14.5 Databases & Storage Engine Deep Dive

1. Relational Database & Indexing Architecture

OmniPost uses SQLAlchemy 2.0 with asynchronous drivers (aiosqlite for tests, asyncpg for production PostgreSQL) across 9 relational tables:

Critical Indexes & Execution Plans

1. (tenant_id, idempotency_key): Unique composite index guaranteeing duplicate prevention in $O(\log N)$ time.
2. (queue_name, locked_until, priority, enqueued_at): Compound B-tree index enabling microsecond worker polling via index scans rather than sequential table scans.

2. Say It Out Loud

"I chose PostgreSQL as our relational backbone because notification platforms cannot compromise on data integrity. The composite unique index on (tenant_id, idempotency_key) guarantees that concurrent identical requests never create duplicate alerts. Our queue table uses compound B-tree indexing on priority and lease expiration timestamps, allowing our asynchronous workers to claim jobs in under two milliseconds using index-only scans."