About

I am Vijay Kumar, a full-stack developer in Dublin, Ireland. I write about work that shows up when you try to ship it: Postgres and query plans, systems, and applied ML — LLMs, RAG, fine-tuning, agents, and MCPs.

These notes are practical, engineer-to-engineer writing on Postgres, systems, and applied ML. I prefer a concrete setup, a failed experiment, or a measurement over a survey of papers. The topics that keep showing up are databases, query plans, PEFT, agents, RAG, evaluation, latency, cost, and the glue between a notebook and a system other people can run.

I have spent 10+ years in product and engineering — Nutanix, Oracle, Cisco, and earlier work at Hansel.io, IGP.com, and Mantra Labs.

If a piece is still a draft, it is not on this site. The public repo only holds approved posts.