Comment by fbotelho

I like your point, but it also says that this isn't easy:

> It may sound surprising that a single-primary architecture can meet the demands of OpenAI’s scale; however, making this work in practice isn’t simple.

And it also says that this approach has cornered them into a solution that isn't trivial to change. They now use different database deployments (the single primary one that is the focus of the post and *multiple* other systems, such as Azure CosmosDB, to which some of the write traffic is being directed).

> To mitigate these limitations and reduce write pressure, we’ve migrated, and continue to migrate, shardable (i.e. workloads that can be horizontally partitioned), write-heavy workloads to sharded systems such as Azure Cosmos DB, optimising application logic to minimise unnecessary writes. We also no longer allow adding new tables to the current PostgreSQL deployment. New workloads default to the sharded systems.

I wonder how easy it is for developers to maintain and evolve this solution of miscellaneous database systems.

So yes, you can go far with a single primary, but you can also potentially never easily get away from it.