DBS-C01 Multiple Select — 40 Questions

Question 1

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?

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

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS DMS is the correct service because it is specifically designed for database migrations and provides built-in monitoring of replication lag via the 'CDC latency' metric. Amazon CloudWatch is the correct complementary service because it collects and visualizes DMS metrics, including replication lag and task status, and can trigger alarms if data integrity or latency thresholds are breached.

Answer

Amazon RDS Performance Insights

Answer

AWS Schema Conversion Tool (AWS SCT)

Answer

AWS Glue

Question 2

Which TWO of the following are recommended best practices for designing a relational database on Amazon RDS? (Select TWO.)

Accepted Answer

Use read replicas to scale read-heavy workloads. Amazon RDS read replicas offload read traffic from the primary DB instance, improving performance for read-heavy workloads by providing additional read-only endpoints. This is a core best practice for scaling read capacity without increasing load on the source instance.

Answer

Use LOB data types to store large text fields

Answer

Use non-EBS-optimized instances to reduce costs

Answer

Store large binary objects (BLOBs) in the database

Question 3

A company is designing a database for a social media application that requires storing user profiles, posts, and follower relationships. The application needs low-latency queries for user timelines and social graph traversals. Which TWO AWS database services should the database specialist consider? (Choose TWO.)

Accepted Answer

Amazon Neptune. Amazon Neptune is a fully managed graph database service optimized for storing and querying highly connected data, such as social graphs. It supports property graph and RDF models, enabling low-latency traversals of follower relationships and user timelines using Gremlin or SPARQL queries.

Answer

Amazon Timestream

Answer

Amazon Redshift

Answer

Amazon RDS for MySQL

Question 4

A company uses Amazon Aurora MySQL-Compatible Edition. The security team wants to implement database activity streams to monitor database activity. Which THREE statements are true about Aurora database activity streams?

Accepted Answer

Activity streams can be started and stopped without restarting the database.. Options A, B, and E are correct. Activity streams can be started and stopped without a database restart (A). They are encrypted using a KMS key (B). They publish database activity to Amazon CloudWatch Logs and Amazon Kinesis Firehose (E). Option C is incorrect because activity streams do not automatically mask sensitive data; they capture the actual queries. Option D is incorrect because activity streams capture all SQL statements, including DDL, DML, and SELECT.

Answer

Activity streams automatically mask sensitive data in the logs.

Answer

Activity streams only capture DDL statements, not DML or SELECT.

Question 5

A company is using Amazon Redshift and has a query that is running slowly. The DBA wants to identify if the query is I/O-bound. Which TWO metrics from Amazon CloudWatch can indicate I/O-bound queries?

Accepted Answer

ReadIOPS. Options B and E are correct. ReadIOPS measures the number of read I/O operations per second, and ReadLatency measures the average time per read I/O operation. High values for these metrics indicate that the query is I/O-bound. Option A (NetworkReceiveThroughput) measures network throughput, not I/O. Option C (CPUUtilization) indicates CPU-bound workloads. Option D (WriteIOPS) measures write I/O, which is less likely to be the primary indicator for a slow query, and the question asks for the two metrics that can indicate I/O-bound queries; ReadIOPS and ReadLatency are the most direct I/O metrics.

Answer

NetworkReceiveThroughput

Answer

CPUUtilization

Answer

WriteIOPS

Question 6

A company is migrating a MySQL database to Amazon RDS for MySQL. They want to use AWS DMS for continuous replication. Which TWO prerequisites must be met before starting the migration?

Accepted Answer

Enable binary logging (binlog) on the source MySQL database.. Option A is correct because AWS DMS requires binary logging (binlog) to be enabled on the source MySQL database for continuous replication (change data capture); the binlog_format must be set to ROW and the retention period long enough to cover the migration. Option B is correct because the DMS replication instance must have network connectivity to both the source and target databases, typically via VPC security groups, subnets, and routing, otherwise the endpoints cannot be reached and the task will fail. Option C is not required because DMS performs ongoing replication without forcing the source into read-only mode; writes can continue while changes are captured from the binlog. Option D is not a prerequisite because the source database can reside on-premises or outside a VPC, as long as connectivity to the replication instance is established. Option E is not required because DMS logs are written to Amazon CloudWatch Logs, not to an S3 bucket created for migration logs.

Answer

Set the source database to read-only mode during migration.

Answer

Place the source database in a VPC.

Answer

Create an S3 bucket to store the migration logs.

Question 7

A company is migrating an on-premises Oracle database to Amazon Aurora PostgreSQL. The database contains a large table that is partitioned by date. The company wants to minimize downtime during migration and ensure compatibility. Which TWO actions should the company take?

