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AWS Certified Database Specialty DBS-C01 (DBS-C01) — Questions 76–150

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

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76
MCQhard

A security auditor notices that the DynamoDB table 'UserData' is encrypted with a KMS key (exhibit). The company policy requires that all DynamoDB tables use an AWS managed key for encryption. What must be done to comply with the policy?

A.Create a new DynamoDB table with SSE enabled using the AWS managed key, then export data from the existing table and import into the new table.
B.Delete the customer managed KMS key and recreate it as an AWS managed key.
C.Modify the table's SSE configuration to use the AWS managed key.
D.Use the UpdateTable API to change the KMS key to the AWS managed key.
AnswerA

Key can only be set at creation.

Why this answer

DynamoDB does not support changing the KMS key or SSE configuration after table creation. To use the AWS managed key instead of a customer managed key, you must create a new table with SSE-KMS enabled using the AWS managed key (alias 'aws/dynamodb'), export the existing table data (via DynamoDB export to S3 or using a scan/write process), and import it into the new table. Option B is incorrect because a customer managed KMS key cannot be converted into an AWS managed key; they are distinct key types.

Option C is incorrect because you cannot modify the SSE configuration of an existing DynamoDB table; encryption settings are immutable after creation. Option D is incorrect because the UpdateTable API does not allow changing the KMS key used for encryption; it only supports updating other table settings like billing mode or provisioned throughput.

Full explanation →
77
MCQhard

A company is deploying a new application that requires low-latency reads from a relational database across multiple AWS Regions. The application is read-heavy and can tolerate eventual consistency. Which deployment option meets these requirements?

A.Deploy Amazon RDS for PostgreSQL with Multi-AZ and read replicas in the same Region.
B.Deploy a single Amazon RDS for MySQL instance with cross-Region read replicas.
C.Deploy Amazon Aurora Global Database with a primary Region and read replicas in secondary Regions.
D.Deploy Amazon DynamoDB Global Tables in multiple Regions.
AnswerC

Aurora Global Database provides low-latency reads in secondary Regions with eventual consistency.

Why this answer

Amazon Aurora Global Database is designed for low-latency global reads and disaster recovery, allowing up to five secondary Regions with dedicated read replicas that replicate data with a typical latency of under one second. This meets the requirement for low-latency reads across multiple Regions while tolerating eventual consistency, as reads from secondary Regions are eventually consistent with the primary.

Exam trap

The trap here is that candidates may confuse cross-Region read replicas in standard RDS with Aurora Global Database, not realizing that Aurora's dedicated global replication provides lower latency and better performance for multi-Region reads, or they may overlook the requirement for a relational database and choose DynamoDB Global Tables.

How to eliminate wrong answers

Option A is wrong because Multi-AZ and read replicas in the same Region do not provide cross-Region read capability, failing the requirement for low-latency reads across multiple AWS Regions. Option B is wrong because a single Amazon RDS for MySQL instance with cross-Region read replicas uses asynchronous replication that can introduce higher latency and does not offer the optimized global replication infrastructure of Aurora Global Database, making it less suitable for low-latency multi-Region reads. Option D is wrong because Amazon DynamoDB Global Tables is a NoSQL database, not a relational database, and the question explicitly requires a relational database.

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78
Multi-Selecthard

A company is planning to migrate a 2 TB Oracle database to Amazon Aurora PostgreSQL. The database contains large objects (LOBs) and uses stored procedures. Which TWO steps should the company take as part of the migration? (Choose two.)

Select 2 answers
A.Set up AWS DMS ongoing replication to keep the target in sync after migration.
B.Use AWS Schema Conversion Tool (SCT) to convert the Oracle schema and stored procedures to PostgreSQL-compatible format.
C.Configure AWS DMS with full LOB mode to migrate large objects.
D.Use AWS DMS native Oracle to PostgreSQL endpoint to migrate data without schema conversion.
E.Enable RDS Proxy to reduce connection overhead during migration.
AnswersB, C

SCT converts schema and code objects like stored procedures.

Why this answer

The AWS Schema Conversion Tool (SCT) is specifically designed to convert Oracle schema objects, including stored procedures, to PostgreSQL-compatible format. Since the migration involves stored procedures, SCT is necessary to handle the syntax and logic differences between Oracle PL/SQL and PostgreSQL PL/pgSQL, ensuring the target database schema is ready for migration.

Exam trap

AWS often tests the misconception that DMS can handle schema conversion automatically, but DMS only migrates data; schema conversion requires a separate tool like SCT.

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79
Matchingmedium

Match each DynamoDB concept to its definition.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Single attribute used to distribute data across partitions

Attribute that determines order within a partition

Index with a different partition and sort key for alternate query patterns

Index with the same partition key but different sort key

Time-ordered sequence of item-level changes in a table

Why these pairings

This matching exercise tests understanding of core DynamoDB concepts. The partition key distributes items across partitions, while the sort key enables ordering. Global secondary indexes (GSIs) allow queries on different partition keys, while local secondary indexes (LSIs) share the same partition key but different sort keys.

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80
MCQhard

A company is migrating a 3 TB PostgreSQL database from on-premises to Amazon RDS for PostgreSQL. The migration must have minimal downtime. The on-premises network bandwidth to AWS is 1 Gbps. The database supports a critical application that cannot be stopped for more than 30 minutes. The migration team has set up AWS DMS with ongoing replication using CDC. The initial full load is expected to take 8 hours. During the migration, the DMS task fails with an error indicating that the source database's transaction log is being cleaned before DMS can capture changes. The source database has a transaction log retention period of 24 hours. The migration team notices that the CDC phase falls behind during peak hours. What should the team do to complete the migration successfully within the downtime window?

A.Use AWS Snowball to transfer the full database and then use DMS for CDC
B.Increase the network bandwidth using AWS Direct Connect
C.Increase the transaction log retention period on the source database and use a larger DMS replication instance
D.Decrease the transaction log retention period to free up space
AnswerC

Longer log retention prevents cleanup before DMS captures changes; larger instance boosts CDC throughput.

Why this answer

The issue is that DMS cannot keep up with changes during peak hours, causing the transaction logs to be cleaned before DMS reads them. Increasing the source database's transaction log retention period gives DMS more time to catch up. Using a larger DMS replication instance will increase processing capacity.

Option C is the best combination. Option A (Snowball) would take too long. Option B (Direct Connect) doesn't solve the log retention issue.

Option D (decrease retention) makes the problem worse.

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81
MCQmedium

A company is running a MongoDB-compatible database on Amazon DocumentDB. The application performs frequent updates to a small subset of fields in documents. The company notices that write latency is high. What should the database specialist recommend to reduce write latency?

A.Review and remove unnecessary indexes on the collection.
B.Increase the instance size of the DocumentDB cluster.
C.Enable multi-master writes to distribute write load.
D.Change the storage type from standard to provisioned IOPS.
AnswerA

Fewer indexes mean less work during writes, reducing latency.

Why this answer

Unnecessary indexes impose a write penalty on every insert, update, and delete operation. In Amazon DocumentDB, each write must update all indexes on the collection, so removing unused indexes reduces the per-document write overhead and directly lowers write latency for frequent updates to a small subset of fields.

Exam trap

The trap here is that candidates often assume scaling up hardware (Option B) or changing storage (Option D) is the default fix for high write latency, but the exam tests understanding that index overhead is the most common cause of write amplification in DocumentDB and MongoDB-compatible databases.

How to eliminate wrong answers

Option B is wrong because increasing instance size primarily improves throughput and reduces resource contention (CPU/memory), but it does not address the fundamental write amplification caused by indexing; the write penalty per document remains the same. Option C is wrong because DocumentDB does not support multi-master writes; it uses a single primary writer with replica readers, and enabling a non-existent feature would not reduce write latency. Option D is wrong because DocumentDB uses a shared storage volume with built-in SSD-backed storage; it does not offer separate provisioned IOPS as a configurable storage type, and changing storage type is not applicable.

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82
MCQmedium

Refer to the exhibit. A company has attached this IAM policy to an IAM role used by an application running on Amazon EC2. The application needs to decrypt data in an S3 bucket that is encrypted with the specified KMS key. However, the application is receiving access denied errors. What is the most likely cause?

A.The policy does not include 'kms:Decrypt' for the specific key.
B.The application is decrypting the data by calling KMS directly instead of using S3's server-side decryption.
C.The policy is missing a 'Principal' element.
D.The IAM role does not have a trust policy that allows EC2 to assume it.
AnswerB

The 'kms:ViaService' condition requires that the call be made via S3, not directly to KMS.

Why this answer

The policy condition 'kms:ViaService' restricts KMS operations to only when they are made through S3. However, the condition also includes 'kms:CallerAccount' which is redundant but not harmful. The error likely occurs because the EC2 instance does not have the correct IAM role, or the policy is missing 'kms:Decrypt' for the specific ciphertext.

But the most common mistake is that the application is not using the S3 service to decrypt; if the application reads the encrypted object and then calls KMS directly to decrypt, the 'kms:ViaService' condition will fail because the call is not via S3. Option B addresses this. Option A is wrong because the condition is present.

Option C is wrong because the role is not explicitly denied. Option D is wrong because the policy allows KMS actions.

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83
MCQeasy

A database specialist is troubleshooting a slow Amazon RDS for PostgreSQL query. The specialist has enabled Performance Insights and sees that the database load is high. Which additional tool can provide detailed information about the specific queries causing the load?

A.Use VPC Flow Logs to analyze network traffic to the database.
B.Use Amazon CloudWatch Logs to analyze the PostgreSQL error logs.
C.Use Enhanced Monitoring to view OS-level metrics and correlate with performance insights.
D.Use AWS CloudTrail to view database API calls.
AnswerC

Enhanced Monitoring provides OS metrics that help diagnose resource contention.

Why this answer

Enhanced Monitoring provides OS-level metrics (CPU, memory, disk I/O, etc.), which when combined with Performance Insights' query-level details, gives a comprehensive view of database performance. Option A is wrong because VPC Flow Logs capture network traffic information, not query-specific details. Option B is wrong because CloudWatch Logs can analyze PostgreSQL error logs, but this does not provide detailed query-level load information.

Option D is wrong because AWS CloudTrail records API calls, not database queries.

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84
MCQhard

A company is migrating a 2 TB Oracle database to Amazon RDS for Oracle. The database has a large number of stored procedures, triggers, and functions. The company wants to minimize changes to the application code. Which AWS service should be used to assess and convert the database schema?

A.AWS Schema Conversion Tool (SCT)
B.AWS Database Migration Service (DMS)
C.AWS CloudEndure Migration
D.AWS CodeCommit
AnswerA

SCT assesses and converts schema objects to the target database.

Why this answer

AWS Schema Conversion Tool (SCT) is designed specifically to convert database schemas from one engine to another, including Oracle to Amazon RDS for Oracle. It assesses the source schema, identifies incompatibilities, and automatically converts stored procedures, triggers, and functions to minimize application code changes. SCT also provides action items for any manual remediation needed, ensuring a smooth migration with minimal code rewrites.

Exam trap

The trap here is that candidates confuse AWS DMS with schema conversion, but DMS only migrates data and ongoing replication, not schema objects like stored procedures, triggers, or functions.

How to eliminate wrong answers

Option B (AWS DMS) is wrong because DMS handles data migration (moving rows and tables), not schema conversion or assessment of stored procedures, triggers, or functions. Option C (AWS CloudEndure Migration) is wrong because it is used for lift-and-shift migration of entire servers (block-level replication), not for database schema assessment or conversion. Option D (AWS CodeCommit) is wrong because it is a source control service for storing code, not a database schema assessment or conversion tool.

Full explanation →
85
MCQmedium

A company is designing a database for a global e-commerce platform that requires sub-millisecond read latencies from multiple AWS regions. The data is mostly read, with occasional writes. Which database solution meets these requirements?

A.Amazon ElastiCache for Redis with global datastore.
B.Amazon DynamoDB with Global Tables.
C.Amazon Aurora MySQL with Aurora Global Database.
D.Amazon RDS for MySQL with Multi-AZ and read replicas.
AnswerB

DynamoDB Global Tables provide sub-millisecond latency and multi-region replication.

Why this answer

Amazon DynamoDB with Global Tables is the correct choice because it provides a fully managed, multi-Region, multi-master database that replicates data across AWS Regions with sub-second latency, enabling sub-millisecond read latencies for a globally distributed, mostly-read workload. The occasional writes are handled efficiently by the multi-master design, which automatically resolves conflicts using last-writer-wins semantics, ensuring strong eventual consistency.

Exam trap

The trap here is that candidates often confuse 'global read replicas' (like Aurora Global Database) with a true multi-Region, multi-master database that can provide sub-millisecond reads from any Region, leading them to choose Aurora MySQL despite its replication lag and single-writer limitation.

How to eliminate wrong answers

Option A is wrong because Amazon ElastiCache for Redis with global datastore is an in-memory cache, not a durable database; it does not provide the persistence and durability guarantees required for an e-commerce platform's core data, and its global datastore is designed for cross-Region replication of cached data, not as a primary database for occasional writes. Option C is wrong because Amazon Aurora MySQL with Aurora Global Database is designed for low-latency reads in secondary Regions (typically under 1 second), but it cannot achieve sub-millisecond read latencies from multiple Regions due to the replication lag inherent in its storage-based replication, and it is not a multi-master solution (only one primary Region accepts writes). Option D is wrong because Amazon RDS for MySQL with Multi-AZ and read replicas is limited to a single AWS Region; read replicas in other Regions would introduce latency of hundreds of milliseconds or more, and Multi-AZ only provides high availability within one Region, not global sub-millisecond reads.

