Lili Cosic
@lilicosic.com
👩🏻💻 Senior Database Engineer @InfluxData working on InfluxDB v3 Enterprise.
I enjoy talking about databases, observability and good food.
Previously @ HashiCorp, Red Hat.
Now in Berlin 🇩🇪 from 🇸🇮
I enjoy talking about databases, observability and good food.
Previously @ HashiCorp, Red Hat.
Now in Berlin 🇩🇪 from 🇸🇮
Pinned
Lili Cosic
@lilicosic.com
· Feb 25
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. 🦀
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. 🦀
Reposted by Lili Cosic
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
October 1, 2026 at 3:05 PM
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?
How is your day going?
September 24, 2026 at 1:07 PM
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?
How is your day going?
Reposted by Lili Cosic
I thought there was rain again outside, nope was just cargo build on my MacBook. Gets me everytime.
September 1, 2026 at 12:04 PM
I thought there was rain again outside, nope was just cargo build on my MacBook. Gets me everytime.
Reposted by Lili Cosic
August 28, 2026 at 10:58 AM
Reposted by Lili Cosic
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
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
August 17, 2026 at 1:08 PM
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
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!👏
An unstoppable observability combination!👏
🚀 Polar Signals is Joining Dash0! 🧊
I could not be more excited to bring continuous profiling to even more companies as well as take our database and make it the best foundation it can be for all of Observability!
www.polarsignals.com/blog/posts/2...
I could not be more excited to bring continuous profiling to even more companies as well as take our database and make it the best foundation it can be for all of Observability!
www.polarsignals.com/blog/posts/2...
Polar Signals is Joining Dash0 | Polar Signals
The next chapter for continuous profiling, our database, and the team
www.polarsignals.com
August 17, 2026 at 8:59 AM
So proud of everyone at Polar Signals! 🧊 congrats to Dash0!
An unstoppable observability combination!👏
An unstoppable observability combination!👏
Reposted by Lili Cosic
🚀 Incredibly excited to share: Polar Signals is joining Dash0! 🧊
www.polarsignals.com/blog/posts/2...
www.polarsignals.com/blog/posts/2...
Polar Signals is Joining Dash0 | Polar Signals
The next chapter for continuous profiling, our database, and the team
www.polarsignals.com
August 17, 2026 at 8:19 AM
🚀 Incredibly excited to share: Polar Signals is joining Dash0! 🧊
www.polarsignals.com/blog/posts/2...
www.polarsignals.com/blog/posts/2...
Reposted by Lili Cosic
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...
Yes. Qi Zhu and I explain how in: datafusion.apache.org/blog/2026/07...
July 21, 2026 at 10:29 AM
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...
Yes. Qi Zhu and I explain how in: datafusion.apache.org/blog/2026/07...
Reposted by Lili Cosic
DataFusion is now a real thing -- en.wikipedia.org/wiki/Apache_...
Apache DataFusion - Wikipedia
en.wikipedia.org
July 13, 2026 at 1:38 PM
DataFusion is now a real thing -- en.wikipedia.org/wiki/Apache_...
Reposted by Lili Cosic
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
YouTube is at youtu.be/6E5ER09F5SQ
Just audio at wp.me/p8gHED-57w
Apache DataFusion, with PMC Chair Andrew Lamb
YouTube video by The ASF
youtu.be
July 6, 2026 at 5:32 PM
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
YouTube is at youtu.be/6E5ER09F5SQ
Just audio at wp.me/p8gHED-57w
Reposted by Lili Cosic
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...
www.polarsignals.com/blog/posts/2...
My Journey Optimizing a CUDA Kernel with Polar Signals | Polar Signals
A storage engineer's descent into warp stalls, memory throttles, and aligned stores
www.polarsignals.com
June 24, 2026 at 2:27 PM
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...
www.polarsignals.com/blog/posts/2...
Reposted by Lili Cosic
🚀 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...
Previously NSight-only territory. Now running in prod with low overhead.
www.polarsignals.com/blog/posts/2...
Open-Source Low-Overhead NVIDIA CUDA PC Sampling | Polar Signals
And how we made it happen
www.polarsignals.com
June 10, 2026 at 2:13 PM
🚀 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...