Accepted Answer

Use AWS Database Migration Service (DMS) with ongoing replication to migrate the data.. AWS DMS with ongoing replication (change data capture) allows continuous synchronization from the source Oracle database to the target Aurora PostgreSQL, minimizing downtime by keeping the target nearly up-to-date until the final cutover. This approach supports large partitioned tables and reduces the migration window compared to a full load only.

Answer

Migrate the database using a full load only and accept downtime.

Answer

Use AWS Schema Conversion Tool (SCT) to convert the schema automatically without any manual adjustments.

Answer

Replace the Oracle database with Amazon RDS for MySQL.

Question 8

Which TWO factors should be considered when choosing between Amazon DynamoDB and Amazon RDS for MySQL for a new e-commerce application with variable traffic patterns?

Accepted Answer

Operational overhead: DynamoDB is serverless, RDS requires patching and provisioning.. DynamoDB is a fully managed serverless service that eliminates the need for patching, provisioning, or managing servers, whereas Amazon RDS for MySQL requires manual patching, scaling, and instance provisioning. This operational overhead difference is critical for variable traffic patterns, as DynamoDB automatically handles infrastructure management, reducing administrative burden.

Answer

Ability to perform complex joins and aggregations: DynamoDB supports SQL-like queries.

Answer

Support for ACID transactions in both databases.

Answer

Encryption at rest is only available for RDS.

Question 9

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. Which TWO methods can the database specialist use to minimize downtime during the migration?

Accepted Answer

Use Oracle GoldenGate to replicate data continuously.. Option B is correct because Oracle GoldenGate performs continuous, near-real-time change data capture and replication from the on-premises Oracle database to RDS for Oracle, so the cutover window is limited to a brief final sync rather than the entire data volume. Option C is correct because AWS DMS supports ongoing (change data capture) replication for Oracle sources, keeping the target RDS for Oracle in sync and allowing a short switchover with minimal downtime. Options A, D, and E are not suitable for minimizing downtime: RMAN backup/restore, full backup/restore, and Data Pump export/import are all one-time bulk operations that require the source to be quiesced and the full dataset to be transferred before cutover, resulting in significant downtime proportional to database size.

Answer

Use Oracle Recovery Manager (RMAN) to back up and restore.

Answer

Take a full database backup and restore to RDS.

Answer

Use Oracle Data Pump to export and import the database.

Question 10

A company is migrating a 1 TB PostgreSQL database from on-premises to Amazon RDS for PostgreSQL. The migration must have minimal downtime. Which TWO steps should be taken to achieve this?

Accepted Answer

Configure AWS DMS with ongoing replication from the source to the target.. Option A is correct because AWS Database Migration Service (DMS) supports ongoing replication (change data capture) from an on-premises PostgreSQL source to an RDS for PostgreSQL target, allowing the bulk load to complete and then continuously applying changes so the cutover downtime is only the short final catch-up. Option C is correct because the pglogical extension provides logical replication between PostgreSQL instances, including from on-premises to RDS for PostgreSQL, so the initial data copy plus continuous streaming of changes keeps the target nearly in sync with minimal downtime. Option B is not appropriate because AWS Schema Conversion Tool is used to convert schemas between different database engines (for example, to Aurora), but this migration is PostgreSQL-to-PostgreSQL, so no engine conversion is needed. Option D would cause significant downtime because a pg_dump taken at cutover and imported into RDS requires the source to be offline for the entire dump and load of a 1 TB database. Option E is not possible because RDS Read Replicas can only be created from an existing RDS or Aurora source, not from an on-premises PostgreSQL database.

Answer

Use AWS SCT to convert the schema to Amazon Aurora.

Answer

Take a full backup using pg_dump and import it into RDS during a maintenance window.

Answer

Create an RDS Read Replica of the on-premises database.

Question 11

A security team needs to audit all SQL statements executed against an Amazon Aurora MySQL DB cluster. Which combination of actions should be taken to achieve this? (Choose TWO.)

Accepted Answer

Set the server_audit_logging parameter to 1 in the DB cluster parameter group.. Options D and E are correct. To audit SQL statements in an Aurora MySQL DB cluster, you need to enable the Aurora MySQL audit plugin. This is done by setting the `server_audit_logging` parameter to 1 in the DB cluster parameter group (option D). Then you can configure the DB cluster to publish the audit logs to Amazon CloudWatch Logs (option E) for centralized monitoring and analysis. Option A is incorrect because AWS CloudTrail captures API calls, not SQL statements. Option B is incorrect because Enhanced Monitoring captures OS-level metrics, not SQL queries. Option C is incorrect because RDS event subscriptions notify about events like DB instance changes, not SQL execution.

