DBS-C01 Practice Test 32 — 15 Questions

Question 1

A developer reports that an Amazon RDS for MySQL DB instance is experiencing high CPU utilization. You suspect a specific query is causing the issue. Which CloudWatch metric should you examine to confirm this?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

CPUUtilization. The CPUUtilization metric directly measures the percentage of CPU usage on the DB instance. While it does not isolate a specific query, it confirms that high CPU utilization is occurring. DatabaseConnections, ReadLatency, and FreeableMemory are not direct indicators of CPU usage.

Answer

DatabaseConnections

Answer

ReadLatency

Answer

FreeableMemory

Question 2

A database administrator wants to receive an alert when an RDS instance's storage space drops below 10% of total allocated storage. Which AWS service should be used to set up this alert?

Accepted Answer

Amazon CloudWatch Alarms. Amazon CloudWatch Alarms can monitor the FreeStorageSpace metric for RDS instances and trigger an action (e.g., send an SNS notification) when the storage space drops below 10% of total allocated storage. Option A (Amazon SNS) is a notification service that can be used with CloudWatch Alarms but does not itself monitor metrics. Option B (AWS CloudTrail) records API activity, not storage metrics. Option C (AWS Config) tracks configuration changes. Therefore, Option D is the correct service for setting up the alert.

Answer

Amazon SNS

Answer

AWS CloudTrail

Answer

AWS Config

Question 3

A developer reports that an application's write requests to a DynamoDB table are failing with ProvisionedThroughputExceededException. The table uses provisioned capacity. Which immediate action will resolve the issue?

Accepted Answer

Implement exponential backoff in the application. The correct immediate action is to implement exponential backoff in the application. This retry mechanism gradually increases wait time between retries, reducing the request rate to stay within provisioned throughput limits. Option A is incorrect because switching to on-demand capacity takes time and is not immediate. Option C is incorrect because DAX is a read cache and does not affect write throughput. Option D is incorrect because deleting GSIs does not resolve write throttling to the base table.

Answer

Switch the table to on-demand capacity

Answer

Enable DynamoDB Accelerator (DAX)

Answer

Delete all global secondary indexes

Question 4

A company uses Amazon ElastiCache for Redis. They want to monitor cache hit ratio. Which TWO metrics should be used to calculate the cache hit ratio?

Accepted Answer

CacheHits. Cache hit ratio is calculated as CacheHits / (CacheHits + CacheMisses). Therefore, the two metrics needed are CacheHits (option B) and CacheMisses (option D). Options A, C, and E are not used in this calculation: GetTypeCmds counts total get commands, Evictions indicates memory pressure, and CurItems shows the number of items in the cache.

Answer

GetTypeCmds

Answer

Evictions

Answer

CurItems

Question 5

A database specialist is troubleshooting a slow Amazon RDS for PostgreSQL query. The specialist has enabled Performance Insights and sees that the database load is high. Which additional tool can provide detailed information about the specific queries causing the load?

Accepted Answer

Use Enhanced Monitoring to view OS-level metrics and correlate with performance insights.. Enhanced Monitoring provides OS-level metrics (CPU, memory, disk I/O, etc.), which when combined with Performance Insights' query-level details, gives a comprehensive view of database performance. Option A is wrong because VPC Flow Logs capture network traffic information, not query-specific details. Option B is wrong because CloudWatch Logs can analyze PostgreSQL error logs, but this does not provide detailed query-level load information. Option D is wrong because AWS CloudTrail records API calls, not database queries.

Answer

Use VPC Flow Logs to analyze network traffic to the database.

Answer

Use Amazon CloudWatch Logs to analyze the PostgreSQL error logs.

Answer

Use AWS CloudTrail to view database API calls.

Question 6

A developer needs to monitor the number of throttled read requests for a DynamoDB table. Which CloudWatch metric should be used?

Accepted Answer

ReadThrottleEvents. (ReadThrottleEvents) is the correct CloudWatch metric for monitoring throttled read requests on a DynamoDB table. Option B (ThrottledWriteEvents) tracks write throttles, not reads. Option C (SuccessfulRequestLatency) measures latency, not throttling. Option D (ConsumedReadCapacityUnits) shows read capacity consumption, not throttled requests.

Answer

ThrottledWriteEvents

Answer

SuccessfulRequestLatency

Answer

ConsumedReadCapacityUnits

Question 7

Which TWO actions should be taken to troubleshoot high memory usage on an Amazon ElastiCache for Redis node? (Choose two.)

Accepted Answer

Monitor the Evictions CloudWatch metric.. Monitoring the Evictions CloudWatch metric is the only valid action among the options for troubleshooting high memory usage on an Amazon ElastiCache for Redis node. Option B is incorrect because the maxmemory parameter is determined by the node type and cannot be increased; it is fixed. Options C, D, and E are not direct troubleshooting steps for memory pressure. Option C monitors CPU, not memory. Option D (enabling cluster mode) is a scaling action, not a troubleshooting step for an existing node. Option E (Reserved Memory) is a preventive setting but not a primary troubleshooting action.

Answer

Increase the maxmemory parameter to allow more memory usage.

Answer

Monitor CPUUtilization CloudWatch metric.

Answer

Enable cluster mode to distribute memory across shards.

Answer

Enable Reserved Memory parameter group setting.

Question 8

A company's Amazon RDS for MySQL DB instance is experiencing high CPU utilization. The DB instance is a db.r5.large with 200 GB of General Purpose SSD (gp2) storage. The application is performing many complex queries. Which action would BEST reduce CPU utilization without changing the application code?

