Quick Answer
The correct answer is to run the ANALYZE command on the affected tables. This is because the STL_ALERT_EVENT_LOG table records 'missing statistics' alerts when the Redshift query optimizer lacks up-to-date table statistics, forcing it to generate suboptimal execution plans that can degrade performance. By executing ANALYZE, you refresh the column-level statistics, allowing the optimizer to make informed decisions about join order, distribution, and data filtering. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your understanding of Redshift maintenance operations and how to interpret system tables like STL_ALERT_EVENT_LOG. A common trap is confusing this with VACUUM, which reclaims disk space and sorts rows but does not update statistics. To remember: ANALYZE fixes missing stats, VACUUM fixes missing space—think "A for Alerts, V for Vacuum."
This DEA-C01 practice question tests your understanding of data store management. 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 company is using Amazon Redshift for data warehousing. The data engineer notices that the STL_ALERT_EVENT_LOG table shows many 'missing statistics' alerts. What is the best course of action to address this issue?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Increase the WLM concurrency slots.
Why wrong: WLM affects query queuing, not statistics.
Run VACUUM on the tables.
Why wrong: VACUUM reclaims disk space but does not update statistics.
Enable compression on the tables.
Why wrong: Compression is for storage efficiency, not statistics.
Run ANALYZE on the tables.
ANALYZE updates table statistics, resolving missing statistics alerts.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Run ANALYZE on the tables.
The STL_ALERT_EVENT_LOG table records alerts about query performance issues, including 'missing statistics' alerts. This indicates that the query optimizer lacks up-to-date table statistics, leading to suboptimal query plans. Running the ANALYZE command updates table statistics, enabling the optimizer to generate efficient execution plans. Therefore, option D is the correct course of action.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Increase the WLM concurrency slots.
Why it's wrong here
WLM affects query queuing, not statistics.
Run VACUUM on the tables.
Why it's wrong here
VACUUM reclaims disk space but does not update statistics.
Enable compression on the tables.
Why it's wrong here
Compression is for storage efficiency, not statistics.
Run ANALYZE on the tables.
Why this is correct
ANALYZE updates table statistics, resolving missing statistics alerts.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates often confuse VACUUM (which reorganizes data) with ANALYZE (which updates statistics), assuming both are needed for query performance, but only ANALYZE directly resolves 'missing statistics' alerts.
Detailed technical explanation
The ANALYZE command in Amazon Redshift collects distribution statistics such as min/max values, null counts, and data distribution across slices. These statistics are stored in the pg_statistic system table and are used by the query planner to estimate row counts and join costs. Without accurate statistics, the planner may choose nested loop joins over hash joins or misestimate data distribution, leading to poor performance. In practice, running ANALYZE after significant data modifications (e.g., bulk loads or deletes) is critical, and automated analysis can be configured via the 'analyze_threshold_percent' parameter.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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
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FAQ
Data Store Management — This question tests Data Store Management — Read the scenario before looking for a memorised answer..
The correct answer is: Run ANALYZE on the tables. — The STL_ALERT_EVENT_LOG table records alerts about query performance issues, including 'missing statistics' alerts. This indicates that the query optimizer lacks up-to-date table statistics, leading to suboptimal query plans. Running the ANALYZE command updates table statistics, enabling the optimizer to generate efficient execution plans. Therefore, option D is the correct course of action.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
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.
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