Answer

Enable AWS CloudTrail for the Aurora DB cluster.

Answer

Enable Enhanced Monitoring for the DB cluster.

Answer

Enable RDS event subscription for the DB cluster.

Question 12

A company is using Amazon DynamoDB and wants to restrict access to a specific table so that only users in a particular IAM group can perform read and write operations. Which THREE steps should be taken to achieve this?

Accepted Answer

Create an IAM policy that allows dynamodb:GetItem, dynamodb:PutItem, etc. on the specific table ARN.. The correct answers are A, B, and D. To restrict access to a specific DynamoDB table, you create an IAM policy that allows the required DynamoDB actions on that table's ARN (A). You then attach that policy to an IAM group (B), and add the users who need access to that group (D). Options C and E are incorrect because DynamoDB does not support resource-based policies, and IAM roles are not directly assigned to tables for access control.

Answer

Attach a resource-based policy to the DynamoDB table allowing access from the group.

Answer

Create an IAM role and assign it to the table.

Question 13

Which THREE factors should be considered when choosing between Amazon RDS and Amazon DynamoDB for a new application? (Choose 3.)

Accepted Answer

Access patterns (predictable vs. ad-hoc). Option C is correct because access patterns drive the choice: DynamoDB excels at known, key-based, predictable access at scale, while RDS suits ad-hoc queries via SQL. Option D is correct because DynamoDB scales horizontally with partition keys and on-demand/provisioned capacity, whereas RDS primarily scales vertically by resizing instances (with read replicas for read scaling). Option E is correct because RDS supports complex joins, aggregations, and multi-table transactions through SQL, while DynamoDB has limited join support and requires denormalization or secondary indexes. Option A is not a primary differentiator since both services charge for storage and capacity in different ways, and Option B is not decisive because both RDS and DynamoDB support encryption at rest (KMS).

Answer

Cost of storage

Answer

Need for encryption at rest

Question 14

A company runs an Amazon RDS for MySQL DB instance in a VPC. Security requirements mandate that only specific EC2 instances in the same VPC can connect to the database. The security group attached to the RDS instance currently allows inbound traffic on port 3306 from 0.0.0.0/0. Which combination of steps should a database specialist take to meet the security requirement without impacting existing application connectivity? (Choose two.)

Accepted Answer

Remove the inbound rule for 0.0.0.0/0 on the RDS security group.. Removing the overly permissive inbound rule for 0.0.0.0/0 on the RDS security group eliminates unrestricted access, which is a direct violation of the security requirement. Option C is correct because adding an inbound rule that references the security group ID of the EC2 instances allows traffic only from those instances, leveraging security group referencing for granular, stateful access control within the same VPC.

Answer

Modify the network ACL for the DB subnet to allow inbound port 3306 from the EC2 instance's private IP.

Answer

Modify the DB subnet group to place the RDS instance in a public subnet with a route to the EC2 instance.

Answer

Add an inbound rule to the RDS security group allowing traffic from the VPC CIDR on port 3306.

Question 15

A company is designing a security strategy for Amazon RDS for SQL Server. Which TWO actions should be taken to encrypt data at rest? (Choose TWO.)

Accepted Answer

Enable Transparent Data Encryption (TDE) on the SQL Server database.. Option B is correct because Transparent Data Encryption (TDE) is the SQL Server-native feature that encrypts database files, log files, and backups at rest, and Amazon RDS for SQL Server supports enabling TDE so that data pages are encrypted before being written to storage. Option E is correct because RDS encryption at rest, when enabled at instance creation, uses AWS KMS customer master keys to encrypt the underlying storage volumes, snapshots, and automated backups for the DB instance. Option A is not correct because you cannot directly enable Amazon EBS encryption on the volumes underlying an RDS instance; RDS manages that storage and encryption is controlled through the RDS encryption-at-rest setting tied to KMS. Option C is not correct because CloudHSM is not the mechanism RDS uses to store encryption keys for RDS encryption at rest; RDS integrates with AWS KMS for key management. Option D is not correct because SSL/TLS encrypts data in transit between clients and the SQL Server instance, not data at rest.

Answer

Enable Amazon EBS encryption on the underlying volumes.

Answer

Use AWS CloudHSM to store encryption keys.

Answer

Enable SSL/TLS for connections.

Question 16

A company is using Amazon DynamoDB with provisioned capacity for a table that experiences unpredictable traffic spikes. The table's read capacity is often underutilized, but occasionally throttling occurs. Which THREE steps should be taken to improve performance and cost? (Choose THREE.)

