- A
Default trigger without allowed lateness
Why wrong: Default trigger discards late data; not suitable for late arrivals.
- B
After count trigger with count of 1000
Why wrong: After count trigger does not consider event time; not suitable for late data handling.
- C
Fixed time trigger every 5 minutes
Why wrong: Fixed time triggers ignore event time and may produce inaccurate aggregations for late data.
- D
After watermark trigger with allowed lateness of 1 hour
This configuration ensures late data within 1 hour is included in aggregations.
Question 517 of 1,000
PDE Ingesting and Processing the Data Practice Question
This PDE practice question tests your understanding of ingesting and processing the data. 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 is designing a Dataflow pipeline that reads from Pub/Sub and writes to BigQuery using the Storage Write API in exactly-once mode. The pipeline must handle late-arriving data (up to 1 hour) and maintain correct aggregation results. Which trigger configuration should they use?
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
✓
After watermark trigger with allowed lateness of 1 hour
Option D is correct because the After watermark trigger with allowed lateness of 1 hour ensures that the pipeline waits for the watermark to pass before emitting a pane, while allowing late-arriving data up to 1 hour to be included in the correct aggregation window. This is required for exactly-once processing with the Storage Write API, as it prevents duplicate or dropped records from late data.
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.
- ✗
Default trigger without allowed lateness
Why it's wrong here
Default trigger discards late data; not suitable for late arrivals.
- ✗
After count trigger with count of 1000
Why it's wrong here
After count trigger does not consider event time; not suitable for late data handling.
- ✗
Fixed time trigger every 5 minutes
Why it's wrong here
Fixed time triggers ignore event time and may produce inaccurate aggregations for late data.
- ✓
After watermark trigger with allowed lateness of 1 hour
Why this is correct
This configuration ensures late data within 1 hour is included in aggregations.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that any trigger with a time-based interval (like fixed 5-minute triggers) can handle late data, but only watermark-based triggers with allowed lateness correctly align with event-time windows and late-arriving records.
Detailed technical explanation
How to think about this question
Under the hood, the watermark is a heuristic that estimates the point in event time beyond which no more data is expected; the allowed lateness parameter extends this by keeping the watermark artificially delayed by 1 hour, allowing late records to be merged into the correct window. The Storage Write API in exactly-once mode uses stream offsets and commit protocols to ensure that each record is written exactly once, even if the pipeline retries, which is critical when late data triggers re-processing of windows.
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
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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Ingesting and Processing the Data — study guide chapter
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FAQ
Questions learners often ask
What does this PDE question test?
Ingesting and Processing the Data — This question tests Ingesting and Processing the Data — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: After watermark trigger with allowed lateness of 1 hour — Option D is correct because the After watermark trigger with allowed lateness of 1 hour ensures that the pipeline waits for the watermark to pass before emitting a pane, while allowing late-arriving data up to 1 hour to be included in the correct aggregation window. This is required for exactly-once processing with the Storage Write API, as it prevents duplicate or dropped records from late data.
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.
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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