Why was sharding by account_id chosen? What was the purpose of sharding?

Sharding by account_id is usually chosen to ensure an even distribution of data and load across shards, as account_id is a unique identifier for a user or account, which naturally segments the data. This helps avoid 'hot' shards and simplifies scaling.

The main goal of sharding is to improve system performance and scalability. Instead of storing all data in a single database, which can become a bottleneck, data is divided into parts (shards), each served by a separate server or cluster. This reduces the load on individual nodes, decreases response time, and increases the overall throughput of the system.