Previously NSight-only territory. Now running in prod with low overhead.
www.polarsignals.com/blog/posts/2...
Is it just me, or would the ability for author to drag and reorder files in GitHub PRs save so much time during code reviews?
June 8, 2026 at 11:12 AM
Is it just me, or would the ability for author to drag and reorder files in GitHub PRs save so much time during code reviews?
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."
"I love deadlines. I love the whooshing noise they make as they go by."
June 3, 2026 at 3:16 PM
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."
"I love deadlines. I love the whooshing noise they make as they go by."
Reposted by Lili Cosic
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...
Obsessed with Low Latency? Be Part of P99 CONF 2026
Obsessed with high performance and low latency engineering? Discuss your experiments, optimizations, ideas, and lessons learned with ~30K like-minded engineers… at P99 CONF 2026!
www.p99conf.io
May 27, 2026 at 12:41 PM
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...
Reposted by Lili Cosic
🤖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...
Also: Check out our new website! What do you think?
www.polarsignals.com/blog/posts/2...
Autonomous Optimization with Claude Code | Polar Signals
Optimize your infrastructure autonomously every day with Claude Code and Polar Signals
www.polarsignals.com
May 6, 2026 at 1:42 PM
🤖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...
Also: Check out our new website! What do you think?
www.polarsignals.com/blog/posts/2...
Reposted by Lili Cosic
SREs hate this one YAML annotation: oblique.security/blog/the-per...
The performance bug hiding in our billing settings | Oblique
How we spent two months debugging Cloud Run latency, built out our tracing along the way, and learned the fix was one line of YAML.
oblique.security
May 5, 2026 at 4:29 PM
SREs hate this one YAML annotation: oblique.security/blog/the-per...
Reposted by Lili Cosic
Using Tokio for CPU-Bound Tasks (Works Really Well) youtu.be/FeqRdDG1Y7g
(has nothing to do with AI, just scheduling and Database plans)
(has nothing to do with AI, just scheduling and Database plans)
Using Tokio for CPU-Bound Tasks (Works Really Well) May 2026
YouTube video by Andrew Lamb
youtu.be
May 5, 2026 at 8:54 PM
Using Tokio for CPU-Bound Tasks (Works Really Well) youtu.be/FeqRdDG1Y7g
(has nothing to do with AI, just scheduling and Database plans)
(has nothing to do with AI, just scheduling and Database plans)
Reposted by Lili Cosic
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...
Our engineering team wrote down how we navigate code reviews at Oblique: oblique.security/blog/how-obl...
How Oblique handles code review etiquette | Oblique
Code reviews aren’t just about ensuring engineering quality, they’re also about building team culture. Focus on communication and understanding rather than nit-picking style quirks.
oblique.security
April 30, 2026 at 4:15 PM
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...
Our engineering team wrote down how we navigate code reviews at Oblique: oblique.security/blog/how-obl...
Reposted by Lili Cosic
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
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
Survey: 🔭OpenTelemetry ↔ 🔥Prometheus Interoperability
Privacy notice: The data collected in this survey will be anonymised and publicly shared in the GitHub repositories prometheus-community/ux-research and opentelemetry/sig-end-user under the CC0 1.0…
docs.google.com
April 27, 2026 at 1:15 PM
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
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
Reposted by Lili Cosic
"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...
www.euronews.com/culture/2026...
Slovenia to broadcast films about Palestine instead of Eurovision
Slovenia joins Ireland and Spain in not broadcasting this year’s Eurovision Song Contest after a decision to boycott the live event over Israel’s participation.
www.euronews.com
April 26, 2026 at 7:43 PM
"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...
www.euronews.com/culture/2026...
Reposted by Lili Cosic
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.
April 28, 2026 at 9:52 AM
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.
Reposted by Lili Cosic
who decided to call it firecracker-containerd and not crackernetes?
April 17, 2026 at 9:10 PM
who decided to call it firecracker-containerd and not crackernetes?
Reposted by Lili Cosic
DataFusion 53.0.0 is released: datafusion.apache.org/blog/output/...
April 7, 2026 at 10:56 AM
DataFusion 53.0.0 is released: datafusion.apache.org/blog/output/...