Data Warehousing on AWS Training Monitoring and Troubleshooting 1 — Questions and Answers
Question 1: Which Amazon CloudWatch metric should you monitor to detect when an Amazon Redshift cluster is running low on available memory?
- CPUUtilization
- PercentageDiskSpaceUsed (Correct answer)
- DatabaseConnections
- NetworkTransmitThroughput
Correct answer: PercentageDiskSpaceUsed
PercentageDiskSpaceUsed monitors local storage consumption on Redshift nodes; high values indicate you may be nearing storage limits.
Question 2: Which system view in Amazon Redshift shows currently running queries along with their resource usage?
- SVL_QUERY_SUMMARY
- STV_INFLIGHT (Correct answer)
- STL_QUERY
- SVV_TABLE_INFO
Correct answer: STV_INFLIGHT
STV_INFLIGHT contains real-time information about queries currently executing on the cluster, including start time and query text.
Question 3: What does a high value in the QueuedQueries CloudWatch metric indicate for an Amazon Redshift cluster?
- Too many open database connections
- Queries are waiting in WLM queues due to insufficient concurrency slots (Correct answer)
- Disk space is nearly full
- The cluster is undergoing a resize operation
Correct answer: Queries are waiting in WLM queues due to insufficient concurrency slots
QueuedQueries counts queries waiting for an available WLM slot; consistently high values indicate the cluster needs more concurrency capacity.
Question 4: Which Redshift system table helps you identify queries that are performing full table scans instead of using zone map filtering?
- STL_LOAD_ERRORS
- SVL_QUERY_SUMMARY
- STL_SCAN (Correct answer)
- STV_BLOCKLIST
Correct answer: STL_SCAN
STL_SCAN records each table scan operation per query, including whether blocks were skipped via zone maps or fully scanned.
Question 5: What does the Redshift EXPLAIN command help you do?
- Show current cluster health metrics
- Display the query execution plan so you can identify bottlenecks before running the query (Correct answer)
- Generate table statistics for the optimizer
- List all active user connections
Correct answer: Display the query execution plan so you can identify bottlenecks before running the query
EXPLAIN returns the query execution plan including join methods, distribution operations, and cost estimates without executing the query.
Question 6: Which Amazon Redshift feature provides automated recommendations and alerts based on cluster performance analysis?
- CloudWatch Alarms
- Redshift Advisor (Correct answer)
- AWS Config Rules
- Performance Insights
Correct answer: Redshift Advisor
Redshift Advisor continuously analyzes cluster metrics and usage patterns, surfacing actionable recommendations in the console.
Data Warehousing on AWS Training Monitoring and Troubleshooting 1
Which Amazon CloudWatch metric should you monitor to detect when an Amazon Redshift cluster is running low on available memory?