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AWS Certified Database Specialty DBS-C01 (DBS-C01) — Questions 676–750

1663 questions total · 23pages · All types, answers revealed

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676

MCQeasy

A database administrator notices that an Amazon RDS for MySQL instance is using 100% of its allocated storage. Which action should be taken first to prevent the instance from becoming inaccessible?

A.Modify the DB instance to increase allocated storage.

B.Create a snapshot and archive it to Amazon S3.

C.Delete old binary logs to free up space.

D.Reboot the DB instance.

AnswerA

Correct. Increasing storage is a direct and safe way to prevent the instance from becoming inaccessible.

Why this answer

When an Amazon RDS for MySQL instance reaches 100% storage utilization, the most immediate action to prevent it from becoming inaccessible is to modify the DB instance to increase allocated storage. This adds storage capacity and allows normal operations to continue. Option B (snapshot and archive to S3) does not free up storage on the instance.

Option C (deleting old binary logs) can free space but is not guaranteed to free enough and may not be a long-term solution; also, binary logs are needed for replication and point-in-time recovery. Option D (reboot) does not resolve the storage shortage.

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677

MCQhard

A company is designing a database for a mobile application that requires offline synchronization. Users should be able to read and write data while offline, and changes should sync when connectivity is restored. Which AWS service supports this pattern?

A.Amazon RDS Proxy

B.Amazon S3 Transfer Acceleration

C.Amazon Cognito

D.AWS AppSync with Amazon DynamoDB

AnswerD

AppSync supports offline data sync with conflict resolution.

Why this answer

AWS AppSync with Amazon DynamoDB is correct because AppSync provides managed GraphQL APIs that support offline data synchronization via its client SDKs. When a mobile app is offline, mutations are queued locally and automatically replayed against DynamoDB once connectivity is restored, using a conflict resolution mechanism (e.g., last-writer-wins or custom resolvers) to merge changes.

Exam trap

The trap here is that candidates may confuse Amazon Cognito's authentication capabilities with the offline sync feature, overlooking that AppSync is the service that actually provides the offline mutation queue and conflict resolution.

How to eliminate wrong answers

Option A is wrong because Amazon RDS Proxy is a connection pooling service for relational databases, not designed for offline sync or mobile client data caching. Option B is wrong because Amazon S3 Transfer Acceleration speeds up uploads to S3 over long distances using edge locations, but it does not provide offline write queuing or conflict resolution for application data. Option C is wrong because Amazon Cognito is an identity and user management service; while it can integrate with AppSync for authentication, it alone does not enable offline data synchronization or local mutation storage.

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678

MCQmedium

An IAM policy is attached to a user who is deploying an RDS database. The user attempts to create a DB instance named 'my-database' using the AWS CLI. Which statement is true?

A.The user cannot create the DB instance because the Deny statement applies to all actions

B.The user cannot create the DB instance because the resource ARN does not exist yet

C.The user cannot create the DB instance because of an error in the policy

D.The user can create the DB instance

AnswerD

The Allow statement explicitly allows CreateDBInstance on the resource.

Why this answer

The IAM policy explicitly allows the `rds:CreateDBInstance` action for the resource `arn:aws:rds:us-east-1:123456789012:db:my-database`. The Deny statement only applies to actions not listed in the Allow statement, but since the specific action and resource match the Allow, the user is permitted to create the DB instance. AWS IAM evaluates policies with an explicit Allow overriding an implicit Deny, and the Deny here does not block the allowed action.

Exam trap

The trap here is that candidates assume a Deny statement always overrides an Allow, but they overlook that the Deny in this policy only applies to actions not explicitly allowed, and the specific Allow for `rds:CreateDBInstance` on the matching resource ARN permits the operation.

How to eliminate wrong answers

Option A is wrong because the Deny statement does not apply to all actions; it only denies actions not explicitly allowed, and the Allow statement explicitly permits `rds:CreateDBInstance` for the specified resource. Option B is wrong because the resource ARN in the policy does not need to exist at the time of policy evaluation; IAM evaluates the ARN pattern against the request, and the ARN `arn:aws:rds:us-east-1:123456789012:db:my-database` matches the intended resource even before creation. Option C is wrong because there is no error in the policy; the policy syntax is valid, and the combination of Allow and Deny statements is correctly structured to permit the specific action.

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679

MCQmedium

A development team is building a serverless application that uses Amazon DynamoDB. The team needs to ensure that only the application's Lambda function can read and write data to a specific DynamoDB table. The Lambda function uses an IAM role. How should the team configure access?

A.Place the DynamoDB table and Lambda function in the same VPC and use a VPC endpoint to control access.

B.Encrypt the DynamoDB table with an AWS KMS key and grant the Lambda function decryption permissions.

C.Create an IAM role for the Lambda function with DynamoDB access, and configure a resource-based policy on the DynamoDB table that allows only that role.

D.Create an IAM role for the Lambda function with a policy that allows DynamoDB access, and attach the role to the function.

AnswerC

The resource-based policy on DynamoDB restricts access to the specified IAM role, ensuring only the Lambda function can access the table.

Why this answer

DynamoDB supports resource-based policies (also known as table policies) that allow you to specify which IAM roles or users can access the table. By attaching such a policy that grants access only to the Lambda function's execution role, you ensure that only that function can read/write to the table. Option A is incorrect because using a VPC endpoint does not inherently control access to the table; it only controls network traffic.

Option B is incorrect because KMS encryption protects data at rest but does not authorize access. Option D is incomplete because while an IAM role with a DynamoDB access policy is necessary, without a resource-based policy on the table that restricts access to that role, other principals with DynamoDB permissions could still access the table.

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680

Multi-Selecthard

A company is using Amazon DynamoDB to store IoT sensor data. The application writes a large volume of data and needs to read recent data by timestamp. The table has a partition key of device_id and a sort key of timestamp. The access pattern is to read the latest data for a specific device. Which TWO design patterns will optimize read performance and reduce costs?

Select 2 answers

A.Use adaptive capacity to evenly distribute traffic across partitions.

B.Use DynamoDB Accelerator (DAX) to cache the most recent reads.

C.Enable auto scaling for the table to handle spikes.

D.Use DynamoDB Transactions for consistent reads.

E.Create a global secondary index (GSI) with device_id as partition key and timestamp as sort key.

AnswersA, B

Adaptive capacity helps handle hot partitions, improving performance and cost efficiency.

Why this answer

Adaptive capacity allows DynamoDB to automatically manage partition traffic distribution, preventing hot partitions when a single device_id receives a high volume of writes. This ensures consistent read performance without manual partition management. Option B is correct because DAX provides an in-memory cache for the most frequently accessed data, reducing read latency and read capacity unit consumption for repeated queries of recent sensor data.

Exam trap

The trap here is that candidates often confuse auto scaling with adaptive capacity, or assume a GSI is always beneficial, not realizing that duplicating the base table key structure adds cost without performance gain.

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681

Multi-Selecteasy

A company is using Amazon RDS for Oracle and needs to comply with regulatory requirements that mandate encryption of all data at rest and in transit. Which TWO actions should be taken to meet these requirements?

Select 2 answers

A.Enable encryption at rest by specifying a KMS key when creating the DB instance.

B.Use Oracle Transparent Data Encryption (TDE) to encrypt the data at rest.

C.Enable encryption for CloudWatch Logs.

D.Configure Oracle Native Network Encryption in the sqlnet.ora file.

E.Enable SSL/TLS encryption by setting the rds.force_ssl parameter and using the RDS SSL certificate.

AnswersA, E

Encryption at rest is enabled by specifying a KMS key when creating the DB instance. This meets the encryption at rest requirement.

Why this answer

Options A and E are correct. Option A enables encryption at rest by specifying a KMS key when creating the DB instance. Option E enables encryption in transit by setting the rds.force_ssl parameter and using the RDS SSL certificate.

Option B is incorrect because Oracle TDE is not required when RDS encryption at rest is used; RDS native encryption with KMS is sufficient. Option C is incorrect because CloudWatch Logs encryption does not encrypt the database data. Option D is incorrect because Oracle Native Network Encryption is less secure than SSL/TLS and is not the recommended method for encryption in transit.

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682

MCQeasy

A company wants to migrate an on-premises Oracle database to Amazon RDS for Oracle with minimal downtime. Which AWS service should be used for the migration?

A.AWS Systems Manager

B.AWS Schema Conversion Tool (SCT)

C.AWS Database Migration Service (DMS)

D.AWS Service Control Policies (SCP)

AnswerC

DMS supports minimal downtime migrations.

Why this answer

AWS Database Migration Service (DMS) is the correct choice because it is specifically designed to migrate databases to AWS with minimal downtime by using ongoing replication (change data capture, CDC) from the source Oracle database to the target Amazon RDS for Oracle instance. DMS supports heterogeneous and homogeneous migrations, and for Oracle-to-Oracle migrations, it can use Oracle LogMiner or binary reader to capture changes continuously, allowing the source to remain operational during the migration.

Exam trap

The trap here is that candidates often confuse AWS Schema Conversion Tool (SCT) as a full migration service, but SCT only handles schema conversion and must be paired with DMS for actual data movement, making DMS the correct answer for minimal downtime migration.

How to eliminate wrong answers

Option A is wrong because AWS Systems Manager is an operations management service for patching, configuration, and automation of EC2 and on-premises instances, not a database migration tool. Option B is wrong because AWS Schema Conversion Tool (SCT) is used to convert database schema and code objects (e.g., from Oracle to Amazon Aurora) but does not handle the actual data migration or ongoing replication; it is often used alongside DMS, not as a standalone migration service. Option D is wrong because AWS Service Control Policies (SCP) are part of AWS Organizations for managing permissions across accounts, not for migrating database workloads.

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683

Multi-Selectmedium

A company is migrating an on-premises MongoDB database to Amazon DocumentDB (with MongoDB compatibility). The security team requires that data be encrypted at rest and in transit. Additionally, the team wants to use IAM roles to authenticate applications. Which THREE steps should the database specialist take to meet these requirements?

Select 3 answers

A.Use IAM roles to authenticate applications to the DocumentDB cluster.

B.Use a custom certificate authority for SSL/TLS.

C.Enable encryption at rest for the DocumentDB cluster.

D.Create a VPC endpoint for DocumentDB to enforce encryption.

E.Enable encryption in transit by using TLS for all connections.

AnswersA, C, E

Correct. IAM roles can be used to authenticate applications to DocumentDB, providing a secure and manageable authentication method.

Why this answer

Options A, C, and E are correct. IAM roles (A) can be used for authentication to DocumentDB, enabling fine-grained access control. Encryption at rest (C) can be enabled when creating the cluster, as DocumentDB supports encrypted storage using AWS KMS.

Encryption in transit (E) is achieved by using TLS for all connections. Option B is incorrect because DocumentDB uses a trusted certificate authority for TLS, not a custom CA. Option D is incorrect because VPC endpoints provide private connectivity but do not enforce encryption; encryption is handled at the cluster level and via TLS.

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684

MCQmedium

A company uses Amazon DynamoDB for a highly transactional application. The application is experiencing increased latency and throttled requests. The operations team notices that the DynamoDB table's read and write capacity utilization is consistently near 100%. The table uses on-demand capacity mode. What is the MOST likely cause of the throttling?

A.The table has reached the per-table throughput limit for on-demand mode.

B.The table is configured as a global table and cross-region replication is causing write conflicts.

C.The application is not using DynamoDB Accelerator (DAX) to cache reads.

D.The table's partition key design is causing hot partitions, and adaptive capacity is not enabled.

AnswerA

On-demand mode has a maximum throughput per table; exceeding it causes throttling.

Why this answer

On-demand DynamoDB tables have a per-table throughput limit (e.g., 40,000 read/write units per second). When sustained traffic exceeds this limit, requests are throttled. Option B is incorrect because global table replication does not cause throttling; it replicates writes asynchronously.

