DBS-C01 Practice Exam 55 — 20 Questions

Question 1

Refer to the exhibit. A DBA deploys this CloudFormation stack. After creation, the DBA needs to enable deletion protection for the DB instance. Which modification to the template would accomplish this?

Accepted Answer

Add 'DeletionProtection': true to the Properties.. Option D is correct. Adding DeletionProtection: true enables deletion protection. Option A is wrong because DeletionPolicy is a CloudFormation attribute, not a property. Option B is wrong because PreventRDSDeletion is not a valid property. Option C is wrong because the syntax is incorrect.

Answer

Add 'DeletionPolicy: Retain' to the resource.

Answer

Add 'PreventRDSDeletion: true' to the Properties.

Answer

Add 'DeletionProtection': 'Enabled' to the Properties.

Question 2

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB in size and has a high transaction rate. The migration must have minimal downtime. Which migration strategy should a database specialist recommend?

Accepted Answer

Use AWS DMS with ongoing replication to capture changes.. Option B is correct because AWS DMS with ongoing replication can minimize downtime by capturing changes. Option A is incorrect because native export/import requires downtime. Option C is incorrect because RMAN backup and restore requires downtime for restore. Option D is incorrect because copying dump files also requires downtime.

Answer

Copy the data files to Amazon S3 and then load into RDS.

Answer

Use Oracle Data Pump to export and import the database.

Answer

Perform an RMAN backup and restore to RDS.

Question 3

A company's Amazon RDS for Oracle instance is running out of storage space. The database administrator wants to add storage without downtime. Which action should be taken?

Accepted Answer

Use the 'Modify DB Instance' action to increase the allocated storage.. Option C is correct because RDS supports modifying allocated storage online with minimal downtime. Option A is wrong because creating a new instance and migrating involves downtime. Option B is wrong because increasing storage is not a backup. Option D is wrong because deleting logs may cause issues.

Answer

Delete old archived redo logs to free up space.

Answer

Take a snapshot and restore to a larger instance.

Answer

Create a new DB instance with larger storage and migrate the data.

Question 4

A company is running an Amazon RDS for SQL Server DB instance. The company needs to capture changes to a specific table and replicate them to an Amazon S3 bucket in near real time. Which AWS service should be used to achieve this?

Accepted Answer

AWS Database Migration Service (AWS DMS) with ongoing replication. AWS DMS with ongoing replication (change data capture) can capture changes and replicate them to S3. Option B (AWS Glue) is for ETL jobs, not real-time CDC. Option C (Amazon Kinesis Data Streams) could ingest data but requires additional configuration. Option D (Amazon RDS for SQL Server replication) does not directly write to S3.

Answer

AWS Glue

Answer

Amazon RDS for SQL Server native replication

Answer

Amazon Kinesis Data Streams

Question 5

A database specialist is configuring an Amazon RDS for PostgreSQL instance with automated backups enabled. The backup retention period is set to 7 days. The instance experiences a failure and becomes unavailable. What is the maximum amount of time the specialist has to recover the database to the most recent possible point in time?

Accepted Answer

7 days. Option C is correct because with automated backups and a retention period of 7 days, the latest restorable time is typically within the last 5 minutes, but the maximum point-in-time recovery window is 7 days. Option A is wrong because it is too short. Option B is wrong because it is the backup window, not recovery window. Option D is wrong because it exceeds the retention period.

Answer

1 hour

Answer

14 days

Answer

35 minutes

Question 6

A database administrator sees repeated 'Aborted connection' warnings in the RDS for MySQL error log. The application team reports intermittent connection errors. What is the most likely cause of these aborted connections?

Accepted Answer

The application is closing the database connection abruptly without completing the handshake.. The error 'Got an error reading communication packets' typically indicates a network issue or the client disconnecting unexpectedly. The most common cause is that the database connection is being closed by the application without properly closing the connection, or the network between the application and database is unstable. Option C is plausible but less likely because the error message points to communication issues.

