--- title: "Ujjwal Agarwal (@ujjwalcode) | Hashnode" description: "Full Stack Engineer | Backend Engineer | AI Engineer. Read the latest articles by Ujjwal Agarwal on Hashnode." url: "https://hashnode.com/@ujjwalcode" --- @ujjwalcode # Ujjwal Agarwal @ujjwalcode · Joined December 2021 Full Stack Engineer | Backend Engineer | AI Engineer ### [Jev: What If Software Doesn't Need an LLM to Make Every Decision?](https://guidetodevelopment.hashnode.dev/jev-decision-model?utm_source=hashnode&utm_medium=feed) Jev is a System One decision model built for fast, structured decisions. Here's why software may not need an LLM for every decision. 12 min read · [guidetodevelopment.hashnode.dev](https://guidetodevelopment.hashnode.dev/jev-decision-model?utm_source=hashnode&utm_medium=feed) [Oct 5](https://hashnode.com/posts/jev-decision-model/6ac39d1d86edecd838b3cc0a) ### [AI System Design: DoorDash Search System](https://guidetodevelopment.hashnode.dev/ai-system-design-doordash-search-system?utm_source=hashnode&utm_medium=feed) LLM + Knowledge Graph + Hybrid Retrieval 5 min read · [guidetodevelopment.hashnode.dev](https://guidetodevelopment.hashnode.dev/ai-system-design-doordash-search-system?utm_source=hashnode&utm_medium=feed) [3](https://hashnode.com/posts/ai-system-design-doordash-search-system/6a9e926c1e6787a4df21d7cb) [Sep 7](https://hashnode.com/posts/ai-system-design-doordash-search-system/6a9e926c1e6787a4df21d7cb) ### [What Actually Happens Inside PostgreSQL When You UPDATE a Row?](https://guidetodevelopment.hashnode.dev/what-actually-happens-inside-postgresql-when-you-update-a-row?utm_source=hashnode&utm_medium=feed) What happens when you UPDATE a row in PostgreSQL? Understand pages, CTIDs, indexes, MVCC, tuple versions, HOT updates, and VACUUM. 7 min read · [guidetodevelopment.hashnode.dev](https://guidetodevelopment.hashnode.dev/what-actually-happens-inside-postgresql-when-you-update-a-row?utm_source=hashnode&utm_medium=feed) [Aug 16](https://hashnode.com/posts/what-actually-happens-inside-postgresql-when-you-update-a-row/6a8240ebb155766e35ab18e9) ### [Why Traditional Search Breaks](https://guidetodevelopment.hashnode.dev/why-traditional-search-breaks?utm_source=hashnode&utm_medium=feed) Why modern search is no longer just about matching words or finding similar vectors. Introduction If you've used apps like Zomato, Swiggy, or Uber Eats, you've probably noticed that search has become 7 min read · [guidetodevelopment.hashnode.dev](https://guidetodevelopment.hashnode.dev/why-traditional-search-breaks?utm_source=hashnode&utm_medium=feed) [Aug 9](https://hashnode.com/posts/why-traditional-search-breaks/6a78b92d8033def57c0cb9d4) ### [A quick guide to useState Hook](https://guidetodevelopment.hashnode.dev/a-quick-guide-to-usestate-hook?utm_source=hashnode&utm_medium=feed) The blog contains brief intro to useState and how to use it with React hooks and also tells about common mistakes newbiew developers make and to avoid them. 3 min read · [guidetodevelopment.hashnode.dev](https://guidetodevelopment.hashnode.dev/a-quick-guide-to-usestate-hook?utm_source=hashnode&utm_medium=feed) [Oct 28, 2023](https://hashnode.com/posts/a-quick-guide-to-usestate-hook/653d509e4cb2a140eafb876f)