"Extremely Fast, Extremely Versatile, Extremely Cost-Efficient" — Luzmo's 8-Year ClickHouse Journey

Interviewer: Zoe Steinkamp, Developer Advocate, ClickHouse
Guest: Haroen Vermylen, Co-Founder & CTO, Luzmo

What does Luzmo do?

Luzmo is an embedded analytics platform. We offer reports, data visualization, conversational analytics, and dashboards that our clients — typically software companies — can embed inside their products to give their customers insights into all the data that's been captured on them.

Can you give an example of a customer?

We have clients across a wide variety of sectors. A typical SaaS use case is Selegens, a marketing analytics platform powering ROI dashboards and campaign impact reports inside their Marketing Cloud. An entirely different sector is Proximus, the largest Belgian telecom provider, who use Luzmo to visualize location intelligence data — anonymized movement data inside Belgium — and monetize it. All the user interfaces and reports are built on Luzmo.

Where does ClickHouse fit in?

We first discovered ClickHouse in 2017 — it's been eight years now, and ClickHouse has been quite infectious inside our company. We started with it as our internal warehouse for storing data that customers share with us. We're a federated platform — not all client data lives on our platform, but some clients want us to be responsible for storing it. We want to make it fast for them, which is why we settled on ClickHouse.

When did you move from open source to Cloud?

Quite quickly after it became generally available — 2022, I believe.

What made you switch?

Running clusters isn't our core business. We're in the business of building analytics and reporting, so that was a task we wanted to get rid of. ClickHouse Cloud seemed like the right offering to make that happen.

Did Cloud enable wider adoption internally?

Definitely. We're now also storing our query logs and plugin logs on ClickHouse — more of an observability use case. Within our platform, our software customers can review what queries are happening, identify slow queries, and trace which data source on their side is causing the issue. At which point we advise them to switch to ClickHouse.

Most exciting features in the past year or two?

I'm generally quite impressed with ClickHouse's speed of execution and interest in non-obvious use cases. Things like ANOVA tables available out of the box — I've never seen that in another database. More recently, we've started using ClickHouse as a vector database for storing embeddings of metadata and data. It's already there, it makes sense, and the implementation is quite good.

What made ClickHouse stand out when you first evaluated it?

We evaluated a number of players at the time, but ClickHouse was doing things differently. The big talk back then was distributed systems — you can handle big workloads but you need 100 servers, which isn't cost-effective and adds a lot of complexity. ClickHouse came out and it worked on my laptop. That was pretty amazing. The raw performance increase it gave for most of our workloads was the reason to keep following it.

Any challenges on Cloud?

A couple of gotchas, some of which have already been solved. Because we don't know our clients' data until we receive it, we have tens of thousands of different tables, and ClickHouse can sometimes struggle with that workload. We've also built our own query engine to efficiently optimize queries — ordering them correctly, pulling data from other systems in the best way. We can automatically group incoming queries and consolidate them into single operations, reducing pressure on ClickHouse. The new JSON data type is also very interesting — we're not using it to maximum effect yet, but we're watching it closely.

Three words to describe ClickHouse?

Extremely fast, extremely versatile, extremely cost-efficient.