Give me 2 minutes, and I'll teach you how Google Ads was able to support 4.77 billion users with a SQL database (not joking):
➟ They store Ads data in a distributed SQL database
➟ They use 2-phase commit protocol for atomicity across database partitions
➟ They provide strong consistency at a global level by ordering writes with timestamps
➟ They use TrueTime to maintain same time across servers in the world
➟ They use Paxos to coordinate writes among replicas and avoid data conflicts