Accepted Answer

Scale up the DB instance to db.r5.xlarge. Scaling up the DB instance to db.r5.xlarge provides more CPU capacity, directly reducing CPU utilization. Option A is wrong because read replicas help with read scaling but do not reduce CPU on the writer instance. Option B is wrong because changing storage type to gp3 does not affect CPU. Option D is wrong because the query cache is deprecated in MySQL 8.0 and its impact on CPU is minimal for complex queries.

Answer

Create a read replica and route write queries to it

Answer

Modify the storage type to gp3

Answer

Enable the query cache parameter

Question 9

A developer reports that an Amazon RDS for MySQL DB instance is experiencing high CPU utilization. You suspect a specific query is causing the issue. Which CloudWatch metric should you examine to confirm this?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Modify the DB instance to increase allocated storage. Modifying the allocated storage for an RDS instance is a dynamic operation that can increase storage without downtime. Option A is wrong because creating a read replica requires the source to have available storage and does not resolve the storage issue on the primary instance. Option C is wrong because deleting old automated snapshots does not free up storage on the instance; snapshots are stored separately. Option D is wrong because rebooting does not free storage; it only restarts the instance.

Answer

Create a read replica and promote it

Answer

Delete old automated snapshots

Answer

Reboot the DB instance

Question 10

A company is running a production Amazon RDS for MySQL DB instance. The application team reports intermittent connection timeouts. The DBA notices that the DB instance's CPU utilization spikes to 100% during these times. Which metric should be monitored to determine if the issue is due to a specific query?

Accepted Answer

Queries (engine-specific counter). The RDS for MySQL engine-specific counter 'Queries' reflects the number of queries executed. Option A is wrong because DatabaseConnections shows connections, not query performance. Option B is wrong because ReadIOPS measures disk I/O, not query volume. Option C is wrong because NetworkThroughput measures network traffic.

Answer

DatabaseConnections

Answer

NetworkThroughput

Answer

ReadIOPS

Question 11

A developer is troubleshooting an issue where an application using Amazon DynamoDB is receiving occasional 'ThrottlingException' errors. The application uses eventually consistent reads. What is the MOST likely cause of this error?

Accepted Answer

The read capacity units are set too low for the current traffic pattern. ThrottlingException occurs when the request rate exceeds the provisioned throughput capacity. Option A is incorrect because an incorrect table name would result in a ResourceNotFoundException, not a ThrottlingException. Option C is incorrect because eventually consistent reads consume half the read capacity units compared to strongly consistent reads, making them less likely to cause throttling. Option D is incorrect because network connectivity issues would typically cause timeout or connection errors, not ThrottlingException.

Answer

The application is using an incorrect table name

Answer

The application is using eventually consistent reads instead of strongly consistent reads

Answer

There is a network connectivity issue between the application and DynamoDB

Question 12

A database administrator notices that an Amazon RDS for Oracle DB instance's CPU utilization is consistently above 90% during peak hours. The application is read-heavy. Which action can reduce CPU load?

Accepted Answer

Create a read replica and direct read traffic to it. Creating a read replica offloads read traffic from the primary instance, reducing CPU utilization. For a read-heavy workload, this is an effective scaling strategy. Option A is incorrect because disabling Multi-AZ does not free up significant resources and reduces availability. Option B (increase storage) does not directly reduce CPU load; it addresses storage capacity. Option C (Performance Insights) helps identify performance bottlenecks but does not reduce CPU load by itself.

Answer

Disable Multi-AZ to free up resources

Answer

Increase the allocated storage

Answer

Enable Performance Insights to optimize queries

Question 13

A developer notices that an Amazon RDS for PostgreSQL DB instance is running low on free storage space. The instance has 100 GB of allocated storage. What is the recommended first step to troubleshoot this issue?

Accepted Answer

Check for unused indexes or table bloat using pg_repack or similar tools. Checking for unused indexes or bloat is a typical starting point for storage issues. Option A is wrong because enabling storage auto scaling is a preventive measure, not a troubleshooting step. Option B is wrong because modifying storage is a solution, not a troubleshooting step. Option D is wrong because deleting transaction logs may not recover significant space and can affect point-in-time recovery.

Answer

Enable storage auto scaling

Answer

Modify the DB instance to increase allocated storage

Answer

Delete the oldest transaction logs

Question 14

A company is running an Amazon Aurora MySQL-Compatible DB cluster. The application is experiencing increased latency during peak hours. The DB cluster's CPU utilization is at 40%, but the ReadReplicaLag metric is high. Which of the following is the most likely cause?

Accepted Answer

The writer instance is experiencing I/O bottlenecks, causing slow replication. High replica lag indicates the replica is falling behind, often due to insufficient I/O capacity on the writer or replica. Option B is wrong because read replicas handle SELECT queries. Option C is wrong because the DB cluster parameter group is shared and misconfiguration is not the most likely cause for high replica lag. Option D is wrong because binary log retention period does not affect replica lag directly.

Answer

The read replica is receiving too many write requests

Answer

The DB cluster parameter group is misconfigured

Answer

The binary log retention period is too long

Question 15

A database administrator is troubleshooting a failover event for an Amazon RDS for SQL Server Multi-AZ DB instance. The failover occurred automatically. Which AWS service or feature should the administrator use to view the failover history and the reason for the failover?

Accepted Answer

The Amazon RDS console Events page.. The Amazon RDS console Events page stores RDS events, including failover events with reasons. This is the best place to view failover history and reason. CloudTrail records API calls but not internal failover reasons. CloudWatch Logs does not automatically log failover reasons. The AWS Status Dashboard shows service health, not instance-specific failover history.

Answer

Amazon CloudWatch Logs for the DB instance.

Answer

AWS CloudTrail logs to view the failover API call.

Answer

The AWS Status Dashboard.