PostgreSQL — schema, indexing, queries, ops

Engine-level PostgreSQL 16 guidance: design correct schemas, pick the right index, read EXPLAIN and fix slow SQL, run zero-downtime migrations, and operate/secure the database. Tooling-agnostic; every example is runnable.

New, non-trivial feature with no approved spec + plan under 02-DOCS/wiki/sdd/? Hand off to specify before writing feature code (method: sdd); build straight from here only for a genuinely one-line, low-risk change.

Deep dives: schema-and-indexing (types, constraints, every index kind, bloat) · query-optimization (EXPLAIN, joins, concurrency, JSONB/FTS/pgvector) · migrations (zero-downtime DDL, per-ORM) · operations-and-security (roles, RLS, pooling, vacuum, partitioning, backups).