Redis

The catalog is specific: UNLOGGED tables instead of Redis, SKIP LOCKED instead of a job queue, pgvector instead of Pinecone, PostGIS instead of your geo stack, with a rule that you may leave Postgres only after documenting why it wasn't enough.

A developer running an email CRM on Redis isn't buying the premise: it's trivial to set up and never crashes, so what difficulty is this genre even describing?

The gist sets a deliberately high bar: pick a separate system only after you have pushed Postgres to its limits, documented why it fell short, and accepted the operational cost. PGMQ stands in for Kafka, pgvector and ParadeDB for Elasticsearch, Apache AGE for Neo4j, TimescaleDB for time-series.

Then a Google SRE flips it: you only reach for Kafka or Snowflake at the point Postgres stops being viable, so the comparison runs backwards. And a 20-year ops veteran argues one big database is harder to run than several small ones.