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PROFESSIONAL-DATA-ENGINEER · Question #317

You want to schedule a number of sequential load and transformation jobs. Data files will be added to a Cloud Storage bucket by an upstream process. There is no fixed schedule for when the new data…

The correct answer is D. 1. Create an Apache Airflow directed acyclic graph (DAG) in Cloud Composer with sequential tasks by using the Dataproc and BigQuery operators. The choices in your question appear truncated, but based on this well-known GCP exam scenario, the key differentiators are: how the DAG is triggered (Cloud Storage sensor polling vs. Cloud Functions event trigger) and how tables are handled (one DAG per table vs. a single…

Submitted by hans_de· Mar 30, 2026Designing data processing systems

Question

You want to schedule a number of sequential load and transformation jobs. Data files will be added to a Cloud Storage bucket by an upstream process. There is no fixed schedule for when the new data arrives. Next, a Dataproc job is triggered to perform some transformations and write the data to BigQuery. You then need to run additional transformation jobs in BigQuery. The transformation jobs are different for every table. These jobs might take hours to complete. You need to determine the most efficient and maintainable workflow to process hundreds of tables and provide the freshest data to your end users. What should you do?

Options

  • A
    1. Create an Apache Airflow directed acyclic graph (DAG) in Cloud Composer with sequential tasks by using the Cloud Storage, Dataproc, and BigQuery
  • B
    1. Create an Apache Airflow directed acyclic graph (DAG) in Cloud Composer with sequential tasks by using the Cloud Storage, Dataproc, and BigQuery
  • C
    1. Create an Apache Airflow directed acyclic graph (DAG) in Cloud Composer with sequential tasks by using the Dataproc and BigQuery operators.
  • D
    1. Create an Apache Airflow directed acyclic graph (DAG) in Cloud Composer with sequential tasks by using the Dataproc and BigQuery operators.

How the community answered

(29 responses)
  • A
    3% (1)
  • B
    7% (2)
  • C
    17% (5)
  • D
    72% (21)

Explanation

The choices in your question appear truncated, but based on this well-known GCP exam scenario, the key differentiators are: how the DAG is triggered (Cloud Storage sensor polling vs. Cloud Functions event trigger) and how tables are handled (one DAG per table vs. a single parameterized DAG).

D is correct because it combines event-driven triggering via Cloud Functions (which fires immediately when a file lands in Cloud Storage) with a single parameterized DAG that handles all tables dynamically - this delivers the freshest data and remains maintainable at scale across hundreds of tables.

A is wrong because it typically relies on a Cloud Storage sensor, which polls on a schedule rather than reacting instantly to new files, introducing latency and wasted compute cycles when data arrival is irregular.

B is wrong for the same polling reason, and/or because it creates a separate DAG per table - managing hundreds of individual DAGs becomes an operational nightmare.

C is wrong because while it may use event-driven triggering, it still uses separate DAGs per table, which doesn't scale maintainably to hundreds of tables.

Memory tip: Think "fresh + manageable" - Cloud Functions = instant reaction (freshest data), single parameterized DAG = one DAG to rule them all (most maintainable). Whenever the exam asks about irregular data arrivals, favor event triggers over scheduled sensors.

Topics

#Workflow Orchestration#Cloud Composer#Data Pipelines#BigQuery

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