Code to Architecture

Part 1 established the main idea: thread pools, DB pools, and GC belong to the same capacity chain. Part 2 is where teams usually get stuck next: once you know they interact, how do you tune the service without chasing symptoms across the wrong layer and making the bottleneck harder to see.

Many performance incidents are not ...

Part 1 established the basic rule: Testcontainers is most valuable when real dependency behavior matters. Part 2 is about the next problem large teams actually hit: once container-backed tests become popular, how do you keep the suite fast, isolated, and economically trustworthy instead of turning every correctness question into a heavyweight integration run.

Part 1 established the real issue: once you add Caffeine, Redis, and invalidation, the design is no longer just about speed. Part 2 is where the harder production question appears: how do you keep that cache hierarchy trustworthy when writes, fan-out lag, and partial failures all arrive at once.

The first cache design ...

Part 1 established the core idea: timeout, bulkhead, and circuit breaker have to operate as one coordinated policy. Part 2 goes deeper into the production problem that usually follows: once those controls exist, how do you tune them per dependency without creating a maze of fallbacks, retries, and contradictory failure behavior.

Part 1 focused on the edge: separating authentication, tenant resolution, and authorization so a valid identity cannot silently become a valid tenant switch. Part 2 goes deeper into the next risk: once the edge accepts a request, how do you preserve tenant truth across downstream calls, async work, and operator access without leaking context or widening trust accidentally.