- A
A custom watermark estimation function
Why wrong: Custom watermarks can help estimate progress, but they do not by themselves allow late data to be accepted. Allowed lateness is still needed.
- B
Using side inputs with a periodic refresh
Why wrong: Side inputs handle enrichment, not late data management.
- C
A trigger that fires on every late element
Why wrong: Triggers control when output is emitted, not whether late data is accepted. Even with a trigger, late data is only processed if allowed lateness is set.
- D
Allowed lateness on the window
Setting allowed lateness (e.g., 1 hour) tells the pipeline to keep the window open for late data within that duration. This is the correct way to handle late-arriving events.
Question 512 of 1,000
PDE Designing Data Processing Systems Practice Question
This PDE practice question tests your understanding of designing data processing systems. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 data engineer needs to design a streaming pipeline that ingests events from multiple sources, enriches them with a lookup table stored in BigQuery (updated every hour), and writes the results to a BigQuery table for real-time dashboards. The pipeline must handle late-arriving data up to 1 hour. Which Dataflow feature should be configured to manage late data?
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
✓
Allowed lateness on the window
Allowed lateness in Apache Beam specifies the maximum delay of late data to be included in the window. Watermark estimation does not control late data acceptance; triggers specify when output is emitted, not how late data is handled. Side inputs are for enrichment, not late data management.
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.
- ✗
A custom watermark estimation function
Why it's wrong here
Custom watermarks can help estimate progress, but they do not by themselves allow late data to be accepted. Allowed lateness is still needed.
- ✗
Using side inputs with a periodic refresh
Why it's wrong here
Side inputs handle enrichment, not late data management.
- ✗
A trigger that fires on every late element
Why it's wrong here
Triggers control when output is emitted, not whether late data is accepted. Even with a trigger, late data is only processed if allowed lateness is set.
- ✓
Allowed lateness on the window
Why this is correct
Setting allowed lateness (e.g., 1 hour) tells the pipeline to keep the window open for late data within that duration. This is the correct way to handle late-arriving events.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Trap categories for this question
Command / output trap
Triggers control when output is emitted, not whether late data is accepted. Even with a trigger, late data is only processed if allowed lateness is set.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- 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 PDE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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Designing Data Processing Systems — study guide chapter
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FAQ
Questions learners often ask
What does this PDE question test?
Designing Data Processing Systems — This question tests Designing Data Processing Systems — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Allowed lateness on the window — Allowed lateness in Apache Beam specifies the maximum delay of late data to be included in the window. Watermark estimation does not control late data acceptance; triggers specify when output is emitted, not how late data is handled. Side inputs are for enrichment, not late data management.
What should I do if I get this PDE question wrong?
Identify which PDE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
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.
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