Answer

The wait_timeout parameter is too low, causing idle connections to be terminated.

Answer

The user 'appuser' does not have permission to connect from host '10.0.0.50'.

Answer

The database instance is running out of memory, causing connection drops.

Question 7

A company is using Amazon RDS for PostgreSQL with Multi-AZ deployment. The database administrator needs to perform a minor version upgrade with minimal downtime. Which TWO actions should the administrator take? (Choose TWO.)

Accepted Answer

Test the upgrade on a separate non-production environment first.. Options A and D are correct. Performing the upgrade during the maintenance window allows RDS to handle the upgrade automatically with a failover, minimizing downtime. Testing the upgrade on a non-production environment first is a best practice to ensure compatibility. Option B is incorrect because taking a snapshot before upgrade is a good practice but does not reduce downtime. Option C is incorrect because disabling Multi-AZ would cause downtime during the upgrade. Option E is incorrect because modifying the DB parameter group is not required for minor version upgrades.

Answer

Disable Multi-AZ before the upgrade to reduce complexity.

Answer

Modify the DB parameter group to set the new version parameters.

Answer

Take a snapshot of the DB instance before the upgrade.

Question 8

A company manages multiple RDS for PostgreSQL instances in different AWS accounts. The security team requires that all DB instances have automated backups enabled with a retention period of at least 14 days. How can the company enforce this policy across all accounts?

Accepted Answer

Use AWS Config rules to evaluate and auto-remediate non-compliant instances.. Option D is correct. AWS Config with managed rules can evaluate RDS instances and enforce backup settings. Option A is wrong because IAM policies cannot enforce backup settings on resources. Option B is wrong because CloudTrail does not enforce configuration. Option C is wrong because Service Control Policies (SCPs) are used for permissions at the organization level, not for resource configuration.

Answer

Use AWS CloudTrail to monitor backup settings and alert on non-compliance.

Answer

Apply a service control policy (SCP) that requires backup retention.

Answer

Create an IAM policy that denies creating DB instances without backup retention.

Question 9

Refer to the exhibit. An RDS for PostgreSQL instance shows frequent checkpoints every 10 seconds. What is the most likely cause?

Accepted Answer

The 'max_wal_size' parameter is set too low, causing frequent WAL switches.. Option A is correct. Frequent checkpoints often indicate the log file size (max_wal_size) is too small, causing frequent WAL switches. Option B is wrong because full_storage? might cause issues but not specifically checkpoints. Option C is wrong because high connections may cause load but not checkpoints directly. Option D is wrong because autovacuum runs independently.

Answer

Autovacuum is not running, causing bloat.

Answer

The instance is running out of storage space.

Answer

There are too many concurrent connections.

Question 10

Which TWO of the following are valid methods to secure data at rest for an Amazon RDS for MySQL DB instance?

Accepted Answer

Enable encryption at rest using AWS KMS.. Option B (encryption at rest using AWS KMS) and Option C (enabling encryption when creating the instance) are correct. Option A is incorrect because SSL/TLS secures data in transit, not at rest. Option D is incorrect because RDS does not support Transparent Data Encryption (TDE) for MySQL. Option E is incorrect because RDS encryption is not enabled at the table level.

Answer

Enable SSL/TLS for connections to the DB instance.

Answer

Implement Transparent Data Encryption (TDE) using Oracle-compatible settings.

Answer

Use Amazon RDS encryption at the table level using the ENCRYPT option.

Question 11

A database administrator needs to audit all SQL queries executed on an Amazon RDS for PostgreSQL instance, including SELECT statements. What is the most efficient way to achieve this?

Accepted Answer

Install the pgAudit extension and configure it to log all statements.. Option D is correct because enabling pgAudit extension logs all queries including SELECT. Option A is wrong because CloudTrail does not capture SQL queries. Option B is wrong because enhanced monitoring does not log queries. Option C is wrong because database logs may not capture all queries without audit extension.

