From what I understand they basically couldn't scale writes in PostgreSQL to their needs and had to offload what they could to Azure's NoSQL database.

I wonder, is there another popular OLTP database solution that does this better?

> For write traffic, we’ve migrated shardable, write-heavy workloads to sharded systems such as Azure CosmosDB.

> Although PostgreSQL scales well for our read-heavy workloads, we still encounter challenges during periods of high write traffic. This is largely due to PostgreSQL’s multiversion concurrency control (MVCC) implementation, which makes it less efficient for write-heavy workloads. For example, when a query updates a tuple or even a single field, the entire row is copied to create a new version. Under heavy write loads, this results in significant write amplification. It also increases read amplification, since queries must scan through multiple tuple versions (dead tuples) to retrieve the latest one. MVCC introduces additional challenges such as table and index bloat, increased index maintenance overhead, and complex autovacuum tuning.