Option C is incorrect because DynamoDB Accelerator (DAX) is a read cache that reduces latency, but throttling still occurs if the table itself reaches its throughput limit. Option D is incorrect because adaptive capacity automatically handles hot partitions by splitting them; however, the primary cause here is hitting the on-demand throughput limit, not a partition design issue.

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685

MCQmedium

A company is running a MySQL database on an EC2 instance and wants to migrate to Amazon RDS for MySQL with minimal downtime. The database is 500 GB in size and has a high write workload. Which migration approach is most appropriate?

A.Export data to Amazon S3 and use AWS Glue to load into RDS.

B.Copy the MySQL data directory to Amazon EBS and attach to RDS.

C.Take a mysqldump from the source and import into RDS.

D.Use AWS Database Migration Service (DMS) with ongoing replication.

AnswerD

DMS supports live migration with minimal downtime.

Why this answer

AWS DMS with ongoing replication (change data capture) is the most appropriate approach because it allows you to migrate the 500 GB database with minimal downtime. DMS performs a full load of the existing data and then continuously replicates ongoing changes from the source MySQL EC2 instance to the target Amazon RDS for MySQL, enabling a cutover with only a brief pause in writes.

Exam trap

The trap here is that candidates often choose mysqldump (Option C) because it is a familiar tool, but they overlook the requirement for minimal downtime and the impact of a high write workload on the time needed to complete a consistent export.

How to eliminate wrong answers

Option A is wrong because AWS Glue is an ETL service designed for transforming and loading data into data lakes or analytics services, not for direct database migration with minimal downtime; it cannot handle ongoing replication of MySQL binary logs. Option B is wrong because you cannot attach an EBS volume to an RDS instance; RDS manages its own storage and does not allow direct mounting of external EBS volumes. Option C is wrong because mysqldump is a logical backup tool that requires taking the source database offline or locking tables to ensure consistency, resulting in significant downtime for a 500 GB database with a high write workload.

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686

MCQmedium

A company is running an Amazon Redshift cluster with a single node. They need to improve query performance for large analytical workloads. Which action would provide the most immediate performance improvement?

A.Distribute the data across all slices.

B.Apply compression encodings to all columns.

C.Increase the number of nodes in the cluster.

D.Run the VACUUM command to reclaim space.

AnswerC

Adding nodes increases processing power and memory.

Why this answer

Adding more nodes to the cluster distributes the workload and improves parallelism. Option A is wrong because using a single node, distributing data across slices is limited. Option B is wrong because compression is already used typically.

Option D is wrong because VACUUM reclaims space but does not significantly improve performance for large workloads.

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687

MCQmedium

A company is running an Amazon RDS for MySQL DB instance. The DB instance is experiencing high CPU utilization due to a sudden increase in read traffic. The company needs to reduce the load on the primary DB instance with minimal downtime. Which solution should be used?

A.Modify the DB instance to a larger instance class.

B.Use an Amazon ElastiCache cluster to cache frequent queries.

C.Enable Multi-AZ on the DB instance.

D.Create an RDS read replica and redirect read queries to it.

AnswerD

Read replicas offload read traffic and can be created without downtime.

Why this answer

Creating an Amazon RDS read replica allows you to offload read traffic from the primary DB instance to one or more read replicas, which can handle SELECT queries. This reduces CPU utilization on the primary instance with minimal downtime, as read replicas are asynchronous replicas that can be promoted to a primary if needed. Redirecting read queries to the read replica effectively distributes the load without requiring a change to the primary instance's configuration.

Exam trap

The trap here is that candidates often confuse Multi-AZ (which provides high availability but does not offload read traffic) with read replicas (which are designed to offload read traffic), leading them to select Option C incorrectly.

How to eliminate wrong answers

Option A is wrong because modifying the DB instance to a larger instance class requires a reboot, causing downtime, and it addresses the symptom (high CPU) by scaling vertically rather than distributing the read load, which is less cost-effective for read-heavy workloads. Option B is wrong because while Amazon ElastiCache can cache frequent queries and reduce read load, it requires application changes to implement caching logic and does not directly offload existing read traffic from the RDS instance; it is a complementary solution, not a direct replacement for read replicas in this scenario. Option C is wrong because enabling Multi-AZ provides high availability by creating a standby replica in another Availability Zone, but the standby cannot serve read traffic; it only handles failover, so it does not reduce CPU utilization on the primary instance.

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688

MCQeasy

A developer accidentally deleted a production RDS for PostgreSQL DB instance. The company has automated backups enabled with a retention period of 7 days. What is the fastest way to restore the database to the state just before the deletion?

A.Recover the instance from the Amazon RDS Recycle Bin.

B.Restore from the latest automated snapshot that was taken before deletion.

C.Use the AWS DMS to migrate the data from the deleted instance to a new one.

D.Create a new DB instance and use point-in-time recovery to the time just before deletion.

AnswerD

Point-in-time recovery can be used to restore to any time within the retention window, even for deleted instances.

Why this answer

When automated backups are enabled, you can perform point-in-time recovery (PITR) to restore the database to any point within the retention period, including just before deletion. RDS retains the automated backups and transaction logs for the retention period even after the instance is deleted. Option A is incorrect because Amazon RDS does not use a Recycle Bin for DB instances.

Option B is incorrect because restoring from the latest automated snapshot would not recover transactions after that snapshot; you need PITR to get the state just before deletion. Option C is incorrect because AWS DMS is for migrating data between databases, not for recovering a deleted instance.

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689

Multi-Selecthard

A company is migrating a 10 TB Oracle data warehouse to Amazon Redshift. The migration must minimize data transfer costs and ensure data integrity. Which TWO steps should the company take?

Select 2 answers

A.Use AWS DMS to replicate data directly over the internet

B.Use Amazon Kinesis Data Streams to stream data to Redshift

C.Use Amazon Redshift Spectrum to query data in S3 after loading

D.Use AWS Schema Conversion Tool (SCT) to convert the Oracle schema to Redshift

E.Use AWS Snowball Edge to physically transfer the data

AnswersD, E

SCT helps convert and optimize schema for Redshift.

Why this answer

The AWS Schema Conversion Tool (SCT) is specifically designed to convert Oracle database schemas to Amazon Redshift-compatible schemas, handling data type mappings, stored procedures, and other schema objects. This step is critical for a successful migration as it ensures the target schema is optimized for Redshift's columnar storage and MPP architecture, reducing manual rework and potential data integrity issues.

Exam trap

The trap here is that candidates may assume AWS DMS is always the best choice for database migrations, but for very large datasets (e.g., 10 TB) where cost minimization is a key requirement, physical transfer via Snowball Edge is more cost-effective and reliable than network-based replication.

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690

MCQeasy

A startup is building a mobile app backend using Amazon DynamoDB. They anticipate unpredictable traffic spikes. Which DynamoDB feature should they use to handle the spikes without manual intervention?

A.Use DynamoDB Accelerator (DAX) as a cache layer.

B.Enable DynamoDB Auto Scaling for read and write capacity.

C.Set up a TTL (Time to Live) to automatically expire old items.

D.Implement DynamoDB Global Tables for multi-region replication.

AnswerB

Auto Scaling adjusts capacity based on traffic patterns, handling spikes automatically.

Why this answer

DynamoDB Auto Scaling (option B) automatically adjusts the provisioned read and write capacity based on actual traffic patterns, using CloudWatch alarms and the Application Auto Scaling service. This allows the startup to handle unpredictable spikes without manual intervention, as the service will increase capacity during high demand and decrease it during low demand, ensuring consistent performance and cost efficiency.

Exam trap

The DBS-C01 exam often tests the misconception that caching (DAX) or data expiration (TTL) can handle traffic spikes, but the key is that Auto Scaling directly adjusts the provisioned capacity to match demand, while DAX only caches reads and TTL only manages data lifecycle.

How to eliminate wrong answers

Option A is wrong because DynamoDB Accelerator (DAX) is an in-memory cache that reduces read latency but does not handle write capacity spikes or automatically adjust provisioned throughput; it addresses performance, not scaling. Option C is wrong because TTL (Time to Live) is used to automatically expire and delete old items to manage storage costs and data retention, not to handle traffic spikes or scale capacity. Option D is wrong because DynamoDB Global Tables provide multi-region replication for disaster recovery and low-latency global access, but they do not automatically scale read/write capacity in response to traffic spikes; each replica table still requires its own capacity management.

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691

MCQmedium

Refer to the exhibit. An application team notices that the MySQL RDS instance 'mydb' is running at 80% CPU utilization during peak hours. They need to improve read performance without increasing the CPU load on the primary instance. Which action should they take?

A.Increase the DB instance class to db.r5.xlarge

B.Create a Read Replica in the same region

C.Change storage type to io1 with higher IOPS

D.Enable Multi-AZ deployment

AnswerB

Read Replica offloads read queries, reducing CPU on primary.

Why this answer

Creating a Read Replica offloads read traffic from the primary MySQL RDS instance, reducing CPU load on the primary while improving read performance for applications. Read Replicas asynchronously replicate data using MySQL’s native binlog-based replication, allowing the primary to focus on write operations without additional CPU overhead from serving reads.

Exam trap

The trap here is confusing Multi-AZ (which provides failover but no read scaling) with Read Replicas (which offload reads), leading candidates to select Multi-AZ when the goal is to reduce CPU load on the primary.

How to eliminate wrong answers

Option A is wrong because increasing the DB instance class to db.r5.xlarge would add more CPU and memory to the primary instance, but it does not offload read traffic; the primary would still handle all read requests, potentially increasing CPU utilization further. Option C is wrong because changing storage type to io1 with higher IOPS improves disk I/O performance but does not reduce CPU load; CPU utilization is driven by query processing, not storage throughput. Option D is wrong because enabling Multi-AZ deployment provides high availability and automatic failover via synchronous standby replication, but it does not offload read traffic; the standby replica cannot serve reads, so CPU load on the primary remains unchanged.

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692

MCQhard

A company runs an Amazon Aurora MySQL database. The database experiences a sudden spike in connections and then becomes unresponsive. The DB instance has a db.r5.large class with 8 GB memory. The maximum connections parameter is set to the default. Which is the most likely cause of the unresponsiveness?

A.The DB instance's EBS burst balance dropped to zero

B.The storage volume ran out of allocated space

C.The number of connections exceeded the max_connections limit

D.A read replica had high replication lag

AnswerC

Exceeding max_connections can cause the database to reject connections and become unresponsive.

Why this answer

The default max_connections for Aurora MySQL is based on memory, and with 8 GB, it is about 800. A spike exceeding that can exhaust resources. Option A is wrong because storage auto-scaling is seamless.

Option B is wrong because burst balance applies to gp2 volumes, but Aurora uses cluster storage. Option D is wrong because replica lag would affect reads, not make the instance unresponsive.

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693

MCQeasy

A mobile gaming company needs a database to store player scores and leaderboards. The data must be updated in real time as players finish games. The database must support high write throughput and provide sub-millisecond read latency for leaderboard queries. Which database is best suited?

A.Amazon RDS for MySQL with read replicas

B.Amazon Redshift

C.Amazon ElastiCache for Redis

D.Amazon DynamoDB

AnswerD

DynamoDB offers consistent single-digit millisecond latency and high throughput.

Why this answer

Amazon DynamoDB is the best choice because it is a fully managed NoSQL key-value and document database designed for single-digit millisecond read and write performance at any scale. Its DAX (DynamoDB Accelerator) caching layer can further reduce read latency to sub-millisecond for leaderboard queries, while its auto-scaling write capacity handles the high write throughput required for real-time player score updates.

Exam trap

The trap here is that candidates often choose ElastiCache for Redis (Option C) because of its sub-millisecond latency, but they overlook the requirement for a durable database that persists player scores and leaderboards, which Redis does not guarantee without additional configuration and risk of data loss.