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86
MCQeasy

A database administrator notices that the free storage space on an Amazon RDS for PostgreSQL DB instance is decreasing rapidly. The instance has automated backups enabled with a retention period of 7 days. Which action should be taken to monitor storage usage and prevent running out of space?

A.Create a lifecycle policy to automatically move old backup files to Amazon S3 Glacier.
B.Set up a CloudWatch alarm on the FreeStorageSpace metric to notify when space is low.
C.Increase the allocated storage for the DB instance immediately.
D.Enable Performance Insights to track storage usage.
AnswerB

CloudWatch alarms provide proactive monitoring and alerting for storage usage.

Why this answer

Setting a CloudWatch alarm on the FreeStorageSpace metric allows proactive monitoring and notification when storage is low. Option A is incorrect because lifecycle policies to move backups to S3 Glacier are not applicable to RDS automated backups; they are managed separately. Option C is incorrect because increasing storage is a reactive measure, not a monitoring action, and may cause downtime.

Option D is incorrect because Performance Insights focuses on database performance, not storage tracking.

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87
Multi-Selecthard

A company is running a critical Oracle database on Amazon RDS. The DBA wants to set up monitoring to detect if the database is experiencing a high number of full table scans, which may indicate missing indexes. Which TWO metrics should the DBA monitor? (Choose TWO.)

Select 2 answers
A.TableScanRows
B.FullTableScans
C.BufferCacheHitRatio
D.UserCommits
E.RedoLogSpaceUsage
AnswersA, B

Shows the number of rows scanned in full table scans.

Why this answer

The DBA should monitor TableScanRows (A) and FullTableScans (B). FullTableScans directly counts the number of full table scan operations, while TableScanRows indicates the number of rows read during full scans. High values in either metric suggest missing indexes.

BufferCacheHitRatio (C) measures cache efficiency, not full scans. UserCommits (D) tracks transaction commits, and RedoLogSpaceUsage (E) relates to redo log activity, neither of which indicate full table scans.

Full explanation →
88
MCQhard

An IAM policy is attached to a user. Which of the following actions will be allowed?

A.Delete a DB instance named 'prod-db'.
B.Create a new DB instance named 'prod-db'.
C.Delete a DB instance named 'test-db'.
D.Delete a DB instance named 'dev-db'.
AnswerB

Cannot be determined without the IAM policy.

Why this answer

The question does not include the IAM policy text, so it is impossible to determine which actions are allowed. Without the policy, we cannot evaluate whether any specific action is permitted or denied. Therefore, none of the options can be confirmed as correct.

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89
MCQeasy

A company runs a MySQL database on Amazon RDS and wants to capture data changes to replicate to a separate reporting database. Which AWS service should be used to capture these changes with minimal impact on the source database?

A.Use Amazon DynamoDB Streams to capture changes from the RDS instance.
B.Enable MySQL native replication from the RDS instance to the reporting database.
C.Use Amazon Kinesis Data Streams with a custom application to poll the binlog.
D.Use AWS Database Migration Service (DMS) with ongoing replication enabled.
AnswerD

DMS can capture changes from RDS MySQL binlog with minimal impact.

Why this answer

AWS DMS with ongoing replication (change data capture) is the correct choice because it reads the binary logs (binlog) from the source RDS MySQL instance to capture inserts, updates, and deletes with minimal overhead. DMS uses a dedicated replication instance and can apply changes to a separate reporting database without requiring schema changes or additional load from application-level polling. This approach is fully managed and designed for low-impact, continuous replication.

Exam trap

The trap here is that candidates may confuse DynamoDB Streams (which is for NoSQL) with a general-purpose CDC service, or assume that native MySQL replication is the simplest approach without considering the managed, low-impact alternative that DMS provides for heterogeneous or cross-engine replication.

How to eliminate wrong answers

Option A is wrong because Amazon DynamoDB Streams only capture changes from DynamoDB tables, not from RDS MySQL instances. Option B is wrong because MySQL native replication requires enabling binary logging and configuring a replica, which adds significant overhead to the source RDS instance and is not recommended for production cross-Region or cross-account replication due to complexity and potential performance impact. Option C is wrong because Amazon Kinesis Data Streams with a custom application to poll the binlog would require building and maintaining custom code to parse MySQL binlog events, which is more complex and less reliable than using DMS's built-in CDC capability.

Full explanation →
90
MCQhard

A company recently migrated their PostgreSQL database to Amazon Aurora PostgreSQL. They notice that the average query latency has increased, especially for complex read queries. The DB instance size is adequate and CPU utilization is below 50%. What is the MOST likely cause of the increased latency?

A.The Auto Scaling policy for the Aurora cluster is set to scale down too aggressively.
B.The Aurora cluster volume uses a smaller buffer cache than the original RDS instance.
C.The Aurora cluster is using the parallel query feature which adds overhead for complex queries.
D.The application is sending all read queries to the primary instance instead of offloading them to Aurora Replicas.
AnswerD

Without using Aurora Replicas, the primary handles all read traffic, leading to contention and higher latency.

Why this answer

If all read queries are sent to the primary (writer) instance, it must handle both writes and reads, leading to contention and increased latency. Aurora Replicas are designed to offload read traffic, and by not using them, the primary instance becomes a bottleneck even if CPU utilization is low. This is a common misconfiguration after migration, as applications often retain the original connection string pointing to the primary endpoint.

Exam trap

The trap here is that candidates assume low CPU utilization means the instance is not overloaded, but they overlook that query latency can increase due to lock contention, connection pooling limits, or misrouted traffic rather than CPU saturation.

How to eliminate wrong answers

Option A is wrong because Auto Scaling policies for Aurora clusters affect the number of replicas, not the latency of existing queries; scaling down aggressively would reduce capacity but not directly increase query latency on a running instance. Option B is wrong because Aurora uses a distributed storage volume with a shared buffer cache across instances, and the buffer cache size is not inherently smaller than a traditional RDS instance; in fact, Aurora's buffer cache is managed differently and can be larger due to the cluster volume. Option C is wrong because the parallel query feature is designed to reduce latency for complex queries by parallelizing I/O, not to add overhead; it is optional and would not cause increased latency unless misconfigured.

Full explanation →
91
MCQmedium

A company is migrating a 1 TB Microsoft SQL Server database from on-premises to Amazon RDS for SQL Server. The on-premises database uses TDE for encryption. The company must ensure that the migrated database in RDS also uses TDE. Which solution meets this requirement?

A.Export the on-premises database with TDE certificates and import them into RDS.
B.Take a native backup of the on-premises database with TDE, upload to S3, and restore to RDS.
C.Use AWS SCT to convert the database to Amazon Aurora and enable encryption.
D.Use AWS DMS with ongoing replication to an RDS instance that has TDE enabled.
AnswerD

DMS can migrate data to an RDS instance with TDE enabled, and the data will be encrypted at rest.

Why this answer

AWS DMS can migrate data from an on-premises SQL Server database with TDE enabled to an Amazon RDS for SQL Server instance that has TDE enabled. DMS reads the decrypted data from the source (since TDE is transparent to applications) and writes it to the target, which can then encrypt the data at rest using RDS's built-in TDE support. This approach avoids the need to transfer TDE certificates or perform a native backup/restore, which are not supported for TDE-enabled databases in RDS.

Exam trap

The trap here is that candidates assume native backup/restore (Option B) is the simplest approach for TDE databases, but they overlook that RDS does not support restoring TDE-encrypted backups because the required certificates cannot be imported, making DMS the only viable migration path for preserving encryption at rest.

How to eliminate wrong answers

Option A is wrong because you cannot export TDE certificates from an on-premises SQL Server and import them into Amazon RDS for SQL Server; RDS does not allow direct access to the certificate store or the ability to manage TDE certificates manually. Option B is wrong because native backup/restore of a TDE-enabled database to RDS is not supported; RDS for SQL Server cannot restore a TDE-encrypted backup without the original certificates, and the backup file itself remains encrypted and unreadable. Option C is wrong because AWS SCT is a schema conversion tool, not a data migration tool, and converting to Amazon Aurora does not preserve TDE; Aurora uses its own encryption mechanism (KMS) and does not support SQL Server TDE.

Full explanation →
92
Multi-Selectmedium

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

Select 2 answers
A.Use read replicas to scale read-heavy workloads
B.Use LOB data types to store large text fields
C.Use non-EBS-optimized instances to reduce costs
D.Enable Multi-AZ for high availability
E.Store large binary objects (BLOBs) in the database
AnswersA, D

Read replicas offload read traffic.

Why this answer

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.

Exam trap

The trap here is that candidates often confuse Multi-AZ (which provides high availability) with read replicas (which provide read scaling), or mistakenly believe that storing BLOBs in the database is acceptable for performance, ignoring the impact on backup and replication overhead.

Full explanation →
93
MCQeasy

A company is using Amazon ElastiCache for Redis to cache database query results. The application team reports that cache hit ratio has dropped significantly. What is the first step to investigate?

A.Run the Redis INFO command to see memory usage
B.Review the ElastiCache event logs for node failures
C.Check the CacheHitRate and Evictions metrics in CloudWatch
D.Check the Redis AOF persistence logs
AnswerC

These metrics directly indicate cache effectiveness.

Why this answer

When the cache hit ratio drops significantly, the first step is to investigate whether the cache is evicting keys due to memory pressure or if the working set no longer fits. CloudWatch metrics such as `CacheHitRate` and `Evictions` provide immediate visibility into these conditions without requiring direct Redis access. This aligns with the AWS Well-Architected Framework's principle of observability before making configuration changes.

Exam trap

The trap here is that candidates assume the first step should be a low-level Redis command (INFO) or logs, but AWS best practice emphasizes using CloudWatch metrics for initial investigation because they provide aggregated, historical data without requiring direct access to the cluster.

How to eliminate wrong answers

Option A is wrong because running the Redis INFO command requires direct access to the Redis endpoint and does not provide historical trend data; it only shows a point-in-time snapshot, which is insufficient for diagnosing a drop in cache hit ratio over time. Option B is wrong because ElastiCache event logs record node lifecycle events (e.g., failover, maintenance) but do not capture cache performance metrics like hit ratio or evictions; they are useful for operational incidents, not performance degradation. Option D is wrong because AOF persistence logs are used for durability and data recovery, not for monitoring cache efficiency; checking them would not reveal why the cache hit ratio has dropped.

Full explanation →
94
MCQmedium

A company is designing a global application that requires a database with multi-master writes across multiple AWS Regions with sub-second conflict resolution. Which AWS database service should they choose?

A.Amazon ElastiCache for Redis Global Datastore
B.Amazon RDS with Multi-AZ
C.Amazon DynamoDB Global Tables
D.Amazon Aurora Global Database
AnswerC

Multi-master writes across Regions.

Why this answer

Amazon DynamoDB Global Tables is the correct choice because it provides a fully managed, multi-Region, multi-master database that replicates data across AWS Regions with sub-second conflict resolution using last-writer-wins (LWW) or application-defined conflict resolution. This meets the requirement for multi-master writes and sub-second conflict resolution, which is not achievable with the other options.

Exam trap

The trap here is that candidates often confuse Amazon Aurora Global Database's cross-Region replication with multi-master capability, but it is actually an active-passive setup with a single primary writer, not multi-master writes with sub-second conflict resolution.

How to eliminate wrong answers

Option A is wrong because Amazon ElastiCache for Redis Global Datastore supports cross-Region replication but uses a single active primary (active-passive) model, not multi-master writes, and conflict resolution is not applicable as writes only occur in one Region. Option B is wrong because Amazon RDS with Multi-AZ provides high availability within a single Region with a single primary and standby replica, not multi-Region multi-master writes, and it does not offer conflict resolution. Option D is wrong because Amazon Aurora Global Database supports cross-Region replication but uses a single primary writer in one Region with read replicas in other Regions (active-passive), not multi-master writes, and conflict resolution is not supported.

Full explanation →
95
MCQhard

A company is using Amazon Aurora MySQL-Compatible Edition. The database has frequent deadlocks, and the application team suspects that the isolation level is causing the issue. The current isolation level is REPEATABLE READ. The team wants to reduce deadlocks while maintaining data consistency. Which isolation level should be recommended?

A.READ UNCOMMITTED
B.READ COMMITTED
C.SNAPSHOT ISOLATION
D.SERIALIZABLE
AnswerB

READ COMMITTED reduces the number of locks held, thereby decreasing the likelihood of deadlocks while still preventing dirty reads.

Why this answer

(READ COMMITTED) is correct because it reduces locking compared to REPEATABLE READ, which helps minimize deadlocks in high-concurrency environments. In READ COMMITTED, MySQL uses row-level locks only for the duration of the statement, not the entire transaction, reducing the chance of deadlocks. It still provides consistent reads at the statement level, avoiding dirty reads.

Option A (READ UNCOMMITTED) is wrong because it allows dirty reads and is not suitable for transactional consistency. Option C (SNAPSHOT ISOLATION) is wrong because it is not supported by MySQL; it is a SQL Server feature. Option D (SERIALIZABLE) is wrong because it increases locking, leading to more deadlocks.

Full explanation →
96
Multi-Selectmedium

A company is using Amazon RDS for MySQL with Multi-AZ deployment. The DBA receives an alert that the standby replica is lagging behind the primary. Which TWO actions should the DBA take to investigate the issue? (Choose TWO.)

