Sample questions
AWS Certified Database Specialty DBS-C01 practice questions
Match each AWS service to its primary purpose.
Drag a concept onto its matching description — or click a concept then click the description.
Relational database service with managed instances
NoSQL key-value and document database
In-memory caching service supporting Redis and Memcached
Petabyte-scale data warehouse
MongoDB-compatible document database
A company needs to migrate a 100 GB MongoDB database to Amazon DocumentDB (with MongoDB compatibility). The migration must have minimal impact on the source database performance. Which approach should the company take?
Trap 1: Use AWS DataSync to transfer the MongoDB data files.
AWS DataSync is for file-based data, not for live database migration.
Trap 2: Set up a MongoDB replica set on Amazon EC2 and promote it to…
This adds complexity and does not directly migrate to DocumentDB; it's an intermediate step.
Trap 3: Use mongodump to export the data and mongorestore to import into…
Mongodump can impact source performance and may require downtime if consistency is needed.
- A
Use AWS Database Migration Service (AWS DMS) with ongoing replication from the MongoDB source.
AWS DMS supports MongoDB as a source and can perform continuous replication with minimal impact.
- B
Use AWS DataSync to transfer the MongoDB data files.
Why wrong: AWS DataSync is for file-based data, not for live database migration.
- C
Set up a MongoDB replica set on Amazon EC2 and promote it to primary, then migrate to DocumentDB.
Why wrong: This adds complexity and does not directly migrate to DocumentDB; it's an intermediate step.
- D
Use mongodump to export the data and mongorestore to import into DocumentDB.
Why wrong: Mongodump can impact source performance and may require downtime if consistency is needed.
A company is designing a database for an IoT application that ingests sensor data from thousands of devices. Each device sends a reading every minute. The data includes device_id, timestamp, temperature, humidity, and pressure. The application needs to store this data and support queries that retrieve all readings for a specific device within a time range. The company expects high write throughput and moderate read frequency. The data must be stored with high durability. Which TWO database designs are appropriate for this workload? (Choose TWO.)
Trap 1: Use Amazon DynamoDB with device_id as partition key and store all…
The list would grow too large and exceed the 400 KB item limit.
Trap 2: Use Amazon S3 to store compressed JSON files per device per hour,…
This is not suitable for real-time queries and high write frequency.
Trap 3: Use Amazon RDS for MySQL with a single table and index on device_id…
A single RDS instance cannot scale to high write throughput from thousands of devices.
- A
Use Amazon DynamoDB with device_id as partition key and store all readings for a device as a list attribute in a single item, updating the list every minute.
Why wrong: The list would grow too large and exceed the 400 KB item limit.
- B
Use Amazon S3 to store compressed JSON files per device per hour, and query using Amazon Athena.
Why wrong: This is not suitable for real-time queries and high write frequency.
- C
Use Amazon DynamoDB with device_id as partition key and timestamp as sort key.
DynamoDB can handle high write throughput and efficient queries by device and time range.
- D
Use Amazon RDS for MySQL with a single table and index on device_id and timestamp.
Why wrong: A single RDS instance cannot scale to high write throughput from thousands of devices.
- E
Use Amazon Timestream, a time series database, with device_id as dimension and timestamp as time column.
Timestream is purpose-built for time series data and handles high write throughput.
Arrange the steps to troubleshoot a connection timeout issue from an EC2 instance to an Amazon RDS for SQL Server DB instance in the correct order.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Arrange the steps to configure a read replica for an Amazon RDS for PostgreSQL DB instance in a different AWS Region in the correct order.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Arrange the steps to perform a point-in-time recovery (PITR) for an Amazon RDS for MySQL DB instance in the correct order.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Arrange the steps to migrate an on-premises Oracle database to Amazon RDS for Oracle using AWS DMS (Database Migration Service) in the correct order.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Arrange the steps to restore an Amazon RDS for MySQL DB instance to a new instance from a manual snapshot in the correct order.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Arrange the steps to enable automated backups for an Amazon RDS for PostgreSQL DB instance in the correct order.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Arrange the steps to set up cross-Region read replicas for an Amazon Aurora MySQL DB cluster in the correct order.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
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.
Arrange the steps to switch over from a primary Amazon RDS for Oracle DB instance to a standby in a Multi-AZ deployment (planned failover) in the correct order.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
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.
