My current company uses Postgres by default and we have a lot of different usecases. Again, another million+ users company with 10+ countries. It does indeed scale.
The problem is how people think about SQL vs K/V. They fall into the normalization trap a lot and create complex procedures and read operations. This usage causes once a month DB CPU spikes and some inident.
We are currently advocating for; de-normalized tables with K/V usage of Postgres and pushing the complexity to the application layer. Essentially, use Postgres at its bare minimums.
In short, to make Postgres scale; you essentially need to forget your "expert SQL knowledge" and use it as a K/V.
The problem is how people think about SQL vs K/V. They fall into the normalization trap a lot and create complex procedures and read operations. This usage causes once a month DB CPU spikes and some inident.
We are currently advocating for; de-normalized tables with K/V usage of Postgres and pushing the complexity to the application layer. Essentially, use Postgres at its bare minimums.
In short, to make Postgres scale; you essentially need to forget your "expert SQL knowledge" and use it as a K/V.