The new payment method is missing from the fact table
A payment method launched last week. It appears in the source system and in the raw layer, and it is entirely absent from `fct_payments`. Every task is green and the total is only slightly lower than expected.
What you would do first
Answer before revealing anything. The value of the exercise is entirely in committing to a diagnosis you can be wrong about.
- 1Count the affected rows in raw and in the fact table for the same period. The gap is the size of the loss.
- 2Anti-join the raw rows against the fact table and group the result. If everything missing shares one attribute value, the join is the suspect.
- 3Check the dimension for that key. Its absence, rather than any error, is the cause.
- 4Look at the run order: a dimension refreshed after the facts that reference it will produce exactly this on every new value.
What is actually going on
The trap
The fix that looks right. Read it even if you got the answer — especially then.
Insert the missing dimension row by hand and re-run. The number is right this week, the inner join is still a silent filter, and the same thing happens on the next new payment method, region or product category — each time as a fresh incident.