DBS-C01 Management and Operations Practice Test 14 — 15 Questions

Question 1

A database administrator runs the 'describe-db-clusters' CLI command and sees the above output. The earliest restorable time is December 1, 2023. However, the backup retention period is 7 days. Why is the earliest restorable time earlier than 7 days from now (assuming today is December 5, 2023)?

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

Accepted Answer

Automated backups are only kept for 7 days, but manual snapshots extend the recovery window.. The earliest restorable time shown is December 1, 2023, which is earlier than the 7-day backup retention period (which would be November 28, 2023 from today December 5, 2023). This discrepancy occurs because manual snapshots taken prior to the automated backup window extend the restorable range. While automated backups are retained for only 7 days, manual snapshots persist independently and can provide restore points further back in time, effectively making the earliest restorable time earlier than the automated retention period alone would allow.

Answer

The backup retention period is misconfigured; it should be 30 days.

Answer

The cluster was created on December 1, so that is the earliest point available.

Answer

The 'earliestRestorableTime' is calculated based on the latest transaction log, not backup retention.

Question 2

A company is running an Amazon RDS for MySQL DB instance with Multi-AZ deployment. The database experiences a failover due to a hardware failure. After the failover, the application team reports that a critical stored procedure is missing. What should the database administrator do to prevent this issue in the future?

Accepted Answer

Modify the DB parameter group to enable binary logging.. In Amazon RDS MySQL Multi-AZ deployments, all database objects including stored procedures are replicated via synchronous storage-level replication. Therefore, a missing stored procedure after a failover is unlikely and indicates a potential replication issue. To prevent this, enabling binary logging ensures that DDL statements (such as CREATE PROCEDURE) are captured in binary logs. This allows binary log replication to maintain consistency, reduces the risk of orphaned objects, and provides the ability to recover using point-in-time restore if needed. Thus, modifying the DB parameter group to enable binary logging is the best preventive measure.

Answer

Create the stored procedure as a function instead.

Answer

Ensure that the stored procedure is created on both the primary and standby instances by using a script or manually recreating it after failover.

Answer

Increase the binlog retention period to ensure the stored procedure is captured.

Question 3

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.. On-demand capacity mode in DynamoDB automatically scales based on the table's previous peak throughput. If current traffic suddenly exceeds that previous peak, DynamoDB may throttle requests until it adapts to the new traffic level, even if the requests are within the eventual on-demand limits. Option B is incorrect because although a hot partition can cause throttling, the question states that read and write requests are within the throughput limits, implying the issue is not at the partition level but rather a sudden spike beyond the adapted peak. Option C is incorrect because on-demand mode has no maximum throughput limit; it scales automatically. Option D is incorrect because on-demand mode does not use provisioned capacity; it scales without manual configuration.

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 4

A database administrator is monitoring Amazon RDS for PostgreSQL using CloudWatch. The DB instance shows high CPU utilization, but the number of connections is normal. What is the most likely cause of the high CPU utilization?

Accepted Answer

There are long-running queries or missing indexes causing high CPU usage.. High CPU utilization with a normal number of connections often indicates inefficient queries or missing indexes, which cause full table scans and excessive CPU usage. Option A is incorrect because gp2 burst balance affects storage performance, not CPU. Option B is incorrect because memory pressure and swapping typically cause high I/O wait times, not sustained high CPU. Option D is incorrect because Read Replicas offload read traffic, they do not cause high CPU on the primary instance.

Answer

The DB instance has a low burst balance for gp2 storage.

Answer

The instance is low on memory and is swapping.

Answer

The DB instance has a large number of Read Replicas.

Question 5

A company is using Amazon Redshift for data warehousing. They notice that query performance has degraded over time. The database administrator checks the system tables and finds that there is significant skew in data distribution across slices. What action should be taken to improve query performance?

Accepted Answer

Recreate the table with a different distribution style, such as KEY distribution on a column with high cardinality.. Data skew causes some slices to have more data, leading to slower queries. Recreating the table with a different distribution style, such as KEY distribution on a column with high cardinality, can distribute data more evenly across slices. Option B is incorrect because adding more nodes does not automatically redistribute existing data; the skewed distribution persists. Option C is incorrect because running VACUUM reclaims space and updates statistics but does not address data skew. Option D is incorrect because modifying sort keys improves query performance by optimizing data ordering but does not fix uneven data distribution across slices.

Answer

Increase the number of nodes in the cluster.

Answer

Run the VACUUM command to reclaim space and update statistics.

Answer

Modify the sort keys to better match the query patterns.

