DEA-C01 Practice Test 26 — 15 Questions

Question 1

A company is migrating a MySQL database to Amazon RDS for MySQL. The database is 2 TB in size and the company can only afford minimal downtime. The migration must be secure and use AWS DMS. Which TWO configuration steps are required? (Choose TWO.)

Accepted Answer

Create a source endpoint pointing to the on-premises MySQL database.. AWS DMS requires a source endpoint (source database connection) and a target endpoint (RDS instance). Option C is the source endpoint, option D is the target endpoint. The other options are not required for DMS: SSL/TLS is optional but recommended, replication instance is created by DMS, and VPC peering is not typically needed if using the same VPC.

Answer

Configure SSL/TLS encryption for the DMS endpoints.

Answer

Set up VPC peering between the on-premises network and the Amazon VPC.

Answer

Create a DMS replication instance.

Question 2

A data engineer needs to ensure that an Amazon Redshift cluster only accepts encrypted connections. Which parameter should be modified?

Accepted Answer

require_SSL. Option A is correct. The require_SSL parameter enforces SSL connections. Option B is wrong because enable_user_activity_logging is for auditing. Option C is wrong because max_concurrency_scaling_clusters is for concurrency. Option D is wrong because wlm_json_configuration is for workload management.

Answer

enable_user_activity_logging

Answer

max_concurrency_scaling_clusters

Answer

wlm_json_configuration

Question 3

A data engineering team is using Amazon DynamoDB to store user session data for a web application. The application experiences sudden spikes in traffic, causing throttling on the DynamoDB table. The team wants to minimize throttling without over-provisioning read/write capacity. Which solution should the team implement?

Accepted Answer

Enable DynamoDB Accelerator (DAX) caching layer.. Option D is correct because DynamoDB Accelerator (DAX) provides a fully managed in-memory cache that reduces read load on the table, thus minimizing throttling for read-heavy workloads. Option A is incorrect because disabling auto scaling would worsen throttling. Option B is incorrect because read replicas are for RDS, not DynamoDB. Option C is incorrect because adding a TTL does not reduce throttling; it only expires old data.

Answer

Enable DynamoDB Time to Live (TTL) to automatically delete expired items.

Answer

Disable auto scaling and manually set a high provisioned capacity.

Answer

Use Amazon RDS read replicas to offload read traffic.

Question 4

A company uses Amazon DynamoDB to store metadata for a document management system. The table has a partition key of document_id and a sort key of version. The application frequently queries for the latest version of a document by document_id. The data engineer notices that these queries are consuming a lot of read capacity. How can the engineer optimize the read performance and reduce read capacity consumption?

Accepted Answer

Create a global secondary index (GSI) and use DynamoDB Accelerator (DAX).. Option B is correct because creating a global secondary index (GSI) with document_id as partition key and version as sort key, but with a different projection, can allow queries to use the index with fewer items returned. More importantly, using DynamoDB Accelerator (DAX) would cache the results of frequent queries, reducing read capacity consumption. Option A is incorrect because changing the sort key order does not reduce read capacity for the same query. Option C is incorrect because read replicas are not a feature of DynamoDB. Option D is incorrect because decreasing ReadCapacityUnits would cause throttling.

Answer

Change the sort key to store version in descending order.

Answer

Enable DynamoDB Streams and use a read replica.

Answer

Decrease the ReadCapacityUnits of the table to force caching.

Question 5

A company runs a production Amazon RDS for PostgreSQL database. The database is experiencing performance degradation due to a high number of concurrent read queries. The data engineer needs to improve read performance without significantly increasing costs. Which TWO actions should the engineer take? (Choose TWO.)

Accepted Answer

Create one or more read replicas in the same region.. Option A is correct because read replicas offload read traffic from the primary instance. Option D is correct because performance insights help identify bottlenecks. Option B is incorrect because Multi-AZ does not improve read performance. Option C is incorrect because increasing storage size may not help with read performance. Option E is incorrect because deleting indexes would degrade performance.

Answer

Enable Multi-AZ deployment for automatic failover.

