Polyglot Persistence and Trade-offs

Once services own their data, each service can choose the database that fits its workload.

A search service may use Elasticsearch, a cart service Redis, and an orders service PostgreSQL. This is polyglot persistence: using different databases for different needs instead of forcing one database across the whole system.

The benefit is better fit. The cost is operational complexity.

This chapter covers common database choices, their trade-offs, how to limit database sprawl, and why Postgres everywhere is sometimes enough.