Question 6

A company is running a MongoDB-compatible Amazon DocumentDB cluster. The application experiences high write latency during peak hours. The database administrator checks the CloudWatch metrics and notices that the Write IOPS metric is consistently at the maximum for the instance size. What should the administrator do to reduce write latency?

Accepted Answer

Increase the instance size to a larger instance class with higher IOPS limits.. Increasing the instance size provides more IOPS capacity, which can reduce write latency if the instance is hitting IOPS limits. Option B is incorrect because switching to a memory-optimized instance class does not directly increase IOPS capacity; it improves memory performance, not I/O throughput. Option C is incorrect because increasing allocated storage size may increase IOPS if using gp2, but the issue is hitting the maximum IOPS for the current instance, and simply increasing storage does not guarantee a proportional increase in IOPS limits. Option D is incorrect because enabling Multi-AZ adds a standby replica for high availability but does not offload writes or increase write IOPS capacity on the primary.

Answer

Switch to a memory-optimized instance class.

Answer

Increase the allocated storage size to improve I/O performance.

Answer

Enable Multi-AZ deployment to offload writes to the standby.

Question 7

A company uses Amazon DynamoDB with provisioned capacity. The application team reports occasional ProvisionedThroughputExceededException errors. The database administrator notices that the errors occur during periods of high traffic. What is the most cost-effective way to handle these errors without over-provisioning capacity?

Accepted Answer

Implement exponential backoff and retry logic in the application.. Implementing exponential backoff and retry logic allows the application to handle throttling errors gracefully by retrying requests after a delay, which is the most cost-effective solution as it avoids over-provisioning capacity. Option A is incorrect because increasing capacity to peak levels is costly and inefficient. Option B is incorrect because DAX is a caching layer that reduces read load but does not help with write throttling or prevent ProvisionedThroughputExceededException errors for writes. Option D is incorrect because switching to on-demand capacity mode can be more expensive for predictable traffic patterns, and the question asks for the most cost-effective approach without over-provisioning.

Answer

Increase the provisioned read and write capacity to the peak traffic level.

Answer

Use DynamoDB Accelerator (DAX) to cache frequently accessed items.

Answer

Switch to on-demand capacity mode.

Question 8

A company is running an Amazon RDS for SQL Server DB instance. The database administrator needs to perform a major version upgrade. What is the recommended approach to minimize downtime?

Accepted Answer

Use AWS Database Migration Service (DMS) to migrate the database to a new instance with the new version.. For Amazon RDS for SQL Server, creating a Read Replica with a different major version is not supported. Therefore, the recommended approach to minimize downtime is to use AWS Database Migration Service (DMS) to migrate the database to a new instance with the new version. DMS allows for minimal downtime by continuously replicating data and then switching over. Options C and D cause significant downtime during the snapshot/restore or direct upgrade process.

Answer

Create a Read Replica of the DB instance with the new version, promote it to a standalone instance, and then redirect application traffic.

Answer

Take a snapshot of the DB instance and restore it with the new version.

Answer

Modify the DB instance directly and apply the new version during the maintenance window.

Question 9

A company is using Amazon Aurora MySQL-Compatible Edition. The database administrator notices that the Aurora cluster has a high number of binary log (binlog) files in the cluster volume, consuming significant storage. The binlog retention period is set to 24 hours. What is the most efficient way to reduce the storage consumed by binlog files without compromising point-in-time recovery (PITR)?

Accepted Answer

Disable binary logging on the Aurora cluster by setting the binlog_format parameter to OFF.. Aurora MySQL does not rely on binlogs for point-in-time recovery (PITR); it uses its own storage-based recovery. Disabling binary logging eliminates binlog generation entirely, saving storage and reducing I/O overhead. Option A is incorrect because manually deleting binlog files is not recommended by AWS and does not address the root cause. Option B is incorrect because exporting binlogs to Amazon S3 does not reduce the storage consumed within the cluster volume. Option D is incorrect because reducing the retention period only limits how long binlogs are kept, but binlogs still accumulate and consume storage until they expire.

Answer

Manually delete binlog files from the DB instance using the 'PURGE BINARY LOGS' command.

Answer

Use the 'Binary Log Export' feature to export binlogs to Amazon S3 and delete them from the cluster.

Answer

Reduce the binlog retention period to 1 hour.

Question 10

A company is using Amazon DynamoDB with global tables. The application writes to a table in the us-east-1 region. The database administrator notices that updates made in us-east-1 are not appearing in the replica table in eu-west-1. What is the most likely cause?

