Question 440
A billing application consumes Delta changes to incrementally update its downstream aggregates. The team implements Perform a controlled full resynchronization and reset its checkpoint. The goal was: The source CDF history was pruned beyond a consumer's checkpoint. Which observed result best verifies success?
Explanation
Correct Answer
The rebuilt target agrees with current source without missing updates is the matching outcome for the implemented control (Perform a controlled full resynchronization and reset its checkpoint) and the stated requirement “The source CDF history was pruned beyond a consumer's checkpoint.”
Incorrect Answers
The aggregate applies intended postimages without counting preimages as additions would demonstrate the separate action Filter and interpret CDF change types correctly for the target, which addresses “Update preimage rows would double-count aggregate changes if processed as new current values.” It does not verify the requirement “The source CDF history was pruned beyond a consumer's checkpoint” following Perform a controlled full resynchronization and reset its checkpoint.
Only post-checkpoint changes enter the update logic would demonstrate the separate action Read Delta Change Data Feed starting at the stored version, which addresses “Downstream needs changed rows since a tracked Delta version.” It does not verify the requirement “The source CDF history was pruned beyond a consumer's checkpoint” following Perform a controlled full resynchronization and reset its checkpoint.
This signal belongs to the adjacent case “A downstream process must track the last successfully applied change version,” whose remedy is Persist the consumed Delta version with the committed target state. The observed result for the present requirement is The rebuilt target agrees with current source without missing updates.