Vitess is a MySQL-compatible, cloud-native database system originally built at YouTube to scale MySQL. PlanetScale runs Vitess as a managed service. Core capabilities:
| Keyspace | Logical database mapping to one or more shards. Analogous to a MySQL schema. | | Shard | A horizontal partition of a keyspace, each backed by a separate MySQL instance. | | VSchema | Configuration defining how tables map to shards, vindex (sharding) keys, and routing rules. |
| Vindex | Sharding function mapping column values to shards (hash, unicodeloosexxhash, lookup). | | VTGate | Stateless proxy that plans and routes queries to the correct shard(s). | | Online DDL | Non-blocking schema migrations. On PlanetScale, use deploy requests for production changes. |
Vitess best practices, query optimization, and connection troubleshooting for PlanetScale Vitess databases. Load when working with Vitess databases, sharding, VSchema configuration, keyspace management, or MySQL scaling issues. Source: planetscale/database-skills.