How to eliminate wrong answers

Option A is wrong because Amazon RDS for MySQL with read replicas is a relational database that cannot achieve sub-millisecond read latency for leaderboard queries at high write throughput; read replicas introduce replication lag and are not designed for real-time, high-frequency writes. Option B is wrong because Amazon Redshift is a petabyte-scale data warehouse optimized for complex analytical queries on large datasets, not for real-time, high-write-throughput transactional workloads or sub-millisecond reads. Option C is wrong because Amazon ElastiCache for Redis is an in-memory cache, not a durable database; while it provides sub-millisecond latency, it lacks the persistence and durability guarantees needed for storing player scores and leaderboards as a primary database, and data loss can occur on node failure.

Full explanation →

694

MCQeasy

A company is using Amazon Aurora MySQL-Compatible Edition. The security team wants to audit all database login attempts and store the logs in Amazon S3 for 90 days. Which solution meets these requirements with the LEAST operational overhead?

A.Enable the Aurora audit log and publish logs to Amazon CloudWatch Logs. Create a CloudWatch Logs subscription filter to stream the logs to an Amazon S3 bucket.

B.Enable the Aurora audit log and configure the DB cluster to publish logs directly to an S3 bucket.

C.Install a custom audit plugin on the Aurora cluster that writes logs to a file, then use an AWS Lambda function to upload the file to S3.

D.Enable the Aurora audit log and use Amazon Kinesis Data Firehose to stream the logs to S3.

AnswerA

This uses managed services with minimal configuration.

Why this answer

Amazon Aurora can publish audit logs to Amazon CloudWatch Logs. A CloudWatch Logs subscription filter can then stream those logs to an Amazon S3 bucket for long-term storage. This approach requires minimal operational overhead because it uses native AWS services without custom scripts or additional infrastructure.

Option B is incorrect because Aurora does not support writing audit logs directly to S3. Option C is incorrect because installing a custom audit plugin and using a Lambda function introduces unnecessary complexity and operational overhead. Option D is incorrect because using Amazon Kinesis Data Firehose adds an extra streaming service that is not needed; a CloudWatch Logs subscription filter is simpler and more direct.

Full explanation →

695

Multi-Selectmedium

Which TWO actions will help protect an Amazon RDS for MySQL database from a SQL injection attack? (Select TWO.)

Select 2 answers

A.Use parameterized queries in the application code.

B.Enable encryption at rest for the RDS instance.

C.Place the RDS instance in a private VPC subnet.

D.Restrict database user permissions to only required operations.

E.Enable auto minor version upgrade on the RDS instance.

AnswersA, D

Parameterized queries prevent injection.

Why this answer

Using parameterized queries (prepared statements) prevents SQL injection. Also, restricting database user permissions to only necessary operations limits damage. Enabling encryption at rest does not prevent injection.

Using a VPC does not prevent injection. Enabling auto minor version upgrade does not prevent injection.

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696

Multi-Selectmedium

Which THREE actions can be performed using the AWS CLI for Amazon Aurora? (Choose three.)

Select 3 answers

A.Create a DB cluster from a snapshot using 'aws rds restore-db-cluster-from-snapshot'

B.Fail over an Aurora DB cluster using 'aws rds failover-db-cluster'

C.Modify the DB cluster parameter group using 'aws rds modify-db-cluster-parameter-group'

D.Change the storage type of an Aurora cluster using 'aws rds modify-db-instance'

E.Enable auto-scaling for Aurora Replicas using 'aws rds enable-autoscaling'

AnswersA, B, C

Valid CLI command.

Why this answer

All three are valid AWS CLI actions for Aurora. RestoreDBClusterFromS3 is for MySQL, but it exists.

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697

Multi-Selectmedium

A company is migrating a large on-premises Oracle database to Amazon RDS for Oracle. The database is 5 TB in size, and the migration must be completed within a week. The company has a dedicated 10 Gbps AWS Direct Connect connection. Which TWO AWS services should the company use to minimize downtime during the migration?

Select 2 answers

A.AWS Schema Conversion Tool (AWS SCT)

B.AWS DataSync

C.AWS Snowball

D.AWS Database Migration Service (AWS DMS)

E.Amazon RDS for Oracle

AnswersA, D

SCT can convert the Oracle schema to Amazon RDS for Oracle compatible schema, if needed.

Why this answer

AWS DMS can handle ongoing replication to minimize downtime. AWS SCT can convert the schema if needed, and AWS DMS can migrate data. AWS Snowball is for offline data transfer, which may not be needed with Direct Connect.

RDS is the target, not a migration service. AWS DataSync is for file data, not databases. The correct options are A and D.

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698

MCQeasy

A company uses Amazon DynamoDB and notices that some queries are taking longer than expected. The table has a partition key only. The 'ConsumedReadCapacityUnits' is below the provisioned throughput. What is the most likely cause of the slow queries?

A.DAX is misconfigured and slowing down reads

B.Global tables replication is causing delays

C.DynamoDB Streams is enabled and consuming read capacity

D.The partition key is not distributed evenly, causing hot partitions

AnswerD

A hot partition can throttle requests even if overall capacity is underused.

Why this answer

If the partition key is not chosen well, data can be skewed, causing hot partitions. Even if total consumed capacity is below provisioned, a single partition may receive more requests than its share of capacity, causing throttling on that partition, which slows queries. Option A is wrong because DAX is a caching layer that speeds up reads, not slows them.

Option B is wrong because global tables replication does not affect read latency on the source table. Option C is wrong because DynamoDB Streams do not consume read capacity for reads from the table; they use separate capacity.

Full explanation →

699

MCQmedium

A company's security team wants to encrypt data at rest for an existing RDS for PostgreSQL DB instance. The instance is currently unencrypted. Which steps should the team take to enable encryption with minimal downtime?

A.Modify the DB instance and enable encryption in the RDS console.

B.Create a read replica of the DB instance and promote it to a standalone instance.

C.Create a new option group with encryption enabled and associate it with the DB instance.

D.Take a snapshot of the DB instance, copy the snapshot with encryption enabled, and restore a new DB instance from the encrypted snapshot.

AnswerD

This is the standard method to encrypt an existing unencrypted RDS instance.

Why this answer

Amazon RDS does not support enabling encryption directly on an existing unencrypted DB instance. The only supported method is to take a snapshot of the instance, copy the snapshot with encryption enabled, and restore a new DB instance from the encrypted snapshot. Option A is incorrect because the RDS console does not allow enabling encryption on an existing instance.

Option B is incorrect because a read replica of an unencrypted instance is also unencrypted; promoting it does not add encryption. Option C is incorrect because option groups control database engine configuration, not encryption at rest. Encryption at rest is a storage-level feature that can only be enabled during instance creation or via snapshot operations.

Full explanation →

700

MCQhard

A company uses Amazon Aurora MySQL-Compatible Edition for its e-commerce platform. During flash sales, the database experiences high write contention on the 'orders' table, causing slow inserts and deadlocks. The development team wants to reduce contention without changing the application code. Which database design strategy is MOST effective?

A.Implement manual sharding across multiple Aurora clusters

B.Add more read replicas to offload read traffic

C.Use a larger instance type with higher IOPS

D.Enable Aurora Multi-Master to allow multiple write nodes

AnswerD

Multi-Master allows concurrent writes, reducing contention.

Why this answer

Aurora Multi-Master enables multiple writer nodes to accept write operations concurrently, which directly reduces write contention on the 'orders' table during high-volume flash sales. Unlike single-master Aurora, Multi-Master allows each writer to handle inserts independently, minimizing deadlocks and improving throughput without requiring application code changes.

Exam trap

The trap here is that candidates often assume scaling up the instance type (Option C) or adding read replicas (Option B) will solve write contention, but they fail to recognize that only a multi-writer architecture directly addresses the bottleneck of a single writer node.

How to eliminate wrong answers

Option A is wrong because manual sharding across multiple Aurora clusters requires significant application code changes to route queries, which violates the constraint of not changing application code. Option B is wrong because adding read replicas only offloads read traffic and does nothing to reduce write contention or deadlocks on the primary writer. Option C is wrong because using a larger instance type with higher IOPS can improve performance but does not address the fundamental issue of concurrent write contention; it still relies on a single writer node, which remains a bottleneck.

Full explanation →

701

MCQmedium

A company is experiencing slow query performance on an Amazon RDS for PostgreSQL DB instance. The DB instance is a db.r5.large with 16 GB RAM and 500 GB gp2 storage. Which metric in Amazon CloudWatch would most directly help identify if the performance issue is due to memory pressure?

A.Monitor FreeableMemory to see if available memory is low.

B.Monitor ReadIOPS to see if there is a high I/O rate due to swapping.

C.Monitor DatabaseConnections to check for a high number of connections consuming memory.

D.Monitor CPUUtilization to check for high CPU usage.

AnswerA

FreeableMemory directly indicates the amount of available RAM.

Why this answer

FreeableMemory shows the amount of available RAM. Low FreeableMemory indicates memory pressure, which can cause swapping and slow queries. Option B is wrong because ReadIOPS measures I/O operations, not memory.

Option C is wrong because DatabaseConnections tracks connections, not memory. Option D is wrong because CPUUtilization measures CPU, not memory.

Full explanation →

702

MCQmedium

A company uses Amazon RDS for MySQL and wants to ensure that database users are authenticated using IAM database authentication. Which action must be performed to enable this?

A.Create database users with MySQL native password authentication.

B.Attach an IAM role to the RDS instance for database authentication.

C.Change the database port to 3306 to enable IAM authentication.

D.Set the parameter 'require_secure_transport' to ON and use the AWSAuthenticationPlugin.

AnswerD

IAM auth requires SSL and the AWSAuthenticationPlugin.

Why this answer

IAM database authentication requires a specific parameter group setting (require_secure_transport=ON) and authentication plugin. Option A is wrong because native MySQL authentication is not IAM. Option B is wrong because IAM roles for RDS are for API access, not database authentication.

Option C is wrong because the standard MySQL port is 3306.

Full explanation →

703

MCQeasy

A company needs to store and query graph data (nodes and edges) for a social network. They require low-latency traversals. Which AWS database is best suited?

A.Amazon Neptune

B.Amazon RDS for MySQL

C.Amazon ElastiCache for Redis

D.Amazon DynamoDB

AnswerA

Purpose-built graph database for low-latency traversals.

Why this answer

Amazon Neptune is a fully managed graph database service optimized for storing and querying highly connected data, such as social network nodes and edges. It supports both property graph (Gremlin) and RDF (SPARQL) models, enabling low-latency traversals of complex relationships. This makes it the ideal choice for workloads requiring efficient graph queries over interconnected data.

Exam trap

The trap here is that candidates often choose DynamoDB or Redis because they associate NoSQL with flexibility for graph data, but they overlook the critical requirement for native graph traversal capabilities and low-latency multi-hop queries, which only a dedicated graph database like Neptune can provide.

How to eliminate wrong answers

Option B is wrong because Amazon RDS for MySQL is a relational database that uses SQL joins and indexes to model relationships, which becomes inefficient and slow for deep graph traversals as the number of connections grows. Option C is wrong because Amazon ElastiCache for Redis is an in-memory key-value store, not a graph database; while it can store adjacency lists, it lacks native graph query capabilities like Gremlin or SPARQL, and traversals require application-level logic. Option D is wrong because Amazon DynamoDB is a NoSQL key-value and document database that does not support graph-specific operations; modeling graph data in DynamoDB requires manual adjacency lists and results in high-latency multi-hop queries due to its lack of native graph traversal engines.

Full explanation →

704

MCQmedium

A company runs a production Amazon RDS for PostgreSQL database. The database specialist needs to perform a major version upgrade with minimal downtime. Which strategy should the specialist use?

A.Create a read replica with the new major version, promote it to primary, and update the application connection string.

B.Take a snapshot of the database, launch a new instance from the snapshot, and upgrade it.

C.Modify the DB instance to the new version directly using the AWS Management Console.

D.Schedule a maintenance window during off-peak hours and apply the upgrade.

AnswerA

This minimizes downtime by using a replica.

Why this answer

Creating a read replica with the new major version, promoting it to primary, and updating the application connection string minimizes downtime by allowing the replica to catch up with the source database before promotion. This approach avoids the prolonged unavailability associated with in-place upgrades, as the promotion process typically takes only a few seconds, and the application can be switched over with a simple connection string update.