Accepted Answer

Switch the table to on-demand capacity mode.. Switching to on-demand capacity mode eliminates the need to manage provisioned capacity, automatically scaling to handle unpredictable traffic spikes without throttling. This improves performance by preventing throttling during spikes and optimizes cost by charging only for consumed reads/writes, avoiding the waste of underutilized provisioned capacity.

Answer

Reduce the provisioned read capacity units to save cost.

Answer

Disable auto scaling to avoid cost fluctuations.

Question 17

A company is building a microservices architecture and needs a database for a service that stores JSON documents with variable schema. The database must support high availability and automatic scaling. Which TWO services meet these requirements? (Choose two.)

Accepted Answer

Amazon DynamoDB. Amazon DynamoDB (B) is correct because it is a fully managed NoSQL key-value and document database that natively stores JSON-style items with flexible, schema-less attributes, and it provides built-in high availability via multi-AZ replication plus automatic horizontal scaling of throughput and storage. Amazon DocumentDB (C) is correct because it is a fully managed document database with MongoDB compatibility, designed to store JSON-like documents with variable schema, and it supports high availability through a multi-AZ cluster with up to 15 read replicas and automatic storage scaling. Amazon ElastiCache for Redis (A) is an in-memory cache/store, not a durable primary document database for variable-schema JSON persistence. Amazon Neptune (D) is a graph database optimized for highly connected data using nodes and edges, not general JSON document storage. Amazon RDS for MySQL (E) is a relational database with a fixed schema, so it does not natively fit variable-schema JSON documents or the same automatic scaling model.

Answer

Amazon ElastiCache for Redis

Answer

Amazon Neptune

Answer

Amazon RDS for MySQL

Question 18

A company is migrating an on-premises Oracle database with complex stored procedures and triggers to AWS. They want to minimize code changes. Which AWS database service should they consider?

Accepted Answer

Amazon RDS for Oracle. Amazon RDS for Oracle is the most direct migration target because it uses the same Oracle Database engine, allowing existing stored procedures, triggers, and PL/SQL code to run with minimal or no modification. Amazon Aurora PostgreSQL with Babelfish is not suitable for Oracle migrations because Babelfish provides compatibility with SQL Server T-SQL, not Oracle PL/SQL. Therefore, only RDS for Oracle minimizes code changes for Oracle stored procedures.

Answer

Amazon DynamoDB

Answer

Amazon S3

Answer

Amazon Redshift

Answer

Amazon Aurora PostgreSQL with Babelfish

Question 19

Which TWO factors should you consider when choosing between Amazon RDS and Amazon DynamoDB for a new application?

Accepted Answer

RDS requires a predefined schema, while DynamoDB is schema-less.. Option A is correct because Amazon RDS is a relational database service that requires you to define a fixed schema (tables, columns, data types) before storing data, whereas DynamoDB is a NoSQL key-value and document store that is schemaless—each item can have different attributes. Option E is correct because DynamoDB excels with unstructured or semi-structured data at massive scale with single-digit millisecond latency, while RDS is designed for structured data requiring complex joins, transactions, and relational integrity. Option B is wrong because DynamoDB can be accessed over the public internet via its HTTPS endpoint (or privately via VPC endpoints), and RDS can also be made publicly accessible or kept private. Option C is wrong because DynamoDB offers built-in multi-AZ replication automatically, and RDS also supports Multi-AZ deployments. Option D is wrong as a distinguishing factor because while both services do support encryption at rest and in transit, it does not help you choose between them for an application.

Answer

DynamoDB can only be accessed from within a VPC, while RDS can be public.

Answer

Only RDS supports Multi-AZ deployments for high availability.

Answer

Both services support encryption at rest and in transit.

Question 20

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. They need to minimize downtime. Which TWO actions should they take?

Accepted Answer

Set up AWS DMS with change data capture (CDC) from the source. Option A is correct because AWS Database Migration Service (DMS) with change data capture (CDC) continuously replicates ongoing changes from the on-premises Oracle source to the RDS target after the initial full load, allowing a short cutover window and thus minimizing downtime. Option C is correct because AWS Schema Conversion Tool (SCT) analyzes and converts the source Oracle schema, stored procedures, and other objects to be compatible with the RDS for Oracle target, catching incompatibilities before migration and preventing failed or delayed cutovers. Option B is not relevant because increasing allocated storage addresses capacity/IOPS, not migration downtime. Option D is wrong because Single-AZ reduces availability and does not simplify or improve replication for a minimal-downtime migration. Option E is wrong because disabling Oracle archivelog mode would break CDC/redo-based replication and risk data loss, not speed up a safe migration.

Answer

Increase the allocated storage on the target RDS instance to improve performance

Answer

Deploy the target RDS instance as a Single-AZ to simplify replication

Answer

Disable Oracle archivelog mode to speed up data transfer