The correct answer is that idle-in-transaction connections hold locks and prevent cleanup of dead tuples, leading to bloat. These connections keep their transaction open, which means PostgreSQL’s autovacuum process cannot remove dead rows that are still visible to that transaction, causing table and index bloat that degrades query performance over time. On the AWS Certified Database Specialty DBS-C01 exam, this concept tests your understanding of transaction management and vacuuming in PostgreSQL, often appearing as a trap where candidates confuse idle-in-transaction with simple idle connections—the key difference is that idle-in-transaction actively holds locks and blocks vacuum, while idle connections do not. A common memory tip: think of an open transaction as a “locker” that keeps dead tuples alive, so “idle-in-transaction = bloat factory.”
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 performance issue on a self-managed PostgreSQL database that they plan to migrate to Amazon RDS. The database has a high number of 'idle in transaction' connections. What is the impact of these connections on the database?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
They hold locks and prevent cleanup of dead tuples, leading to bloat.
Option D is correct because idle-in-transaction connections hold locks and can cause bloat, reducing performance. Option A is wrong because they do not prevent new connections from being established. Option B is wrong because CPU usage is low for idle connections. Option C is wrong because they do not affect disk I/O directly.
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.
✗
They increase CPU usage due to constant polling.
Why it's wrong here
Idle connections consume minimal CPU.
✓
They hold locks and prevent cleanup of dead tuples, leading to bloat.
Why this is correct
Idle transactions keep locks and prevent autovacuum from marking dead tuples.
Related concept
Read the scenario before looking for a memorised answer.
✗
They prevent new connections from being established.
Why it's wrong here
Connection limits are separate; idle transactions do not block new connections.
✗
They cause increased disk I/O from write-ahead logging.
Why it's wrong here
Idle transactions may hold back cleanup but do not directly increase I/O.
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: They hold locks and prevent cleanup of dead tuples, leading to bloat. — Option D is correct because idle-in-transaction connections hold locks and can cause bloat, reducing performance. Option A is wrong because they do not prevent new connections from being established. Option B is wrong because CPU usage is low for idle connections. Option C is wrong because they do not affect disk I/O directly.
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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This DBS-C01 practice question is part of Courseiva's free Amazon Web Services 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 DBS-C01 exam.
Question Discussion
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