Ian Duncan

Making Haskell Talk to PostgreSQL Without Suffering

Ian Duncan — Fri, 20 Feb 2026 00:00:00 GMT

How to eliminate the three performance taxes that make database queries slow: encoding overhead, round-trip latency, and N+1 query patterns.

Archive: Automatic Optimal Pipelining of Redis Commands

Ian Duncan — Tue, 17 Feb 2026 00:00:00 GMT

Archived from Informatikr (originally published January 18, 2012). Describes how the Haskell Redis client Hedis achieves automatic and optimal pipelining by combining lazy I/O with a synchronous-looking API, getting the best of both synchronous and asynchronous approaches.

TIL: HTTP/3 Is Not Always Faster Than HTTP/2

Ian Duncan — Tue, 10 Feb 2026 00:00:00 GMT

Local benchmarks revealed HTTP/3 can be 50-100x slower than HTTP/2. QUIC's userspace implementation loses to decades of kernel TCP optimizations on high-bandwidth, low-latency networks.

What Functional Programmers Get Wrong About Systems

Ian Duncan — Mon, 09 Feb 2026 00:00:00 GMT

Type systems verify properties of programs. Production correctness is a property of systems. The gap between these is where the interesting failures live.

In Praise of Control Planes, or: Why You Need a Place to Stand

Ian Duncan — Sat, 07 Feb 2026 00:00:00 GMT

The control plane pattern (a coordinator that tells workers what to do) shows up everywhere good infrastructure exists. The concept is simple. Naming it is useful.

Your Best Thinking Is Wasted on the Wrong Decisions

Ian Duncan — Sat, 07 Feb 2026 00:00:00 GMT

Some engineering decisions punish you for being wrong. Most don't. Learning to tell the difference and calibrate your deliberation accordingly might be the most valuable skill your team never explicitly develops.

No, Really, Bash Is Not Enough: Why Large-Scale CI Needs an Orchestrator

Ian Duncan — Fri, 06 Feb 2026 00:00:00 GMT

A deeper dive into why shell scripts cannot replace a proper CI control plane, drawn from years of building and operating CI systems at scale.

GitHub Actions Is Slowly Killing Your Engineering Team

Ian Duncan — Thu, 05 Feb 2026 00:00:00 GMT

Why GitHub Actions is the Internet Explorer of CI, and why Buildkite offers a better path forward for teams that care about developer experience.

Punycode: My New Favorite Algorithm

Ian Duncan — Mon, 01 Dec 2025 00:00:00 GMT

A deep dive into how Punycode works, and why I think it's so neat.

The CRDT Dictionary: A Field Guide to Conflict-Free Replicated Data Types

Ian Duncan — Thu, 27 Nov 2025 00:00:00 GMT

A comprehensive guide to CRDTs and their tradeoffs, from counters to sequences. Written in the spirit of the Typeclassopedia, exploring how different CRDTs solve the distributed consensus puzzle.

JSON Schema Demystified: Understanding Schemas, Dialects, Vocabularies, and Metaschemas

Ian Duncan — Mon, 24 Nov 2025 00:00:00 GMT

An accessible guide to understanding the confusing terminology around JSON Schema. What are schemas, dialects, vocabularies, and metaschemas, and how do they all fit together?

Event Design for Streaming Systems: A Primer

Ian Duncan — Fri, 14 Nov 2025 00:00:00 GMT

How to use event streams in an effective, scalable, future-proof way.

Accidental or Essential? Understanding Complexity in Software Design

Ian Duncan — Mon, 26 May 2025 00:00:00 GMT

Understanding the difference between essential and accidental complexity in software design.

What You Need to Know About Trump\

Ian Duncan — Thu, 24 Apr 2025 00:00:00 GMT

A look at the Trump administration\

Actuarial Murder and Other Diffuse Acts of Violence

Ian Duncan — Fri, 21 Feb 2025 00:00:00 GMT

An exploration of how institutional decisions and systemic policies can cause widespread harm with less accountability than direct violence, examining cases from healthcare to education where bureaucratic choices have life-altering consequences despite being treated as mere business decisions.

The Cadence of Salting

Ian Duncan — Mon, 13 Jan 2025 00:00:00 GMT

When you salt matters as much as how much you salt. Understanding the timing changes everything.

Welcome to Published Notes

Ian Duncan — Mon, 13 Jan 2025 00:00:00 GMT

An example note showing how Logseq notes can be published to your website

Embracing Flexibility in Haskell Libraries: The Power of Records of Functions

Ian Duncan — Fri, 26 Jan 2024 00:00:00 GMT

Improve the robustness and flexibility of your Haskell apps by changing how you design your libraries.

Hi, Barbie! Higher kinded records made easy(er)

Ian Duncan — Thu, 11 Jan 2024 00:00:00 GMT

We often need to make and manipulate derived types that are similar to each other, but not quite the same. Higher-kinded records provide a way to do this in a generic way, but are clunky. We\

Haskell Best Practices– Wildcards aren\

Ian Duncan — Thu, 31 Aug 2023 00:00:00 GMT

An argument for using really exhaustive pattern matching.

There and Back Again: Turning Haskell functions into RPC calls- Part 2

Ian Duncan — Wed, 30 Aug 2023 00:00:00 GMT

In the last post, we figured out an interface for the RPC caller to invoke remote Haskell functions. In this post, we\

There and Back Again: Turning Haskell functions into RPC calls- Part 1

Ian Duncan — Wed, 30 Aug 2023 00:00:00 GMT

Integrating a large Tokio-based Rust library with Haskell

Ian Duncan — Wed, 30 Aug 2023 00:00:00 GMT

A lot of the Rust <-> Haskell interop examples out there are for small, synchronous libraries. They also tend to omit how to actually package the Rust library. We\

One Serialization Class to Rule Them All

Ian Duncan — Tue, 29 Aug 2023 00:00:00 GMT

Typical serialization libraries in the Haskell ecosystem target a single format. We explore how to provide composite serialization for data types that chooses the best format for each data type.

OpenTelemetry Gotchas– Phantom Spans

Ian Duncan — Mon, 28 Aug 2023 00:00:00 GMT

We struggled for several months with a mysterious tracing issue in our production environment. Unrelated web requests were being linked together in the same trace, but we could never see the root trace span. This is the story of how we found and fixed root cause.

The Cruel Part Is

Ian Duncan — Sun, 01 Jan 2023 00:00:00 GMT

A poem

Vignettes

Ian Duncan — Sun, 01 Jan 2023 00:00:00 GMT

A collection of memories

Garbage in, Never out

Ian Duncan — Mon, 04 Oct 2021 00:00:00 GMT

Adventures in streaming algorithms.

Using React with GHCJS

Ian Duncan — Tue, 16 Dec 2014 00:00:00 GMT

Early explorations in data-driven Haskell applications in the browser.

Introducing Growler, a simple HTTP server toolkit

Ian Duncan — Thu, 13 Nov 2014 00:00:00 GMT

Sinatra-esque Haskell web apps.