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Writing

17 August 2026Pinned
A live screen is mostly not live
An operations screen joins a fast event stream to slow reference data from another system. Built the obvious way, both refresh at the speed of the fast one, and the bill lands entirely on the half that never changed. Dataverse, Fabric and a few megabytes of Redis.
8 min · caching · data platform · redis · fabric
16 June 2026Pinned
What the medallion is actually for
Bronze, silver, gold is drawn as three tidy boxes. Building one taught me the layers are not about cleanliness. They are about who is allowed to be wrong.
4 min · data platform · fabric · pyspark
28 September 2026
A rule that only moves things
In a rule editor, a rule that adds a step and a rule that only orders one look almost identical. Mixing them up passes every check you have, so each kind of rule needs a contract for what it is allowed to change.
6 min · rules · testing
21 September 2026
A cache that fought itself
Our Redis layer was correct and it was burning 600 million commands a month. Four independent kinds of waste, one non-obvious bug, and a pricing change that turned a free problem into a twelve-hundred-dollar one.
8 min · caching · redis · serverless · fabric
11 August 2026
The cheapest classifier is a business rule
Our extractor was reading product codes off the summary page. The obvious fix was to train a model to recognise pages. The fix we shipped was one sentence of domain knowledge.
6 min · document ai · ml · pipelines
10 August 2026
A canvas twice the size of its container
A three.js model sat perfectly centred on every machine I tested and in the corner on someone else's. The bug was one boolean.
2 min · three.js · debugging
8 August 2026
One Big Table, and the join that lies
Flattening a model into one wide table makes queries simple and makes one specific mistake almost inevitable. The mistake is not the joins. It is what a join does to a sum.
3 min · data platform · modelling
4 August 2026
A full week is full
The planning rule that mattered most wasn't in any textbook. It came from a planner refusing to accept a schedule that pretended capacity was elastic.
2 min · planning · pyspark
21 July 2026
Density is not a swatch
Letting customers change a stone's colour in the 3D viewer sounds like a paint bucket. It is only useful if the number underneath it changes too.
2 min · cad · three.js
8 July 2026
Stop storing status
A status column is a cache of something the event log already knows. Ours drifted, and the fix was to delete the cache rather than fix the writes.
3 min · data platform · modelling

Writing

A live screen is mostly not live

What the medallion is actually for

A rule that only moves things

A cache that fought itself

The cheapest classifier is a business rule

A canvas twice the size of its container

One Big Table, and the join that lies

A full week is full

Density is not a swatch

Stop storing status