--- title: PGSimCity - How PostgreSQL Works | daily.dev description: PGSimCity is an interactive 3D browser-based visualization of how PostgreSQL works internally, covering backends, shared buffers, WAL, checkpoints, autovacuum,... canonical: https://daily.dev/posts/pgsimcity---how-postgresql-works-nhueeeyjn twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: PGSimCity - How PostgreSQL Works | daily.dev og:description: PGSimCity is an interactive 3D browser-based visualization of how PostgreSQL works internally, covering backends, shared buffers, WAL, checkpoints, autovacuum,... og:url: https://daily.dev/posts/pgsimcity---how-postgresql-works-nhueeeyjn og:image: https://api.daily.dev/og/posts/nhUEEEYJn.png og:image:alt: PGSimCity - How PostgreSQL Works og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # PGSimCity - How PostgreSQL Works **[Hacker News](https://daily.dev/sources/hn)** · 1 min read · 4 upvotes · 1 comments ## Summary PGSimCity is an interactive 3D browser-based visualization of how PostgreSQL works internally, covering backends, shared buffers, WAL, checkpoints, autovacuum, and replication. Built with WebGL2, it runs live in the browser and is currently an early prototype open to community corrections via GitHub issues or pull requests. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community take How the wider developer community reacted, aggregated from 1 discussion and 52 comments across hackernews (as of 2026-07-31). **TL;DR:** The community is genuinely impressed by PGSimCity's creative concept of visualizing PostgreSQL internals as a SimCity-style 3D city, but broadly agrees the UX needs significant polish — too much UI clutter, the tour is overwhelming, and controls are hard to discover. **Sentiment:** 55% positive · 35% mixed · 10% skeptical **The case for** - Commenters praise the novel idea of using a city metaphor to make complex database internals (scheduling, MVCC, transactions) intuitive and engaging. - Several note it was built rapidly from a single prompt using Claude Opus 5, highlighting the potential of LLM-assisted development for educational tools. - The open-source nature is seen as a strength, with suggestions it could be reused for other domains like Kubernetes or cloud computing. **The pushback** - The UI is too cluttered — popups and info boxes cover most of the 3D visual, especially on mobile and laptop screens. - The tour is passive and auto-advancing, making it hard to follow; commenters want interactive, step-by-step control including firing individual transactions. - Camera controls are difficult to use, and the simulation runs too fast even at 0.1x speed for meaningful learning. - The 'SimCity' name may be an active EA trademark, posing a legal risk. - Some question the accuracy/review process for an LLM-generated educational tool. **By community** - hackernews (mixed): Enthusiastic about the concept but consistently critical of UX issues including UI clutter, passive tour design, and lack of interactive query tracing. **Hottest debate:** Whether a 'tour' is an acceptable UX pattern or a sign that the core interface needs redesign. **Open questions** - Could users input a live query and watch it flow through the entire system step by step? - Will MVCC and transaction visibility be visualized? - How accurate is the LLM-generated representation of PostgreSQL internals? **Highlights** > I imagined as soon I saw the initial visual that I would somehow be able to enter a query and it would walk me through the flow through the entire system starting from input parsing to all the way to delivering output and perhaps along the way understand some of the autonomous processes that happen in parallel that aren't query specific but run constantly. What others are saying - fantastic attempt, but don't know where to start or where to end. > — [narmiouh on hackernews · 1 comments](https://news.ycombinator.com/item?id=49064172) > I love what is trying to be done here. Some feedback to improve would be to cut out a lot of the noise with the "Take tour". There are too many boxes and things changing on the screen to get a sense of what is happening. Also make it interactive rather than automatically switch onto the next subject. Being a passive observer to so much information trying to be conveyed is very confusing. I really do like these kinds of approaches to showing the inner workings of different kinds of tech, so think this is on the good path to being a very useful tool, but needs some focus rather than more data/graphs/info boxes. > — [layoric on hackernews · 2 comments](https://news.ycombinator.com/item?id=49064136) > 3.86B tokens to build a visual simulator of a database that runs on a fraction of that compute. we're using the expensive brain to draw pictures of the cheap brain. > — [luciana1u on hackernews](https://news.ycombinator.com/item?id=49064860) > Ah indeed there is. Totally didn't notice that, thanks. But even at .1x it's too quick. :) I should be able to fire individual transactions and watch them flow. > — [jedberg on hackernews](https://news.ycombinator.com/item?id=49065253) > Understanding how scheduling works inside a database used to require numerous architecture diagrams to explain. I was amazed when I saw PGSimCity — it presents such a complex technical implementation process in such an engaging way. Since it's already open‑source, I think the same idea can be reused in other domains, such as cloud computing, Kubernetes, and so on. > — [Curtis\_Guan on hackernews · 1 comments](https://news.ycombinator.com/item?id=49064171) **Source threads** - [hackernews](https://news.ycombinator.com/item?id=49063754) · 83 points · 52 comments --- Tags: [#webdev](https://daily.dev/tags/webdev), [#postgresql](https://daily.dev/tags/postgresql) [View this post on daily.dev](https://daily.dev/posts/pgsimcity---how-postgresql-works-nhueeeyjn) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"PGSimCity - How PostgreSQL Works","url":"https://daily.dev/posts/pgsimcity---how-postgresql-works-nhueeeyjn","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/pgsimcity---how-postgresql-works-nhueeeyjn"},"datePublished":"2026-07-27T01:57:02.420Z","dateModified":"2026-07-31T18:47:11.723Z","description":"PGSimCity is an interactive 3D browser-based visualization of how PostgreSQL works internally, covering backends, shared buffers, WAL, checkpoints, autovacuum,...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/bcd4747525f343f0b5c0a087afae7c2a?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/bcd4747525f343f0b5c0a087afae7c2a?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Hacker News","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Hacker News","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/hn","url":"https://daily.dev/sources/hn"},"commentCount":1,"discussionUrl":"https://daily.dev/posts/pgsimcity---how-postgresql-works-nhueeeyjn","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":4},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":1}],"keywords":"webdev,postgresql","timeRequired":"PT1M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Hacker News","item":"https://daily.dev/sources/hn"},{"@type":"ListItem","position":3,"name":"PGSimCity - How PostgreSQL Works"}]} ```