Select 2 answers
A.Check the 'Replica Lag' metric for any read replicas.
B.Verify network latency between the primary and standby.
C.Check the 'ReplicaLag' metric in Amazon CloudWatch.
D.Increase the allocated storage to improve IOPS.
E.Change the replication type from asynchronous to synchronous.
AnswersB, C

High network latency can cause replication lag.

Why this answer

The correct answers are B and C. In Amazon RDS Multi-AZ deployments, the standby replica is synchronously replicated from the primary, and the 'ReplicaLag' metric in CloudWatch is used to monitor the replication delay. Checking this metric (option C) helps identify lag.

Additionally, verifying network latency between the primary and standby (option B) can uncover connectivity issues causing lag. Option A is incorrect because Multi-AZ does not have read replicas; Read Replicas are separate from the Multi-AZ standby. Option D is incorrect because storage size does not directly affect replication lag.

Option E is incorrect because Multi-AZ uses synchronous replication, and changing to asynchronous would not solve the issue and is not a supported change for Multi-AZ.

Full explanation →
97
MCQeasy

A developer is deploying an application that uses Amazon DynamoDB as its database. The application experiences sudden spikes in traffic. Which DynamoDB feature should the developer use to handle the spikes without manual intervention?

A.DynamoDB Accelerator (DAX)
B.DynamoDB on-demand capacity mode
C.DynamoDB auto scaling
D.DynamoDB global tables
AnswerC

Auto scaling adjusts read/write capacity automatically based on traffic.

Why this answer

DynamoDB auto scaling (option C) is the correct choice because it automatically adjusts the provisioned read and write capacity based on actual traffic patterns using the AWS Application Auto Scaling service. This allows the application to handle sudden spikes in traffic without manual intervention by increasing capacity when utilization rises and decreasing it when traffic subsides, all while maintaining a target utilization percentage.

Exam trap

The trap here is that candidates often confuse DynamoDB on-demand capacity mode (option B) with a feature that handles spikes without manual intervention, but the question specifically asks for a 'feature' that adjusts provisioned capacity, and on-demand is a capacity mode that eliminates the need for provisioning altogether, not a feature that handles spikes within a provisioned model.

How to eliminate wrong answers

Option A is wrong because DynamoDB Accelerator (DAX) is an in-memory caching layer that improves read latency but does not handle write capacity spikes or automatically adjust throughput provisioning. Option B is wrong because DynamoDB on-demand capacity mode handles spikes by scaling instantly, but it is not a feature that requires manual intervention—it is a capacity mode, not a feature that the developer 'uses' to handle spikes without manual intervention; the question asks for a feature that handles spikes without manual intervention, and on-demand is a billing and capacity mode that does this automatically, but the exam context often distinguishes auto scaling as the feature for provisioned capacity, and on-demand is a separate mode, not a feature that adjusts provisioned capacity. Option D is wrong because DynamoDB global tables provide multi-region replication for disaster recovery and low-latency reads, but they do not handle sudden traffic spikes by adjusting capacity.

Full explanation →
98
Multi-Selecteasy

Which TWO AWS services can be used to monitor the performance of an Amazon DynamoDB table and send alerts when throttling occurs? (Choose two.)

Select 2 answers
A.Amazon Inspector
B.Amazon CloudWatch Alarms
C.VPC Flow Logs
D.AWS Config
E.Amazon CloudWatch
AnswersB, E

CloudWatch Alarms can trigger notifications based on metrics.

Why this answer

Amazon CloudWatch provides metrics such as ConsumedReadCapacityUnits, ConsumedWriteCapacityUnits, and ThrottledRequests for DynamoDB. You can create CloudWatch Alarms to monitor these metrics and send notifications (e.g., via SNS) when throttling occurs. Therefore, both B (CloudWatch Alarms) and E (CloudWatch) are correct.

Option A (Amazon Inspector) is a security assessment service, not a monitoring service. Option C (VPC Flow Logs) captures network traffic, not database performance. Option D (AWS Config) tracks resource configuration changes, not performance metrics.

Full explanation →
99
Multi-Selectmedium

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?

Select 2 answers
A.Use Oracle Recovery Manager (RMAN) to back up and restore.
B.Use Oracle GoldenGate to replicate data continuously.
C.Use AWS Database Migration Service (DMS) with ongoing replication.
D.Take a full database backup and restore to RDS.
E.Use Oracle Data Pump to export and import the database.
AnswersB, C

GoldenGate provides real-time replication with minimal downtime.

Why this answer

Oracle GoldenGate enables continuous, real-time data replication from the source Oracle database to Amazon RDS for Oracle, allowing the source to remain fully operational during the migration. When the cutover is performed, only a brief pause is needed to apply any final transactions, minimizing downtime to seconds or minutes.

Exam trap

The trap here is that candidates often assume any backup-and-restore or export/import method (like RMAN or Data Pump) can be performed with minimal downtime, but these methods inherently require the source database to be offline or in a consistent state for a significant period, unlike continuous replication technologies such as GoldenGate or DMS with CDC.

Full explanation →
100
MCQeasy

A company is migrating a PostgreSQL database to Amazon RDS for PostgreSQL. They want to automate the deployment of the RDS instance using infrastructure as code. Which AWS service should they use?

A.Amazon EC2 Auto Scaling.
B.AWS Management Console.
C.AWS CloudFormation.
D.AWS Command Line Interface (CLI).
AnswerC

CloudFormation enables declarative provisioning of RDS instances.

Why this answer

AWS CloudFormation is the correct service for automating the deployment of an RDS for PostgreSQL instance using infrastructure as code. It allows you to define the entire RDS instance configuration—including DB instance class, storage, backup retention, and security groups—in a declarative JSON or YAML template, which can be version-controlled and reused for consistent, repeatable deployments.

Exam trap

The trap here is that candidates often confuse the AWS CLI (a scripting tool) with infrastructure as code, but the CLI lacks the declarative, state-management, and drift-detection capabilities that define true IaC services like CloudFormation.

How to eliminate wrong answers

Option A is wrong because Amazon EC2 Auto Scaling is designed to automatically adjust the number of EC2 instances based on demand, not to provision or manage RDS instances; it cannot create or configure a PostgreSQL database. Option B is wrong because the AWS Management Console is a manual, point-and-click interface that does not support infrastructure as code or automation; it is not suitable for repeatable, version-controlled deployments. Option D is wrong because the AWS Command Line Interface (CLI) is a scripting tool that can automate RDS creation via commands, but it is not an infrastructure-as-code service—it lacks declarative templates, drift detection, and stack management capabilities that CloudFormation provides.

Full explanation →
101
MCQhard

A company is migrating a 500 GB database from Amazon RDS for MySQL to Amazon Aurora MySQL. The migration must be completed with minimal downtime and no data loss. The RDS instance is Multi-AZ. Which approach should be used?

A.Use AWS DMS with ongoing replication from RDS to Aurora
B.Take a snapshot of the RDS instance and restore to Aurora
C.Set up native MySQL replication from the RDS Multi-AZ standby to Aurora
D.Create an Aurora MySQL read replica from the RDS MySQL instance, then promote it
AnswerD

Aurora MySQL supports creating a read replica from RDS MySQL, allowing minimal downtime.

Why this answer

Creating an Aurora MySQL read replica from the RDS MySQL instance uses the native MySQL binary log (binlog) replication to keep the Aurora cluster synchronized with minimal downtime. Once the replica lag reaches zero, you promote the Aurora cluster to make it the primary database, ensuring no data loss and a very short cutover window.

Exam trap

The trap here is that candidates may assume AWS DMS is always the best choice for minimal-downtime migrations, but for MySQL-to-Aurora migrations, native MySQL replication is simpler, faster, and avoids the overhead of an additional DMS instance.

How to eliminate wrong answers

Option A is wrong because AWS DMS with ongoing replication requires a full load plus change data capture (CDC), which introduces additional latency and complexity, and is not the most efficient method for a 500 GB database when native MySQL replication is available. Option B is wrong because taking a snapshot and restoring to Aurora is a one-time, offline migration that does not support ongoing replication, resulting in significant downtime while the snapshot is taken and restored. Option C is wrong because you cannot set up native MySQL replication from the RDS Multi-AZ standby to Aurora; the standby is not directly accessible for replication, and MySQL replication must originate from the primary instance's binlog.

Full explanation →
102
MCQhard

A company is using Amazon DynamoDB with auto scaling for a social media application. The table has a partition key of 'user_id'. The application performs many small writes (update user profile) and reads (fetch user profile). Recently, the application's response time has increased. The DBA checks CloudWatch and sees that 'ConsumedWriteCapacityUnits' is close to 'ProvisionedWriteCapacityUnits', and 'WriteThrottleEvents' is low. However, 'ReadThrottleEvents' is high. The table has 1000 WCU and 1000 RCU provisioned. The auto scaling is configured to add capacity when utilization exceeds 70%. The DBA also notices that 'ReadThrottleEvents' spikes during peak hours. What should the DBA do to reduce read throttling?

A.Decrease the provisioned write capacity to 500 WCU to free up resources.
B.Increase the auto scaling target utilization to 90% to allow more headroom.
C.Change the storage type to General Purpose SSD (gp2) to improve I/O.
D.Increase the provisioned read capacity to 2000 RCU or implement DAX caching.
AnswerD

Increasing RCU reduces throttling; DAX offloads reads.

Why this answer

Increasing provisioned read capacity to 2000 RCU would directly address the read throttling, and implementing DAX caching would offload read traffic, reducing the load on the DynamoDB table. Option A is incorrect because decreasing write capacity does not free up read capacity; DynamoDB provisioned capacity for reads and writes is independent. Option B is incorrect because increasing the auto scaling target utilization to 90% would actually cause scaling to trigger at a higher utilization, potentially leading to more throttling, not less.

Option C is incorrect because DynamoDB does not use storage types like GP2; that is a concept for Amazon EBS volumes, not applicable to DynamoDB.

Full explanation →
103
MCQmedium

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. They want to use Oracle GoldenGate for replication. Which AWS service can be used to simplify the setup of GoldenGate on AWS?

A.AWS DMS
B.Amazon RDS for Oracle with GoldenGate enabled
C.AWS CloudFormation
D.AWS Marketplace
AnswerD

Marketplace offers pre-configured GoldenGate AMIs for EC2.

Why this answer

AWS Marketplace offers pre-configured Oracle GoldenGate AMIs that simplify the setup and deployment of GoldenGate on EC2, reducing the manual installation and configuration effort. This is the correct choice because the question asks for a service that simplifies the setup of GoldenGate itself, not the migration tool or infrastructure orchestration.

Exam trap

The trap here is that candidates often confuse AWS DMS (a managed migration service) with Oracle GoldenGate, or assume that Amazon RDS for Oracle natively supports GoldenGate as a feature, when in fact GoldenGate must be run on a separate EC2 instance or on-premises.

How to eliminate wrong answers

Option A is wrong because AWS DMS is a managed migration service that can perform homogenous and heterogeneous migrations, but it does not simplify the setup of Oracle GoldenGate; DMS and GoldenGate are separate replication technologies. Option B is wrong because Amazon RDS for Oracle does not have a 'GoldenGate enabled' feature; GoldenGate must be installed on a separate EC2 instance or on-premises, and RDS does not allow direct installation of custom software like GoldenGate. Option C is wrong because AWS CloudFormation can automate the deployment of infrastructure, including EC2 instances for GoldenGate, but it does not simplify the setup of GoldenGate itself—it only automates the provisioning of resources, not the configuration of the GoldenGate software.

Full explanation →
104
MCQeasy

A company needs to store and analyze JSON documents that contain nested fields. The data is used for real-time dashboards and ad-hoc queries. The team wants a fully managed solution that supports both key-value lookups and SQL-like queries. Which AWS service should they use?

A.Amazon DynamoDB
B.Amazon Redshift
C.Amazon RDS for PostgreSQL with JSONB
D.Amazon DocumentDB
AnswerA

DynamoDB supports JSON documents, key-value lookups, and PartiQL for SQL-like queries.

Why this answer

Amazon DynamoDB is correct because it is a fully managed NoSQL key-value and document database that supports single-digit millisecond latency for key-value lookups, and its PartiQL-compatible query language enables SQL-like queries on JSON documents with nested fields. DynamoDB also integrates with AWS services like Lambda and Kinesis for real-time dashboards, and its adaptive capacity handles ad-hoc query patterns without manual scaling.

Exam trap

The trap here is that candidates often choose Amazon DocumentDB because it is a document database, but they overlook DynamoDB's superior key-value lookup performance and PartiQL's SQL-like query capability, which are explicitly required for real-time dashboards and ad-hoc queries in a fully managed serverless environment.

How to eliminate wrong answers

Option B (Amazon Redshift) is wrong because it is a columnar data warehouse optimized for complex analytical queries on structured data, not for real-time key-value lookups or storing JSON documents with nested fields; its JSON support is limited and incurs higher latency for point lookups. Option C (Amazon RDS for PostgreSQL with JSONB) is wrong because while JSONB supports nested JSON and SQL queries, it is not fully managed in the sense of serverless scaling for unpredictable workloads, and it requires manual provisioning and maintenance of database instances, unlike DynamoDB's auto-scaling. Option D (Amazon DocumentDB) is wrong because it is a MongoDB-compatible document database that supports JSON-like documents and SQL-like queries via MongoDB's aggregation framework, but it is not optimized for single-digit millisecond key-value lookups and does not natively support PartiQL or DynamoDB's consistent low-latency access patterns for real-time dashboards.

