Data Warehousing on AWS Training Performance Optimization

Question 1

Which Amazon Redshift feature automatically sorts and distributes data to optimize query performance?

Accepted Answer

Automatic Table Optimization (ATO)

Answer

Automatic Table Optimization (ATO) in Redshift automatically applies sort keys and distribution keys based on query patterns.

Question 2

What is the purpose of the VACUUM command in Amazon Redshift?

Accepted Answer

Reclaim storage and resort rows

Answer

VACUUM reclaims storage from deleted rows and re-sorts rows to maintain query performance.

Question 3

Which distribution style should you choose for a large fact table that is frequently joined with dimension tables?

Accepted Answer

KEY

Answer

KEY distribution places matching values on the same node slice, reducing data movement during joins.

Question 4

What does the ANALYZE command do in Amazon Redshift?

Accepted Answer

Updates table statistics for the query planner

Answer

ANALYZE collects statistics about table data so the query optimizer can generate efficient execution plans.

Question 5

Which Redshift feature allows you to cache the results of repeated queries in memory?

Accepted Answer

Result Caching

Answer

Result caching stores query results in memory so identical subsequent queries are returned instantly without re-execution.

Data Warehousing on AWS Training Practice Test