- A
Increase the disk size of the Cloud SQL instance before migration to improve performance.
Why wrong: Increasing disk size does not directly reduce migration downtime; it addresses storage capacity, not migration speed.
- B
Use pg_dump to export the database and pg_restore to import into Cloud SQL.
Why wrong: pg_dump/pg_restore requires the source database to be in a consistent state, typically causing downtime; it's not a minimal-downtime approach.
- C
Set up a Cloud SQL read replica and promote it to the primary after migration.
Using a read replica allows the source to remain online during replication, and promoting the replica minimizes cutover downtime.
- D
Decrease max_connections to reduce load during migration.
Why wrong: Decreasing max_connections can cause application errors and does not help minimize downtime; it might even increase complexity.
- E
Use Database Migration Service (DMS) with continuous replication from the source.
DMS supports continuous replication, enabling near-zero downtime migration by keeping the target in sync until cutover.
PCDE Plan and manage database infrastructure Practice Question
This PCDE practice question tests your understanding of plan and manage database infrastructure. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 migrating its on-premises PostgreSQL database to Cloud SQL for PostgreSQL. They want to minimize downtime during the migration. Which TWO actions should they take?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"minimum / minimize"Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
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
Set up a Cloud SQL read replica and promote it to the primary after migration.
Option C is correct because setting up a Cloud SQL read replica from the source PostgreSQL database and then promoting it to primary allows for a controlled cutover with minimal downtime. The replica stays in sync with the source using PostgreSQL's native streaming replication, and promotion is a fast metadata operation that typically takes seconds, not minutes or hours.
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.
- ✗
Increase the disk size of the Cloud SQL instance before migration to improve performance.
Why it's wrong here
Increasing disk size does not directly reduce migration downtime; it addresses storage capacity, not migration speed.
- ✗
Use pg_dump to export the database and pg_restore to import into Cloud SQL.
Why it's wrong here
pg_dump/pg_restore requires the source database to be in a consistent state, typically causing downtime; it's not a minimal-downtime approach.
- ✓
Set up a Cloud SQL read replica and promote it to the primary after migration.
Why this is correct
Using a read replica allows the source to remain online during replication, and promoting the replica minimizes cutover downtime.
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Decrease max_connections to reduce load during migration.
Why it's wrong here
Decreasing max_connections can cause application errors and does not help minimize downtime; it might even increase complexity.
- ✓
Use Database Migration Service (DMS) with continuous replication from the source.
Why this is correct
DMS supports continuous replication, enabling near-zero downtime migration by keeping the target in sync until cutover.
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the distinction between logical backup tools (pg_dump/pg_restore) which cause downtime, and continuous replication methods (DMS or read replicas) which minimize it, leading candidates to incorrectly choose the familiar dump-and-restore approach.
Detailed technical explanation
How to think about this question
Database Migration Service (DMS) with continuous replication uses PostgreSQL's logical replication (via the pglogical extension or native publication/subscription) to stream changes in near real-time, allowing the source to remain fully operational until the cutover. The read replica approach in Cloud SQL leverages PostgreSQL's physical streaming replication, which replicates at the block level and requires the replica to be in the same region or a supported cross-region configuration; promotion breaks the replication link and makes the replica a standalone primary.
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 PCDE question test?
Plan and manage database infrastructure — This question tests Plan and manage database infrastructure — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set up a Cloud SQL read replica and promote it to the primary after migration. — Option C is correct because setting up a Cloud SQL read replica from the source PostgreSQL database and then promoting it to primary allows for a controlled cutover with minimal downtime. The replica stays in sync with the source using PostgreSQL's native streaming replication, and promotion is a fast metadata operation that typically takes seconds, not minutes or hours.
What should I do if I get this PCDE 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: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
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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