Full explanation →
105
MCQhard

A team is deploying a new Amazon Aurora MySQL database and needs to load 5 TB of data from an existing Amazon RDS for MySQL database with minimal downtime. The data is stored in InnoDB tables. Which approach is MOST efficient?

A.Take a snapshot of the RDS for MySQL instance and restore to Aurora
B.Use AWS DMS with full load and ongoing replication
C.Use mysqldump to export the database and import into Aurora
D.Create an Aurora read replica from the RDS for MySQL instance using binlog replication
AnswerD

This method minimizes downtime by replicating data continuously.

Why this answer

Creating an Aurora read replica from an RDS for MySQL instance using binlog replication allows the Aurora cluster to synchronize with the source database in near real-time. Once the replica lag reaches zero, you can promote the Aurora cluster to become the primary database, achieving minimal downtime. This approach leverages the native MySQL binlog replication, which is efficient for large datasets like 5 TB and avoids the overhead of exporting or snapshotting the entire database.

Exam trap

The trap here is that candidates often assume AWS DMS is the best tool for all migrations, but for homogeneous MySQL-to-Aurora migrations with large datasets and minimal downtime, native binlog replication is more efficient because it avoids the overhead of DMS's change data capture (CDC) and schema conversion layers.

How to eliminate wrong answers

Option A is wrong because taking a snapshot of the RDS for MySQL instance and restoring it to Aurora requires a significant downtime window to ensure data consistency, and the snapshot does not capture ongoing changes, so it cannot achieve minimal downtime. Option B is wrong because AWS DMS with full load and ongoing replication can be used, but it is less efficient for a 5 TB dataset compared to binlog replication due to the overhead of the DMS transformation engine and the need to handle schema conversion; additionally, DMS may introduce additional latency and complexity for a homogeneous MySQL-to-Aurora migration. Option C is wrong because using mysqldump to export and import 5 TB of data would require a prolonged downtime period, as the export locks tables or requires a consistent snapshot, and the import process is slow, making it unsuitable for minimal downtime.

Full explanation →
106
MCQmedium

A company is running an RDS for MySQL database and needs to ensure that all connections to the database use SSL encryption. Which configuration step is required?

A.Set 'require_secure_transport' to ON in the DB parameter group.
B.Enable 'Enable SSL' in the RDS console.
C.Set 'rds.force_ssl' to 1 in the DB parameter group.
D.Set 'ssl' to 'require' in the DB parameter group.
AnswerA

This forces all connections to use SSL.

Why this answer

Setting 'require_secure_transport' to ON in the DB parameter group forces all connections to the RDS for MySQL database to use SSL/TLS encryption. This parameter is supported in MySQL 5.7 and later, and when enabled, the server rejects non-encrypted connections, ensuring compliance with security policies.

Exam trap

The trap here is that candidates confuse the MySQL-specific parameter 'require_secure_transport' with the PostgreSQL-specific parameter 'rds.force_ssl', or assume a generic 'Enable SSL' console option exists, leading them to pick incorrect answers.

How to eliminate wrong answers

Option B is wrong because there is no 'Enable SSL' toggle in the RDS console; SSL is always available for RDS MySQL, but enforcement requires a parameter group change. Option C is wrong because 'rds.force_ssl' is not a valid parameter for RDS MySQL; this parameter exists for RDS for PostgreSQL, not MySQL. Option D is wrong because setting 'ssl' to 'require' is not a valid parameter in the MySQL DB parameter group; the correct parameter is 'require_secure_transport'.

Full explanation →
107
MCQhard

A company is using Amazon RDS for SQL Server with Multi-AZ deployment. The security team requires that all database activity be monitored for suspicious queries. The database specialist enabled RDS Database Activity Streams and configured AWS Lambda to process the stream. However, the Lambda function fails to process some events when the database fails over to the standby instance. What is the most likely cause?

A.The security group does not allow the Lambda function to connect to the new primary instance.
B.The Lambda function does not re-establish the stream session after a failover event.
C.The parameter group for the standby instance does not have the activity stream enabled.
D.The KMS key used to encrypt the activity stream is not available in the standby instance's Region.
AnswerB

The Lambda function must re-establish the stream session after a failover. If it does not, events are lost.

Why this answer

When a failover occurs, the RDS Database Activity Stream session is tied to the original primary instance. The Lambda function must re-establish the stream session to the new primary instance to continue processing events. If it does not, events during failover are lost.

Option A is incorrect because the security group controls network access to the RDS endpoint, which remains the same after failover; connectivity is not the issue. Option C is incorrect because parameter group settings apply to both primary and standby instances; the activity stream setting is not parameter group-dependent. Option D is incorrect because the KMS key used for encryption is available in the same region; region unavailability is not a factor in Multi-AZ deployments within a single region.

Full explanation →
108
MCQmedium

A company is migrating a 5 TB Oracle database to Amazon Aurora PostgreSQL. The database has a 4-hour maintenance window weekly. Which migration approach minimizes downtime?

A.Use Oracle Data Pump to export and pg_restore to import.
B.Use AWS Database Migration Service (DMS) with change data capture (CDC).
C.Use AWS Schema Conversion Tool (SCT) to convert schema and then copy data.
D.Use AWS DMS full load only and then manually sync.
AnswerB

DMS with CDC provides near-zero downtime.

Why this answer

AWS DMS with CDC allows you to perform an initial full load of the 5 TB database and then continuously replicate ongoing changes from the source Oracle database to the target Aurora PostgreSQL. This minimizes downtime because you can keep the source database fully operational during the migration and only perform a brief cutover to switch applications to the new database, well within the 4-hour maintenance window.

Exam trap

The trap here is that candidates often assume a full load plus manual sync (Option D) is sufficient, but they overlook the fact that for a 5 TB database, the manual sync window would be too long to fit within the 4-hour maintenance window, whereas CDC enables a near-zero-downtime cutover.

How to eliminate wrong answers

Option A is wrong because Oracle Data Pump export and pg_restore import require the source database to be offline or in a restricted state for the entire duration of the export and import, which for a 5 TB database would far exceed the 4-hour maintenance window. Option C is wrong because the AWS Schema Conversion Tool (SCT) only converts the schema and does not handle data migration; you would still need a separate data copy step that would cause significant downtime. Option D is wrong because AWS DMS full load only copies a snapshot of the data at a point in time, and then you would need to manually sync any changes made during the load, which is error-prone and would require a longer downtime window to ensure consistency.

Full explanation →
109
MCQmedium

A company is running a production Amazon Aurora MySQL database. The database performance has degraded over the past week. The DBA suspects an increase in lock waits. Which tool should be used to identify queries experiencing lock waits?

A.Amazon CloudWatch Logs
B.Amazon RDS Enhanced Monitoring
C.Amazon RDS Performance Insights
D.AWS Trusted Advisor
AnswerC

Performance Insights shows wait events like lock waits.

Why this answer

Amazon RDS Performance Insights provides a database load visualization and detailed wait event analysis, allowing you to identify queries experiencing lock waits. Option A is incorrect because CloudWatch Logs captures log streams but does not directly show lock wait events. Option B is incorrect because Enhanced Monitoring provides OS-level metrics (CPU, memory, disk I/O) but not database-specific lock waits.

Option D is incorrect because AWS Trusted Advisor offers best-practice recommendations but does not monitor real-time database performance or lock waits.

Full explanation →
110
MCQeasy

A web application uses Amazon DynamoDB as its database. The application frequently queries items using a secondary index. The index's partition key has high cardinality, but the query latency is higher than expected. Which action would MOST likely improve query performance?

A.Use a Scan operation instead of Query to retrieve items from the index.
B.Add additional sort key attributes to the index to better distribute the data.
C.Convert the global secondary index to a local secondary index.
D.Increase the read capacity units (RCU) for the global secondary index.
AnswerD

Insufficient read capacity on the index can cause throttling and higher latency.

Why this answer

A Global Secondary Index (GSI) has its own provisioned read capacity, separate from the base table. If the GSI's read capacity units (RCU) are insufficient to handle the query workload, requests may be throttled, leading to higher latency. Increasing the RCU for the GSI directly addresses this bottleneck by allowing more concurrent read operations against the index.

Exam trap

The trap here is that candidates often assume high cardinality automatically guarantees good performance, overlooking that the GSI's provisioned read capacity is a separate resource that must be scaled independently to avoid throttling.

How to eliminate wrong answers

Option A is wrong because a Scan operation reads every item in the index or table, which is far less efficient and slower than a Query operation, especially for high-cardinality partition keys; it would increase latency, not reduce it. Option B is wrong because adding sort key attributes does not affect data distribution across partitions; the partition key alone determines distribution, and high cardinality already ensures good distribution—adding sort keys would not improve query performance for the described scenario. Option C is wrong because converting a GSI to an LSI would not help; LSIs share the base table's partition key and read capacity, and they cannot be created after table creation if the table lacks a sort key, nor would this change address throttling or latency issues.

Full explanation →
111
MCQhard

A company is running an Oracle database on Amazon RDS. The database has a large table that is frequently accessed by multiple applications. The DBA notices that the table has a high number of index scans but the queries are still slow. Upon investigation, the buffer cache hit ratio is low. Which design change would BEST improve performance?

A.Convert the table to columnar storage using Amazon Redshift
B.Add a read replica to offload queries
C.Migrate the table to Amazon DynamoDB with DAX
D.Increase the instance size to provide more memory
AnswerD

More memory increases buffer cache capacity, reducing disk I/O.

Why this answer

The low buffer cache hit ratio indicates that the database's memory (buffer cache) is insufficient to cache frequently accessed data blocks, causing excessive physical I/O. Increasing the instance size provides more memory, which expands the buffer cache and allows more data to be cached, reducing disk reads and improving query performance. This directly addresses the root cause of the slow queries despite efficient index scans.

Exam trap

The trap here is that candidates often choose a read replica (Option B) thinking it will distribute the load, but they fail to recognize that the low buffer cache hit ratio is a memory constraint on the primary instance, not a CPU or connection bottleneck, so offloading queries does not solve the underlying caching issue.

How to eliminate wrong answers

Option A is wrong because converting to Amazon Redshift would require a complete architectural change to a columnar data warehouse, which is not designed for high-frequency transactional access and would introduce significant latency and complexity for the existing Oracle RDS workload. Option B is wrong because adding a read replica offloads read queries but does not increase the buffer cache size on the primary instance; the low buffer cache hit ratio on the primary remains unchanged, so queries against the primary will still be slow. Option C is wrong because migrating to DynamoDB with DAX is a NoSQL solution that does not support the relational schema, SQL queries, and transactional integrity of the existing Oracle database, and it would require extensive application rewrites.

Full explanation →
112
MCQmedium

A company is using Amazon RDS for MySQL and wants to restrict access to a specific database so that an application user can only perform SELECT and INSERT operations on tables within that database. The application user already exists. Which SQL statement should be executed?

A.GRANT SELECT ON app_db.* TO 'app_user'@'%';
B.GRANT CREATE, ALTER, SELECT, INSERT ON app_db.* TO 'app_user'@'%';
C.GRANT SELECT, INSERT ON app_db.* TO 'app_user'@'%';
D.GRANT ALL PRIVILEGES ON app_db.* TO 'app_user'@'%';
AnswerC

This grants exactly the required permissions.

Why this answer

It grants exactly the required SELECT and INSERT privileges on all tables within the app_db database. Option A is incorrect because it only grants SELECT, missing INSERT. Option B is incorrect because it includes unnecessary DDL privileges (CREATE, ALTER) which are not needed and could be a security risk.

Option D is incorrect because it grants ALL PRIVILEGES, which is too permissive for an application user.

Full explanation →
113
MCQmedium

A company is designing a database for an IoT application that collects sensor data every second from millions of devices. The data is time-series and must be stored for 90 days, with occasional queries for recent data. Which AWS database solution is MOST cost-effective and performant?

A.Amazon Timestream
B.Amazon Redshift
C.Amazon DynamoDB with TTL to expire old data
D.Amazon RDS for MySQL with partitioning
AnswerA

Timestream is built for time-series data, cost-effective, and supports automatic retention.

Why this answer

Amazon Timestream is purpose-built for time-series data, offering automatic storage tiering (in-memory for recent data and magnetic for historical data) and serverless scaling, which makes it the most cost-effective and performant choice for ingesting sensor data every second from millions of devices and retaining it for 90 days with occasional queries on recent data.

Exam trap

The trap here is that candidates often choose DynamoDB with TTL because they associate it with high throughput and automatic expiration, but they overlook the lack of native time-series query support and the cost of provisioning for sustained high write capacity.

How to eliminate wrong answers

Option B (Amazon Redshift) is wrong because it is a columnar data warehouse optimized for complex analytical queries on large datasets, not for high-frequency time-series ingestion; its per-hour billing and compute overhead would be prohibitively expensive for this use case. Option C (Amazon DynamoDB with TTL) is wrong because while DynamoDB can handle high write throughput, it is a key-value and document database that lacks native time-series optimizations like automatic downsampling or time-based partitioning, and TTL only deletes expired items without providing efficient time-range queries. Option D (Amazon RDS for MySQL with partitioning) is wrong because a relational database with manual partitioning cannot scale to millions of writes per second without significant cost and operational overhead, and it lacks the serverless, auto-scaling ingestion and storage tiering that Timestream provides.

Full explanation →
114
MCQhard

A company is migrating an on-premises Oracle database to AWS. The database is 5 TB and supports a critical OLTP application with high transaction rates. The application requires stored procedures, triggers, and strong consistency. Which AWS database service is most appropriate with minimal application changes?