Exam trap

The trap here is that candidates often assume in-place upgrades via maintenance windows or direct modification are sufficient for minimal downtime, but they fail to recognize that major version upgrades require significant offline time, whereas the read replica promotion strategy effectively decouples the upgrade process from the production workload.

How to eliminate wrong answers

Option B is wrong because taking a snapshot and launching a new instance from it requires restoring the snapshot, which can take hours for large databases, and then upgrading the new instance, resulting in significant downtime. Option C is wrong because modifying the DB instance directly to a new major version using the AWS Management Console triggers an in-place upgrade that requires the database to be offline for the duration of the upgrade process, which can be lengthy and cause unacceptable downtime. Option D is wrong because scheduling a maintenance window during off-peak hours still performs an in-place major version upgrade, which requires the database to be offline and does not reduce downtime compared to the read replica promotion method.

Full explanation →

705

MCQeasy

A startup is building a real-time leaderboard for a gaming application. The data is highly dynamic with frequent updates and requires single-digit millisecond latency. Which database is most suitable?

A.Amazon Neptune

B.Amazon Redshift

C.Amazon DynamoDB

D.Amazon RDS for PostgreSQL

AnswerC

DynamoDB offers consistent single-digit millisecond performance, ideal for real-time leaderboards.

Why this answer

Amazon DynamoDB is the most suitable choice because it is a fully managed NoSQL key-value and document database that delivers single-digit millisecond latency at any scale, making it ideal for real-time leaderboards with high-frequency updates. Its DAX (DynamoDB Accelerator) caching layer can further reduce read latency to microseconds, while its auto-scaling and on-demand capacity modes handle the highly dynamic workload without downtime.

Exam trap

The DBS-C01 exam often tests the misconception that a relational database like PostgreSQL is inherently faster for all real-time workloads, but the trap here is that the question explicitly requires 'single-digit millisecond latency' and 'highly dynamic with frequent updates'—characteristics that DynamoDB's NoSQL architecture is specifically designed to meet, whereas RDS for PostgreSQL would introduce latency from locking, indexing overhead, and connection pooling that prevents it from consistently achieving that performance under high write loads.

How to eliminate wrong answers

Option A is wrong because Amazon Neptune is a graph database optimized for highly connected data (e.g., social networks, fraud detection), not for high-throughput, low-latency key-value access patterns required by a real-time leaderboard. Option B is wrong because Amazon Redshift is a petabyte-scale data warehouse designed for complex analytical queries on large datasets, not for single-digit millisecond transactional updates or real-time point lookups. Option D is wrong because Amazon RDS for PostgreSQL is a relational database that, while capable, introduces overhead from ACID transactions, indexing, and connection management that typically results in higher latency (often 5–20 ms or more) compared to DynamoDB's optimized NoSQL engine, and it does not natively support the auto-scaling or DAX caching needed for such a dynamic workload.

Full explanation →

706

MCQmedium

A company is using Amazon RDS for MySQL and needs to encrypt data at rest for an existing DB instance. Which approach meets this requirement with minimal downtime?

A.Take a snapshot of the DB instance, copy the snapshot with encryption enabled, and restore from the encrypted snapshot.

B.Enable encryption directly on the existing DB instance by modifying it.

C.Use the AWS CLI command modify-db-instance with the --storage-encrypted flag.

D.Create a read replica of the DB instance with encryption enabled, then promote it.

AnswerA

This is the standard method to encrypt an existing RDS instance with minimal downtime.

Why this answer

To encrypt an existing unencrypted RDS MySQL DB instance, you cannot directly modify the instance. The standard approach is to take a snapshot, create an encrypted copy of the snapshot, and then restore that encrypted snapshot to a new DB instance. This method typically involves minimal downtime compared to other options.

Option A correctly describes this process. Option B is incorrect because encryption cannot be enabled directly on an existing instance. Option C is incorrect because the AWS CLI modify-db-instance command does not support enabling encryption on an existing instance; the --storage-encrypted flag only applies to new instances.

Option D is incorrect because creating a read replica with encryption does not encrypt the primary instance; you would still need to perform a snapshot restore for the primary's encryption.

Full explanation →

707

Drag & Dropmedium

Arrange the steps to create an Amazon DynamoDB global table (multi-Region) in the correct order.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

Why this order

Global tables require streams enabled, then adding replicas in other Regions for multi-Region replication.

Full explanation →

708

MCQhard

A company is running an Amazon DynamoDB table with global secondary indexes (GSIs). Write activity increases, and the 'ThrottledWriteEvents' metric for a GSI spikes. The table itself is not throttled. What is the most likely cause?

A.The index is too large for the base table.

B.The GSI's partition key is not sufficiently distributed.

C.The table's write capacity is set too low.

D.The GSI's read capacity is set too low.

AnswerB

A skewed partition key causes hot partitions on the GSI, leading to write throttling.

Why this answer

Write sharding on the GSI partition key can cause hot partitions. Option A is wrong because read capacity on the GSI does not affect writes. Option C is wrong because write capacity on the table is separate from GSI.

Option D is wrong because the issue is about throttling on GSI, not table.

Full explanation →

709

Multi-Selecthard

A company is migrating a 3 TB SQL Server database to Amazon RDS for SQL Server. The migration must have minimal downtime and support point-in-time recovery after migration. Which THREE steps should be included in the migration plan? (Choose three.)

Select 3 answers

A.Take a snapshot backup of the source database.

B.Take a differential backup.

C.Take a full backup of the source database.

D.Use AWS DMS for ongoing replication after initial restore.

E.Take transaction log backups.

AnswersC, D, E

Required for initial restore.

Why this answer

A full backup is the foundational step for any SQL Server migration to Amazon RDS. It captures the complete database state at a point in time, which is required for the initial restore into RDS. Without a full backup, you cannot apply differential or transaction log backups to achieve minimal downtime and point-in-time recovery.

Exam trap

The trap here is that candidates confuse snapshot backups (which are not supported for native restore in RDS) with full backups, or think a differential backup can be used as the initial restore point without a preceding full backup.

Full explanation →

710

MCQhard

A company is using AWS Database Migration Service (AWS DMS) to migrate a 5 TB MySQL database to Amazon RDS for MySQL. The migration is taking longer than expected. The company notices that the source database has a high volume of write operations. Which configuration change would MOST likely improve the migration performance?

A.Increase the number of parallel threads in the DMS task settings.

B.Enable Multi-AZ on the target RDS instance.

C.Use a smaller instance class for the replication instance to reduce cost.

D.Set the LOB mode to 'Full LOB mode'.

AnswerA

Parallel threads allow concurrent loading of data, improving throughput for high-write workloads.

Why this answer

Increasing the number of parallel threads in the DMS task settings allows AWS DMS to process multiple table partitions or row changes concurrently, which directly addresses the bottleneck caused by a high volume of write operations on the source. By default, DMS uses a single thread per table, but when the source is under heavy write load, parallel threads can capture and apply changes more efficiently, reducing the overall migration time.

Exam trap

The trap here is that candidates often confuse increasing parallelism with enabling Multi-AZ or changing LOB settings, mistakenly thinking these options directly speed up migration, when in fact they address availability or data type handling, not throughput under heavy write load.

How to eliminate wrong answers

Option B is wrong because enabling Multi-AZ on the target RDS instance provides high availability and automatic failover, but does not improve the throughput or speed of the DMS migration process. Option C is wrong because using a smaller instance class for the replication instance would reduce CPU and memory resources, likely worsening migration performance, not improving it. Option D is wrong because setting LOB mode to 'Full LOB mode' is used for handling large objects (LOBs) and can actually slow down migration due to increased data transfer overhead; it does not address the high volume of write operations.

Full explanation →

711

Multi-Selecteasy

Which TWO of the following are benefits of using Amazon RDS Proxy? (Choose TWO.)

Select 2 answers

A.Reduces the number of database connections by pooling them.

B.Automatically encrypts all traffic between the application and the database.

C.Improves application scalability by handling connection surges.

D.Provides built-in read/write splitting for read replicas.

E.Reduces storage costs by compressing data in transit.

AnswersA, C

Connection pooling reduces the number of open connections.

Why this answer

Amazon RDS Proxy acts as a connection broker between your application and the database, maintaining a pool of established connections. When the application opens a new connection, RDS Proxy reuses an idle connection from the pool, which reduces the total number of database connections and prevents the database from being overwhelmed. This pooling mechanism directly addresses the issue of connection exhaustion, especially in serverless or highly concurrent environments.

Exam trap

The trap here is that candidates often confuse RDS Proxy's connection pooling with other features like encryption, read/write splitting, or compression, which are separate capabilities not provided by the proxy itself.

Full explanation →

712

MCQeasy

A database specialist needs to monitor the number of deadlocks occurring in an Amazon RDS for SQL Server DB instance. Which CloudWatch metric should be used?

A.BlockedTransactions

B.Deadlocks

C.DatabaseConnections

D.LockWaits

AnswerB

This is the correct metric for deadlocks.

Why this answer

The 'Deadlocks' metric in Amazon RDS for SQL Server specifically counts the number of deadlocks that occur on the DB instance. Option A is incorrect because 'BlockedTransactions' tracks transactions that are blocked, not deadlocks. Option C is incorrect because 'DatabaseConnections' is a count of active connections, not related to deadlocks.

Option D is incorrect because 'LockWaits' measures the number of lock waits, which is a different contention event.

Full explanation →

713

MCQmedium

A company has an Amazon DynamoDB table with on-demand capacity mode. The table experiences occasional spikes in traffic. During these spikes, some requests receive ProvisionedThroughputExceededException errors. The company wants to minimize these errors without changing the application. Which solution should be used?

A.Switch the table to provisioned capacity mode and enable auto scaling.

B.Enable DynamoDB Accelerator (DAX) for caching.

C.Increase the read and write capacity units manually.

D.Use DynamoDB global tables to distribute the load across multiple regions.

AnswerA

Provisioned capacity with auto scaling can handle burst traffic more effectively than on-demand in some cases.

Why this answer

DynamoDB on-demand mode automatically scales based on traffic volume, but it has a per-partition throughput limit. During sudden traffic spikes, this limit can be exceeded, causing ProvisionedThroughputExceededException errors. Switching to provisioned capacity mode with auto scaling allows you to set a higher baseline capacity and automatically scale up to handle bursts, reducing the likelihood of hitting per-partition limits.

Option B (DAX) only helps with read caching, not write throughput. Option C (manually increasing capacity) is not applicable in on-demand mode and would not auto-scale. Option D (global tables) replicates data across regions for disaster recovery, not for increasing throughput in a single region.

Full explanation →

714

MCQeasy

A developer is checking the encryption status of an RDS MySQL instance. The CLI output shows StorageEncrypted is true. What does this indicate?

A.Connections to the database are encrypted in transit.

B.The database is encrypted using the AWS managed key for RDS.

C.The database does not have encryption at rest enabled.

D.The database is encrypted at rest using a KMS key.

AnswerD

StorageEncrypted true confirms at-rest encryption.

Why this answer

When StorageEncrypted is true, it indicates that the RDS MySQL instance is encrypted at rest using a KMS key. Option A is incorrect because StorageEncrypted does not relate to encryption in transit. Option B is incorrect because it can be either AWS managed or customer managed KMS key.

Option C is incorrect because StorageEncrypted: true means encryption at rest is enabled.

Full explanation →

715

MCQmedium

A company is migrating a 500 GB on-premises Oracle database to Amazon RDS for Oracle. The migration must have minimal downtime. Which AWS service should be used for the initial data load and ongoing replication?

A.AWS Snowball Edge for offline data transfer

B.AWS Database Migration Service (AWS DMS)

C.Amazon S3 to store backup files and restore

D.AWS DataSync

AnswerB

DMS supports full load and CDC replication for minimal downtime.

