The answer is to create an index on columns used in WHERE and JOIN clauses, increase the instance size, and enable query caching. Creating appropriate indexes directly addresses the root cause of a large table scan by allowing the query engine to locate rows without scanning every page, which is the most effective aurora mysql slow query optimization technique for this scenario. Increasing the instance size provides additional memory and CPU resources, which can accelerate query execution when the workload is resource-bound, while enabling query caching stores results of frequently repeated queries to avoid redundant processing. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your understanding of performance tuning fundamentals, often presenting traps like changing isolation levels or enabling parallel query, which are not universally beneficial and can introduce side effects such as locking issues or increased I/O. Remember the mnemonic “I-C-E” for Index, Capacity, and Execution caching to quickly recall the three primary levers for optimizing slow queries in Aurora MySQL.
DBS-C01 Monitoring and Troubleshooting Practice Question
This DBS-C01 practice question tests your understanding of monitoring and troubleshooting. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 database specialist is troubleshooting a slow-running query on an Amazon Aurora MySQL DB cluster. The query performs a large table scan. Which THREE actions would likely improve query performance?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Increase the size of the DB instance to provide more memory and CPU.
Creating appropriate indexes can speed up queries by avoiding table scans. Increasing the instance size provides more memory and CPU for query execution. Enabling query caching can store results of repeated queries. Changing isolation level and enabling parallel query may not help in all cases and may have side effects.
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 size of the DB instance to provide more memory and CPU.
Why this is correct
More resources can speed up query execution.
Related concept
Read the scenario before looking for a memorised answer.
✗
Change the transaction isolation level to SERIALIZABLE.
Why it's wrong here
SERIALIZABLE adds overhead and does not improve performance.
✓
Enable the query cache feature to cache the results of the query.
Why this is correct
Query caching can improve performance for repeated identical queries.
Related concept
Read the scenario before looking for a memorised answer.
✗
Enable Aurora Parallel Query to parallelize the table scan.
Why it's wrong here
Parallel Query is not automatically beneficial and may require specific conditions.
✓
Create an index on columns used in WHERE and JOIN clauses.
Why this is correct
Indexes reduce the need for full table scans.
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.
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 DBS-C01 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.
Monitoring and Troubleshooting — This question tests Monitoring and Troubleshooting — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Increase the size of the DB instance to provide more memory and CPU. — Creating appropriate indexes can speed up queries by avoiding table scans. Increasing the instance size provides more memory and CPU for query execution. Enabling query caching can store results of repeated queries. Changing isolation level and enabling parallel query may not help in all cases and may have side effects.
What should I do if I get this DBS-C01 question wrong?
Identify which DBS-C01 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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Question Discussion
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