A.Amazon Aurora PostgreSQL
B.Amazon DynamoDB
C.Amazon RDS for Oracle
D.Amazon Redshift
AnswerC

Fully compatible with Oracle, minimal changes needed.

Why this answer

Amazon RDS for Oracle is the most appropriate choice because it provides native Oracle compatibility, supporting stored procedures, triggers, and strong consistency with minimal application changes. The company can use Oracle's PL/SQL code directly, and RDS for Oracle offers full ACID compliance for OLTP workloads, avoiding the need to rewrite application logic or adapt to a different consistency model.

Exam trap

The DBS-C01 exam often tests the misconception that any AWS-managed database can replace Oracle with minimal changes, but the trap here is that candidates overlook the critical dependency on Oracle-specific PL/SQL stored procedures and triggers, which are not directly portable to PostgreSQL, DynamoDB, or Redshift.

How to eliminate wrong answers

Option A is wrong because Amazon Aurora PostgreSQL, while offering strong consistency and high performance, would require significant application changes to migrate from Oracle's PL/SQL stored procedures and triggers to PostgreSQL's PL/pgSQL, and does not support Oracle-specific features like REF CURSORs or Oracle SQL syntax. Option B is wrong because Amazon DynamoDB is a NoSQL key-value and document database that does not support stored procedures or triggers in the traditional sense (its streams and Lambda-based triggers are not equivalent), and it provides only eventual consistency by default, not the strong consistency required for this OLTP application. Option D is wrong because Amazon Redshift is a columnar data warehouse optimized for analytical queries and batch processing, not for high-transaction OLTP workloads, and it does not support stored procedures or triggers in the same way as a relational database.

Full explanation →
115
MCQmedium

A developer is trying to connect to an RDS for PostgreSQL instance using the endpoint shown in the exhibit. The connection fails with a timeout. Which of the following is the most likely cause?

A.The endpoint address is incorrect.
B.The DB instance requires SSL encryption to connect.
C.The security group does not allow inbound traffic on port 5432 from the client IP.
D.The DB instance is in a Multi-AZ configuration and requires a different endpoint.
AnswerC

Correct. A timeout often indicates network connectivity issues, such as security group rules blocking the port.

Why this answer

The most likely cause is that the security group does not allow inbound traffic on port 5432 from the client IP, causing a timeout. Option A is incorrect because the endpoint is correctly provided by AWS; an incorrect endpoint would produce a different error. Option B is incorrect because SSL encryption is not required by default; if it were, the error would be an SSL handshake failure, not a timeout.

Option D is incorrect because Multi-AZ configurations use the same endpoint; no separate endpoint is needed.

Full explanation →
116
MCQmedium

A company is deploying a new application that requires a relational database with automatic failover and cross-Region disaster recovery. The application is read-heavy and expects up to 10 GB of data. Which combination of AWS services should be used?

A.Amazon RDS for MySQL with Multi-AZ and a read replica in another Region
B.Amazon S3 with AWS Glue and Amazon Athena
C.Amazon Aurora with Multi-AZ and an Aurora global database
D.Amazon DynamoDB with global tables
AnswerC

Aurora global database provides cross-Region replication and fast failover.

Why this answer

Amazon Aurora with Multi-AZ provides high availability within a single Region, while Aurora Global Database enables cross-Region disaster recovery with typical replication latency of under one second. Aurora is optimized for read-heavy workloads and scales automatically, making it ideal for the 10 GB dataset and the application's requirements.

Exam trap

The trap here is that candidates often confuse Multi-AZ with cross-Region disaster recovery, assuming a read replica in another Region provides automatic failover, but in RDS MySQL, read replicas require manual promotion and do not support automatic cross-Region failover.

How to eliminate wrong answers

Option A is wrong because Amazon RDS for MySQL with Multi-AZ provides automatic failover within a single Region, but a read replica in another Region does not support automatic cross-Region failover for disaster recovery; you would need to manually promote the read replica, which does not meet the automatic failover requirement. Option B is wrong because Amazon S3 with AWS Glue and Athena is a serverless analytics and query service, not a relational database; it lacks transactional consistency, automatic failover, and relational database features required by the application. Option D is wrong because Amazon DynamoDB with global tables is a NoSQL key-value and document database, not a relational database; it does not support SQL queries, joins, or relational constraints, which the application explicitly requires.

Full explanation →
117
MCQeasy

A company uses Amazon DynamoDB to store application logs. The logs have a TTL of 7 days. The operations team needs to run ad-hoc analytical queries on logs older than 7 days, which are automatically deleted by TTL. Which solution should the team implement to retain and analyze old logs?

A.Use DynamoDB Streams to export logs to Amazon S3 and query with Amazon Athena.
B.Disable TTL and use a scheduled Lambda function to archive logs to Amazon S3.
C.Increase the TTL to 30 days and query the logs directly in DynamoDB.
D.Use AWS Glue to crawl DynamoDB tables and create a data catalog for Athena queries.
AnswerA

Streams capture data before deletion, and Athena can query S3 data cost-effectively.

Why this answer

DynamoDB Streams can capture item deletions (including TTL-based deletions) and export them to Amazon S3. Once the logs are in S3, Amazon Athena can run ad-hoc SQL queries directly on the data, providing a cost-effective and serverless analytical solution for logs older than 7 days.

Exam trap

The trap here is that candidates may think AWS Glue can directly query DynamoDB for historical analysis, but Glue is an ETL service that crawls existing data, not a query engine for deleted items, and TTL-deleted logs are permanently removed from DynamoDB.

How to eliminate wrong answers

Option B is wrong because disabling TTL would retain all logs indefinitely in DynamoDB, increasing costs and violating the 7-day retention policy; archiving via a scheduled Lambda function is unnecessary when DynamoDB Streams can automatically export deleted items. Option C is wrong because increasing TTL to 30 days does not solve the need to analyze logs older than 7 days—it only delays deletion, and querying large volumes of old logs directly in DynamoDB is inefficient and expensive for ad-hoc analytical queries. Option D is wrong because AWS Glue crawling a DynamoDB table does not retain deleted logs; TTL-deleted items are removed and cannot be crawled, and Athena cannot query DynamoDB directly without exporting data to S3 first.

Full explanation →
118
Multi-Selecteasy

Which TWO options are valid methods for migrating an on-premises SQL Server database to Amazon RDS for SQL Server with minimal downtime? (Choose TWO.)

Select 2 answers
A.Use AWS CloudEndure to replicate the entire server.
B.Copy the database files to Amazon S3 and restore to RDS.
C.Use SQL Server Import/Export Wizard.
D.Use AWS DMS with ongoing replication from the source.
E.Use native backup and restore with log shipping to RDS.
AnswersD, E

DMS can perform continuous replication to keep the target in sync.

Why this answer

AWS DMS with ongoing replication (change data capture, CDC) is a valid method for migrating to Amazon RDS for SQL Server with minimal downtime because it allows you to perform a full load of the database and then continuously replicate incremental changes from the source until you cut over. This keeps the target nearly in sync, reducing the downtime window to seconds or minutes.

Exam trap

The trap here is that candidates often confuse 'native backup and restore with log shipping' (Option E) as a valid minimal-downtime method, but while log shipping can reduce downtime, it requires manual setup of a secondary database and is not natively supported by Amazon RDS for SQL Server without using AWS DMS or other tools; however, in this question, Option E is actually correct because you can use native backup/restore to seed the RDS instance and then use log shipping (via AWS DMS or manual T-SQL) to apply transaction log backups, achieving minimal downtime.

Full explanation →
119
MCQhard

A company wants to migrate a 2 TB PostgreSQL database from on-premises to Amazon Aurora PostgreSQL. The database has high write throughput and the migration must have minimal impact on source performance. Which solution is MOST appropriate?

A.Create a read replica of the on-premises database and promote it to Aurora.
B.Use AWS DMS with ongoing replication from the source to Aurora.
C.Use pglogical to set up logical replication from the source to Aurora.
D.Set up native PostgreSQL streaming replication from on-premises to Aurora.
AnswerC

pglogical provides logical replication with minimal overhead on the source.

Why this answer

Pglogical is a PostgreSQL extension that provides logical replication with minimal overhead on the source, making it ideal for high-write-throughput databases. It allows selective table replication and does not require physical changes to the source, thus avoiding performance impact. AWS DMS (Option B) can also perform ongoing replication but introduces additional overhead and complexity, and it is not as tightly integrated with PostgreSQL's native replication mechanisms as pglogical.

Exam trap

The trap here is that candidates often assume AWS DMS is always the best choice for minimal-impact migrations, but for PostgreSQL-to-Aurora migrations, native logical replication via pglogical is more efficient and less intrusive on high-write-throughput sources.

How to eliminate wrong answers

Option A is wrong because creating a read replica of an on-premises database and promoting it to Aurora is not a supported migration path; read replicas are a feature of Amazon RDS/Aurora, not on-premises PostgreSQL. Option B is wrong because AWS DMS with ongoing replication can be used but it adds extra load on the source due to its change data capture (CDC) mechanism, which can impact high-write-throughput workloads, and it is less efficient than native logical replication. Option D is wrong because native PostgreSQL streaming replication (physical replication) cannot be set up from on-premises to Aurora as Aurora does not accept physical WAL streaming from external sources; it only supports logical replication via pglogical or DMS.

Full explanation →
120
MCQmedium

Refer to the exhibit. A database administrator runs the AWS CLI command to describe events for an RDS instance. Which conclusion is most likely correct based on the output?

A.The Multi-AZ failover failed and the instance restarted.
B.The DB instance was manually restarted by an administrator.
C.The DB instance experienced a Multi-AZ failover and subsequently restarted.
D.The DB instance was restored from a snapshot and then restarted.
AnswerC

The sequence shows a failover completed, then the instance restarted.

Why this answer

The output shows a failover event followed by a restart, which is typical after a failover. Option A is incorrect because the events show a failover, not a manual restart. Option B is incorrect because the failover was completed, not failed.

Option D is incorrect because there is no indication of a snapshot restore.

Full explanation →
121
MCQhard

A security engineer is troubleshooting an issue where an application using IAM role 'app-role' with a trust policy to assume the 'app-user' user is unable to decrypt an RDS database that uses a customer-managed KMS key. The above key policy is attached to the KMS key. What is the likely cause of the failure?

A.The 'kms:ViaService' condition requires the request to come from RDS, but the application is making KMS API calls directly.
B.The policy has a missing 'Effect': 'Deny' statement that is blocking access.
C.The principal in the policy is 'app-user', but the application uses an IAM role that does not have the necessary permissions.
D.The condition 'kms:ViaService' restricts the key to be used only with RDS, but the application is using a different service.
AnswerC

The policy grants permissions to the user 'app-user', but the application uses a role. The role needs to be added to the key policy.

Why this answer

The KMS key policy specifies the principal as 'app-user', which is an IAM user. However, the application uses an IAM role 'app-role' to make the decryption requests. Since the principal in the key policy does not include the role or its associated permissions, the KMS key policy denies access to the role, causing the decryption failure.

The trust policy on the role allows the user to assume it, but that does not grant the role any KMS permissions unless explicitly added.

Exam trap

The trap here is that candidates often confuse the trust policy of an IAM role with the permissions granted to the role, assuming that if a user can assume a role, the role inherits the user's KMS permissions, when in fact the role must be explicitly authorized in the key policy or via an IAM policy.

How to eliminate wrong answers

Option A is wrong because the 'kms:ViaService' condition in the key policy allows requests coming via RDS, not that the request must come from RDS; the application making direct KMS API calls would still be allowed if the principal matches, so this is not the cause. Option B is wrong because the policy does not have a missing 'Deny' statement; the issue is that the principal is incorrect, not that a Deny is needed. Option D is wrong because the 'kms:ViaService' condition is set to 'rds.amazonaws.com', which permits RDS to use the key, but the application is not using RDS to make the decryption call; however, the primary failure is the principal mismatch, not the service condition.

Full explanation →
122
MCQmedium

Refer to the exhibit. A CloudFormation stack was deployed to create an RDS instance. The application team reports they cannot connect to the database using the endpoint provided. The security group allows inbound traffic on port 3306 from the application's security group. What is the most likely cause?

A.The RDS instance is in a Multi-AZ deployment and the endpoint is for the standby
B.The security group inbound rule is missing the port 3306
C.The database password is not provided in the stack outputs; the team may be using the wrong password
D.The RDS endpoint is incorrect; it should include the port number
AnswerC

The password is not output; they likely need to retrieve it from Secrets Manager.

Why this answer

The CloudFormation stack outputs typically do not include the database password for security reasons. The application team may be using an incorrect password, which would cause authentication failures even if the network connectivity and security group rules are properly configured. Without the correct password, the RDS instance will reject the connection attempt at the MySQL/MariaDB protocol level.

Exam trap

The trap here is that candidates focus on network connectivity issues (security groups, endpoints) and overlook the fact that authentication credentials are not automatically provided in stack outputs, leading them to choose options like B or D instead of recognizing the password mismatch as the root cause.

How to eliminate wrong answers

Option A is wrong because Multi-AZ deployments use a single DNS endpoint that automatically points to the primary instance; the endpoint does not resolve to the standby. Option B is wrong because the question explicitly states that the security group allows inbound traffic on port 3306 from the application's security group, so the rule is present. Option D is wrong because the RDS endpoint provided by CloudFormation includes the DNS name and port number (e.g., mydb.xxxxxx.rds.amazonaws.com:3306) by default, so the port is already part of the endpoint.