Answer

Increase the allocated storage size to improve IOPS.

Answer

Delete unnecessary indexes to reduce write overhead.

Question 6

A company runs an Amazon RDS for PostgreSQL instance for an OLTP application. The database size is 500 GB. The company wants to minimize downtime during backups and ensure point-in-time recovery (PITR) for the last 7 days. Which TWO features should the company use? (Choose TWO.)

Accepted Answer

Enable Multi-AZ deployment for high availability.. Automated backups with a 7-day retention provide PITR. Multi-AZ deployment ensures high availability and reduces downtime during backups. Manual snapshots are not needed. Enhanced Monitoring is for performance. Read replicas are for read scaling, not backup.

Answer

Create a read replica in a different Availability Zone.

Answer

Create daily manual snapshots and copy them to another region.

Answer

Enable Enhanced Monitoring to track backup progress.

Question 7

A company is designing a data lake on AWS using Amazon S3. The data includes sensitive customer information that must be encrypted at rest. The company requires that encryption keys be managed by AWS, but the keys must be rotated automatically every year. Which TWO options meet these requirements? (Choose TWO.)

Accepted Answer

Use Server-Side Encryption with Amazon S3-Managed Keys (SSE-S3).. SSE-S3 uses Amazon S3-managed keys with automatic rotation every year. SSE-KMS with automatic key rotation (enabled by default) also meets the key rotation requirement. SSE-C does not use AWS-managed keys. SSE-KMS with manual rotation is not automatic. Client-side encryption does not use AWS keys.

Answer

Use client-side encryption with an AWS KMS key.

Answer

Use Server-Side Encryption with Customer-Provided Keys (SSE-C).

Answer

Use Server-Side Encryption with AWS KMS-Managed Keys (SSE-KMS) with manual key rotation.

Question 8

A data engineer needs to store streaming data from multiple sources into Amazon S3. The data should be organized by source, date, and hour. The engineer wants to minimize processing overhead. Which THREE S3 features should the engineer use to achieve this? (Choose THREE.)

Accepted Answer

S3 Inventory to list objects and their metadata.. S3 prefixes organize objects into a hierarchy. S3 Inventory provides a list of objects. S3 Event Notifications trigger downstream processing. Batch Operations are for bulk actions, not organization. Object Lock is for retention. S3 Select is for querying within files.

Answer

S3 Object Lock to prevent object modifications.

Answer

S3 Batch Operations to rename objects after upload.

Question 9

A company uses Amazon DynamoDB as a key-value store for a high-traffic application. The table has a provisioned read capacity of 10,000 RCUs and write capacity of 5,000 WCUs. The application experiences occasional throttling during peak hours. Which TWO actions can reduce throttling without changing the application code? (Choose TWO.)

Accepted Answer

Enable DynamoDB Auto Scaling for both read and write capacity.. Enabling Auto Scaling adjusts capacity automatically. Adding a read replica (DAX) reduces read load. Adding a Global Table does not increase capacity. Changing to on-demand mode can help but may increase cost. Reducing read consistency is not recommended.

Answer

Switch to on-demand capacity mode for the table.

Answer

Change the read consistency model from eventually consistent to strongly consistent.

Answer

Use DynamoDB Global Tables to distribute the workload across regions.

Question 10

A company uses AWS Glue to catalog data stored in Amazon S3. The data is in Parquet format and partitioned by date. The company wants to improve query performance in Amazon Athena and reduce costs. Which THREE actions should the company take? (Choose THREE.)

Accepted Answer

Partition the data by date so Athena can use partition pruning.. Using columnar formats like Parquet improves performance and reduces scanned data. Partitioning by date allows Athena to prune partitions. Compressing data reduces storage and scan costs. Converting to JSON would hurt performance. Increasing partition count may help but is not a guarantee. Using Glue DataBrew is for data preparation, not performance optimization.

Answer

Convert the data to JSON format for better schema evolution.

Answer

Use Glue DataBrew to clean the data before querying.

