The correct answer is to use DISTKEY to distribute data evenly across nodes and to define sort keys based on common query patterns. This is because Amazon Redshift is a columnar, massively parallel processing database where performance hinges on minimizing data movement and I/O. A well-chosen DISTKEY ensures data is distributed evenly across compute nodes, avoiding data skew and allowing parallel processing to work efficiently, while sort keys physically order data on disk, enabling the query optimizer to skip irrelevant blocks using zone maps during scans. On the AWS Certified Data Engineer Associate DEA-C01 exam, this concept tests your understanding of physical table design for large-scale migrations, often appearing in scenario-based questions where you must choose between distribution styles and sort key columns. A common trap is assuming all large tables should use DISTKEY ALL, which can waste storage; instead, prioritize even distribution for fact tables. Memory tip: think of DISTKEY as “distribute the load” and SORT KEY as “sort to skip the scan.”
DEA-C01 Data Store Management Practice Question
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. 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 data engineer is migrating a large Oracle data warehouse to Amazon Redshift. The engineer needs to ensure optimal performance. Which TWO practices should the engineer follow?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Choose appropriate sort keys based on common query patterns.
Option A is correct because Amazon Redshift uses sort keys to physically order data on disk, which allows the query optimizer to skip large blocks of data during scans via zone maps. Choosing sort keys based on common query patterns (e.g., range filters or frequent GROUP BY columns) dramatically reduces I/O and improves query performance, especially for large tables.
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.
✓
Choose appropriate sort keys based on common query patterns.
Why this is correct
Sort keys reduce the amount of data scanned.
Related concept
Read the scenario before looking for a memorised answer.
✗
Design the schema as a normalized star schema with row-based storage.
Why it's wrong here
Redshift is columnar; normalized schemas are not optimal.
✗
Manually define compression encodings for each column.
Why it's wrong here
Redshift automatically applies compression, manual settings are not needed.
✗
Stage data in Amazon S3 before loading into Redshift.
Why it's wrong here
Data is typically loaded directly from S3, but it's not a practice for performance; it's a method.
✓
Use DISTKEY to distribute data evenly across nodes.
Why this is correct
Even distribution prevents data skew and improves parallelism.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse Redshift's columnar storage with row-based storage and assume a normalized star schema is optimal, when in fact Redshift is designed for denormalized, columnar tables with explicit sort and distribution keys.
Detailed technical explanation
How to think about this question
Sort keys in Redshift are implemented as interleaved or compound keys; compound sort keys are most effective for queries with equality and range filters on leading columns, while interleaved keys give equal weight to all columns but incur higher maintenance costs during COPY and VACUUM operations. DISTKEY (distribution key) determines how rows are distributed across slices; using a DISTKEY that matches the join key on large tables can eliminate the need for data redistribution during joins, which is a major performance bottleneck in distributed systems.
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.
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
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 exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Data Store Management — This question tests Data Store Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Choose appropriate sort keys based on common query patterns. — Option A is correct because Amazon Redshift uses sort keys to physically order data on disk, which allows the query optimizer to skip large blocks of data during scans via zone maps. Choosing sort keys based on common query patterns (e.g., range filters or frequent GROUP BY columns) dramatically reduces I/O and improves query performance, especially for large tables.
What should I do if I get this DEA-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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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