Full explanation →
123
MCQhard

A media company is migrating a 5 TB MongoDB database to Amazon DocumentDB. The migration must have minimal downtime. The source MongoDB uses sharding across 10 shards. Which migration strategy is MOST appropriate?

A.Use native MongoDB replication to sync to DocumentDB
B.Use AWS DMS with MongoDB as source and DocumentDB as target, enabling CDC
C.Export data to S3 and use AWS Glue to load into DocumentDB
D.Use mongoexport to export data and mongoimport to import into DocumentDB
AnswerB

DMS supports MongoDB to DocumentDB migration with CDC for minimal downtime.

Why this answer

AWS DMS with CDC (Change Data Capture) is the most appropriate strategy because it supports ongoing replication from a sharded MongoDB source to Amazon DocumentDB, enabling near-zero downtime migration. DMS can handle the 5 TB dataset and 10 shards by using the MongoDB oplog to capture changes after the initial full load, ensuring minimal interruption to the media company's operations.

Exam trap

The trap here is that candidates assume native MongoDB replication (Option A) works because DocumentDB claims MongoDB compatibility, but DocumentDB does not implement the MongoDB replication protocol, making DMS with CDC the only viable near-zero downtime option.

How to eliminate wrong answers

Option A is wrong because native MongoDB replication uses the MongoDB replication protocol to sync data between MongoDB instances, but Amazon DocumentDB does not support the MongoDB replication protocol as a replica set member, so direct replication is not possible. Option C is wrong because exporting data to S3 and using AWS Glue to load into DocumentDB is a batch-oriented approach that does not support CDC, resulting in significant downtime during the migration of a 5 TB dataset. Option D is wrong because mongoexport and mongoimport are offline tools that export/import data in JSON or CSV format, requiring the source database to be quiesced or taken offline, which does not meet the minimal downtime requirement.

Full explanation →
124
MCQeasy

A company wants to migrate a 500 GB SQL Server database to Amazon RDS for SQL Server with the least amount of downtime. The on-premises network has a 1 Gbps connection to AWS. Which approach should be used?

A.Use AWS DMS with ongoing replication from on-premises to RDS
B.Use AWS Snowball to transfer the database backup, then restore to RDS
C.Copy database files to S3 and then use RDS import
D.Use native SQL Server backup to S3, then restore to RDS
AnswerA

DMS with CDC minimizes downtime by synchronizing changes until cutover.

Why this answer

AWS DMS with ongoing replication (change data capture, CDC) allows you to perform a full load of the 500 GB database while continuously replicating ongoing changes from the on-premises SQL Server to Amazon RDS for SQL Server. This minimizes downtime to a brief cutover window when you stop writes on the source and redirect traffic to the target. The 1 Gbps connection is sufficient for the initial load and ongoing replication, making this the most effective approach for minimal downtime.

Exam trap

The trap here is that candidates often choose native backup/restore (Option D) thinking it is the fastest because it is familiar, but they overlook that it requires a full backup (causing downtime) and lacks ongoing replication, whereas DMS with CDC provides near-zero downtime by replicating changes continuously.

How to eliminate wrong answers

Option B is wrong because AWS Snowball is designed for offline data transfer of large datasets (typically >10 TB or over slow networks) and introduces significant logistical delays (shipping, processing), which does not achieve the least amount of downtime for a 500 GB database over a 1 Gbps connection. Option C is wrong because copying database files to S3 and then using RDS import is not a supported method for SQL Server; RDS for SQL Server does not support importing from raw database files in S3—you must use native backup/restore or DMS. Option D is wrong because native SQL Server backup to S3 and restore to RDS requires taking a full backup, which locks the database and incurs downtime during the backup process, and does not provide ongoing replication to minimize the cutover window.

Full explanation →
125
MCQeasy

A company is migrating an on-premises DynamoDB table to Amazon DynamoDB in another AWS region. What is the most efficient method to migrate the data?

A.Use DynamoDB global tables to replicate data across regions.
B.Export the table to S3 using AWS Data Pipeline, then import into DynamoDB in the target region.
C.Set up DynamoDB Streams and write a custom consumer to replicate data to the target region.
D.Use AWS DMS to replicate data from on-premises to DynamoDB.
AnswerA

Global tables automatically replicate data across regions, simplifying migration.

Why this answer

DynamoDB global tables provide a fully managed, multi-region, multi-master replication solution that automatically replicates data across AWS regions with low latency. This eliminates the need for custom code or external tools, making it the most efficient method for migrating an on-premises DynamoDB table to another region, as it handles ongoing replication and conflict resolution natively.

Exam trap

The trap here is that candidates often confuse DynamoDB global tables with DynamoDB Streams or AWS DMS, assuming that manual replication or database migration services are necessary, when in fact global tables are the simplest and most efficient solution for cross-region migration of DynamoDB tables.

How to eliminate wrong answers

Option B is wrong because exporting to S3 via AWS Data Pipeline and then importing is a batch-oriented approach that requires manual orchestration, does not support continuous replication, and introduces additional latency and complexity compared to the native replication of global tables. Option C is wrong because setting up DynamoDB Streams with a custom consumer requires developing, deploying, and maintaining custom code to handle replication, which is less efficient and more error-prone than using the built-in global tables feature. Option D is wrong because AWS DMS is designed for migrating relational databases and does not support DynamoDB as a source or target for replication; it cannot be used to migrate data from an on-premises DynamoDB table to DynamoDB in another region.

Full explanation →
126
MCQmedium

A company is planning to migrate a MongoDB database to Amazon DocumentDB. The database has several sharded collections. Which migration strategy should be used?

A.Set up MongoDB replica set to replicate directly to DocumentDB.
B.Use AWS DMS with MongoDB as source and DocumentDB as target, enabling ongoing replication.
C.Use AWS Schema Conversion Tool (SCT) to convert the schema, then manually migrate data.
D.Export data using mongodump and import using mongorestore.
AnswerB

DMS supports homogeneous migration with minimal downtime.

Why this answer

AWS DMS supports MongoDB as a source and Amazon DocumentDB as a target, and it can perform ongoing replication (change data capture) to keep the target synchronized with the source during migration. This is essential for sharded MongoDB collections because it minimizes downtime by allowing the source to remain operational while data is migrated and changes are continuously applied.

Exam trap

The trap here is that candidates may assume a simple dump-and-restore (Option D) is sufficient for sharded collections, overlooking the need for minimal downtime and ongoing replication that AWS DMS provides.

How to eliminate wrong answers

Option A is wrong because MongoDB replica sets cannot replicate directly to DocumentDB; DocumentDB uses its own replication protocol and is not a MongoDB replica set member. Option C is wrong because AWS Schema Conversion Tool (SCT) is designed for schema conversion of relational databases, not for NoSQL databases like MongoDB or DocumentDB, and it does not handle data migration. Option D is wrong because mongodump and mongorestore perform a one-time, offline export/import, which does not support ongoing replication and would require significant downtime, especially for sharded collections.

Full explanation →
127
MCQhard

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

A.Reboot the DB instance to apply the pending parameter group changes.
B.Take a snapshot of the DB instance before applying changes.
C.Modify the DB parameter group to change the parameter values.
D.Modify the DB instance to set the backup retention period to 7.
AnswerA

The ParameterApplyStatus shows 'pending-reboot', so a reboot is required to apply the parameter changes.

Why this answer

The output shows 'ParameterApplyStatus: pending-reboot', which indicates that changes to the DB parameter group (specifically the parameter modifications) require a reboot to take effect. While there are also pending modifications for the backup retention period and master user password, these do not necessitate a reboot. Therefore, the correct action is to reboot the DB instance (Option A).

Options B, C, and D are incorrect: taking a snapshot is not required, modifying the parameter group has already been done (the status reflects pending-reboot), and altering the backup retention period is not the immediate action needed for the pending reboot.

Full explanation →
128
MCQhard

An e-commerce company is migrating its PostgreSQL database to Amazon RDS for PostgreSQL. The database has multiple large tables (over 500 GB each) and the migration window is only 2 hours. Which strategy would be MOST effective to meet the time constraint?

A.Use a single DMS task with full LOB mode.
B.Use AWS DMS with parallel load by splitting tables into multiple tasks.
C.Increase the RDS instance size and use pg_dump.
D.Use AWS SCT to optimize schema and then one DMS task.
AnswerB

Parallel load accelerates migration.

Why this answer

AWS DMS with parallel load by splitting tables into multiple tasks allows concurrent data transfer across multiple threads, maximizing throughput for large tables. This approach directly addresses the 2-hour migration window by distributing the workload, whereas a single task would be bottlenecked by sequential processing. Parallel load is specifically designed for high-volume migrations where time is critical.

Exam trap

The trap here is that candidates assume a single DMS task with full LOB mode is sufficient for large tables, underestimating the severe performance penalty of sequential LOB processing, and overlook the parallel load feature designed specifically for this scenario.

How to eliminate wrong answers

Option A is wrong because a single DMS task with full LOB mode processes LOB data sequentially and can be extremely slow for large tables, often failing to meet tight migration windows due to single-threaded LOB handling. Option C is wrong because increasing the RDS instance size and using pg_dump still relies on a single-threaded dump process, which cannot parallelize across multiple tables or partitions, and the migration window is too short for 500 GB+ tables. Option D is wrong because AWS SCT optimizes schema but does not accelerate data transfer; using one DMS task afterward still suffers from the same single-task bottleneck as option A.

Full explanation →
129
MCQhard

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

A.Autovacuum is not running, causing bloat.
B.The instance is running out of storage space.
C.There are too many concurrent connections.
D.The 'max_wal_size' parameter is set too low, causing frequent WAL switches.
AnswerD

Low max_wal_size leads to frequent checkpoints.

Why this answer

Frequent checkpoints in PostgreSQL are often caused by small WAL size settings. The 'max_wal_size' parameter controls the maximum size of WAL files before a checkpoint is triggered. If set too low, the database will perform checkpoints more frequently to recycle WAL segments.

Option A is incorrect because autovacuum bloat does not directly cause frequent checkpoints. Option B is incorrect because storage space issues may cause other symptoms, but not specifically checkpoint frequency. Option C is incorrect because concurrent connections may increase workload but do not directly cause frequent checkpoints; the checkpoint timing is driven by WAL generation rate and WAL size limits.

Full explanation →
130
MCQhard

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

A.The table's previous peak throughput was lower than the current traffic, and DynamoDB is still adapting.
B.The table has a hot partition that is receiving more requests than the partition can handle.
C.The table has exceeded the maximum allowed throughput for on-demand capacity mode.
D.The table's provisioned read/write capacity is set too low.
AnswerA

On-demand capacity mode can throttle if traffic exceeds the table's previous peak by a large margin, as DynamoDB needs time to scale up.

Why this answer

On-demand capacity mode in DynamoDB automatically scales based on the table's previous peak throughput. If current traffic suddenly exceeds that previous peak, DynamoDB may throttle requests until it adapts to the new traffic level, even if the requests are within the eventual on-demand limits. Option B is incorrect because although a hot partition can cause throttling, the question states that read and write requests are within the throughput limits, implying the issue is not at the partition level but rather a sudden spike beyond the adapted peak.

Option C is incorrect because on-demand mode has no maximum throughput limit; it scales automatically. Option D is incorrect because on-demand mode does not use provisioned capacity; it scales without manual configuration.

Full explanation →
131
MCQhard

A company is migrating a 5 TB Microsoft SQL Server database to Amazon RDS for SQL Server. The migration must have minimal downtime. The source database is hosted on an EC2 instance. Which combination of steps should be taken?

A.Take a native backup of the source, upload to S3, and restore to RDS
B.Use AWS DMS with full load and ongoing replication
C.Create an RDS read replica from the EC2-hosted database
D.Use the SQL Server Import and Export Wizard
AnswerA

Native backup/restore is efficient for large databases and supports minimal downtime.

Why this answer

Native backup and restore to Amazon RDS for SQL Server is the fastest and most reliable method for migrating a large database like 5 TB with minimal downtime. By taking a full backup, uploading it to Amazon S3, and restoring it to RDS, you avoid the overhead of ongoing replication setup and can schedule the final cutover during a brief maintenance window. This approach leverages RDS's native support for restoring from S3, ensuring data integrity and minimizing the migration window.

Exam trap

The trap here is that candidates often assume AWS DMS is always the best choice for minimal downtime migrations, but for large SQL Server databases, native backup and restore to RDS is simpler, faster, and more reliable, especially when the source is on EC2 and the target is RDS.

How to eliminate wrong answers

Option B is wrong because AWS DMS with full load and ongoing replication, while capable of minimal downtime, introduces additional complexity and potential performance bottlenecks for a 5 TB database, and the ongoing replication requires continuous change data capture (CDC) which may not be supported or optimal for SQL Server in all scenarios. Option C is wrong because RDS read replicas cannot be created from an EC2-hosted database; read replicas are only supported between RDS instances, not from external sources. Option D is wrong because the SQL Server Import and Export Wizard is a row-by-row data movement tool that is extremely slow for large databases and does not support ongoing replication, making it unsuitable for a 5 TB migration with minimal downtime requirements.

Full explanation →
132
MCQhard

A security team is auditing IAM policies for Amazon RDS. They want to ensure that all RDS snapshots shared with other AWS accounts are encrypted. Which IAM policy condition key should be used to enforce this?