Question 11

A data engineer needs to ingest data from an on-premises Oracle database into Amazon S3 on a nightly basis. The data volume is approximately 10 GB per night. The database is accessible over the internet. Which AWS service is MOST appropriate for this task?

Answer

AWS Glue ETL job with a JDBC connection

Answer

AWS DataSync

Answer

AWS Transfer Family

Answer

Amazon Kinesis Data Streams

Question 12

A company is ingesting log files from EC2 instances into CloudWatch Logs and then wants to deliver them to S3 for long-term storage and analysis. The data engineer needs to ensure the logs are delivered to S3 within 5 minutes of being generated. Which approach meets this requirement?

Accepted Answer

Use CloudWatch Logs subscription filter with Kinesis Data Firehose to deliver to S3. Option A (Use CloudWatch Logs subscription filter with Kinesis Data Firehose to deliver to S3) is correct because Firehose can deliver to S3 with low latency (typically <1 minute). Option B (CloudWatch Logs export to S3) is a batch process that can take hours. Option C (Use a Lambda function to read from CloudWatch Logs and write to S3) is slower and less reliable. Option D (Use CloudWatch Logs Insights) is for querying, not delivery.

Answer

Configure a CloudWatch Logs metric filter and invoke a Lambda function to write to S3

Answer

Use CloudWatch Logs Insights to query logs and save results to S3

Answer

Use the CloudWatch Logs export to S3 feature

Question 13

A company is using Amazon DynamoDB as a data store for a real-time application. The application reads a single item by primary key and occasionally updates it. The data engineer notices high read latency during peak hours. Which TWO actions would most effectively reduce read latency?

Accepted Answer

Increase the read capacity units for the table.. Option B: Increasing read capacity units reduces throttling, which reduces latency. Option D: Enabling DynamoDB Accelerator (DAX) adds an in-memory cache, reducing read latency. Option A is wrong because disabling auto-scaling could make things worse. Option C is wrong because global tables are for multi-region, not latency. Option E is wrong because sparse indexes don't help single-item reads.

Answer

Enable DynamoDB global tables.

Answer

Add a local secondary index on the table.

Answer

Disable auto-scaling and set a fixed read capacity.

Question 14

A company is using Amazon Kinesis Data Streams to ingest real-time clickstream data. The data is consumed by a fleet of EC2 instances running a custom application that processes the records and writes to DynamoDB. The application is experiencing high latency and records are being processed slower than they are produced. The stream has 5 shards. Which action would MOST effectively improve processing speed?

Accepted Answer

Increase the number of shards in the Kinesis stream.. Increasing the number of shards increases the throughput of the stream, allowing more parallel consumers. Option A is wrong because increasing instance size may not help if the bottleneck is the stream. Option C is wrong because adding more consumers without more shards doesn't help (each shard supports one consumer per application). Option D is wrong because KCL handles shard distribution, but more shards are needed.

Answer

Use the Kinesis Client Library (KCL) to automatically distribute shards among instances.

Answer

Increase the EC2 instance size to provide more CPU and memory.

Answer

Add more EC2 instances consuming from the same stream without changing shard count.

Question 15

A data engineer is designing a data ingestion pipeline to load data from an on-premises Oracle database to Amazon S3. The pipeline should capture changes in near real-time (within minutes) and minimize impact on the source database. The source table has a 'last_modified' timestamp column. Which service combination would meet these requirements?

Accepted Answer

AWS DMS with a replication task in CDC mode, writing to S3 in Parquet format.. AWS Database Migration Service (DMS) with change data capture (CDC) can capture changes from Oracle in near real-time and write to S3. Option A is wrong because Glue does not support CDC. Option B is wrong because Data Pipeline is batch-oriented. Option D is wrong because Firehose does not connect to databases directly.

Answer

Amazon Kinesis Data Firehose with a Lambda function that queries Oracle.

Answer

AWS Data Pipeline with a periodic SQL query activity to copy full table snapshots.

Answer

AWS Glue with a JDBC connection to Oracle, running a crawler every 5 minutes.