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.

Organic Maps

https://organicmaps.app/
278•tosh•2h ago•67 comments

Introduction to Compilers and Language Design

https://dthain.github.io/books/compiler/
153•AlexeyBrin•4h ago•19 comments

The Plight of the Martian Farmer

https://mceglowski.substack.com/p/the-plight-of-the-martian-farmer
8•zdw•38m ago•3 comments

Run Windows 2000 on a DEC Alpha with a new es40 fork

https://raymii.org/s/blog/Run_Windows_2000_for_Dec_Alpha_on_a_new_es40_fork.html
32•jandeboevrie•2h ago•8 comments

Airplane Boneyards List and Map

https://airplaneboneyards.com/airplane-boneyards-list-and-map.htm
37•hyperific•1d ago•4 comments

Medieval-style fortifications are back in the Sahel

https://www.economist.com/middle-east-and-africa/2026/06/25/medieval-style-fortifications-are-bac...
44•andsoitis•4d ago•31 comments

If you're a button, you have one job

https://unsung.aresluna.org/if-youre-a-button-you-have-one-job/
437•nozzlegear•14h ago•222 comments

Shadcn/UI now defaults to Base UI instead of Radix

https://ui.shadcn.com/docs/changelog
230•dabinat•11h ago•122 comments

Rayfish, Peer-to-peer mesh VPN with no server to trust

https://rayfish.xyz/blog/01-introducing-rayfish
26•captain_dfx•4d ago•11 comments

Solar rail could become common in Europe after successful trial in Switzerland

https://www.euronews.com/2026/07/05/italy-could-be-the-next-country-to-build-a-solar-railway-afte...
42•neilfrndes•1h ago•22 comments

Pandoc Lua Filters

https://pandoc.org/lua-filters.html
114•ankitg12•2d ago•10 comments

Show HN: KiCad in the Browser

https://demo.pcbjam.com/
51•ViktorEE•4h ago•22 comments

The GNU Emacs Architecture: Unlocking the Core [pdf]

https://www.diva-portal.org/smash/get/diva2:2052282/FULLTEXT01.pdf
133•cenazoic•4d ago•8 comments

Autonomous flying umbrella follows and shields users from rain and sunlight

https://www.designboom.com/technology/autonomous-flying-umbrella-follows-users-rain-sunlight-i-bu...
14•amichail•53m ago•5 comments

Phosh 0.56.0

https://phosh.mobi/releases/rel-0.56.0/
120•edward•3h ago•38 comments

Fast Software, the Best Software (2019)

https://craigmod.com/essays/fast_software/
94•ustad•9h ago•49 comments

Why DMARC's new "NP" tag can fail with DNSSEC

https://dmarcwise.io/blog/dmarc-np-incompatibility-with-dnssec
4•matteocontrini•1h ago•0 comments

Cannabis Users Face Substantially Higher Risk of Heart Attack (2025)

https://www.acc.org/about-acc/press-releases/2025/03/17/15/35/cannabis-users-face-substantially-h...
107•RickJWagner•4h ago•132 comments

EU Council forces Chat Control via fast-track

https://www.heise.de/en/news/Chat-Control-1-0-EU-Council-forces-messenger-scans-via-fast-track-11...
131•stavros•4h ago•43 comments

Knowledge Should Not Be Gated

https://www.formaly.io/blog/knowledge-should-not-be-gated
68•nezhar•8h ago•47 comments

Megawatts by Microwave

https://computer.rip/2026-07-04-microwave-and-power.html
59•eternauta3k•10h ago•5 comments

Moby Dick Workout (2022)

https://www.hogbaysoftware.com/posts/moby-dick-workout/
85•helloplanets•12h ago•27 comments

Command and Conquer Generals natively ported to macOS, iPhone, iPad using Fable

https://github.com/ammaarreshi/Generals-Mac-iOS-iPad/tree/main
621•asronline•21h ago•261 comments

Trust your compiler: Modern C++

https://categorica.io/blog/2026.06.29_trust_your_compiler/
54•foxhill•4d ago•32 comments

Meta's Un-Stable Signature

https://hackerfactor.com/blog/index.php?/archives/1098-Metas-Un-Stable-Signature.html
128•ementally•3d ago•21 comments

Artful Cats: Feline-Inspired Art and Artifacts

https://www.si.edu/spotlight/art-cats
72•jruohonen•3d ago•5 comments

The Log is the Agent

https://arxiv.org/abs/2605.21997
84•iacguy•13h ago•34 comments

Atomic Force Microscope [video]

https://www.youtube.com/watch?v=DyIQkqBXhS0
106•mhb•2d ago•15 comments

GPT-5.5 Codex reasoning-token clustering may be leading to degraded performance

https://github.com/openai/codex/issues/30364
335•maille•18h ago•139 comments

Functional Programming in hica

https://www.hica.dev/docs/functional-programming/
39•cladamski79•3d ago•10 comments