Question 1,399 of 1,786
Data Store ManagementhardMultiple ChoiceObjective-mapped

PostgreSQL Autovacuum Tuning: Reducing Lock Contention

This DEA-C01 practice question tests your understanding of data store management. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: autovacuum. 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 runs a transactional database on Amazon RDS for PostgreSQL with Multi-AZ deployment. The database size is 2 TB and experiences moderate write load. The company recently enabled RDS Performance Insights and noticed a high number of 'TupleLock' wait events during peak hours. The development team reports that a batch update job runs every hour, updating millions of rows in a large table. The job takes longer than expected. The DBA suspects that excessive row-level locking is causing contention. The team wants to minimize lock contention without changing the application code. Which solution should be implemented?

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

Tune the autovacuum settings (e.g., autovacuum_vacuum_scale_factor and autovacuum_vacuum_threshold) to run more frequently and aggressively.

The correct answer is A because tuning autovacuum settings (autovacuum_vacuum_scale_factor and autovacuum_vacuum_threshold) reduces lock contention by cleaning up dead tuples more frequently. In PostgreSQL, row-level locks on heavily updated tables can cause 'TupleLock' wait events. Frequent autovacuum prevents accumulation of dead tuples, reducing the need for lock escalation and shortening update times. Option B (increasing instance size) may improve throughput but does not directly address lock contention. Option C (RDS Proxy) manages connections, not locks. Option D (pg_partman partitioning) reduces row contention but requires application code changes (stem prohibits code changes).

Key principle: Autovacuum

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Tune the autovacuum settings (e.g., autovacuum_vacuum_scale_factor and autovacuum_vacuum_threshold) to run more frequently and aggressively.

    Why this is correct

    Correct. Tuning autovacuum reduces dead tuple accumulation, minimizing row-level lock contention without application changes.

    Clue confirmation

    The clue word "minimum / minimize" in the question point toward this answer.

    Related concept

    Autovacuum

  • Increase the RDS instance size to a larger instance class with more vCPUs and memory.

    Why it's wrong here

    Incorrect. Increasing instance size provides more resources but does not address the root cause of lock contention from dead tuples.

  • Enable RDS Proxy to manage database connections and reduce connection overhead.

    Why it's wrong here

    Incorrect. RDS Proxy manages database connections and connection pooling, not lock contention on row-level operations.

  • Implement table partitioning using the pg_partman extension to split the large table into smaller partitions.

    Why it's wrong here

    Incorrect. Table partitioning with pg_partman can reduce lock contention by distributing updates across partitions, but it requires changing table schemas and application queries, which is not allowed.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Candidates often assume that increasing instance size resolves all performance issues, but lock contention due to dead tuples requires database-level tuning like autovacuum.

Detailed technical explanation

How to think about this question

Treat this as a scenario question. Identify the problem, the constraint, and the best action. Then compare each option against those facts.

KKey Concepts to Remember

  • Autovacuum
  • TupleLock Wait Event
  • Dead Tuples
  • Multi-AZ Deployment

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

Autovacuum

Real-world example

How this comes up in practice

An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.

What to study next

Got this wrong? Here's your next step.

Review autovacuum, then practise related DEA-C01 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this DEA-C01 question test?

Data Store Management — This question tests Data Store Management — Autovacuum.

What is the correct answer to this question?

The correct answer is: Tune the autovacuum settings (e.g., autovacuum_vacuum_scale_factor and autovacuum_vacuum_threshold) to run more frequently and aggressively. — The correct answer is A because tuning autovacuum settings (autovacuum_vacuum_scale_factor and autovacuum_vacuum_threshold) reduces lock contention by cleaning up dead tuples more frequently. In PostgreSQL, row-level locks on heavily updated tables can cause 'TupleLock' wait events. Frequent autovacuum prevents accumulation of dead tuples, reducing the need for lock escalation and shortening update times. Option B (increasing instance size) may improve throughput but does not directly address lock contention. Option C (RDS Proxy) manages connections, not locks. Option D (pg_partman partitioning) reduces row contention but requires application code changes (stem prohibits code changes).

What should I do if I get this DEA-C01 question wrong?

Review autovacuum, then practise related DEA-C01 questions on the same topic to reinforce the concept.

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?

Autovacuum

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Last reviewed: Jun 20, 2026

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This DEA-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 DEA-C01 exam.