Why this answer

AWS Database Migration Service (AWS DMS) is the correct choice because it supports both full-load migration of the initial 500 GB Oracle database and ongoing change data capture (CDC) replication to keep the target RDS for Oracle instance synchronized with minimal downtime. DMS uses Oracle LogMiner or binary reader to capture changes from the source redo logs and apply them continuously, enabling a near-zero downtime migration.

Exam trap

The trap here is that candidates often confuse AWS DataSync or Snowball Edge as viable for database migrations with minimal downtime, but neither supports the continuous change capture required for live replication, which is the core requirement of the question.

How to eliminate wrong answers

Option A is wrong because AWS Snowball Edge is an offline data transfer device designed for moving large volumes of data physically, but it cannot perform ongoing replication or CDC, so it would not achieve minimal downtime for a live database migration. Option C is wrong because storing backup files in Amazon S3 and restoring them to RDS for Oracle is a one-time, offline method that does not support ongoing replication; any changes made after the backup would be lost, causing significant downtime. Option D is wrong because AWS DataSync is optimized for moving large datasets over the network between on-premises storage and AWS, but it does not support database-specific CDC or schema conversion, making it unsuitable for live database replication with minimal downtime.

Full explanation →

716

MCQeasy

A financial services company is migrating its Oracle database to Amazon Aurora PostgreSQL. The database runs a critical batch processing job every night that updates millions of rows. The company needs the migration to minimize downtime and ensure data integrity. Which AWS service should the database specialist use to perform the migration?

A.AWS Database Migration Service (AWS DMS) with ongoing replication from Oracle to Aurora PostgreSQL

B.AWS Data Pipeline to export data from Oracle and import into Aurora PostgreSQL

C.AWS Schema Conversion Tool (AWS SCT) to convert the schema and then use native PostgreSQL tools to migrate data

D.AWS Glue to extract data from Oracle and load into Aurora PostgreSQL

AnswerA

AWS DMS can perform a one-time migration and then use ongoing replication to keep the target in sync with the source, minimizing downtime.

Why this answer

AWS DMS with ongoing replication (change data capture, CDC) is the correct choice because it enables a near-zero-downtime migration by continuously replicating changes from the source Oracle database to the target Aurora PostgreSQL while the source remains fully operational. After the initial full load, DMS applies ongoing transactions, allowing you to cut over with minimal interruption. This directly addresses the requirement to minimize downtime for the nightly batch job and ensures data integrity through transactional consistency.

Exam trap

The trap here is that candidates often confuse AWS DMS with ETL tools like Glue or Data Pipeline, assuming any data movement service can handle live migrations, but only DMS provides the transactional consistency and CDC required for near-zero-downtime database migrations.

How to eliminate wrong answers

Option B is wrong because AWS Data Pipeline is a workflow orchestration service, not a database migration tool; it lacks built-in CDC capabilities and would require manual scripting to handle ongoing replication, leading to significant downtime. Option C is wrong because AWS SCT only converts the schema and code, not the data; using native PostgreSQL tools for data migration would require the source database to be offline or heavily throttled, causing unacceptable downtime for the nightly batch job. Option D is wrong because AWS Glue is an ETL service designed for data transformation and analytics, not for transactional database migrations; it does not support ongoing replication (CDC) and would require the source to be quiesced, breaking the requirement for minimal downtime.

Full explanation →

717

MCQmedium

A company is building a real-time chat application using Amazon DynamoDB. Each message has a conversation ID, timestamp, sender, and content. The primary access pattern is to retrieve the most recent 50 messages for a given conversation, ordered by timestamp. Which table design minimizes cost and latency?

A.Use a composite primary key of conversation ID and message ID, and enable DynamoDB Streams to process messages.

B.Use DynamoDB Accelerator (DAX) to cache the most recent messages.

C.Use conversation ID as partition key and timestamp as sort key; query with ScanIndexForward=false and Limit=50.

D.Use conversation ID as partition key and a GSI on timestamp.

AnswerC

Directly supports the access pattern without additional indexes.

Why this answer

Using conversation ID as the partition key and timestamp as the sort key allows a single Query operation with ScanIndexForward=false to retrieve items in reverse chronological order, and Limit=50 ensures only the most recent 50 messages are returned. This design minimizes cost by avoiding full table scans or additional indexes, and minimizes latency by leveraging DynamoDB's native sort key ordering without needing external caching or streams.

Exam trap

The trap here is that candidates may over-engineer the solution by adding unnecessary components like DAX or GSIs, when DynamoDB's native sort key and query parameters directly solve the access pattern with minimal cost and latency.

How to eliminate wrong answers

Option A is wrong because enabling DynamoDB Streams adds cost and complexity without addressing the access pattern; streams are for change data capture, not for efficient querying of recent messages. Option B is wrong because DAX is an in-memory cache that reduces read latency but adds cost and complexity; the primary access pattern can be efficiently served directly from DynamoDB without caching, making DAX unnecessary and more expensive. Option D is wrong because using a GSI on timestamp introduces additional storage and write costs, and the query still requires a ScanIndexForward=false with Limit=50 on the GSI, which is redundant since the base table's sort key already supports the same pattern more efficiently.

Full explanation →

718

MCQhard

A financial services company uses Amazon Aurora MySQL-Compatible Edition for transaction processing. They need to run complex analytical queries on the same data without impacting transactional performance. Which solution meets these requirements?

A.Use Aurora Zero-ETL integration with Amazon Redshift

B.Enable Performance Insights and use RDS Proxy

C.Export data to Amazon S3 and query with Athena

D.Create an Aurora Replica and run analytical queries against it

AnswerA

Zero-ETL integration allows Redshift to query Aurora data directly without impacting performance.

Why this answer

Aurora Zero-ETL integration with Amazon Redshift allows you to run complex analytical queries on transactional data without impacting Aurora's performance. It eliminates the need for extract, transform, and load (ETL) pipelines by automatically replicating data from Aurora to Redshift in near real-time, ensuring that analytical workloads are offloaded to a separate, optimized analytics engine.

Exam trap

The trap here is that candidates often assume an Aurora Replica (Option D) is sufficient for read-heavy analytics, but they overlook that it still shares the same storage subsystem and can cause I/O contention and replication lag under heavy analytical loads.

How to eliminate wrong answers

Option B is wrong because Performance Insights and RDS Proxy are designed for monitoring and connection management, not for offloading analytical queries; they do not prevent analytical workloads from consuming Aurora's compute and I/O resources. Option C is wrong because exporting data to S3 and querying with Athena introduces latency and manual ETL steps, and Athena is optimized for ad-hoc querying of data lakes, not for continuous, complex analytical queries on live transactional data. Option D is wrong because an Aurora Replica shares the same underlying storage and can still impact the primary instance's performance during heavy analytical queries, as it competes for storage I/O and can cause replication lag.

Full explanation →

719

MCQhard

A company is deploying a global application that requires a database with sub-millisecond read latency across multiple regions. Which AWS database service should they use?

A.Amazon ElastiCache for Redis

B.Amazon Aurora Global Database

C.Amazon DynamoDB Global Tables

D.Amazon RDS for MySQL with cross-region Read Replicas

AnswerC

Provides sub-millisecond latency with multi-region active-active replication.

Why this answer

Amazon DynamoDB Global Tables provides a fully managed, multi-Region, multi-active database that delivers single-digit millisecond read and write latency anywhere in the world. It replicates data across AWS Regions automatically, ensuring sub-millisecond read latency by serving reads from the local Region. This makes it the ideal choice for a global application requiring low-latency reads across multiple regions.

Exam trap

The trap here is that candidates often confuse Amazon Aurora Global Database's cross-region read replicas with true multi-region active-active capability, but Aurora Global Database still requires a single primary Region for writes and can experience replication lag, making it unsuitable for sub-millisecond read latency across all regions.

How to eliminate wrong answers

Option A is wrong because Amazon ElastiCache for Redis is an in-memory cache, not a durable database, and it does not natively provide cross-region replication or global active-active capabilities for persistent storage. Option B is wrong because Amazon Aurora Global Database is designed for cross-region replication but typically has a primary Region for writes and secondary Regions for reads, which can introduce replication lag (often 1 second or more) and does not guarantee sub-millisecond read latency from all Regions simultaneously. Option D is wrong because Amazon RDS for MySQL with cross-region Read Replicas is asynchronous and can have replication lag of seconds or more, and it does not provide sub-millisecond read latency across multiple regions due to the latency of cross-region data transfer.

Full explanation →

720

MCQeasy

A company is designing a database for an IoT application that ingests millions of small sensor readings per second. The data is time-series and queries are mostly range scans over time. The company needs a cost-effective solution with high write throughput. Which AWS service should the database specialist recommend?

A.Amazon Redshift with auto-ingest

B.Amazon Timestream

C.Amazon RDS for PostgreSQL with pg_partman extension

D.Amazon DynamoDB with time-series data modeling

AnswerB

Timestream is a serverless time-series database optimized for IoT data.

Why this answer

Amazon Timestream is a purpose-built time-series database designed for IoT and operational applications that ingest millions of data points per second. It automatically manages storage tiers (in-memory and magnetic) to optimize cost, and its query engine is optimized for range scans over time, making it the most cost-effective and high-throughput choice for this workload.

Exam trap

The trap here is that candidates often default to DynamoDB for high-throughput workloads without recognizing that Timestream is the only AWS service purpose-built for time-series data, offering automatic tiering and optimized time-range queries that DynamoDB cannot match without complex custom sharding and indexing.

How to eliminate wrong answers

Option A is wrong because Amazon Redshift is a columnar data warehouse optimized for complex analytical queries on large datasets, not for high-velocity, high-volume time-series ingestion; its auto-ingest feature cannot handle millions of writes per second without significant cost and latency. Option C is wrong because Amazon RDS for PostgreSQL with pg_partman is a relational database that, even with partitioning, cannot sustain millions of writes per second due to single-writer limitations and transaction overhead, and it lacks the specialized storage tiering for time-series data. Option D is wrong because while DynamoDB can be modeled for time-series data, it is not purpose-built for time-series workloads; it requires manual partitioning and TTL management, and its query model is less efficient for range scans over time compared to Timestream's native time-based indexing.

Full explanation →

721

MCQhard

A company is designing a security strategy for an Amazon Aurora MySQL database. They need to ensure that database activity is monitored for suspicious behavior and that alerts are sent when anomalies are detected. Which AWS services should be combined to achieve this? (Select TWO.)

A.Amazon GuardDuty

B.Amazon RDS Database Activity Streams

C.AWS WAF

D.Amazon EventBridge

E.Amazon Inspector

AnswerA, B

Amazon GuardDuty is a threat detection service that monitors for suspicious activity and anomalous behavior across AWS workloads, including Aurora database activity when integrated with Database Activity Streams.

Why this answer

Options A and B are correct. Amazon GuardDuty (A) is a threat detection service that monitors for suspicious activity and anomalous behavior. Amazon RDS Database Activity Streams (B) provide a near-real-time stream of database activity, which can be integrated with GuardDuty for monitoring.

Option C (AWS WAF) is a web application firewall, not for database activity monitoring. Option D (Amazon EventBridge) is an event bus service that can trigger alerts but does not itself detect anomalies. Option E (Amazon Inspector) is for vulnerability assessment on EC2 instances.

Full explanation →

722

MCQmedium

A company is running an Amazon RDS for MySQL Multi-AZ DB instance. They notice increased latency during peak hours. The DB instance type is db.r5.large, and the storage is General Purpose SSD (gp2) with 500 GB. The application is read-heavy with frequent SELECT queries. Which action would most likely resolve the latency issue without changing the DB instance class?

A.Enable Performance Insights and analyze queries.

B.Create an Amazon RDS read replica in the same region.

C.Enable Multi-AZ on the existing DB instance.

D.Increase the allocated storage to 1,000 GB.

AnswerB

Adding a read replica offloads read traffic from the primary instance, reducing latency.

