Database Engineering, Declarative Schemas & MCP Observability

### Moving from Chronological Migrations to Declarative State Managing production relational databases has historically required maintaining chronological chains of migration scripts. When distributed development teams branch simultaneously, timestamp collisions and out-of-order schema mutations create deployment instability. Modern cloud databases are adopting **declarative desired-state schemas**: 1. **AST-Based DDL Diffs**: Developers commit a single target `schema.sql` representation. The deployment engine parses the Abstract Syntax Tree against the target database catalog and calculates the exact non-destructive DDL patch. 2. **Decoupled Compute & Storage**: Decoupling virtual compute instances from distributed NVMe storage volumes allows vertical CPU/RAM resizing in under 45 seconds with zero storage replication downtime. 3. **Agentic Observability via MCP**: Local coding agents inspect live Postgres query plans, connection pool saturation, and error codes through standardized Model Context Protocol servers.