Accepted Answer

DynamoDB Streams are not enabled on the table.. DynamoDB global tables rely on DynamoDB Streams to replicate changes. If streams are not enabled, updates will not be replicated to other regions. Option B is incorrect because DynamoDB does not have a configurable replication delay; replication is near real-time. Option C is incorrect because point-in-time recovery is a backup feature and does not affect replication. Option D is incorrect because insufficient IAM permissions would typically cause error messages or failures, not a silent lack of replication.

Answer

The replication delay is set too high.

Answer

Point-in-time recovery is not enabled on the replica table.

Answer

The IAM role for replication does not have sufficient permissions.

Question 11

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 B and D are correct. Testing the upgrade on a separate non-production environment first (B) is a best practice to verify compatibility and avoid issues. Scheduling the upgrade during the maintenance window (D) allows Amazon RDS to perform the upgrade automatically with a failover, minimizing downtime. Option A is incorrect because disabling Multi-AZ would eliminate the failover benefit and cause downtime. Option C is incorrect because minor version upgrades do not require modifying the DB parameter group; AWS RDS handles parameter compatibility automatically. Option E is incorrect because taking a snapshot is a good practice for recovery but does not reduce downtime during the upgrade.

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 12

A company is using Amazon DynamoDB with on-demand capacity mode. The application experiences occasional throttling during traffic spikes. The database administrator wants to implement a solution to reduce throttling. Which THREE actions should the administrator take? (Choose THREE.)

Accepted Answer

Use DynamoDB Accelerator (DAX) to cache frequently accessed items.. Options A, D, and E are correct. Using DynamoDB Accelerator (DAX) caches frequently accessed items, offloading read capacity from the table and reducing read throttling. Implementing exponential backoff and retry logic in the application (option D) and designing the application to handle throttling by retrying with backoff (option E) both ensure that requests are retried gracefully during spikes, reducing the impact of throttling. Option B is incorrect because auto scaling is not applicable to on-demand capacity mode, which scales automatically. Option C is incorrect because switching to provisioned capacity does not inherently reduce throttling; on-demand already handles sudden spikes, but throttling may still occur if the workload exceeds table limits momentarily.

Answer

Enable auto scaling for the table.

Answer

Switch the table to provisioned capacity mode with auto scaling.

Question 13

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 E are correct. Analyzing tables updates statistics for the query optimizer, enabling efficient query plan generation. Running VACUUM reclaims space and re-sorts data, improving data distribution and query performance. Option A is incorrect because increasing nodes is a scaling action, not an optimization action, and adds cost. Option C is incorrect because enabling encryption does not directly impact query performance. Option D is incorrect because disabling compression increases storage and I/O, degrading 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 14

Refer to the exhibit. A database administrator runs the AWS CLI command to check the status of an Amazon RDS MySQL DB instance. Based on the output, what action is required to apply the pending modifications?

Accepted Answer

Reboot the DB instance to apply the pending parameter group changes.. The output shows 'ParameterApplyStatus: pending-reboot', which indicates that changes to the DB parameter group (specifically the parameter modifications) require a reboot to take effect. While there are also pending modifications for the backup retention period and master user password, these do not necessitate a reboot. Therefore, the correct action is to reboot the DB instance (Option A). Options B, C, and D are incorrect: taking a snapshot is not required, modifying the parameter group has already been done (the status reflects pending-reboot), and altering the backup retention period is not the immediate action needed for the pending reboot.

Answer

Take a snapshot of the DB instance before applying changes.

Answer

Modify the DB parameter group to change the parameter values.

Answer

Modify the DB instance to set the backup retention period to 7.

Question 15

Refer to the exhibit. A database administrator is writing an IAM policy to manage Amazon RDS snapshots. The policy allows actions on all RDS resources but denies deletion of any DB instance with the prefix 'production-'. A developer attempts to delete a snapshot named 'production-snapshot-2020'. Will this action be allowed?

Accepted Answer

Yes, because the Deny statement only applies to deleting DB instances, not snapshots.. The Deny statement in the policy only applies to the 'rds:DeleteDBInstance' action, not to 'rds:DeleteDBSnapshot'. The Allow statement explicitly allows all actions including 'rds:DeleteDBSnapshot' on all resources. Since there is no explicit deny for deleting snapshots, the allow takes effect. Option A is incorrect because the developer's permissions are not relevant; the policy allows the action. Option B is incorrect because the Deny does not apply to snapshots. Option D is incorrect because the Deny condition only matches deletions of DB instances, not snapshots.

Answer

Yes, but only if the developer has the necessary permissions.

Answer

No, because the Deny statement overrides the Allow statement.

Answer

No, because the snapshot name starts with 'production-', which matches the resource pattern in the Deny statement.