Databases & Data Storage
Choose, design, and scale the right database — relational, NoSQL, vector, and cloud-native options compared.
Courses
Learn how relational, NoSQL, vector, and cloud databases work — and how to pick, design, and query the right one for your application.
From fundamentals to production — caching strategies, eviction policies, invalidation, Redis, CDN caching, and multi-level architectures. Practical patterns and a guided final project you build in your own stack (no bundled starter repo).
Articles
An order database's primary data center suffers a catastrophic, unrecoverable event — not a transient node failure, an actual disaster. Two …
A multi-tenant analytics platform partitions incoming events by tenant_id, hashed onto 16 shards — a design that looked perfectly balanced i…
A URL shortener's redirect endpoint, GET /r/{code}, looks purely read-heavy — billions of redirects against a handful of short codes created…
A payment service keeps processing requests with zero dropped transactions while one of its three nodes crashes mid-request — that's fault t…
A shopping cart write to cart-77 needs to land on enough replicas that a later read is guaranteed to see it — but "enough" is a number you c…
A user changes their display name, refreshes the page a second later from a phone on a different network, and sees the old name. Nothing cra…
An order API can return responses all day and still charge the wrong amount. It can be temporarily unreachable while every stored order rema…
Checkout slows while product pages remain healthy. CPU is moderate, but the orders table shows rising lock waits and writes queue behind one…
A product page is easy to cache until a price changes: the CDN still has the old response, one app instance has an older in-process value, a…
Two support agents both open the same account balance, both see $100, both independently process a $50 withdrawal, and the balance ends up a…
PostgreSQL never overwrites a row in place. An UPDATE writes a new version of the row and marks the old one as replaced; a DELETE only marks…
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