Practical writing on reconciliation, regulatory reporting, data analytics, ETL design, data modeling, and building systems you can trust.
When a merchant moves from Ireland to the UK, your regulatory report needs to reflect where they were at the time of each transaction, not where they are now. That is what SCD Type 2 solves.
Your pipeline will fail and someone will rerun it. Idempotency is what keeps your data correct when that happens.