Implementing an Azure Data Solution (legacy) — Question 41

You plan to build a structured streaming solution in Azure Databricks. The solution will count new events in five-minute intervals and report only events that arrive during the interval. The output will be sent to a Delta Lake table.
Which output mode should you use?

Answer options

• A. complete
• B. update
• C. append

Correct answer: C

Explanation

The correct choice is 'append' because it allows the system to add only the new events that occur during each interval to the Delta Lake table, which aligns with the requirement of reporting only the events that arrive in that specific time frame. The 'complete' mode would attempt to overwrite the entire output each time, while 'update' would only modify existing records, neither of which fits the specified need for counting new events.