Why it matters in real pipelines
Checks
Your gates
Records meet the gates in this order. The first check a record fails sends it to quarantine, where it is held out of the warehouse.
Source0 waiting
Quarantine
Flagged, let through
Warehouse
Rows stored0
Bad rows in—
Incoming batch
Find the records that should never reach the warehouse. Scroll the table sideways to see it all.
After a run, each row is marked: ✓ handled correctly · ✗ bad row got in · ! false alarm or missed warning