https://blog.vnykmshr.com/writing/tags/redis/Recent content in Redis on vnykmshrHugoenThu, 20 Jun 2024 00:00:00 +0000https://blog.vnykmshr.com/writing/redis-caching-patterns/Thu, 20 Jun 2024 00:00:00 +0000https://blog.vnykmshr.com/writing/redis-caching-patterns/<p>Put Redis in front of a database and reads get fast. The cost is a cache layer that&rsquo;s now load-bearing, and a set of failure modes that come with that.</p> <p>Three write patterns, three hard problems. The patterns determine consistency. The problems determine whether your cache layer is a net positive or a source of outages.</p> <h2 id="write-patterns">Write patterns</h2> <p><strong>Cache-aside</strong> (lazy loading). The application checks cache on read. On miss, it reads from the database and populates cache. Writes go directly to the database; cache entries are either invalidated or left to expire.</p>https://blog.vnykmshr.com/writing/url-mapping-in-redis/Sun, 10 Jun 2012 00:00:00 +0000https://blog.vnykmshr.com/writing/url-mapping-in-redis/<p>I&rsquo;m working on an e-commerce app in Node.js. The store has SEO-friendly URLs &ndash; <code>/blue-widget/SKU12345/p/</code> for products, <code>/category-name.html</code> for categories, <code>/brand-name/</code> for brands. Those URLs are indexed, bookmarked, linked from everywhere. They can&rsquo;t change.</p> <p>Express routes are defined in code. The catalog has enough products, categories, and brands that I&rsquo;m not writing a route for each one. I need a way to map the friendly URL to an internal route at runtime.</p>