GuideTechnology
14 min read
If you cannot observe a system, you cannot operate it. Learn the three signals (structured logs, metrics and distributed traces), the golden signals and RED and USE methods, percentiles and histograms, trace context propagation and OpenTelemetry, SLIs, SLOs and error-budget alerts, health checks and synthetic monitoring, and how to observe asynchronous systems without drowning in data.
GuideTechnology
15 min read
Why a query over millions of rows can take seconds or milliseconds depending on one index. Learn how B-tree indexes work, why they stay shallow, composite index column order, covering and partial indexes, selectivity, reading a query plan at a high level, why indexes are sometimes ignored, and what every index costs on writes.
GuideTechnology
20 min read
Caching as a design decision: where caches live, hit ratios, cache-aside, read-through, write-through and write-back, TTLs and invalidation, LRU and other eviction policies, cache stampedes, hot keys, negative caching and distributed caches such as Redis, with the trade-off between faster reads, stale data and invalidation complexity.
GuideTechnology
17 min read
Follow one request from a phone to a database and back: DNS lookup, TCP and TLS handshakes, HTTP, the edge, the load balancer, the application and the data stores. Learn where the time goes, why round trips and distance dominate latency, and where requests fail.
