A practical field guide to Couchbase indexing. Covers primary vs GSI indexes, composite key ordering, index-order sorting, covering and partial indexes, array indexes (including replacing OR and LIKE), IntersectScan and UnionScan avoidance, replication and partitioning, projection selectivity, the ADVISE and INFER tools, scan consistency, and pagination, all with runnable SQL++ (N1QL) examples against the travel-sample dataset.

"The database that runs your app cannot be the database that analyzes your app". It's a hard lesson learned at scale. Early on, Postgres does it all. But as you hit massive scale, your analytics queries start killing your login APIs. This post breaks down the physics of Row-oriented (Couchbase) vs Column-oriented (ClickHouse) databases, and how to bridge them using Change Data Capture (CDC) for a robust, lag-free architecture.