A company is migrating a 500 GB on-premises PostgreSQL database to Amazon RDS for PostgreSQL. The migration must have minimal downtime and support ongoing replication after the initial load. Which AWS service should be used?
Trap 1: AWS Schema Conversion Tool (SCT)
SCT converts schema but does not handle data migration or replication.
Trap 2: AWS Database Migration Service (DMS) with full load only
Full load only causes downtime; CDC is needed for ongoing replication.
Trap 3: AWS Glue
Glue is for ETL, not live database migration with replication.
- A
AWS Schema Conversion Tool (SCT)
Why wrong: SCT converts schema but does not handle data migration or replication.
- B
AWS Database Migration Service (DMS) with full load only
Why wrong: Full load only causes downtime; CDC is needed for ongoing replication.
- C
AWS Database Migration Service (DMS) with ongoing replication
DMS supports full load plus CDC for minimal downtime.
- D
AWS Glue
Why wrong: Glue is for ETL, not live database migration with replication.
A team is migrating an on-premises database to Amazon RDS using AWS DMS. After the full load completed, the task stopped. The team needs to perform ongoing replication to minimize downtime. What change should the team make to the DMS task?
Trap 1: Restart the replication task with the same settings.
Restarting a full-load task will re-run the full load, not enable ongoing replication.
Trap 2: Create a new replication instance and start a new full-load task.
This does not enable ongoing replication; it's just a new full load.
Trap 3: Use AWS Schema Conversion Tool to convert the schema again.
Schema conversion is not related to replication type.
- A
Modify the replication task to change the migration type to 'full-load-and-cdc'.
Changing to 'full-load-and-cdc' enables both full load and ongoing change data capture replication.
- B
Restart the replication task with the same settings.
Why wrong: Restarting a full-load task will re-run the full load, not enable ongoing replication.
- C
Create a new replication instance and start a new full-load task.
Why wrong: This does not enable ongoing replication; it's just a new full load.
- D
Use AWS Schema Conversion Tool to convert the schema again.
Why wrong: Schema conversion is not related to replication type.
A company is migrating an on-premises MongoDB database to Amazon DocumentDB (with MongoDB compatibility). They want to validate that the data is consistent after migration. Which tool should they use?
Trap 1: mongoexport and mongoimport
These are for data transfer, not validation.
Trap 2: dbHash command on both databases
dbHash checks consistency of a single instance, not cross-database.
Trap 3: DocumentDB native consistency check tool
DocumentDB does not have a native consistency check tool for migration.
- A
mongoexport and mongoimport
Why wrong: These are for data transfer, not validation.
- B
dbHash command on both databases
Why wrong: dbHash checks consistency of a single instance, not cross-database.
- C
DocumentDB native consistency check tool
Why wrong: DocumentDB does not have a native consistency check tool for migration.
- D
AWS DMS data validation
DMS can validate data between source and target.
A team is using AWS DMS to migrate a 3 TB Oracle database to Amazon Aurora PostgreSQL. They configured the task as shown. After the full load completes, they notice that the target tables have no indexes, primary keys, or foreign keys. What is the most likely cause?
Exhibit
Refer to the exhibit.
-- AWS DMS Migration Task JSON excerpt:
{
"MigrationType": "full-load",
"TableMappings": {
"rules": [
{
"rule-type": "selection",
"rule-id": "1",
"rule-name": "1",
"object-locator": {
"schema-name": "%",
"table-name": "%"
},
"rule-action": "include"
}
]
},
"TargetTablePrepMode": "DROP_AND_CREATE"
}Trap 1: The migration task did not include transformation rules to create…
Transformation rules can add metadata but are not required; the issue is with the default behavior of DROP_AND_CREATE.
Trap 2: The table selection rule uses wildcards and excludes system tables,…
Table selection rules filter tables but do not affect index creation on included tables.
Trap 3: The task is using a full load without LOB support, which prevents…
LOB support does not affect index creation.
- A
The migration task did not include transformation rules to create indexes and constraints.
Why wrong: Transformation rules can add metadata but are not required; the issue is with the default behavior of DROP_AND_CREATE.
- B
The table selection rule uses wildcards and excludes system tables, which also excludes index definitions.
Why wrong: Table selection rules filter tables but do not affect index creation on included tables.
- C
The TargetTablePrepMode is set to DROP_AND_CREATE, which creates tables without indexes or constraints.
