- A
Run comparison queries (e.g., row counts, checksums) between source and target.
This validates data consistency.
- B
Take a snapshot of the source database before migration.
Why wrong: Snapshotting is a backup step, not a validation step.
- C
Disable foreign key constraints on the target to speed up migration.
Why wrong: Disabling constraints can lead to data integrity issues; not a validation step.
- D
Perform load testing on the Cloud SQL instance using production data shape.
Load testing ensures the target can handle the workload.
- E
Implement shadow writes from the application to both databases simultaneously.
Why wrong: Shadow writes are complex and could affect production; not recommended for validation.
Question 421 of 999
PCD Migrate Data Solutions Practice Question
This PCD practice question tests your understanding of migrate data solutions. 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 from Oracle to Cloud SQL for PostgreSQL using Database Migration Service. They need to ensure that the migration is validated before cutover. Which TWO actions should they take?
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
✓
Run comparison queries (e.g., row counts, checksums) between source and target.
Option A is correct because running comparison queries (e.g., row counts, checksums) between the source Oracle database and the target Cloud SQL for PostgreSQL instance is a standard validation technique to ensure data consistency and completeness before cutover. Database Migration Service (DMS) handles continuous replication, but manual validation using queries like SELECT COUNT(*) or checksum functions (e.g., MD5 on concatenated columns) catches any discrepancies that might have been introduced during migration or replication lag.
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.
- ✓
Run comparison queries (e.g., row counts, checksums) between source and target.
Why this is correct
This validates data consistency.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Take a snapshot of the source database before migration.
Why it's wrong here
Snapshotting is a backup step, not a validation step.
- ✗
Disable foreign key constraints on the target to speed up migration.
Why it's wrong here
Disabling constraints can lead to data integrity issues; not a validation step.
- ✓
Perform load testing on the Cloud SQL instance using production data shape.
Why this is correct
Load testing ensures the target can handle the workload.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Implement shadow writes from the application to both databases simultaneously.
Why it's wrong here
Shadow writes are complex and could affect production; not recommended for validation.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between 'validation' actions (verifying data integrity) and 'cutover' or 'backup' actions, so the trap here is confusing operational steps like snapshots or shadow writes with the specific validation checks needed to confirm migration readiness.
Detailed technical explanation
How to think about this question
Under the hood, Database Migration Service uses logical replication (e.g., pglogical for PostgreSQL) to stream changes from Oracle to Cloud SQL. Validation queries like row counts and checksums should be run after the initial load and during the continuous replication phase to confirm that the target has caught up and that no data corruption occurred during transformation (e.g., Oracle NUMBER to PostgreSQL NUMERIC). A real-world scenario is when Oracle uses non-standard date formats or BFILE data types that require custom conversion, and checksum mismatches can reveal silent data loss.
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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Migrate Data Solutions — study guide chapter
Learn the concepts, then practise the questions
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FAQ
Questions learners often ask
What does this PCD question test?
Migrate Data Solutions — This question tests Migrate Data Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Run comparison queries (e.g., row counts, checksums) between source and target. — Option A is correct because running comparison queries (e.g., row counts, checksums) between the source Oracle database and the target Cloud SQL for PostgreSQL instance is a standard validation technique to ensure data consistency and completeness before cutover. Database Migration Service (DMS) handles continuous replication, but manual validation using queries like SELECT COUNT(*) or checksum functions (e.g., MD5 on concatenated columns) catches any discrepancies that might have been introduced during migration or replication lag.
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
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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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