Answer

Enable AWS CloudTrail for the RDS instance.

Answer

Configure the DB instance to export logs to Amazon CloudWatch Logs.

Answer

Enable Enhanced Monitoring for the DB instance.

Question 12

A company runs a critical application on an Amazon RDS for MySQL DB instance. The company requires that the database be available with minimal downtime during a disaster recovery scenario. The current RDS instance is in us-east-1. The company wants to have a standby database in us-west-2 with automatic failover. What should the company do to meet this requirement?

Accepted Answer

Create a cross-region read replica in us-west-2. Configure automatic failover using Amazon Route 53 health checks.. An RDS cross-region read replica can be promoted to a standalone instance in a disaster. Option A (Multi-AZ in us-east-1) does not provide cross-region failover. Option B (snapshots) has downtime. Option D (Multi-AZ in us-west-2) does not help if us-east-1 fails.

Answer

Create a Multi-AZ deployment in us-west-2 and use Amazon Route 53 to failover.

Answer

Take daily snapshots and copy them to us-west-2. Restore from snapshot in us-west-2 during a disaster.

Answer

Create a Multi-AZ deployment in us-east-1.

Question 13

A company is using Amazon DynamoDB for a high-traffic web application. The table has on-demand capacity mode. During a marketing event, the application experiences throttling. Which TWO actions should the database specialist take to prevent throttling in future events?

Accepted Answer

Pre-create a DynamoDB global table to distribute write traffic.. Options B and D are correct. Option B: Pre-creating a global table can distribute write traffic across regions, reducing load on a single table. Option D: Using DynamoDB Accelerator (DAX) can offload read traffic, reducing read capacity consumption. Option A is wrong because switching to provisioned capacity requires capacity planning but does not automatically prevent throttling. Option C is wrong because increasing read capacity units is not applicable to on-demand mode. Option E is wrong because decreasing write capacity is counterproductive.

Answer

Increase the read capacity units of the table.

Answer

Switch the table to provisioned capacity mode and increase write capacity units.

Answer

Decrease the write capacity units to reduce throttling.

Question 14

A company is using Amazon DynamoDB with on-demand capacity mode. The application experiences occasional throttling on a table during peak hours. The table's read and write requests are within the throughput limits, but the provisioned read/write capacity is exceeded. What is the most likely cause of this throttling?

Accepted Answer

The table's previous peak throughput was lower than the current traffic, and DynamoDB is still adapting.. Option B is correct because on-demand capacity mode automatically scales to handle up to the table's previous peak throughput, but it can throttle if there is a sudden spike beyond that peak. Option A is incorrect because on-demand capacity mode does not use provisioned capacity; it scales automatically. Option C is incorrect because partition hot spots can cause throttling even if total throughput is within limits, but the question states that read and write requests are within limits. Option D is incorrect because on-demand capacity mode does not have a table-wide throughput limit; it scales automatically.

Answer

The table has a hot partition that is receiving more requests than the partition can handle.

Answer

The table has exceeded the maximum allowed throughput for on-demand capacity mode.

Answer

The table's provisioned read/write capacity is set too low.

Question 15

A company is using Amazon Redshift for data warehousing. The database administrator needs to optimize query performance. Which TWO actions should the administrator take? (Choose TWO.)

Accepted Answer

Analyze the tables to update statistics for the query optimizer.. Options B and D are correct. Running VACUUM reclaims space and re-sorts data, improving performance. Analyzing tables updates statistics for the query optimizer. Option A is incorrect because increasing the number of nodes improves performance but is not an optimization action; it's a scaling action. Option C is incorrect because disabling compression reduces performance. Option E is incorrect because enabling encryption does not directly affect query performance.

Answer

Increase the number of nodes in the cluster.

Answer

Enable encryption for the cluster.

Answer

Disable compression on the tables to reduce CPU overhead.

