The correct answer is that the 'max_wal_size' parameter is set too low, causing frequent WAL switches. When this threshold is too small, PostgreSQL is forced to perform checkpoints more often than necessary—every 10 seconds in this case—because the system runs out of allocated WAL space and must flush dirty buffers to disk to reuse log segments. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of PostgreSQL checkpoint tuning and the relationship between WAL generation and checkpoint frequency. A common trap is confusing checkpoint frequency with storage issues or connection load, but the core concept is that max_wal_size directly controls how much WAL can accumulate before a checkpoint is triggered. Remember the memory tip: "Small WAL, frequent squall"—a low max_wal_size leads to a storm of checkpoints.
DBS-C01 Management and Operations Practice Question
This DBS-C01 practice question tests your understanding of management and operations. 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.
Exhibit
Refer to the exhibit.
-- RDS for PostgreSQL log excerpt:
2023-04-01 10:15:00 UTC LOG: checkpoint starting: time
2023-04-01 10:15:00 UTC LOG: checkpoint complete: wrote 50000 buffers (5.0%); 0 transaction log file(s) added, 0 removed; 10.2 seconds
2023-04-01 10:15:10 UTC LOG: checkpoint starting: time
2023-04-01 10:15:10 UTC LOG: checkpoint complete: wrote 52000 buffers (5.2%); 0 transaction log file(s) added, 0 removed; 10.5 seconds
Refer to the exhibit. An RDS for PostgreSQL instance shows frequent checkpoints every 10 seconds. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The 'max_wal_size' parameter is set too low, causing frequent WAL switches.
Option A is correct. Frequent checkpoints often indicate the log file size (max_wal_size) is too small, causing frequent WAL switches. Option B is wrong because full_storage? might cause issues but not specifically checkpoints. Option C is wrong because high connections may cause load but not checkpoints directly. Option D is wrong because autovacuum runs independently.
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.
✗
Autovacuum is not running, causing bloat.
Why it's wrong here
Bloat may cause but not directly frequent checkpoints.
✗
The instance is running out of storage space.
Why it's wrong here
Storage issues may cause freezes, not checkpoints.
✗
There are too many concurrent connections.
Why it's wrong here
Connections do not directly cause checkpoints.
✓
The 'max_wal_size' parameter is set too low, causing frequent WAL switches.
Why this is correct
Low max_wal_size leads to frequent checkpoints.
Clue confirmation
The clue word "most likely" 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
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 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 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.
Management and Operations — This question tests Management and Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The 'max_wal_size' parameter is set too low, causing frequent WAL switches. — Option A is correct. Frequent checkpoints often indicate the log file size (max_wal_size) is too small, causing frequent WAL switches. Option B is wrong because full_storage? might cause issues but not specifically checkpoints. Option C is wrong because high connections may cause load but not checkpoints directly. Option D is wrong because autovacuum runs independently.
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.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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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