A.rds:Encrypted
B.rds:SnapshotEncrypted
C.rds:StorageEncrypted
D.s3:x-amz-server-side-encryption
AnswerA

This condition key checks whether the snapshot is encrypted.

Why this answer

Rds:Encrypted. This condition key verifies that a snapshot is encrypted when sharing with other AWS accounts. Option B (rds:SnapshotEncrypted) is not a valid condition key.

Option C (rds:StorageEncrypted) is used to check if the DB instance's storage is encrypted, not the snapshot. Option D (s3:x-amz-server-side-encryption) is an S3 condition key and not applicable to RDS snapshots.

Full explanation →
133
MCQmedium

A company is launching a new application that requires an Amazon RDS for PostgreSQL database. The database will store highly sensitive data, and the security team mandates that all data at rest must be encrypted. The company also requires that the encryption keys be managed by the security team using AWS CloudHSM. What is the MOST efficient way to meet these requirements?

A.Enable EBS encryption on the RDS instance's underlying volumes using a KMS key.
B.Enable Transparent Data Encryption (TDE) using a CloudHSM key in the RDS instance.
C.Use AWS KMS with a customer-managed key (CMK) for RDS encryption.
D.Implement client-side encryption in the application before writing data to the database.
AnswerC

RDS encryption with a customer-managed KMS key encrypts data at rest and can be backed by CloudHSM via custom key store.

Why this answer

Amazon RDS for PostgreSQL does not support Transparent Data Encryption (TDE). TDE is only available for Oracle and SQL Server. The most efficient way to meet the requirements is to use RDS encryption with a customer-managed key (CMK) in AWS KMS, which encrypts the underlying storage and automated backups.

The security team can manage the CMK via CloudHSM by using a KMS custom key store, thus satisfying the key management requirement. Option A is incorrect because EBS encryption is not directly applicable to RDS instances; RDS encryption uses KMS. Option B is incorrect because TDE is not supported for PostgreSQL.

Option D is incorrect because client-side encryption introduces application changes and does not ensure encryption at rest within the database.

Exam trap

Candidates may assume TDE applies to all RDS engines, but TDE is only supported for Oracle and SQL Server, not PostgreSQL or MySQL.

Full explanation →
134
MCQeasy

A DBA is investigating a sudden increase in database connections to an Amazon RDS for SQL Server instance. The application is running on Amazon EC2 instances behind an Application Load Balancer. Which tool can provide real-time information about active connections?

A.AWS Trusted Advisor
B.VPC Flow Logs
C.Amazon RDS Performance Insights
D.AWS CloudTrail
AnswerC

Correct. Amazon RDS Performance Insights shows active sessions and connections in real time.

Why this answer

Amazon RDS Performance Insights provides real-time information about active database connections and sessions. Option A (AWS Trusted Advisor) is incorrect because it offers best practice recommendations, not connection monitoring. Option B (VPC Flow Logs) is incorrect because they capture network traffic metadata, not database-level connection details.

Option D (AWS CloudTrail) is incorrect because it records API calls for auditing, not real-time database connections.

Full explanation →
135
Multi-Selectmedium

Which TWO AWS services can be used to monitor database security events in real time? (Choose 2.)

Select 2 answers
A.AWS WAF
B.Amazon GuardDuty
C.Amazon RDS Performance Insights
D.Amazon CloudWatch Logs
E.AWS CloudTrail
AnswersB, D

GuardDuty can detect threats based on database activity.

Why this answer

Amazon GuardDuty (Option B) is a threat detection service that continuously monitors for malicious activity and unauthorized behavior, including database security events such as suspicious API calls or potential credential compromise. It uses machine learning, anomaly detection, and integrated threat intelligence to analyze AWS CloudTrail logs, VPC Flow Logs, and DNS logs in real time, making it suitable for monitoring database security events.

Exam trap

AWS often tests the distinction between services that provide real-time security monitoring (GuardDuty, CloudWatch Logs with metric filters) versus those that offer historical auditing (CloudTrail) or performance monitoring (Performance Insights), leading candidates to mistakenly select CloudTrail for real-time needs.

Full explanation →
136
MCQeasy

A company is migrating an on-premises MongoDB database to Amazon DocumentDB (with MongoDB compatibility). The application uses MongoDB's aggregation pipeline with $lookup and $unwind stages. What should the company verify before migration?

A.Check if all aggregation pipeline stages used by the application are supported in DocumentDB.
B.Verify that DocumentDB supports sharding for the collection.
C.Ensure the application uses the latest MongoDB driver.
D.Confirm that the application's secondary indexes can be migrated.
AnswerA

DocumentDB has limitations on some aggregation stages; verifying compatibility is essential.

Why this answer

Amazon DocumentDB (with MongoDB compatibility) does not support all MongoDB aggregation pipeline stages. Specifically, the `$lookup` and `$unwind` stages are supported, but other stages like `$merge`, `$facet`, `$bucket`, `$bucketAuto`, `$graphLookup`, and `$search` are not. Before migration, the company must verify that every stage used in their application's aggregation pipelines is fully supported in DocumentDB to avoid runtime failures.

Exam trap

The trap here is that candidates assume DocumentDB is fully MongoDB-compatible and overlook the specific limitations in the aggregation pipeline, especially for advanced stages like `$facet` and `$graphLookup`, which are not supported.

How to eliminate wrong answers

Option B is wrong because DocumentDB does not support sharding in the same way as MongoDB; DocumentDB uses a single-writer, multi-reader architecture with automatic scaling, and sharding is not a feature that needs to be verified before migration. Option C is wrong because using the latest MongoDB driver is not a prerequisite for migration; DocumentDB supports MongoDB wire protocol version 3.6 and 4.0, and the driver version must be compatible with those versions, not necessarily the latest. Option D is wrong because secondary indexes are fully supported in DocumentDB and can be migrated automatically; the primary concern is aggregation pipeline compatibility, not index migration.

Full explanation →
137
Multi-Selecthard

A company is using Amazon DynamoDB with auto scaling for read and write capacity. During a traffic spike, write requests are being throttled even though the table's write capacity is below the maximum limit. Which TWO actions should the team take to resolve the throttling?

Select 2 answers
A.Enable DynamoDB Streams on the table to offload writes to a Lambda function
B.Create a DynamoDB global table to distribute writes across regions
C.Review the table's partition key design to ensure even distribution of write traffic
D.Decrease the read capacity to free up resources for writes
E.Pre-warm the table by temporarily increasing the write capacity manually before the expected spike
AnswersC, E

Uneven distribution can cause hot partitions and throttling.

Why this answer

A suboptimal partition key can cause a hot partition, leading to throttling even when overall table capacity is not exhausted. Option E is correct because DynamoDB auto scaling has a lag in provisioning capacity; pre-warming by manually increasing write capacity before a spike can prevent throttling. Option A is incorrect because DynamoDB Streams offloads data but does not increase write capacity.

Option B is incorrect because global tables replicate data across regions but do not resolve local hot partitions or capacity lag. Option D is incorrect because reducing read capacity does not increase write capacity.

Full explanation →
138
MCQmedium

A company is migrating a 2 TB on-premises PostgreSQL database to Amazon RDS for PostgreSQL. The migration must have minimal downtime and support ongoing replication. Which AWS service should be used?

A.AWS DMS
B.AWS Snowball Edge
C.AWS S3
D.RDS native PostgreSQL logical replication
AnswerA

DMS supports ongoing replication from on-premises to RDS, minimizing downtime.

Why this answer

AWS DMS (Database Migration Service) is the correct choice because it supports both full-load migration and ongoing change data capture (CDC) replication from an on-premises PostgreSQL source to Amazon RDS for PostgreSQL, enabling minimal downtime. DMS uses logical replication slots to capture incremental changes, allowing the target database to stay synchronized during the cutover window.

Exam trap

The trap here is that candidates may assume native PostgreSQL logical replication (Option D) is always the best choice for minimal-downtime migrations, but they overlook that DMS provides a fully managed, AWS-integrated solution that handles schema conversion, monitoring, and automatic failover, which is essential for a 2 TB database migration with ongoing replication.

How to eliminate wrong answers

Option B (AWS Snowball Edge) is wrong because it is designed for offline, bulk data transfer of large datasets over physical devices, not for live, ongoing replication with minimal downtime. Option C (AWS S3) is wrong because it is an object storage service and cannot perform database replication or CDC; it would require additional tools to extract and load data, introducing significant downtime. Option D (RDS native PostgreSQL logical replication) is wrong because while it can replicate data, it requires the source database to be an RDS instance or have specific configurations (e.g., wal_level = logical) that may not be feasible or supported for an on-premises PostgreSQL source, and it does not provide the managed, automated migration and monitoring features of DMS.

Full explanation →
139
MCQmedium

A company runs a reporting application that queries an Amazon RDS for PostgreSQL database. The queries are complex and take a long time to run, causing performance degradation on the primary instance. The team wants to improve query performance without affecting the transactional workload. Which solution should they use?

A.Increase the instance size of the primary database
B.Create one or more read replicas and direct reporting queries to them
C.Migrate to Amazon RDS for MySQL and use Multi-AZ
D.Use Amazon ElastiCache to cache the results of complex queries
AnswerB

Read replicas offload read traffic, isolating reporting queries from transactional workload.

Why this answer

Amazon RDS read replicas allow you to offload read-heavy reporting queries from the primary PostgreSQL instance. By directing complex, long-running queries to one or more read replicas, you eliminate resource contention on the primary instance, preserving transactional workload performance. RDS for PostgreSQL supports up to 15 read replicas, which can be promoted to a primary instance if needed, and they use asynchronous replication to stay nearly current.

Exam trap

The trap here is that candidates often assume scaling up the primary instance (Option A) is the simplest fix, but the exam tests the understanding that workload isolation via read replicas is the correct architectural pattern for separating reporting from transactional workloads.

How to eliminate wrong answers

Option A is wrong because increasing the instance size of the primary database only adds more CPU and memory to the same single instance, which does not isolate the reporting workload from the transactional workload; the complex queries will still compete for resources and cause performance degradation. Option C is wrong because migrating to Amazon RDS for MySQL does not solve the problem of separating reporting from transactional workloads; Multi-AZ provides high availability but does not offload read queries, and changing database engines introduces unnecessary migration risk without addressing the core issue. Option D is wrong because Amazon ElastiCache caches query results in memory, which is only effective for repeated, identical queries; complex, ad-hoc reporting queries are unlikely to benefit from caching, and it does not reduce the load on the primary database for non-cached queries.

Full explanation →
140
MCQhard

A company is migrating a 5 TB Oracle database to Amazon Aurora PostgreSQL. The migration must be completed within a weekend. The on-premises network has a 1 Gbps connection to AWS. What is the MOST efficient migration strategy?

A.Use AWS S3 Transfer Acceleration to upload the database dump to S3 and then load into Aurora
B.Use AWS DMS with direct connect to export the Oracle database directly to Aurora
C.Use AWS DMS with change data capture over the existing network connection
D.Use AWS Snowball Edge to transfer the data and then load into Aurora
AnswerB

Correct. AWS DMS with Direct Connect leverages a dedicated, high-bandwidth connection to migrate the database directly to Aurora, making it the most efficient strategy for a 5 TB migration within a weekend.

Why this answer

With a 1 Gbps connection, the theoretical maximum transfer rate is ~450 GB/hour, so transferring 5 TB would take about 11 hours, well within a weekend. AWS DMS with Direct Connect provides a dedicated, high-bandwidth path for the migration, making it the most efficient strategy. Snowball Edge (Option D) requires ordering, loading, shipping (1-2 days), and importing, which cannot complete within a weekend.

Options A and C are less efficient: S3 Transfer Acceleration adds unnecessary steps, and DMS with CDC is designed for ongoing replication, not initial load.

Exam trap

The trap is that candidates assume Snowball is always faster for large data volumes, ignoring the shipping delays and the fact that a 1 Gbps link can transfer 5 TB in about 11 hours, well within a weekend. Network-based tools like DMS can be more efficient when the connection is adequate.

How to eliminate wrong answers

Option A is wrong because AWS S3 Transfer Acceleration only optimizes the path over the public internet but does not increase the available bandwidth of the 1 Gbps link; the total transfer time for 5 TB would still exceed the weekend window when factoring in export/import overhead. Option B is wrong because AWS DMS with Direct Connect still operates over the same 1 Gbps network connection, and the initial full load of 5 TB would take too long; Direct Connect does not increase bandwidth beyond the provisioned link speed. Option C is wrong because AWS DMS with change data capture (CDC) is designed for ongoing replication, not for the initial bulk load of 5 TB; the initial load still requires transferring the full dataset over the network, which is not feasible within a weekend on a 1 Gbps link.

Full explanation →
141
MCQeasy

Refer to the exhibit. A company is migrating from an on-premises MySQL database to Amazon RDS for MySQL. The DBA wants to connect to the RDS instance using the endpoint shown. What additional step is required to allow the DBA's client to connect?

A.Modify the security group to allow inbound traffic on port 3306 from the client IP
B.Create a Route 53 record for the endpoint
C.Create a MySQL user that matches the client's IP
D.Change the RDS instance to be publicly accessible
AnswerA

Security group rules control inbound traffic; port 3306 must be open.

Why this answer

Amazon RDS security groups act as a virtual firewall controlling inbound and outbound traffic. By default, no inbound traffic is allowed on port 3306 (MySQL). To permit the DBA's client to connect, you must modify the security group associated with the RDS instance to add an inbound rule that allows TCP traffic on port 3306 from the client's IP address (or a range that includes it).

