Data Warehousing on AWS Training Monitoring and Troubleshooting

Question 1

Which Amazon CloudWatch metric should you monitor to detect when an Amazon Redshift cluster is running low on available memory?

Accepted Answer

PercentageDiskSpaceUsed

Answer

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?

Accepted Answer

STV_INFLIGHT

Answer

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?

Accepted Answer

Queries are waiting in WLM queues due to insufficient concurrency slots

Answer

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?

Accepted Answer

STL_SCAN

Answer

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?

Accepted Answer

Display the query execution plan so you can identify bottlenecks before running the query

Answer

EXPLAIN returns the query execution plan including join methods, distribution operations, and cost estimates without executing the query.

Data Warehousing on AWS Training Practice Test