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PROFESSIONAL-DATA-ENGINEER · Question #48

You work for a manufacturing plant that batches application log files together into a single log file once a day at 2:00 AM. You have written a Google Cloud Dataflow job to process that log file. You

The correct answer is C. Create a cron job with Google App Engine Cron Service to run the Cloud Dataflow job.. Option C is correct because App Engine Cron Service provides a managed, serverless scheduling mechanism that can trigger the Dataflow job automatically at a fixed time each day (e.g., shortly after 2:00 AM), requiring no infrastructure to maintain and incurring minimal cost - you

Submitted by tunde_lagos· Mar 30, 2026Building and operationalizing data processing systems

Question

You work for a manufacturing plant that batches application log files together into a single log file once a day at 2:00 AM. You have written a Google Cloud Dataflow job to process that log file. You need to make sure the log file in processed once per day as inexpensively as possible. What should you do?

Options

  • AChange the processing job to use Google Cloud Dataproc instead.
  • BManually start the Cloud Dataflow job each morning when you get into the office.
  • CCreate a cron job with Google App Engine Cron Service to run the Cloud Dataflow job.
  • DConfigure the Cloud Dataflow job as a streaming job so that it processes the log data immediately.

How the community answered

(37 responses)
  • A
    8% (3)
  • B
    16% (6)
  • C
    70% (26)
  • D
    5% (2)

Explanation

Option C is correct because App Engine Cron Service provides a managed, serverless scheduling mechanism that can trigger the Dataflow job automatically at a fixed time each day (e.g., shortly after 2:00 AM), requiring no infrastructure to maintain and incurring minimal cost - you only pay when the job actually runs.

Why the others are wrong:

  • A (Dataproc) is a cluster-based Hadoop/Spark service; switching to it adds complexity and cost without solving the scheduling problem, and clusters often sit idle between jobs.
  • B (Manual start) is not automated, is error-prone, depends on a person being available, and is the opposite of "inexpensive" in operational terms.
  • D (Streaming job) keeps the pipeline running continuously 24/7, which is far more expensive than a batch job that runs once a day - it's the wrong tool when data only arrives once daily.

Memory tip: Think "batch data = batch job = scheduled trigger." When you see "once per day" + "as inexpensively as possible," map that to a cron-style scheduler (App Engine Cron) launching a bounded Dataflow batch job - streaming is for continuous data, not daily dumps.

Topics

#Dataflow#Scheduling#Cost Optimization#Batch Processing

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