DROP_AND_CREATE mode creates target tables with only the column definitions, not indexes or constraints.
- D
The task is using a full load without LOB support, which prevents index creation.
Why wrong: LOB support does not affect index creation.
A company is migrating an on-premises Microsoft SQL Server database to Amazon RDS for SQL Server. The database uses SQL Server Agent jobs, custom CLR assemblies, and cross-database queries. Which of the following will require modification before migration?
Trap 1: Cross-database queries
Cross-database queries are supported.
Trap 2: Custom CLR assemblies
CLR assemblies are supported.
Trap 3: Stored procedures that use dynamic SQL
Dynamic SQL is supported.
- A
Cross-database queries
Why wrong: Cross-database queries are supported.
- B
Custom CLR assemblies
Why wrong: CLR assemblies are supported.
- C
Stored procedures that use dynamic SQL
Why wrong: Dynamic SQL is supported.
- D
SQL Server Agent jobs
SQL Server Agent is not available in RDS; jobs require alternative solutions.
A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB and has a high number of small transactions. The company needs to minimize downtime during the migration. Which TWO strategies should be used together? (Choose two.)
Trap 1: Use Oracle Data Pump to export the database and import into RDS.
Data Pump requires downtime during export/import and does not provide ongoing replication.
Trap 2: Set up a VPN connection between on-premises and AWS for direct…
A VPN provides connectivity but does not automate migration or reduce downtime.
Trap 3: Create a manual snapshot of the RDS instance during the migration.
Manual snapshots are for backup, not for migration from on-premises.
- A
Use Oracle Data Pump to export the database and import into RDS.
Why wrong: Data Pump requires downtime during export/import and does not provide ongoing replication.
- B
Set up a VPN connection between on-premises and AWS for direct database link.
Why wrong: A VPN provides connectivity but does not automate migration or reduce downtime.
- C
Create a manual snapshot of the RDS instance during the migration.
Why wrong: Manual snapshots are for backup, not for migration from on-premises.
- D
Use AWS Database Migration Service (DMS) to perform a full load and ongoing replication.
DMS can migrate data with minimal downtime by using continuous replication after the full load.
- E
Configure change data capture (CDC) on the source database and apply to RDS.
DMS supports CDC to capture ongoing changes and apply them to the target, minimizing downtime.
A company is running a production Amazon DynamoDB table with on-demand capacity. The table experiences occasional throttling during traffic spikes. The table's partition key is a timestamp, and the workload is write-heavy. The operations team needs to reduce throttling. Which THREE actions should the team take? (Choose three.)
Trap 1: Increase the read capacity units for the table.
The issue is write throttling, not read.
Trap 2: Enable DynamoDB global tables to distribute write traffic.
Global tables do not solve local partition hot spots.
- A
Add a random suffix to the partition key to distribute writes evenly.
This prevents hot partitions.
- B
Increase the read capacity units for the table.
Why wrong: The issue is write throttling, not read.
- C
Use DynamoDB Accelerator (DAX) to cache read-heavy queries.
Reducing read load frees capacity for writes.
- D
Switch to provisioned capacity mode with auto scaling.
Provisioned capacity with auto scaling can handle spikes better than on-demand.
- E
Enable DynamoDB global tables to distribute write traffic.
Why wrong: Global tables do not solve local partition hot spots.
A company is using Amazon RDS for MySQL and notices that database connections are being rejected intermittently. The application logs show 'Too many connections' errors. The DB instance has 1000 max_connections. Which action should the DBA take to troubleshoot and resolve this issue without impacting performance?
Trap 1: Increase the max_connections parameter to 5000 in the DB parameter…
Increasing max_connections can cause memory pressure and performance degradation.
Trap 2: Create a read replica to offload read traffic
Read replicas do not reduce the number of connections to the primary instance.
Trap 3: Set the 'wait_timeout' parameter to a lower value to close idle…
Reducing wait_timeout may cause active queries to be terminated prematurely.
- A
Increase the max_connections parameter to 5000 in the DB parameter group
Why wrong: Increasing max_connections can cause memory pressure and performance degradation.
- B
Create a read replica to offload read traffic
Why wrong: Read replicas do not reduce the number of connections to the primary instance.