Why this answer

Adding a read replica offloads read traffic from the primary instance, reducing latency. Option A is wrong because enabling Performance Insights is for monitoring and analysis, not directly improving performance. Option C is wrong because Multi-AZ is for high availability, not read scaling.

Option D is wrong because increasing storage size may improve IOPS but does not directly address the read load.

Full explanation →

723

MCQmedium

A company uses Amazon DynamoDB with global tables. They notice that changes made in one region are not appearing in another region after several minutes. Which CloudWatch metric should be monitored to check the replication lag?

A.ConsumedWriteCapacityUnits

B.SuccessfulRequestLatency

C.ReplicationLatency

D.ThrottledRequests

AnswerC

ReplicationLatency directly measures the time between an update on the source table and its appearance on a replica, making it the correct metric to monitor replication lag.

Why this answer

ReplicationLatency measures the time between the last update on the source table and the last update on the replica table. Option A (ConsumedWriteCapacityUnits) is wrong because it measures write capacity usage, not replication lag. Option B (SuccessfulRequestLatency) is wrong because it measures request latency, not replication lag.

Option D (ThrottledRequests) is wrong because it indicates throttling, not replication lag.

Full explanation →

724

Multi-Selecthard

A company is using Amazon DynamoDB with auto scaling enabled. Despite auto scaling, the application is still experiencing throttling during traffic spikes. Which THREE actions should the company take to resolve this issue? (Choose THREE.)

Select 3 answers

A.Implement exponential backoff in the application code

B.Enable DynamoDB Accelerator (DAX) to cache read-heavy workloads

C.Use DynamoDB global tables to distribute write traffic across regions

D.Switch to on-demand capacity mode

E.Disable auto scaling and set fixed capacity

AnswersA, B, C

Exponential backoff helps retry throttled requests without overwhelming the system.

Why this answer

Exponential backoff (A) is a best practice to retry throttled requests gracefully, reducing retry storms. DAX (B) caches read-heavy workloads, reducing read capacity unit consumption and mitigating hot key issues. Global tables (C) distribute write traffic across multiple regions, alleviating write throttling.

Option D (on-demand capacity) could help but may be cost-prohibitive and does not address hot keys. Option E (disable auto scaling) would worsen throttling by fixing capacity. Therefore, A, B, and C are correct.

Full explanation →

725

Multi-Selectmedium

Which THREE measures can help protect an Amazon RDS database from a DDoS attack? (Choose 3.)

Select 3 answers

A.Place the RDS instance in a private subnet without direct internet access.

B.Use security groups to restrict inbound traffic to known IP addresses.

C.Make the RDS instance publicly accessible for easy monitoring.

D.Use AWS Shield Advanced.

E.Disable audit logging to reduce resource usage.

AnswersA, B, D

Reduces exposure to DDoS attacks.

Why this answer

Placing the RDS instance in a private subnet without direct internet access (Option A) prevents any external traffic from reaching the database endpoint, removing the attack surface entirely. Using security groups to restrict inbound traffic to known IP addresses (Option B) limits the sources that can initiate connections, reducing the potential for volumetric attacks. AWS Shield Advanced (Option D) provides additional DDoS mitigation capabilities, including detection and automatic application-layer protections.

These three measures work together to defend against different attack vectors.

Exam trap

The trap here is that candidates may think making an RDS instance publicly accessible is acceptable for monitoring purposes, but AWS best practices require all database access to go through a bastion host or VPN, and disabling audit logging is a common distractor that appears to reduce overhead but actually removes critical security visibility without any DDoS benefit.

Full explanation →

726

Multi-Selectmedium

A database administrator is troubleshooting a performance issue on an Amazon Aurora MySQL cluster. The application is experiencing high latency on write operations. Which TWO CloudWatch metrics should the administrator analyze to identify the root cause?

Select 2 answers

A.ReadLatency

B.DMLThroughput

C.CommitLatency

D.SelectLatency

E.FreeableMemory

AnswersB, C

DMLThroughput measures the rate of write operations (INSERT/UPDATE/DELETE) and helps identify if high throughput is causing contention.

Why this answer

The correct metrics to analyze for high write latency are DMLThroughput and CommitLatency. DMLThroughput measures the rate of Data Manipulation Language operations, including INSERT, UPDATE, and DELETE, which are write-intensive. High DMLThroughput may indicate excessive write operations.

CommitLatency measures the time taken to commit transactions; high commit latency directly contributes to write latency. The other options are not directly related to write performance.

Full explanation →

727

Multi-Selecteasy

A database team is troubleshooting a performance issue on an Amazon RDS for PostgreSQL instance. They notice that the 'DiskQueueDepth' metric is consistently high. Which TWO actions should the team take to resolve this issue? (Choose TWO.)

Select 2 answers

A.Increase the number of database connections.

B.Enable storage auto scaling.

C.Increase the provisioned IOPS for the instance.

D.Enable query caching in PostgreSQL.

E.Enable Multi-AZ deployment.

AnswersB, C

Auto scaling can increase throughput and reduce queue depth.

Why this answer

Options B and C are correct. A high disk queue depth indicates an I/O bottleneck on the RDS instance. Enabling storage auto scaling (B) allows the storage to automatically scale up when I/O demand increases, which can reduce queue depth.

Increasing provisioned IOPS (C) directly improves the I/O performance by providing more throughput. Option A is incorrect because increasing connections can increase I/O contention, not reduce it. Option D is incorrect because PostgreSQL does not support query caching in the same way as MySQL, and it is not a solution to an I/O bottleneck.

Option E is incorrect because Multi-AZ provides high availability but does not directly improve I/O performance.

Full explanation →

728

MCQmedium

A company is designing a database for an IoT application that receives millions of sensor readings per second. Each reading is a small JSON payload (timestamp, device_id, metric, value). The primary query pattern retrieves the most recent reading for a given device. Which AWS database service is BEST suited for this workload?

A.Amazon Aurora

B.Amazon DynamoDB

C.Amazon ElastiCache for Redis

D.Amazon RDS for MySQL

AnswerB

Handles high write throughput and supports efficient point queries with sort key.

Why this answer

Amazon DynamoDB is best suited because it is a fully managed NoSQL key-value database that delivers single-digit millisecond latency at any scale. The primary query pattern—retrieving the most recent reading for a given device—maps directly to a DynamoDB table with a composite primary key (device_id as partition key, timestamp as sort key) and a Query operation with ScanIndexForward=false and Limit=1. This design handles millions of writes per second with consistent performance, unlike relational databases that struggle with such high-velocity ingestion.

Exam trap

The trap here is that candidates often choose ElastiCache for Redis because they assume 'most recent reading' implies a caching solution, but the question specifies a database for the workload, and Redis lacks the durability and query flexibility (e.g., filtering by timestamp range) needed for a primary data store of sensor readings.

How to eliminate wrong answers

Option A is wrong because Amazon Aurora is a relational database optimized for OLTP workloads with moderate write throughput; it cannot sustain millions of writes per second without significant scaling challenges and incurs higher latency for simple key-value lookups. Option C is wrong because Amazon ElastiCache for Redis is an in-memory cache, not a durable database; while it can serve recent data quickly, it lacks the persistence, durability, and query capabilities (e.g., filtering by timestamp) required for a primary data store of sensor readings. Option D is wrong because Amazon RDS for MySQL is a relational database with limited write scalability and higher per-request overhead; it would require complex sharding and still struggle with the ingestion rate and the need for a simple, fast 'latest reading' query.

Full explanation →

729

MCQmedium

A company is migrating their on-premises Oracle database to Amazon RDS for Oracle. They need to ensure minimal downtime. During the migration, they observe that the change data capture (CDC) is falling behind. What is the most effective approach to catch up?

A.Disable supplemental logging on the source

B.Increase the instance size of the target RDS instance

C.Pause the CDC task and resume later

D.Stop the CDC and perform a full load migration

AnswerB

More CPU/memory can help the apply process catch up.

Why this answer

Increasing the instance size of the target RDS instance provides more CPU and memory resources for the CDC process, allowing it to process more changes per unit time and catch up on lag. Option A is incorrect because disabling supplemental logging on the source Oracle database would prevent the capture of necessary change data, breaking CDC entirely and preventing any catch-up. Option C is incorrect because pausing the CDC task would stop processing changes, allowing the lag to grow further, not catch up.

Option D is incorrect because stopping CDC and performing a full load migration would cause significant downtime, which contradicts the requirement for minimal downtime.

Full explanation →

730

Multi-Selectmedium

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?

Select 2 answers

A.Increase the read capacity units of the table.

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

C.Pre-create a DynamoDB global table to distribute write traffic.

D.Decrease the write capacity units to reduce throttling.

E.Implement DynamoDB Accelerator (DAX) to offload read traffic.

AnswersC, E

Global tables spread writes across regions, reducing throttling.

Why this answer

Options C and E are correct. Option C: Pre-creating a DynamoDB global table can distribute write traffic across multiple regions, reducing the load on any single table and helping to prevent throttling during traffic spikes. Option E: Implementing DynamoDB Accelerator (DAX) offloads read traffic from the main table, reducing read capacity consumption and potential throttling.

Option A is incorrect because on-demand mode does not use read capacity units; it scales automatically. Option B is incorrect because switching to provisioned capacity requires capacity planning and does not automatically prevent throttling. Option D is incorrect because decreasing write capacity would likely worsen throttling.

Full explanation →

731

MCQeasy

A company is building a social network application that needs to store user profiles, friend relationships, and a feed of posts. The feed queries are complex, involving graph traversals (e.g., friends of friends). Which database is best suited for the relationship data?

A.Amazon DynamoDB

B.Amazon RDS for MySQL

C.Amazon ElastiCache for Redis

D.Amazon Neptune

AnswerD

Neptune is a graph database purpose-built for traversing relationships.

Why this answer

Amazon Neptune is a fully managed graph database service optimized for storing and querying highly connected data. It supports both property graph and RDF models, and it uses graph traversal languages like Gremlin and SPARQL, making it ideal for complex friend-of-friend queries and social network relationship data.

Exam trap

The trap here is that candidates often choose DynamoDB for its scalability or RDS for its familiarity with JOINs, failing to recognize that graph databases are purpose-built for relationship-heavy workloads and that the exam specifically tests the ability to match database types to query patterns.

How to eliminate wrong answers

Option A is wrong because Amazon DynamoDB is a key-value and document database that does not natively support graph traversals; querying friends of friends would require multiple expensive client-side joins or scans. Option B is wrong because Amazon RDS for MySQL is a relational database that can model relationships with JOINs, but it suffers from performance degradation and complexity as the depth of graph traversals increases, lacking native graph traversal optimizations. Option C is wrong because Amazon ElastiCache for Redis is an in-memory data store primarily used for caching, session management, and simple data structures; while it can store adjacency lists, it does not provide a graph query language or support complex multi-hop traversals efficiently.

Full explanation →

732

Multi-Selecthard

Which THREE are valid methods to encrypt data at rest in Amazon DynamoDB? (Choose 3.)

Select 3 answers

A.Use a customer managed CMK.

B.Use S3 server-side encryption.

C.Use an AWS-owned CMK.

D.Use an AWS managed CMK.

E.Use client-side encryption with the DynamoDB Encryption Client.

AnswersA, C, D

Correct. Customer managed CMKs are fully supported for DynamoDB encryption at rest, providing control over key policies and rotation.

Why this answer

DynamoDB encryption at rest is implemented through AWS KMS, supporting three types of customer master keys (CMKs): AWS-owned CMKs (default), AWS managed CMKs, and customer managed CMKs. Option A is correct because customer managed CMKs are fully supported, allowing you to create, manage, and control key policies and rotation. Option C (AWS-owned) and D (AWS managed) are also correct.

Option E (client-side encryption with DynamoDB Encryption Client) is not an encryption-at-rest method provided by DynamoDB; it encrypts data before transmission, but data at rest is still encrypted by DynamoDB's server-side encryption. Option B is irrelevant as S3 server-side encryption does not apply to DynamoDB.

