Data Warehousing on AWS Training Cost Management 2 — Questions and Answers
Question 1: What is the charge model for Redshift Spectrum queries?
- Per hour of cluster time used
- Per TB of data scanned in S3 (Correct answer)
- Per number of rows returned
- Per Redshift Processing Unit (RPU) second
Correct answer: Per TB of data scanned in S3
Redshift Spectrum charges $5 per TB of data scanned in S3, incentivizing use of columnar compressed formats to minimize scan size.
Question 2: Which S3 storage class should you use for Redshift Spectrum external tables that are accessed monthly?
- S3 Standard
- S3 Standard-IA
- S3 Glacier Instant Retrieval
- S3 Intelligent-Tiering (Correct answer)
Correct answer: S3 Intelligent-Tiering
S3 Intelligent-Tiering automatically moves data between access tiers based on actual usage patterns, optimizing cost without manual intervention.
Question 3: What is the most effective way to reduce Redshift Spectrum costs when querying partitioned data?
- Increase cluster node count
- Use partition pruning in WHERE clauses to limit scanned partitions (Correct answer)
- Store data in CSV format
- Disable result caching
Correct answer: Use partition pruning in WHERE clauses to limit scanned partitions
Partition pruning uses WHERE clause filters on partition columns (e.g., year, month) to skip scanning irrelevant S3 partitions entirely.
Question 4: How does column compression in Redshift directly impact storage costs?
- It has no impact on storage billing
- It reduces the amount of data stored, lowering S3 and node storage costs (Correct answer)
- It only affects query performance, not storage
- It increases storage costs due to compression metadata
Correct answer: It reduces the amount of data stored, lowering S3 and node storage costs
Column compression encodings like ZSTD can reduce data size by 3-10x, directly reducing the amount of storage billed.
Question 5: Which AWS Cost Explorer feature helps identify unexpected increases in Redshift spending?
- Trusted Advisor Cost Optimization checks
- AWS Cost Anomaly Detection (Correct answer)
- AWS Compute Optimizer
- AWS Billing Dashboard
Correct answer: AWS Cost Anomaly Detection
AWS Cost Anomaly Detection uses machine learning to identify unusual spending patterns and sends alerts when anomalies are detected.
Question 6: What is the purpose of Redshift's automatic table optimization with respect to cost management?
- It automatically resizes the cluster based on cost thresholds
- It reduces unnecessary full-table scans by optimizing sort and distribution keys, lowering query compute time (Correct answer)
- It migrates cold data to Glacier automatically
- It deduplicates data to reduce storage consumption
Correct answer: It reduces unnecessary full-table scans by optimizing sort and distribution keys, lowering query compute time
Optimized sort and distribution keys reduce data shuffling and scanning, which decreases query run time and therefore Concurrency Scaling charges.
Data Warehousing on AWS Training Cost Management 2
What is the charge model for Redshift Spectrum queries?