- C
Enable Performance Insights and review the 'DB Connections' metric to identify spikes and troubleshoot application connection pooling
Performance Insights helps identify the source of connection bursts and allows tuning of the application's connection pooling behavior.
- D
Set the 'wait_timeout' parameter to a lower value to close idle connections faster
Why wrong: Reducing wait_timeout may cause active queries to be terminated prematurely.
A company is migrating its on-premises Oracle database to Amazon RDS for Oracle. The database specialist needs to monitor the migration process and ensure data consistency. Which TWO AWS services should be used together to continuously monitor the replication lag and data integrity?
Trap 1: Amazon RDS Performance Insights
Performance Insights is for database load analysis, not replication lag.
Trap 2: AWS Schema Conversion Tool (AWS SCT)
SCT converts schema, does not monitor replication.
Trap 3: AWS Glue
Glue is for ETL jobs, not real-time replication.
- A
Amazon RDS Performance Insights
Why wrong: Performance Insights is for database load analysis, not replication lag.
- B
AWS Schema Conversion Tool (AWS SCT)
Why wrong: SCT converts schema, does not monitor replication.
- C
AWS Database Migration Service (AWS DMS)
DMS provides replication tasks and publishes latency metrics.
- D
AWS Glue
Why wrong: Glue is for ETL jobs, not real-time replication.
- E
Amazon CloudWatch
CloudWatch collects DMS replication metrics for monitoring.
A database engineer is reviewing Amazon RDS for MySQL error logs and sees repeated authentication failures from the same IP address. The application team confirms the password is correct. What is the most likely cause of these errors?
Exhibit
Refer to the exhibit. From Amazon CloudWatch Logs: 2023-04-01T12:00:00Z [ERROR] [Client] Authentication failed for user 'app_user' from host '10.0.1.50' using method 'mysql_native_password' 2023-04-01T12:01:00Z [ERROR] [Client] Access denied for user 'app_user'@'10.0.1.50' (using password: YES) 2023-04-01T12:02:00Z [ERROR] [Client] Access denied for user 'app_user'@'10.0.1.50' (using password: YES)
Trap 1: The password is incorrect
The application team confirmed the password is correct.
Trap 2: The 'app_user' account is locked
A locked account would show a different error.
Trap 3: The database requires SSL connections
SSL requirement would show a different error.
- A
The password is incorrect
Why wrong: The application team confirmed the password is correct.
- B
The user 'app_user' does not have access from host '10.0.1.50'
The user may be defined as 'app_user'@'%' or from a different host, causing a mismatch.
- C
The 'app_user' account is locked
Why wrong: A locked account would show a different error.
- D
The database requires SSL connections
Why wrong: SSL requirement would show a different error.
Refer to the exhibit. A security engineer has applied this key policy to a customer managed KMS key used to encrypt a Secrets Manager secret containing database credentials. An application running on an Amazon EC2 instance in the same account and region is unable to decrypt the secret. What is the MOST likely cause?
Exhibit
Refer to the exhibit.
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "kms:Decrypt",
"Resource": "arn:aws:kms:us-east-1:123456789012:key/abc12345-...",
"Condition": {
"StringEquals": {
"kms:ViaService": "secretsmanager.us-east-1.amazonaws.com",
"kms:CallerAccount": "123456789012"
}
}
}
]
}Trap 1: The KMS key ARN in the resource field is incorrect.
Option A is incorrect: The ARN format appears correct.
Trap 2: The policy is missing an encryption context that matches the…
Option C is incorrect: The policy does not specify an encryption context, so the condition is not based on it.
Trap 3: The policy only allows Decrypt, but the application needs Encrypt…
Option D is incorrect: The application needs Decrypt, not Encrypt.
- A
The condition kms:ViaService restricts the decryption to requests made via Secrets Manager, but the application is calling KMS directly.
Option B is correct: The condition kms:ViaService requires the request to come via Secrets Manager, but the application likely decrypts directly using the KMS API.
- B
The KMS key ARN in the resource field is incorrect.
Why wrong: Option A is incorrect: The ARN format appears correct.
- C
The policy is missing an encryption context that matches the secret's encryption context.
Why wrong: Option C is incorrect: The policy does not specify an encryption context, so the condition is not based on it.
- D
The policy only allows Decrypt, but the application needs Encrypt permission.
Why wrong: Option D is incorrect: The application needs Decrypt, not Encrypt.
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