Four meters, their real proportions, and how to attribute compute to a query, a table, and a team so a platform can answer what a dashboard costs to run.
The five layers of the open lakehouse explained, then a lab: Parquet, Iceberg, Polaris, Arrow, and Ossie running in two containers on your own machine.
The format war ended and exit cost did not: where lock-in relocated after open tables won, how to measure it, and which costs are worth keeping down.
Great Expectations, Soda, dbt tests and anomaly detection tools compared on check language, where they run, cost, Iceberg metadata use and 2026 vendor changes.
