frontpage.
newsnewestaskshowjobs

Open Source @Github

fp.

Open in hackernews

Anatomy of a SQL Engine

https://www.dolthub.com/blog/2025-04-25-sql-engine-anatomy/
168•ingve•1y ago

Comments

jimbokun•1y ago
Very nice write up enumerating all the stages of SQL query execution. Interesting even if you don’t care about the DoIt database specifically.
Austizzle•1y ago
Man, this title tripped me up for a minute because I pronounce it with the letters like Ess-Queue-Ell

So the "A" in "A ess-queue-ell" engine felt like it should have been an "An" until I realized it was meant to be pronounced like "sequel"

perching_aix•1y ago
Not necessarily, I see native speakers completely ignore this a lot.

Have you ever considered pronouncing it as squirrel by the way?

kreetx•1y ago
Many (most?) non-native English speakers do pronounce it as ess-queue-ell, especially in their own languages, so yes, the use of "a" instead of "an" does look off from that perspective.
SloopJon•1y ago
When I read SQL for Dummies almost thirty years ago, it made a point of distinguishing "sequel" as a historical predecessor to standard "SQL." As I recall, the author even asserted that SQL is not an acronym/initialism for structured query language. I felt funny saying sequel for the next decade or so, because I wasn't an old timer experienced with this pre-SQL technology.

Now I usually say sequel because everyone else does. That and it rolls off the tongue better than S-Q-L.

jtolmar•1y ago
I prefer "ess queue ell" these days, but the first DBA I ever worked with pronounced it "squirrel".
gopalv•1y ago
This is a great write up about a pull-style volcano SQL engine.

The IR I've used is the Calcite implementation, this looks very concept adjacent enough that it makes sense on the first read.

> tmp2/test-branch> explain plan select count() from xy join uv on x = u;

One of the helpful things we did was to build a graphviz dot export for the explains plans, which saved us days and years of work when trying to explain an optimization problem between the physical and logical layers.

My version would end up displayed as SVG like this

https://web.archive.org/web/20190724161156/http://people.apa...

But the calcite logical plans also have that dot export modes.

https://issues.apache.org/jira/browse/CALCITE-4197

th0ma5•1y ago
This is really great!!
gavinray•1y ago
Calcite also has a relatively-unknown web tool for plan visualization that lets you step through execution.

It's a method from "RuleMatchVisualizer":

https://github.com/apache/calcite/blob/36f6dddd894b8b79edeb5...

Here's a screenshot of what the webpage looks like, for anyone curious:

https://github.com/GavinRay97/GraphQLCalcite/blob/92b18a850d...

ignoreusernames•1y ago
I recommend anyone who works with databases to write a simple engine. It's a lot simpler than you may think and it's a great exercise. If using python, sqlglot (https://github.com/tobymao/sqlglot) let's you skip all the parsing and it even does some simple optimizations. From the parsed query tree it's pretty straightforward to build a logical plan and execute that. You can even use python's builtin ast module to convert sql expressions into python ones (so no need for a custom interpreter!)
Abde-Notte•1y ago
Second this - building even a simple engine gives real insight into query planning and execution. Once parsing is handled, the core ideas are a lot more approachable than they seem.
albert_e•1y ago
Sorry for slight digression.

In a larger system we are building we need a text-to-sql capability for some structured data retrieval.

Is there a way one could utilize this library (sqlglot) to build a multi-dialect sql generator -- that is not currently solved by directly relying on a LLM that is better at code generation in general?

LtdJorge•1y ago
This is a SQL to X library, though. I don’t think it’s what you need.
gavinray•1y ago
You can use an LLM to generate query-builder expressions from popular libraries in whatever language.

For example, on the JVM there is jOOQ, which allows you to write something like:

  select(field("foo"), avg("bar")).from(table("todos"))
And then it will render dialect-specific SQL. It has very advanced emulation functionality for things like JSON aggregations and working around quirks of dialects.

Alternatively, you can ask an LLM to generate a specific dialect of SQL, and then use jOOQ to parse it to an AST, and then render it as a different dialect, like:

    val parser= DSL.using(SQLDialect.POSTGRES).parser()
    val parsedQuery = parser.parseQuery(postgresQuery)
    val renderedMySQL = DSL.using(SQLDialect.MYSQL).renderInlined(parsedQuery)
    println(renderedMySQL)
Unsure if functionality like this exists in other Query Builder libraries for other languages.
KyleBrandt•1y ago
Using dolthub's go-mysql-server for Grafana's upcoming SQL expressions feature (private preview in Grafana 12, but in the OSS version with a feature toggle).

GMS lets you provide your own table and database implementations, so we use GMS to perform SQL queries against Grafana's dataframes - so users can join or manipulate different data source queires, but we don't have to insert the data into SQL to do this thanks to GMS.

genai-analyst•1y ago
another digression here... sorry... i see you're trying to diy text-to-sql—at some point you're gonna hit a bunch of hiccups. like, the model writes a query that “almost” works but joins the wrong tables, or it assumes column names that don’t exist, or it returns the wrong agg because it misread the intent. and retries won’t always save you—it’ll just confidently hallucinate again.

we’ve been through all of that at wobby.ai we ended up building a system where the data team defines guardrails and reusable query templates, so the agent doesn’t just make stuff up. it can still handle user prompts, but within a safe structure. if you want to save yourself from debugging this stuff endlessly, might be worth checking out wobby.ai.

