Question 120 of 499

Quick Answer

The correct long-term solution is to configure the BigQuery sink to use a stored dynamic schema by setting create_disposition to CREATE_NEVER and writing to a temporary table with schema auto-detection. This approach works because the temporary table acts as a staging area where BigQuery’s schema auto-detection can infer new columns from incoming data, while the CREATE_NEVER setting ensures the pipeline writes only to an existing table, preventing failures when the event schema evolves. On the Google Professional Data Engineer exam, this scenario tests your understanding of Dataflow’s BigQuery I/O connector and the trade-off between static and dynamic schema handling—a common trap is assuming you must predefine all columns or use CREATE_IF_NEEDED, which can cause silent data loss or pipeline crashes. For memory, think “temp table, auto-detect, CREATE_NEVER” as the three-part key to handling schema evolution without manual intervention.

PDE Practice Question: Building and operationalizing data processing systems

This PDE practice question tests your understanding of building and operationalizing data processing systems. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A streaming Dataflow pipeline ingests events from Cloud Pub/Sub and writes to BigQuery. The event schema evolves occasionally (new columns added). The pipeline fails when new columns appear. What is the best long-term solution?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "best"

    Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.

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Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

Configure the BigQuery sink to use stored 'dynamic' schema by setting create_disposition to CREATE_NEVER and writing to a temporary table with schema auto-detection

Option A is correct because it leverages BigQuery's schema auto-detection with a temporary table to handle schema evolution dynamically. By setting create_disposition to CREATE_NEVER, the pipeline writes to a table that already exists, while the temporary table with auto-detection allows the pipeline to infer new columns from the incoming data. This approach avoids pipeline failures when new columns appear, as the sink can adapt without manual intervention or pipeline restarts.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Configure the BigQuery sink to use stored 'dynamic' schema by setting create_disposition to CREATE_NEVER and writing to a temporary table with schema auto-detection

    Why this is correct

    Using schema auto-detection on a temporary table and then merging into the main table with wildcard tables or using BigQuery's schema flexibility can handle new columns.

    Clue confirmation

    The clue word "best" in the question point toward this answer.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Stop the pipeline and update the BigQuery schema manually whenever a new column appears

    Why it's wrong here

    Manual intervention is error-prone and not scalable for frequent changes.

  • Switch to Dataproc to process the data with Spark and write to BigQuery using the Avro format

    Why it's wrong here

    This adds complexity and does not inherently solve schema evolution without custom handling.

  • Use a Cloud Function to transform the data and add null columns for missing fields

    Why it's wrong here

    This approach requires maintaining the schema mapping in the function and still fails if new columns are unknown.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Google Cloud often tests the misconception that manual schema updates or external transformations are acceptable long-term solutions, when in fact the correct answer leverages a built-in BigQuery feature (schema auto-detection) to handle schema evolution dynamically without pipeline downtime.

Detailed technical explanation

How to think about this question

Under the hood, BigQuery's schema auto-detection works by scanning the first 1000 rows of a file (or streaming buffer) to infer column names and types, which is why using a temporary table with this feature allows the pipeline to adapt to new columns. However, note that auto-detection has limitations: it may misinterpret types (e.g., integers as floats) and cannot handle nested schema changes gracefully. In a real-world scenario, if new columns appear frequently, you might also consider using a flexible schema with a JSON column or a schema registry to enforce compatibility, but the temporary table approach is the simplest for occasional additions.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this PDE question test?

Building and operationalizing data processing systems — This question tests Building and operationalizing data processing systems — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Configure the BigQuery sink to use stored 'dynamic' schema by setting create_disposition to CREATE_NEVER and writing to a temporary table with schema auto-detection — Option A is correct because it leverages BigQuery's schema auto-detection with a temporary table to handle schema evolution dynamically. By setting create_disposition to CREATE_NEVER, the pipeline writes to a table that already exists, while the temporary table with auto-detection allows the pipeline to infer new columns from the incoming data. This approach avoids pipeline failures when new columns appear, as the sink can adapt without manual intervention or pipeline restarts.

What should I do if I get this PDE question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Are there clue words in this question I should notice?

Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 30, 2026

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This PDE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PDE exam.