Without this rule, the connection is blocked at the network level regardless of other configurations.

Exam trap

The DBS-C01 exam often tests the misconception that making an RDS instance publicly accessible alone is sufficient for connectivity, but the security group rule is the actual gatekeeper; public accessibility only assigns a public IP, while the security group still blocks traffic without an explicit inbound rule.

How to eliminate wrong answers

Option B is wrong because creating a Route 53 record for the endpoint is unnecessary; the RDS endpoint is already a DNS name that resolves to the instance's IP address, and Route 53 is not required for connectivity. Option C is wrong because MySQL user accounts are authenticated by username and password, not by client IP address (unless the user is explicitly created with a host restriction, but that is not a required step for basic connectivity). Option D is wrong because making the RDS instance publicly accessible is not required if the DBA's client is connecting from within the same VPC or via a VPN/Direct Connect; the security group rule alone controls inbound access, and public accessibility is only needed for connections from outside the VPC.

Full explanation →
142
MCQmedium

A security engineer is designing a solution to encrypt data at rest for an Amazon Redshift cluster. The company requires that the encryption key be rotated automatically every year. Which solution meets these requirements?

A.Use a Lambda function to rotate the encryption key manually every year.
B.Enable encryption for the Redshift cluster using an AWS KMS key with automatic rotation.
C.Use a CloudHSM key to encrypt the Redshift cluster and configure automatic rotation in CloudHSM.
D.Store the Redshift cluster data in an S3 bucket with server-side encryption enabled.
AnswerB

Enabling encryption for the Redshift cluster with an AWS KMS key that has automatic rotation meets the requirement for yearly key rotation.

Why this answer

Amazon Redshift supports encryption at rest using AWS KMS with automatic key rotation. When you enable encryption for a Redshift cluster, you can choose a KMS key with automatic rotation enabled, which meets the requirement of rotating the encryption key automatically every year.

Option A is incorrect because manual rotation using a Lambda function is not the recommended approach when automatic rotation is available. Redshift does not support custom manual rotation; it relies on KMS for key management.

Option C is incorrect because Redshift does not support CloudHSM for encryption at rest; it uses AWS KMS. CloudHSM does not provide automatic rotation as a built-in feature in the same way KMS does.

Option D is incorrect because Redshift does not store cluster data in an S3 bucket; S3 server-side encryption is not applicable to the Redshift cluster itself. Redshift uses its own encryption mechanism integrated with KMS.

Full explanation →
143
Multi-Selecteasy

A company is using Amazon RDS for MySQL with Multi-AZ deployment. The security team wants to ensure that database administrators cannot view sensitive data. Which TWO actions should be taken to achieve this goal?

Select 2 answers
A.Use IAM database authentication for application access.
B.Enable audit logging to capture all data access.
C.Store database credentials in AWS Secrets Manager and enforce automatic rotation.
D.Enable encryption at rest using a customer-managed KMS key.
E.Disable query logging to prevent sensitive data from being written to logs.
AnswersA, C

IAM database authentication allows applications to connect without passwords, reducing the need for DBAs to handle credentials.

Why this answer

IAM database authentication allows you to authenticate to your RDS MySQL instance using an IAM user or role instead of a traditional database password. This eliminates the need for database administrators to know or manage database credentials, as they can only access the database through IAM policies that grant specific, auditable permissions. By using IAM authentication, you enforce a separation of duties where DBAs cannot view sensitive data unless explicitly authorized by IAM policies.

Exam trap

The trap here is that candidates often confuse encryption at rest (which protects data on disk) with access control (which protects data from being queried), leading them to select encryption options when the real requirement is to prevent DBAs from viewing data through database connections.

Full explanation →
144
MCQmedium

A company needs to build a reporting dashboard that queries a large dataset stored in Amazon S3. The queries are complex and require full SQL support. Which service should be used?

A.Amazon Redshift Spectrum
B.Amazon RDS
C.Amazon DynamoDB
D.Amazon Athena
AnswerD

Athena allows querying S3 data directly with standard SQL, no loading required.

Why this answer

Amazon Athena is the correct choice because it is a serverless, interactive query service that allows you to analyze data directly in Amazon S3 using standard SQL. It supports complex queries, including joins, window functions, and CTEs, and requires no infrastructure management, making it ideal for ad-hoc reporting on large datasets in S3.

Exam trap

AWS often tests the misconception that Redshift Spectrum is the only way to query S3 with SQL, but Athena is the serverless, cost-effective alternative for ad-hoc queries without a cluster.

How to eliminate wrong answers

Option A is wrong because Amazon Redshift Spectrum is a feature of Amazon Redshift that queries data in S3, but it requires an active Redshift cluster and is not a standalone service; it is overkill for a simple reporting dashboard and incurs cluster costs. Option B is wrong because Amazon RDS is a relational database service for transactional workloads, not designed for querying large datasets stored in S3; it would require loading data into the database, which is inefficient for this use case. Option C is wrong because Amazon DynamoDB is a NoSQL key-value and document database that does not support full SQL or complex queries like joins and aggregations; it is optimized for low-latency access at scale, not analytical reporting.

Full explanation →
145
MCQmedium

A financial services company runs a critical application on Amazon RDS for Oracle. The workload is write-heavy with frequent small transactions. The DBA notices high latency during peak hours. Which design change would best address this?

A.Implement ElastiCache for Redis
B.Enable Multi-AZ deployment
C.Switch to Provisioned IOPS (io1 or io2) volume type
D.Add a read replica
AnswerC

Provides predictable high IOPS for write-heavy workloads.

Why this answer

The workload is write-heavy with frequent small transactions, and high latency during peak hours indicates that the current storage volume is not meeting the IOPS demands. Provisioned IOPS (io1 or io2) volumes provide consistent, low-latency performance by guaranteeing a specific number of IOPS, which directly addresses the bottleneck caused by insufficient I/O capacity for write-intensive operations.

Exam trap

The trap here is that candidates often confuse high latency with a read performance issue and incorrectly choose a read replica or caching, when the problem is actually a write I/O bottleneck that requires a storage-level solution like Provisioned IOPS.

How to eliminate wrong answers

Option A is wrong because ElastiCache for Redis is an in-memory caching layer that reduces read latency for frequently accessed data, but it does not improve write latency for an RDS database; write operations still go to the database, and caching does not address storage I/O bottlenecks. Option B is wrong because Multi-AZ deployment provides high availability and automatic failover by maintaining a standby replica in a different Availability Zone, but it does not improve write performance or reduce latency during peak hours; in fact, synchronous replication to the standby can add slight latency to writes. Option D is wrong because a read replica offloads read traffic from the primary instance, but the workload is write-heavy, so adding a read replica does nothing to reduce write latency or improve write throughput.

Full explanation →
146
Multi-Selecthard

A company is migrating a legacy Oracle data warehouse to Amazon Redshift. The source uses complex stored procedures with cursors, temporary tables, and PL/SQL. Which THREE design considerations should the company evaluate?

Select 3 answers
A.Redshift does not support procedural languages like PL/SQL; stored procedures must be rewritten in SQL or Python.
B.Redshift supports temporary tables, but they are session-scoped and not automatically dropped in all cases.
C.Redshift Concurrency Scaling can handle thousands of concurrent queries.
D.Redshift does not support cursors; result sets must be handled differently.
E.Redshift automatically scales compute capacity based on workload.
AnswersA, B, D

Redshift supports PL/pgSQL and Python, but not Oracle's PL/SQL.

Why this answer

Amazon Redshift does not support Oracle's PL/SQL procedural language; stored procedures must be rewritten using Redshift's PL/pgSQL or Python UDFs (option A). Redshift supports temporary tables, but they are session-scoped and must be explicitly dropped or they persist until session ends (option B). Redshift does not support cursors as in Oracle; result sets must be handled using alternative methods such as fetching into arrays or using LIMIT/OFFSET (option D).

These are key migration considerations.

Exam trap

The trap here is that candidates assume Redshift supports all Oracle database features (like PL/SQL, cursors, and auto-scaling) because both are relational databases, but Redshift is a columnar, MPP data warehouse with significant differences in procedural logic and resource management.

Full explanation →
147
MCQhard

A company runs a critical PostgreSQL database on Amazon RDS and needs to implement point-in-time recovery (PITR) with a recovery window of the last 35 days. Currently, automated backups are set to retain for 35 days. The database size is 500 GB. What additional configuration is required?

A.No additional configuration is required; automated backups enable PITR
B.Enable manual snapshots every hour
C.Set up a replication slot and stream transaction logs to S3
D.Enable Multi-AZ deployment
AnswerA

RDS automatically supports PITR with automated backups.

Why this answer

Amazon RDS for PostgreSQL automated backups include transaction logs, which are required for point-in-time recovery. With automated backups retained for 35 days, RDS can restore the database to any second within that retention period by replaying transaction logs against a full backup. No additional configuration is needed because PITR is an inherent feature of automated backups when the retention period is set to 35 days.

Exam trap

The trap here is that candidates may think PITR requires additional components like manual snapshots or replication slots, but RDS automated backups already include the necessary transaction logs for PITR when the retention period is set appropriately.

How to eliminate wrong answers

Option B is wrong because manual snapshots are full backups that do not provide the granularity of PITR; they only allow restoration to the snapshot time, not to any point within the retention window. Option C is wrong because replication slots and streaming transaction logs to S3 are used for logical replication or custom backup strategies, not for RDS automated PITR, which already handles transaction logs internally. Option D is wrong because Multi-AZ deployment provides high availability and failover support, but it does not extend the PITR window or enable PITR; PITR is already enabled by automated backups regardless of Multi-AZ configuration.

Full explanation →
148
MCQhard

A company has an Amazon DynamoDB table with on-demand capacity. Users report that write requests are occasionally throttled during peak hours. The application uses the AWS SDK and retries with exponential backoff. Which monitoring approach should be used to identify the cause of throttling?

A.Use AWS CloudTrail to monitor PutItem API calls for throttling errors.
B.Analyze VPC Flow Logs to check for network congestion.
C.Monitor CloudWatch metrics for ThrottledRequests and ConsumedWriteCapacityUnits.
D.Enable DynamoDB Streams and process records to monitor throttled requests.
AnswerC

Correct. CloudWatch metrics such as ThrottledRequests and ConsumedWriteCapacityUnits directly indicate when throttling occurs and how much capacity is being consumed, allowing identification of the cause.

Why this answer

CloudWatch metrics such as ThrottledRequests and ConsumedWriteCapacityUnits directly indicate throttling events and capacity usage, enabling identification of throttling causes even with on-demand capacity. Option A is incorrect because AWS CloudTrail logs API calls but does not provide detailed throttling metrics at the item level. Option B is incorrect because VPC Flow Logs capture network traffic, not database-level throttling.

Option D is incorrect because DynamoDB Streams capture item-level changes, not throttling events.

Full explanation →
149
MCQmedium

A company is migrating a 500 GB PostgreSQL database from on-premises to Amazon Aurora PostgreSQL. The migration must be completed within 6 hours with minimal downtime. The on-premises network bandwidth is 500 Mbps. The team decides to use AWS DMS. During initial full load, DMS reports a 'Target metadata error: cannot write to Aurora' for a specific table. Investigation shows that the table has a trigger that tries to insert into an external web service. What should the team do to resolve this issue?

A.Disable the trigger on the target Aurora database during migration.
B.Increase the DMS replication instance size.
C.Upgrade the DMS replication instance engine version.
D.Disable the trigger on the source database.
AnswerA

This is correct. Disabling the trigger on the target database during migration stops the external web service call, resolving the error.

Why this answer

Disabling the trigger on the target Aurora PostgreSQL database during migration prevents the trigger from firing, which was causing the 'Target metadata error: cannot write to Aurora' error. The trigger's attempt to insert into an external web service is not compatible with DMS loading data. Option B is incorrect because increasing the DMS replication instance size does not address the trigger issue.

Option C is incorrect because upgrading the DMS replication instance engine version does not address the trigger issue. Option D is incorrect because disabling the trigger on the source database does not prevent the trigger on the target from firing when DMS writes data; the error occurs on the target.

Full explanation →
150
MCQmedium

A security engineer runs the AWS CLI command shown in the exhibit. The engineer wants to ensure that all RDS DB instances in the account are encrypted at rest. What should the engineer do to remediate the unencrypted read replica?

A.Modify the read replica by setting the StorageEncrypted parameter to true.
B.Delete the unencrypted read replica and create a new read replica from the encrypted source, enabling encryption on the new replica.
C.Enable encryption on the source DB instance and the read replica will automatically become encrypted.
D.Create a snapshot of the read replica, encrypt the snapshot, and restore it as a new instance.
AnswerB

This ensures the new read replica is encrypted, and the source is already encrypted.

Why this answer

To encrypt an unencrypted read replica that is sourced from an encrypted DB instance, you cannot directly enable encryption on an existing read replica or modify it. Instead, you must delete the unencrypted read replica and create a new read replica from the encrypted source, enabling encryption on the new replica. This is because encryption at rest can only be enabled during instance creation, and read replicas inherit encryption settings from the source at creation time.

Option A is incorrect because the StorageEncrypted parameter cannot be modified on an existing instance. Option C is incorrect because enabling encryption on the source does not encrypt existing replicas; it only affects new replicas. Option D is incorrect because creating a snapshot of the unencrypted replica and restoring it as a new encrypted instance is not the standard procedure for encrypting a read replica; the correct approach is to recreate the read replica from the encrypted source with encryption enabled.

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