Were there any issues with splitting the unified database?

Dividing a single database often causes a number of difficulties:

• Data consistency: It is difficult to ensure transactional integrity and consistency when data is split across multiple databases.
• Managing relationships: In a distributed architecture, it is challenging to maintain relationships between entities located in different databases.
• Migration complexity: Updating the data schema requires coordination between multiple databases.
• Performance: Sometimes, division helps to scale the system, but it can lead to additional delays in cross-database queries.

To address these issues, approaches such as sharding, CQRS, event sourcing, and asynchronous replication are often used.