Kill The Cookie Banner

https://killthecookiebanner.eu/
570•rapnie•7h ago•278 comments

London Gatwick has launched a robotic airport parking service

https://aerospaceglobalnews.com/news/gatwick-airport-robotic-parking-stanley-robotics/
220•agotterer•4h ago•167 comments

Design is compromise

https://stephango.com/design-is-compromise
103•ankitg12•3h ago•44 comments

Decker

https://beyondloom.com/decker/
25•tosh•1h ago•6 comments

Show HN: CheapSecurity – Lightweight, Self-Hosted CCTV for Linux SBCs

https://github.com/gmrandazzo/CheapSecurity
47•zeldone•3h ago•12 comments

Jimothy the raccoon has a rare spinal condition. Here's what that means

https://www.popsci.com/science/whats-jimothy-raccoon-condition/
61•speckx•5d ago•21 comments

Ruff v0.16.0 – Significant new updates – 413 default rules up from 59

https://astral.sh/blog/ruff-v0.16.0
322•vismit2000•10h ago•198 comments

Introduction to Data-Oriented Design [pdf]

https://www.gamedevs.org/uploads/introduction-to-data-oriented-design.pdf
13•tosh•1h ago•3 comments

Htmx 4.0, the first JavaScript library to release exclusively on the Game Boy

https://swag.htmx.org/en-cad/products/htmx-4-the-game
196•rcy•7h ago•66 comments

How to Write English Prose

https://thelampmagazine.com/blog/how-to-write-english-prose
23•geneticdrifts•2h ago•5 comments

Go Analysis Framework: modular static analysis by go team

https://pkg.go.dev/golang.org/x/tools/go/analysis
143•AbuAssar•7h ago•22 comments

The Strongest El Niño Ever

https://www.theclimatebrink.com/p/the-strongest-el-nino-ever
93•ndsipa_pomu•56m ago•31 comments

Building the Grace Cathedral Experience

https://blog.playcanvas.com/building-the-grace-cathedral-experience/
6•ovenchips•4d ago•0 comments

How to Block Some of the Bots

https://nochan.net/b/Internet-Crap/20260606-How-To-Block-Some-Of-The-Bots/
10•Bender•59m ago•6 comments

Using sed to make indexes for books (long)

https://www.pement.org/sed/make_indexes.txt
22•TMWNN•3d ago•2 comments

The New AI Superpowers: Focus and Followthrough

https://www.rickmanelius.com/p/the-new-ai-superpowers-focus-and
70•mooreds•6h ago•24 comments

Show HN: HART OS – an open-source AI OS built so frontier AI needs no datacenter

https://github.com/hertz-ai/HARTOS
6•hevolveai•52m ago•1 comments

I learned PCB design, 3D printing and C just to listen to music

https://pentaton.app/blog/2026-07-12-introducing-pentaton-lp/
128•interfeco•3d ago•25 comments

Using ThinkPad T480 as a mobile phone

https://grego.site/blog/thinkphone
18•marosgrego•2h ago•5 comments

GrapheneOS protections against data extraction from locked devices

https://discuss.grapheneos.org/d/40700-grapheneos-protections-against-data-extraction-from-locked...
316•Cider9986•13h ago•195 comments

What's Under Your Feet in New York City?

https://practical.engineering/blog/2026/7/21/whats-under-your-feet-in-new-york-city
111•sohkamyung•4d ago•19 comments

Show HN: Reverse Minesweeper

https://sunflowersgame.com/
73•pompomsheep•6h ago•25 comments

Google Discloses $94.1B in SpaceX Stock, Marking 6% Stake

https://www.wsj.com/tech/google-discloses-94-1-billion-in-spacex-stock-marking-6-stake-91655d7c
260•1vuio0pswjnm7•6h ago•204 comments

Show HN: The Occult Gatsby

https://occultgatsby.work
14•morganw•54m ago•3 comments

French firefighters face 'pyrocumulonimbus' for first time

https://www.france24.com/en/live-news/20260726-french-firefighters-face-pyrocumulonimbus-for-firs...
43•saaaaaam•1h ago•17 comments

A shell colon does nothing. Use it anyway

https://refp.se/articles/your-shell-and-the-magic-colon
356•olexsmir•1d ago•152 comments

Sum of Cubes via Difference Tables

https://leancrew.com/all-this/2026/07/sum-of-cubes-via-difference-tables/
9•surprisetalk•3d ago•2 comments

An Inside Look at the Token Reseller Market

https://vectoral.com/blog/token-relay-market
93•mlenhard•4h ago•49 comments

Terence Tao: Mathematics in the Age of AI [pdf]

https://teorth.github.io/tao-web/slides/age-of-ai-icm-2026.pdf
66•Anon84•9h ago•28 comments

An ESP32 based plane radar for my desk

https://blog.ktz.me/esp32-plane-radar/
247•alexktz•16h ago•53 comments