- A
Switch to a larger Datastream machine type
Why wrong: Datastream is serverless; you cannot choose machine types.
- B
Enable parallel processing in Datastream source configuration
Parallel streams can increase CDC throughput.
- C
Increase the number of Dataflow workers for the streaming job
More workers handle higher throughput.
- D
Add a Pub/Sub topic between Datastream and Dataflow to buffer changes
Pub/Sub can decouple and buffer, smoothing spikes.
- E
Reduce the retention period of the PostgreSQL WAL logs
Why wrong: Reducing retention may cause data loss if Datastream falls behind.
Question 701 of 980
PCD Practice Question: Manage a Solution that Can Span Multiple Database Systems
This PCD practice question tests your understanding of manage a solution that can span multiple database 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 company is using Datastream to replicate data from an on-premises PostgreSQL database to BigQuery. They encounter high latency in replication. Which THREE steps should they take to improve performance? (Select 3)
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
✓
Enable parallel processing in Datastream source configuration
Option B is correct because enabling parallel processing in the Datastream source configuration allows multiple threads to read from the PostgreSQL database simultaneously, reducing the time to capture and stream changes. This directly addresses high latency by increasing throughput from the source, leveraging PostgreSQL's logical replication slots more efficiently.
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.
- ✗
Switch to a larger Datastream machine type
Why it's wrong here
Datastream is serverless; you cannot choose machine types.
- ✓
Enable parallel processing in Datastream source configuration
Why this is correct
Parallel streams can increase CDC throughput.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Increase the number of Dataflow workers for the streaming job
Why this is correct
More workers handle higher throughput.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Add a Pub/Sub topic between Datastream and Dataflow to buffer changes
Why this is correct
Pub/Sub can decouple and buffer, smoothing spikes.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Reduce the retention period of the PostgreSQL WAL logs
Why it's wrong here
Reducing retention may cause data loss if Datastream falls behind.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that Datastream has configurable machine types like Compute Engine instances, leading candidates to select option A, when in fact Datastream is fully managed and serverless with no such setting.
Detailed technical explanation
How to think about this question
Datastream uses PostgreSQL logical replication slots to capture changes from WAL logs; enabling parallel processing increases the number of concurrent connections to these slots, which is particularly beneficial for high-volume transactional workloads. In real-world scenarios, this setting can reduce end-to-end latency from minutes to seconds when combined with sufficient Dataflow workers and a Pub/Sub buffer to handle backpressure.
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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Manage a Solution that Can Span Multiple Database Systems — study guide chapter
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FAQ
Questions learners often ask
What does this PCD question test?
Manage a Solution that Can Span Multiple Database Systems — This question tests Manage a Solution that Can Span Multiple Database Systems — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Enable parallel processing in Datastream source configuration — Option B is correct because enabling parallel processing in the Datastream source configuration allows multiple threads to read from the PostgreSQL database simultaneously, reducing the time to capture and stream changes. This directly addresses high latency by increasing throughput from the source, leveraging PostgreSQL's logical replication slots more efficiently.
What should I do if I get this PCD 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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jul 4, 2026
This PCD 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 PCD exam.
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