How does Yandex Metrica work?

Question

Yandex.Metrica

Yesterday I thought about how Yandex metrics or any other attendance counter is arranged from the inside. Namely, where is all this information stored? As I imagine, for each user a row is created in the database, with ip, user agent, screen resolution, etc. And even not one line, but a line for each visit. If that's really how it works, then how big should the database be to fit 100 million new records a day (a rough estimate) for ten years?

Answer 1

https://ru.wikipedia.org/wiki/ClickHouse

Answer 2

Regarding the metric, there is an article on Habré .
And Google in all its projects uses its own BigTable DBMS, which is not distributed openly.
Data in BigTable is stored as regular rows with 3 access keys:

• row key
  
• Column key
  
• Timestamp (timestamp)