E5ER09F5SQ Just audio at wp.me/p8gHED-57w

This was a fun one! For @polarsignals.com's latest hackathon, I wrote an FSST decompression CUDA kernel and then optimized it by profiling with our new GPU PC sampling feature. www.polarsignals.com/blog/posts/2...

🚀 Launching today: GPU PC sampling in production. Instruction-level profiling telling you why and where warps stall. Whether it is memory latency, scoreboard waits, or barriers. 🧊 Previously NSight-only territory. Now running in prod with low overhead. www.polarsignals.com/blog/posts/2...

This quote by Douglas Adams is still my favourite and always so relevant: "I love deadlines. I love the whooshing noise they make as they go by."

Have a cool performance optimization you want to share with a community of latency-obsessed engineers? The P99 CONF call for speakers ends this week. 👀 Details at www.p99conf.io/2026/04/01/b...

🤖Using Polar Signals Cloud and Claude Code to autonomously optimize your code every day! 📈 Also: Check out our new website! What do you think? www.polarsignals.com/blog/posts/2...

SREs hate this one YAML annotation: oblique.security/blog/the-per...

Using Tokio for CPU-Bound Tasks (Works Really Well) youtu.be/FeqRdDG1Y7g (has nothing to do with AI, just scheduling and Database plans)

A coworker disappearing into a cave and coming back with 12,000 lines of code you have to review is cause for a heart attack. But, how do you handle the ever-increasing volume of code reviews? Our engineering team wrote down how we navigate code reviews at Oblique: oblique.security/blog/how-obl...

OpenTelemetry ❤️ Prometheus! The #OTel and #Prometheus projects are strengthening interoperability. 🛠️ Building with both? Check out our client library comparison, plus updates on Prometheus compatibility and exporter spec stabilization. Links in 🧵! 🗳️ Running both? Take our survey! buff.ly/XhVm0Fg

"Slovenia stands alongside Ireland, Spain, the Netherlands and Iceland in refusing to take part in this year’s 70th edition of the competition due to the EBU allowing Israel to compete despite criticisms of its conduct in the war in Gaza." 👏 www.euronews.com/culture/2026...

We've been working on a major schema migration at @polarsignals.com that has unlocked some pretty wild improvements. Apart from a 50% (!!) reduction in storage size thanks to logical compression in vortex.dev, there has been a dramatic improvement in query performance.

who decided to call it firecracker-containerd and not crackernetes?

DataFusion 53.0.0 is released: datafusion.apache.org/blog/output/...

🚀 Introducing the Polar Signals VS Code extension! See CPU time, memory allocations, and more as inline annotations, right next to your code. Works with Polar Signals Cloud and self-hosted Parca. www.polarsignals.com/blog/posts/2...

Here is a new blog about Parquet Variant, including use case, and shredding examples parquet.apache.org/blog/2026/02...

TIL: notary in Germany reads out the entire contract before you sign it. It sounds like my personal hell: sitting still for 2 hours while someone reads out loud a contract in German, and then you pay them for the privilege. 🫠

Benito is a threat b/c he makes art so alluring and enjoyable you want to understand everything about it and then you end up learning about sugar and slavery and colonialism and the Taínos and Hawaii and then you probably have some thoughts of your own, and that's why art is powerful and dangerous

Polar Signals at #FOSDEM 2026 day 2! Both talks in the Rust room. Profiling Rust applications with Parca Brennan at 12:30 @ UB2.252A (Rust) fosdem.org/2026/schedul... Frederic at 16:00 @ UB2.252A (Rust) Random seeds and state machines: An approach to DST in Rust fosdem.org/2026/schedul...

Polar Signals at #FOSDEM 2026 day 1! Tommy at 12:30 @ H.1308 (eBPF) OOMProf: Profiling Go heap memory at OOM time fosdem.org/2026/schedul... Thor at 17:25 @ UB2.252A (Databases) From Disks to Distributed: Our Journey of Database Evolution in the Cloud fosdem.org/2026/schedul...

Very excited for this year's #FOSDEM! Lots of talks by Polar Signals folks:

1/5 ➡️ Why Rust Will Help You Deliver Better Low-latency Systems and Happier Developers with Andrew Lamb bit.ly/47kgmwU @andrewlamb1111.bsky.social #RustLang #LowLatency

The hard things in computing: * cache eviction * naming things * figuring out which of your paying customers is DOSing your service

Super exciting to see two speakers from InfluxData here! 🎉

The irony of shortening my Balkan name to "Lili" for the convenience of others, only to have people spell it "Lilli." 🫠

I was laid off last week. I'm excited to start a new chapter where I can put my knowledge and dedication to work. I believe every chapter closes to make room for something more rewarding. I'm keen to discover the next opportunity. Learn more: www.linkedin.com/pos... #OpenToWork

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!

Last couple of sunsets of 2025.

We cut cross-zone traffic for SLO monitoring by 90% using Prometheus subquery optimization. The trick: pre-aggregate data locally instead of shuffling 55M raw samples to Thanos queriers. Coming soon to Pyrra! 🚀 www.polarsignals.com/blog/posts/2...

A simple 50-line code change saves us 30% of CPU across our whole infrastructure. This is the magic of system-wide profiling with @polarsignals.com. Easy to spot, easy to fix.

🚀 We recently announced our NVIDIA CUDA always-on profiler. Check out this blog on how to try it out super quickly with your CUDA workload today!🧊 www.polarsignals.com/blog/posts/2...