Cache Invalidation Is Not the Hard Part
Deleting a key is one line. The hard parts are the copies you forgot, the read-write race that leaves stale data with clean logs, and the stampede at expiry.
5 min read
Posts tagged System Design
8 posts, newest first.
Eventual Consistency Is a Product Decision
Engineers argue consistency via CAP. The answerable question is what a user will forgive seeing, and how to get that from a stakeholder instead of guessing.
5 min read
Microservices Were Never About Scale
Teams split monoliths for throughput and got an org-chart fix. The honest case is deploy cadence and ownership — plus narrow cases where boundaries help load.
5 min read
Premature Sharding: The Decision You Cannot Take Back
Sharding usually arrives years early and charges rent forever in lost joins, transactions and simplicity. What to exhaust first, and the signals that it's time.
6 min read
The Read-Heavy Assumption
"It's read-heavy, so we'll add a cache" is the least examined sentence in system design. Four things that break it, and how to check it in an afternoon.
6 min read
The Requirements Phase Candidates Rush Through
Four clarifying questions branch a design; the rest are ritual. What to ask before drawing, and how to tell a load-bearing answer from one you'll never use.
5 min read
Backpressure and Rate Limiting: The Two Answers Candidates Skip
Adding a queue doesn't absorb a spike, it defers one. What backpressure and rate limiting actually do, why they're different, and the failure they each prevent.
4 min read
Why Static Diagrams Fail You in System Design Interviews
A box-and-arrow diagram can't tell you whether your design works. Here's what interviewers are probing for, and why drawing tools can't help you practice it.
4 min read
