Software Engineering - csen2025.org

The Optimiser Tells You Exactly What It Is About to Do

I remember sitting in a windowless server room during my second year in industry, staring at a terminal until my eyes burned, trying to figure out why a simple join was taking forty minutes. I had been told that the…

An Index Helps the Query You Wrote, Not the One You Meant

I remember sitting in a windowless server room three years ago, watching a dashboard turn a violent shade of red because our “state-of-the-art” indexing strategy had completely collapsed under the weight of actual user behavior. We had followed the textbook…

Schema design fundamentals: normalization and denormalization.

Normalise Until It Hurts, Denormalise Until It Works

I remember sitting in a windowless server room during my first industry research role, staring at a distributed database that was buckling under its own weight. We hadn’t failed because our hardware was weak or our code was sloppy; we…

Perform database migrations safely with schema versioning.

Make the Schema Work With Both Versions of the Code

I still remember the distinct, cold sweat that hit me during my first year in industry, sitting in a dimly lit server room while a “simple” schema update turned into a three-hour outage. I had followed the textbook instructions to…

Effective rollback strategies for database migrations.

Rolling Back a Migration Is Harder Than Rolling Back Code

I remember sitting in a dimly lit server room three years ago, the hum of the cooling fans feeling unusually aggressive, as I watched a “perfectly tested” deployment slowly turn our production database into a graveyard. We had followed every…

Blue green and canary releases traffic strategy.

Send One Percent of Traffic Before You Send All of It

I still remember the frantic, rhythmic clicking of a mechanical calculator in my lab during my PhD—a sound that meant I was trying to manually verify a distribution logic that a script had botched. That same sense of dread hits…

Understanding feature flags and their cost.

Every Flag Is a Branch in Production You Must Test

I remember sitting in a darkened server room three years ago, watching a dashboard bleed red because a “simple” toggle had triggered a cascading failure in a downstream microservice. We had been sold the dream that decoupling deployment from release…

Implementing continuous delivery practices for frequent deployments.

Deploying Often Makes Each Deploy Boring

I remember sitting in a windowless server room during my first industry role, watching a “state-of-the-art” deployment pipeline crumble because someone had prioritized tool complexity over basic system stability. Everyone was obsessed with the latest shiny orchestration layer, but they…

Continuous integration basics: fixing broken builds.

A Broken Build Is Everyone’s Problem Immediately

I remember sitting in a windowless server room during my first industry research role, staring at a terminal while a “successful” build deployment slowly tore a distributed database apart. Everyone around me was celebrating the sheer speed of our pipeline,…

Writing useful commit messages for documentation.

The Commit Message Is the Only Place the Why Survives

I was hunched over a lukewarm cup of coffee at 2:00 AM, staring at a git log that looked less like a technical history and more like a graveyard of laziness. I was trying to trace a race condition in…