Implement CQRS (Command Query Responsibility Segregation) to scale reads independently from writes. Learn command bus patterns, query bus patterns, eventual consistency, projections, CQRS without event sourcing, testing strategies, and when the complexity is justified.
Master connection pooling with PgBouncer and pgpool-II. Learn transaction vs session mode, pool sizing math, Prisma connection pooling, serverless connection pooling, and monitoring.
Test migrations for backwards compatibility, forwards compatibility, rollback safety, and data integrity. Catch schema-code mismatches before deployment.