Question 16

A company is running an Amazon Aurora MySQL-compatible edition DB cluster. The application reports that a recent schema change caused a significant increase in the number of deadlocks. Which parameter should the DBA check and possibly adjust to reduce deadlocks?

Accepted Answer

innodb_lock_wait_timeout. Option C is correct. The innodb_lock_wait_timeout controls how long a transaction waits for a lock before rolling back. Reducing it can help avoid long waits, but deadlocks are often resolved by MySQL automatically; adjusting this parameter may not directly reduce deadlocks but can help. Actually, for deadlocks, the best practice is to examine the application logic. However, among the options, innodb_lock_wait_timeout is relevant. Option A is wrong because transaction isolation level affects concurrency but not deadlocks directly. Option B is wrong because max_connections is about connection count. Option D is wrong because autocommit affects transaction behavior.

Answer

autocommit

Answer

max_connections

Answer

transaction_isolation

Question 17

A company runs an Amazon Aurora MySQL database cluster with one writer and one reader instance. The application experiences intermittent connection timeouts during peak traffic. The DB cluster parameter group has 'connect_timeout' set to 5 seconds. What should a database specialist recommend to reduce connection timeouts?

Accepted Answer

Enable RDS Proxy for the cluster.. Option B is correct because enabling RDS Proxy reduces connection overhead and provides a connection pool, mitigating timeouts. Option A is incorrect because increasing connect_timeout only delays the timeout, not the root cause. Option C is incorrect because adding readers does not help with writer connection timeouts. Option D is incorrect because the issue is not related to TLS.

Answer

Add additional reader instances to distribute the load.

Answer

Increase the 'connect_timeout' parameter to 10 seconds.

Answer

Enable IAM database authentication and require TLS.

Question 18

Which TWO of the following are valid actions to take when an Amazon Redshift query is taking longer than expected due to disk-based operations?

Accepted Answer

Redistribute data across nodes using a distribution style that minimizes data movement.. Option A (increasing the number of nodes) and Option C (distributing data evenly) are correct. Option B is incorrect because Sort keys affect order, not disk spills. Option D is incorrect because WLM queues affect concurrency, not disk operations. Option E is incorrect because column compression reduces storage but may not reduce disk spills.

Answer

Use column compression to reduce the amount of data scanned.

Answer

Increase the number of workload management (WLM) query queues.

Answer

Change the sort keys to match the query's ORDER BY clause.

Question 19

A company is running an Amazon RDS for MySQL instance with Multi-AZ. The primary instance in us-east-1a fails, and the standby in us-east-1b is promoted. The application cannot connect after failover. Which TWO steps should the database administrator take to restore connectivity?

Accepted Answer

Update the application's connection string to point to the new writer endpoint.. Option A is correct because the CNAME updates automatically, but DNS caching may cause delays. Option D is correct because updating the connection string to the new writer endpoint ensures connectivity. Option B is wrong because rebooting the new primary is not required. Option C is wrong because modifying security group is unnecessary; it already allows traffic. Option E is wrong because read replicas are not related.

Answer

Reboot the new primary instance to reset connections.

Answer

Update the security group to allow inbound traffic from the application.

Answer

Create a read replica and promote it to a new primary.

Question 20

A company is using Amazon RDS for PostgreSQL with read replicas to offload read traffic. The company wants to ensure that the read replicas are always in sync with the primary instance. Which metric should the company monitor to detect replication lag?

Accepted Answer

ReplicaLag. RDS provides the ReplicaLag metric in CloudWatch for PostgreSQL read replicas. Option A (DiskQueueDepth) is for storage. Option B (ReadLatency) is for read operations. Option D (TransactionLogsDiskUsage) is not a standard metric.

Answer

DiskQueueDepth

Answer

TransactionLogsDiskUsage

Answer

ReadLatency

DBS-C01 Practice Exam 55 — 20 Questions

Exhibit

DBS-C01 Practice Exam 55 — 20 Questions

Exhibit