Mastering Redshift Distribution Styles: EVEN, KEY, ALL, and AUTO
Which TWO statements are true about Amazon Redshift distribution styles? (Choose TWO.)
Quick Answer
The correct answer is that EVEN distribution distributes rows across slices in a round-robin fashion, and ALL distribution copies the entire table to every node. EVEN distribution works by assigning rows to slices in a sequential, round-robin manner, ensuring each slice gets roughly the same number of rows, which minimizes data movement during parallel processing. ALL distribution, by contrast, places a full copy of the table on every node, dramatically speeding up joins with small tables at the cost of increased storage. On the AWS Certified Data Engineer Associate DEA-C01 exam, this question tests your ability to distinguish between the four Redshift distribution styles—EVEN, KEY, ALL, and AUTO—and a common trap is confusing EVEN with a true ROUND ROBIN style (which Redshift does not offer) or assuming KEY distribution always avoids skew. For a quick memory tip, remember that EVEN is for even load, KEY is for co-located joins but risks skew, ALL is for small lookup tables, and AUTO lets Redshift decide.
⚠ Common exam trap
Watch out — candidates often confuse AUTO distribution with ROUND ROBIN, or assume that KEY distribution is always optimal, when in fact poor key selection can lead to severe data skew and performance degradation.
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
✓
ALL distribution copies the entire table to every node.
The ALL distribution style in Amazon Redshift copies the entire table to every node in the cluster. This is ideal for small, slowly changing dimension tables (like date or location tables) that need to be joined with large fact tables, as it eliminates the need to redistribute data across nodes during query execution.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
KEY distribution is always the best choice to minimize data skew.
Why it's wrong here
KEY distribution can cause skew if the key column has few distinct values.
- ✗
AUTO distribution always selects EVEN distribution.
Why it's wrong here
AUTO distribution can select EVEN, KEY, or ALL based on table size and operations.
- ✓
ALL distribution copies the entire table to every node.
Why this is correct
ALL distribution is useful for small tables that are frequently joined.
- ✗
Redshift automatically assigns a ROUND ROBIN distribution style by default.
Why it's wrong here
Default distribution style is AUTO, not ROUND ROBIN.
- ✓
EVEN distribution distributes rows across slices in a round-robin fashion.
Why this is correct
EVEN distributes rows evenly, which reduces data redistribution during joins.
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Same concept, more angles
2 more ways this is tested on DEA-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which TWO statements about Amazon Redshift data distribution are correct? (Choose two.)
easy- A.DISTSTYLE is a distribution style option
- B.AUTO distribution always chooses EVEN
- ✓ C.KEY distribution places rows with the same distribution key on the same slice
- ✓ D.EVEN distribution distributes rows across slices evenly
- E.ALL distribution distributes data across all slices
Why C: In Amazon Redshift, KEY distribution places all rows with the same distribution key value on the same slice (compute node segment). This ensures that join operations on the distribution key are collocated, reducing data movement across the network and improving query performance.
Variation 2. A data engineer runs the above SQL commands on an Amazon Redshift cluster. The table 'users' is created with DISTSTYLE EVEN. What is the effect of the DISTSTYLE EVEN on query performance?
easy- A.It stores all data on a single node for fast local queries.
- ✓ B.It ensures data is evenly distributed across all nodes to prevent data skew.
- C.It reduces data movement during queries by co-locating data based on user_id.
- D.It improves join performance when joining on user_id.
Why B: DISTSTYLE EVEN in Amazon Redshift distributes rows across all nodes in a round-robin fashion, ensuring each node holds approximately the same amount of data. This prevents data skew, which can cause some nodes to become bottlenecks, and improves overall query performance for workloads that do not benefit from key-based distribution. It is the correct choice because it directly addresses the goal of balanced data distribution.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.