Exam trap

The trap is that candidates often assume client-side encryption counts as 'encryption at rest' for DynamoDB, but encryption at rest refers to server-side encryption by the service itself. Additionally, some may think customer managed CMKs are not supported, but they are.

Full explanation →

733

Multi-Selecteasy

Which TWO CloudWatch Logs features can be used to monitor and troubleshoot Amazon RDS for SQL Server error logs? (Choose TWO.)

Select 2 answers

A.Integrating with AWS X-Ray for trace analysis

B.Setting metric filters to count error occurrences

C.Exporting logs to Amazon S3

D.Using AWS CloudTrail to capture log events

E.Real-time monitoring of log streams

AnswersB, E

Setting metric filters on CloudWatch Logs allows you to count occurrences of specific error patterns, which is useful for monitoring and alerting.

Why this answer

The correct answers are B and E. CloudWatch Logs allows real-time monitoring of log streams (E) and setting metric filters to count specific error occurrences (B). Option A (AWS X-Ray) is for distributed tracing, not log monitoring.

Option C (exporting to S3) is for archival, not real-time monitoring. Option D (CloudTrail) captures API activity, not database error logs.

Full explanation →

734

Multi-Selecthard

A company is migrating an on-premises Oracle database to Amazon Aurora PostgreSQL. The migration must have minimal downtime and support ongoing replication. Which THREE services should the company use? (Choose 3.)

Select 3 answers

A.AWS Snowball Edge

B.Amazon Aurora PostgreSQL

C.AWS DataSync

D.AWS Database Migration Service (AWS DMS)

E.AWS Schema Conversion Tool (AWS SCT)

AnswersB, D, E

Target database for migration.

Why this answer

Amazon Aurora PostgreSQL (Option B) is the target database for the migration. The company is migrating from Oracle to Aurora PostgreSQL, so Aurora PostgreSQL is the required destination. AWS DMS (Option D) handles the ongoing replication with minimal downtime by using change data capture (CDC) to continuously replicate changes from the source Oracle database to the target Aurora PostgreSQL.

AWS SCT (Option E) is necessary to convert the Oracle database schema and any stored procedures, functions, and other code objects to be compatible with PostgreSQL, as the two databases have different SQL dialects and data types.

Exam trap

The trap here is that candidates often confuse AWS DataSync or Snowball Edge as viable options for database migration with ongoing replication, but these services are for file or bulk data transfer, not for continuous change data capture or schema conversion.

Full explanation →

735

MCQeasy

An administrator runs the above AWS CLI command to create an RDS MySQL instance. The command completes successfully. What is the status of the new DB instance immediately after the command returns?

A.available

B.stopped

C.deleting

D.creating

AnswerD

The instance enters 'creating' state until provisioning completes.

Why this answer

When you run the AWS CLI command to create an RDS MySQL instance, the command returns immediately after the API call is accepted and the instance enters the 'creating' state. The instance is not yet available because provisioning, configuring, and booting the database engine takes several minutes. The 'creating' status indicates that AWS is actively setting up the DB instance, and it will transition to 'available' only after the entire creation process completes.

Exam trap

The trap here is that candidates assume the CLI command's successful return means the instance is immediately usable, but AWS CLI commands for resource creation are asynchronous and return before the resource is fully operational.

How to eliminate wrong answers

Option A is wrong because 'available' is the final steady state after creation finishes, not the immediate status when the command returns. Option B is wrong because 'stopped' is a state that applies only to instances that have been explicitly stopped after being available; a newly created instance cannot be stopped. Option C is wrong because 'deleting' is a state that occurs when a deletion request is made, not during creation.

Full explanation →

736

Multi-Selecthard

A company is migrating a 5 TB Oracle database to Amazon RDS for Oracle. The database contains large BFILEs stored in a file system. The company needs to migrate the data with minimal downtime and ensure the BFILEs are migrated. Which THREE steps should the company take?

Select 3 answers

A.Replace BFILEs with BLOBs in the source database before migration.

B.Use AWS SCT to convert any incompatible schema objects.

C.Upload the BFILEs to Amazon S3 and use Oracle Directory objects to reference them.

D.Use AWS CloudEndure Migration to replicate the entire server.

E.Use AWS DMS with the Oracle source endpoint configured to include the BFILE directory path.

AnswersB, C, E

SCT helps convert Oracle-specific objects to RDS-compatible ones.

Why this answer

The correct steps for migrating a 5 TB Oracle database with BFILEs to Amazon RDS for Oracle with minimal downtime are: (B) Use AWS Schema Conversion Tool (SCT) to identify and convert incompatible schema objects, ensuring the target schema is ready. (C) Upload the BFILEs to Amazon S3 and use Oracle Directory objects to reference them in the target database, as BFILEs reference files stored outside the database. (E) Use AWS Database Migration Service (DMS) with the Oracle source endpoint configured to include the BFILE directory path, enabling DMS to migrate the BFILEs during the continuous replication phase, minimizing downtime. Option A (replacing BFILEs with BLOBs) is unnecessary because DMS handles BFILEs natively, and such a change would increase complexity and downtime. Option D (using CloudEndure Migration) is designed for server-level migration, not database-level, and would not be appropriate for this database migration.

Exam trap

The trap here is that candidates assume BFILEs must be converted to BLOBs before migration (Option A), but AWS DMS can handle BFILEs natively during the migration process, avoiding pre-migration schema changes and reducing downtime.

Full explanation →

737

MCQeasy

Refer to the exhibit. A DBA is checking the backup configuration of an RDS MySQL instance. The current time is 2023-03-15T06:00:00Z. What is the most recent point to which the database can be restored?

A.2023-03-15T03:00:00Z

B.2023-03-15T05:30:00Z

C.2023-03-15T04:30:00Z

D.2023-03-15T06:00:00Z

AnswerC

This is the latest restorable time shown.

Why this answer

The latest restorable time is 2023-03-15T04:30:00Z, which is within the backup window. Option A is incorrect because 2023-03-15T03:00:00Z is earlier than the latest restorable time, so it is not the most recent point. Option B is incorrect because 2023-03-15T05:30:00Z is later than the latest restorable time, so it is not within the backup window.

Option D is incorrect because although the backup window ends at 06:00, the latest restorable time is 04:30, not 06:00.

Full explanation →

738

Drag & Dropmedium

Arrange the steps to enable encryption at rest for an existing unencrypted Amazon RDS for MariaDB DB instance in the correct order.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps

Order

1Step 1

2Step 2

3Step 3

4Step 4

Why this order

Encryption at rest for an existing instance requires creating an encrypted snapshot and restoring it, then migrating applications.

Full explanation →

739

MCQeasy

A company wants to ensure that an Amazon RDS for MySQL DB instance is encrypted at rest. Which action should be taken to enable encryption for the first time?

A.Enable encryption on the existing DB instance using the AWS CLI.

B.Create a new encrypted DB instance using AWS KMS.

C.Set the rds.encrypted parameter to true in the DB parameter group.

D.Modify the existing DB instance and enable encryption.

AnswerB

This is correct. Encryption at rest for RDS must be enabled when the DB instance is created, using an AWS KMS key.

Why this answer

Encryption at rest for Amazon RDS can only be enabled when creating a new DB instance. To enable encryption for the first time, you must create a new encrypted DB instance using AWS KMS. Option A is incorrect because encryption cannot be enabled on an existing DB instance via the AWS CLI; it requires creating a new instance.

Option C is incorrect because there is no rds.encrypted parameter in a DB parameter group; encryption is set at instance creation, not via parameters. Option D is incorrect because modifying an existing DB instance does not allow enabling encryption; you must create a new encrypted instance.

Full explanation →

740

Multi-Selecthard

A company is migrating a 500 GB Oracle database to Amazon Aurora PostgreSQL. They need to convert the schema and migrate the data with minimal downtime. Which THREE actions should they take? (Choose three.)

Select 3 answers

A.Use AWS Schema Conversion Tool (SCT) to assess and convert Oracle-specific features like hierarchical queries.

B.Modify the application to use Aurora PostgreSQL-specific SQL syntax before migration.

C.Use AWS Database Migration Service (DMS) with change data capture (CDC) to migrate data.

D.Use AWS Schema Conversion Tool (SCT) to convert the Oracle schema to PostgreSQL-compatible schema.

E.Use AWS Snowball Edge to transfer the data to AWS and then load into Aurora.

AnswersA, C, D

SCT can convert Oracle-specific features to PostgreSQL equivalents.

Why this answer

AWS Schema Conversion Tool (SCT) is the correct tool for assessing and converting Oracle-specific features like hierarchical queries (e.g., CONNECT BY) into PostgreSQL-compatible syntax (e.g., recursive CTEs). This is essential for schema migration to Aurora PostgreSQL, and SCT provides a detailed assessment report to identify and automate conversion of such features.

Exam trap

The trap here is that candidates may think Snowball Edge is suitable for any database migration size, but for sub-10 TB databases with minimal downtime requirements, DMS with CDC is the correct approach, and Snowball is overkill and introduces latency.

Full explanation →

741

MCQeasy

A startup is building a social media analytics platform. The workload is write-heavy, with millions of events per day containing user actions (likes, shares, comments). The data model is simple: each event is a JSON document with a timestamp, user ID, and action type. Queries are primarily aggregations over time (e.g., count of likes per hour) and require low-latency responses for dashboards. The team wants to minimize operational overhead and cost. Which database service is most appropriate?

A.Amazon ElastiCache for Redis to store aggregated counts.

B.Amazon RDS for PostgreSQL with TimescaleDB extension.

C.Amazon Timestream, a purpose-built time-series database.

D.Amazon DynamoDB with global secondary indexes on timestamp and action type.

AnswerC

Timestream is designed for high write throughput and time-based aggregations.

Why this answer

Amazon Timestream is the most appropriate service because it is purpose-built for time-series data, supporting high write throughput and providing built-in aggregation functions for time-based queries. It is serverless, minimizing operational overhead and cost. Option A (ElastiCache) is a caching layer, not a durable database.

Option B (RDS with TimescaleDB) requires manual scaling and management, increasing overhead. Option D (DynamoDB) is optimized for key-value access, not efficient for time-series aggregations without additional processing and secondary indexes.

Full explanation →

742

MCQhard

A company is migrating its on-premises Oracle database to Amazon RDS for Oracle. The database contains sensitive data that must be encrypted at rest and in transit. The security team also requires that the encryption keys be rotated every year. The DBA has enabled encryption at rest using a customer-managed KMS key and SSL/TLS for in-transit encryption. What additional step is needed to meet the key rotation requirement?

A.Manually create a new KMS key every year and update the RDS instance to use the new key.

B.Configure the RDS option group to rotate the encryption key.

C.Use an AWS CloudHSM key and configure automatic rotation.

D.Enable automatic KMS key rotation for the customer-managed key.

AnswerD

KMS can rotate the key automatically every year.

Why this answer

Enable automatic KMS key rotation for the customer-managed key. AWS KMS supports automatic annual rotation of customer-managed keys, which meets the key rotation requirement without manual intervention. Option A is incorrect because manually creating a new key and updating the RDS instance each year is an unnecessary manual process when automatic rotation is available.

Option B is incorrect because RDS option groups do not control encryption key rotation; they are used for managing additional database features. Option C is incorrect because CloudHSM is not integrated with RDS for key management; KMS is the service used for RDS encryption at rest.

Full explanation →

743

MCQeasy

A company is migrating an on-premises MySQL database to Amazon RDS for MySQL. The database is 2 TB in size and the network bandwidth is 100 Mbps. The company needs to minimize downtime. Which migration strategy should be used?

A.Use AWS Database Migration Service (DMS) with ongoing replication.

B.Copy database files to Amazon S3, then restore to RDS using native restore.

C.Use mysqldump to export the database and import it into RDS.

D.Use AWS Server Migration Service to migrate the database server.

AnswerA

AWS DMS can perform a full load followed by continuous replication to keep the target in sync, minimizing downtime.

Why this answer

AWS DMS with ongoing replication is the correct strategy because it allows you to perform a full load of the 2 TB database while simultaneously capturing ongoing changes from the source MySQL binlog. This minimizes downtime by enabling a cutover with only a brief pause to ensure replication lag is zero, rather than requiring a long period of application downtime for a full export and import.

Exam trap

The trap here is that candidates often choose mysqldump (Option C) because it is a familiar tool, but they overlook the fact that for a 2 TB database over a 100 Mbps link, the export and import would take over 48 hours, causing excessive downtime, whereas DMS with ongoing replication allows near-zero downtime by performing the bulk load first and then syncing changes.

How to eliminate wrong answers

Option B is wrong because copying database files to Amazon S3 and restoring via native restore requires taking the source database offline to create a consistent file-level backup, which would cause significant downtime for a 2 TB database over a 100 Mbps link. Option C is wrong because using mysqldump to export and import the database would require the source database to be read-locked during the dump, and the export/import process over 100 Mbps would take many hours or days, resulting in unacceptable downtime. Option D is wrong because AWS Server Migration Service is designed for migrating entire server instances (VMs), not for migrating databases directly; it would replicate the entire OS and application stack, which is inefficient and does not provide the granular replication needed for a MySQL database migration.

Full explanation →

744

MCQmedium

A company uses Amazon RDS for PostgreSQL with Multi-AZ deployment. The security team wants to ensure that any access to the database is logged, including SELECT queries. What should be done to capture these logs?

A.Modify the DB parameter group to enable query logging and publish logs to Amazon CloudWatch Logs.

B.Enable automated backups and export logs to Amazon S3.

C.Enable RDS Performance Insights.

D.Enable RDS Enhanced Monitoring.

AnswerA

This captures query logs and stores them in CloudWatch.

Why this answer

Enabling RDS Enhanced Monitoring does not capture query logs. Enabling automatic backups does not log queries. Enabling RDS Performance Insights does not log queries.

To capture SELECT queries, you need to enable PostgreSQL query logging by setting the appropriate parameter group parameters (e.g., log_statement = 'all' or 'mod') and then export logs to CloudWatch Logs.

Full explanation →

745

MCQmedium

A company is building a mobile application that requires users to be able to query their order history quickly. The data is stored in Amazon DynamoDB, and each user has up to 10,000 orders over time. The application needs to support pagination and filtering by order date. What is the MOST efficient way to model this data in DynamoDB?

A.Scan the entire table and filter on user ID

B.Store all orders as a JSON document in a single item per user

C.Use user ID as the partition key and a Global Secondary Index on order date

D.Use user ID as the partition key and order date as the sort key

AnswerD

Allows range queries on order date and efficient pagination.

Why this answer

Using user ID as the partition key ensures all orders for a user are co-located on a single partition, enabling efficient queries. Adding order date as the sort key allows the application to filter and paginate by date range using the Query API with KeyConditionExpression, which is far more efficient than scanning or using a secondary index.

Exam trap

The trap here is that candidates often choose a Global Secondary Index (Option C) thinking it is necessary for date-based filtering, but the sort key on the base table is more efficient and avoids the cost and eventual consistency of a GSI when the partition key already isolates the user's data.

How to eliminate wrong answers

Option A is wrong because scanning the entire table and filtering on user ID would read every item in the table, consuming excessive read capacity and causing high latency, especially as the table grows. Option B is wrong because storing all orders as a JSON document in a single item per user would exceed DynamoDB's 400 KB item size limit when a user has up to 10,000 orders, and it prevents efficient filtering and pagination by order date. Option C is wrong because while a Global Secondary Index (GSI) on order date could support date-based queries, it would require a separate query to retrieve orders for a specific user and would not be as efficient as using the sort key on the base table, which avoids the eventual consistency and additional cost of a GSI.

Full explanation →

746

MCQmedium

A company is migrating a 2 TB PostgreSQL database from on-premises to Amazon RDS for PostgreSQL with minimal downtime. The database is continuously updated. Which migration strategy should be used?

A.Use AWS Database Migration Service (DMS) with ongoing replication from an on-premises source.

B.Use AWS Schema Conversion Tool (SCT) and AWS Snowball to transfer data.

C.Use AWS Database Migration Service with a full load only, then cut over.

D.Use pg_dump and pg_restore during a maintenance window.

AnswerA

DMS with change data capture (CDC) allows continuous replication with minimal downtime.

Why this answer

AWS DMS supports ongoing replication (change data capture, CDC) from an on-premises PostgreSQL source to Amazon RDS for PostgreSQL, enabling minimal downtime migration. The 2 TB size is well within DMS's capabilities, and CDC captures incremental changes after the full load, allowing near-zero downtime cutover.

Exam trap

The trap here is that candidates often assume pg_dump/pg_restore or full-load-only DMS are sufficient for minimal downtime, but they fail to account for the continuous updates that require ongoing replication to avoid data loss.

How to eliminate wrong answers

Option B is wrong because AWS SCT is a schema conversion tool, not a data migration tool, and AWS Snowball is designed for offline bulk data transfer, which cannot achieve minimal downtime for a continuously updated database. Option C is wrong because a full load only without ongoing replication would miss all changes made during the migration, requiring a separate cutover window and causing downtime. Option D is wrong because pg_dump and pg_restore require a maintenance window to ensure consistency, which contradicts the minimal downtime requirement.

Full explanation →

747

MCQhard

A company is migrating a self-hosted Cassandra cluster to Amazon Keyspaces (for Apache Cassandra). The cluster has 10 nodes and handles 50,000 writes per second. Which migration strategy is MOST efficient?

A.Set up Keyspaces as a new datacenter in the existing Cassandra cluster using native replication.

B.Export data using CQL COPY and import into Keyspaces.

C.Use AWS Glue to extract data from Cassandra and write to Keyspaces.

D.Use AWS DMS with Cassandra as source and Keyspaces as target.

AnswerA

Allows live migration with minimal downtime.

Why this answer

Setting up Amazon Keyspaces as a new datacenter in the existing Cassandra cluster using native replication allows for a live, zero-downtime migration. Cassandra's native replication protocol handles the 50,000 writes per second incrementally, automatically replicating data from the existing cluster to Keyspaces without requiring an export/import step or additional ETL tools.

Exam trap

The trap here is that candidates assume AWS DMS or Glue are universal migration tools, but they fail to recognize that Keyspaces supports the Cassandra wire protocol natively, making datacenter replication the most efficient and least disruptive method for high-throughput workloads.

How to eliminate wrong answers

Option B is wrong because CQL COPY is a batch export/import tool that requires stopping writes or handling consistency manually, and for 50,000 writes per second, it would cause significant downtime and data inconsistency. Option C is wrong because AWS Glue is an ETL service not optimized for real-time Cassandra replication; it would introduce latency and complexity, and cannot handle the continuous write load without custom checkpointing. Option D is wrong because AWS DMS does not support Amazon Keyspaces as a target endpoint; DMS is designed for relational and some NoSQL databases but not for Keyspaces, which uses the Cassandra Query Language (CQL) wire protocol.

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748

MCQeasy

A company runs a time-series application that records sensor data every second. The data volume is 500 GB per month and grows continuously. They need to query the last 30 days of data frequently and older data rarely. Which database design is MOST appropriate?

A.Amazon Timestream

B.Amazon RDS for PostgreSQL with partitioning

C.Amazon DynamoDB with TTL

D.Amazon S3 with Athena and partitioning

AnswerA

Timestream is purpose-built for time-series data with automatic tiering.

Why this answer

Amazon Timestream is purpose-built for time-series data, automatically storing recent data in memory for fast queries and moving older data to a cost-optimized store. This matches the workload of frequent queries on the last 30 days and rare queries on older data, with continuous growth at 500 GB/month.

Exam trap

The trap here is that candidates often choose DynamoDB with TTL because they associate TTL with data lifecycle management, but they overlook that DynamoDB lacks native time-series query capabilities and efficient range scans, making it a poor fit for frequent time-based queries.

How to eliminate wrong answers

Option B is wrong because Amazon RDS for PostgreSQL with partitioning requires manual management of partition maintenance, vacuuming, and scaling, and does not natively separate hot and cold storage tiers for time-series data, leading to higher operational overhead and cost for this volume. Option C is wrong because Amazon DynamoDB with TTL only handles data expiration, not efficient range scans or aggregation queries over time-series data; it lacks native time-based query optimization and can result in high read costs for scanning large time ranges. Option D is wrong because Amazon S3 with Athena and partitioning requires running a query engine that incurs per-scan costs and latency, making it unsuitable for frequent sub-second queries on the last 30 days of data, and it lacks a built-in hot/cold storage tier.

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749

MCQmedium

A company uses a self-hosted MySQL database on EC2. They want to migrate to Amazon RDS for MySQL with minimal downtime and automated failover. Which migration strategy should be used?

A.Set up MySQL replication from EC2 to RDS, then cut over

B.Use mysqldump to export the database and import to RDS

C.Take a snapshot of the EC2 instance and restore to RDS

D.Use AWS DMS with full load and CDC

AnswerA

Native replication allows minimal downtime and automated failover is built into RDS Multi-AZ.

Why this answer

Setting up MySQL native replication from the EC2-hosted MySQL database to an Amazon RDS for MySQL instance allows for near-zero downtime migration. Once replication is established and lag is minimal, you can simply stop writes on the source, verify replication has caught up, and redirect traffic to the RDS endpoint. This approach also supports automated failover by enabling Multi-AZ on the RDS instance, which provides a synchronous standby replica in a different Availability Zone.

Exam trap

The trap here is that candidates often assume AWS DMS is the only tool for minimal-downtime migrations, but native MySQL replication is simpler, more reliable, and directly supports automated failover when combined with Multi-AZ RDS, whereas DMS adds complexity and does not itself provide failover capabilities.

How to eliminate wrong answers

Option B is wrong because using mysqldump to export and import the database requires taking the source database offline or locking tables during the dump, which does not meet the minimal downtime requirement; it also does not provide automated failover. Option C is wrong because taking a snapshot of the EC2 instance and restoring it to RDS is not a supported migration path—RDS does not accept EC2 instance snapshots; you would need to extract the database files and use a tool like Percona XtraBackup or mysqldump instead. Option D is wrong because while AWS DMS with full load and CDC can achieve minimal downtime, it does not inherently provide automated failover for the target RDS instance; automated failover requires Multi-AZ configuration on RDS, which is independent of the migration tool used.

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750

MCQhard

A company is deploying a new application that uses Amazon RDS for MySQL. The database must be highly available with automatic failover. Which deployment configuration meets these requirements?

A.Single-AZ with a Read Replica in the same region

B.Multi-AZ deployment with synchronous replication to a cross-region replica

C.Multi-AZ deployment with a standby replica in a different Availability Zone

D.Single-AZ with automated backups

AnswerC

Multi-AZ provides automatic failover.

Why this answer

A Multi-AZ deployment for Amazon RDS for MySQL automatically provisions and maintains a synchronous standby replica in a different Availability Zone. In the event of a failure, Amazon RDS automatically fails over to the standby, providing high availability without manual intervention. This configuration meets the requirement for automatic failover and high availability within a single AWS region.

Exam trap

The trap here is that candidates often confuse Read Replicas (which are asynchronous and used for read scaling) with Multi-AZ standby replicas (which are synchronous and used for high availability), leading them to incorrectly select Option A as a valid high-availability solution.

How to eliminate wrong answers

Option A is wrong because a Single-AZ deployment with a Read Replica does not provide automatic failover; Read Replicas are asynchronous and require manual promotion to become the primary, which does not meet the high availability requirement. Option B is wrong because Multi-AZ deployment with synchronous replication to a cross-region replica is not a supported configuration; Amazon RDS Multi-AZ uses synchronous replication only within a single region across Availability Zones, and cross-region replication is asynchronous (using MySQL's built-in replication). Option D is wrong because a Single-AZ deployment with automated backups only provides point-in-time recovery, not automatic failover or high availability; if the primary instance fails, the database becomes unavailable until manual recovery is performed.

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