DEA-C01 Practice Test 7 — 10 Questions

Question 1

A data engineer is troubleshooting a Glue ETL job that reads from an S3 bucket and writes to a Redshift table. The job fails with a 'MemoryError' when processing a large dataset. Which TWO actions should the engineer take to resolve this issue? (Choose TWO.)

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

Accepted Answer

Increase the number of DPUs and set 'spark.sql.shuffle.partitions' to a higher value.. Increasing the number of DPUs (Data Processing Units) provides more memory and compute resources to the Glue job, directly addressing the MemoryError. Setting 'spark.sql.shuffle.partitions' to a higher value reduces the amount of data shuffled per partition, preventing out-of-memory errors during wide transformations like joins or aggregations.

Answer

Increase the number of DPUs and set 'coalesce(1)' in the script.

Answer

Decrease the number of DPUs and increase 'spark.shuffle.partitions'.

Answer

Set the 'RedshiftTempDir' parameter to a larger S3 bucket.

Question 2

A data engineer is designing a streaming ingestion pipeline using Amazon Kinesis Data Streams. The stream has 10 shards, and the data volume is expected to grow by 50% over the next month. The engineer needs to ensure that the pipeline can scale without manual intervention. Which approach should be used?

Accepted Answer

Switch the Kinesis stream to on-demand capacity mode. Kinesis Data Streams on-demand capacity mode automatically scales the number of shards based on the incoming traffic pattern, eliminating the need for manual intervention. Option A is incorrect because CloudWatch Alarms can trigger a Lambda function to add shards via the UpdateShardCount API, but this approach requires custom code and does not provide automatic scaling without manual setup. Option B is incorrect because Auto Scaling groups are used for EC2 instances, not for Kinesis stream shards. Option D is incorrect because Lambda functions can be used to scale shards programmatically, but this still requires custom implementation and is not a native automatic scaling feature.

Answer

Set up a CloudWatch Alarm to trigger a Lambda function to add shards

Answer

Use an Auto Scaling group to add more shards

Answer

Configure the stream to use a Lambda function that scales shards

Question 3

A logistics company ingests real-time GPS location data from thousands of delivery vehicles into Amazon Kinesis Data Streams. Each vehicle sends a JSON payload every 10 seconds containing vehicle_id, latitude, longitude, timestamp, and speed. The data must be stored in Amazon S3 for historical analysis, but the company wants to first aggregate the data per vehicle per minute (average speed, min/max coordinates) to reduce storage costs. The solution must be serverless and handle potential duplicate records without double-counting. What should the engineer do?

Accepted Answer

Use Amazon Kinesis Data Analytics for Apache Flink to aggregate data in a 1-minute tumbling window with deduplication logic, then output to Kinesis Data Firehose for delivery to S3.. Amazon Kinesis Data Analytics for Apache Flink can process streaming data with tumbling windows (1-minute) to aggregate per vehicle per minute, and Flink's stateful processing allows deduplication to avoid double-counting. The output is then sent to Kinesis Data Firehose for persistent storage in Amazon S3, all serverless. Option A (EMR with Spark Streaming) is not serverless. Option C (Kinesis Data Firehose with Lambda transformation) cannot perform stateful windowed aggregation and deduplication efficiently—it processes events individually without maintaining state across records. Option D (AWS Glue streaming ETL job) is serverless but adds higher latency and complexity compared to Kinesis Data Analytics, and is not as optimized for low-latency streaming aggregations with deduplication.

Answer

Use Amazon EMR with Spark Streaming to perform the aggregation and write to S3.

Answer

Use Kinesis Data Firehose with a Lambda transformation to aggregate records in a 1-minute window.

Answer

Use an AWS Glue streaming ETL job with Spark Structured Streaming to aggregate and deduplicate.

Question 4

A data engineer needs to transfer 50 TB of data from an on-premises HDFS cluster to Amazon S3. The on-premises network has a 1 Gbps link to AWS. Which AWS service should be used to perform the transfer efficiently?

Accepted Answer

AWS DataSync. AWS DataSync is the correct choice because it is designed for large-scale data transfers over the network, handling 50 TB efficiently over a 1 Gbps link by parallelizing transfers and automating scheduling. Amazon S3 Transfer Acceleration only improves upload speed over long distances but is not a dedicated transfer service. AWS Snowball Edge would be slower due to shipping and is unnecessary since the network link is sufficient. AWS Direct Connect provides a dedicated network connection but is not a data transfer service.

Answer

Amazon S3 Transfer Acceleration

Answer

AWS Snowball Edge

Answer

AWS Direct Connect

Question 5

A company ingests streaming data from social media APIs into Kinesis Data Streams. Each record is approximately 5 KB. The data must be enriched with geolocation information from a DynamoDB table before being stored in S3. The enrichment process takes about 200 ms per record. Which architecture minimizes latency and cost?

Accepted Answer

Use Kinesis Data Firehose with a Lambda function that queries DynamoDB. Kinesis Data Firehose can invoke a Lambda function for per-record enrichment, providing automatic scaling and low operational overhead. Option A is wrong because an EC2 instance adds significant operational overhead and requires manual scaling, increasing complexity and cost. Option B is wrong because AWS Glue ETL jobs are optimized for batch processing, not continuous streaming with low latency per record. Option C is wrong because Kinesis Data Analytics (SQL) is designed for real-time analytics on streaming data, not for per-record enrichment involving external lookups like DynamoDB.

Answer

Use an EC2 instance running a custom application to consume from Kinesis, enrich, and write to S3

Answer

Use AWS Glue ETL jobs running continuously on the stream

Answer

Use Kinesis Data Analytics to perform enrichment with SQL

Question 6

A data engineer is migrating an on-premises Apache HBase workload to Amazon DynamoDB. The application requires strongly consistent reads and the ability to query by a composite key (partition key + sort key). Which DynamoDB table design should be used?

Accepted Answer

Create a table with a partition key and sort key, and use ConsistentRead parameter.. DynamoDB natively supports strongly consistent reads when you use the `ConsistentRead` parameter set to `true` on GetItem, Query, or Scan operations. By defining a table with a partition key and sort key, you can directly query by the composite key (partition key + sort key) with strong consistency, meeting both requirements without additional infrastructure.

Answer

Use a secondary index with strongly consistent reads.

Answer

Use a local secondary index (LSI) with the composite key.

Answer

Create a global secondary index (GSI) with the composite key.

Question 7

Refer to the exhibit. A data engineer is troubleshooting an IAM policy attached to a user. The user reports that they cannot upload objects to the S3 bucket 'data-lake-bucket' unless they explicitly specify the 'x-amz-server-side-encryption' header with value 'AES256'. The engineer wants to modify the policy to allow uploads without requiring encryption headers, but still enforce encryption on the bucket itself. Which change should the engineer make?

Accepted Answer

Remove the entire Deny statement.. Removing the Deny statement eliminates the explicit denial that blocks uploads without the 'x-amz-server-side-encryption' header set to 'AES256'. The Allow statement already grants s3:PutObject, and by removing the Deny, users can upload without specifying encryption headers. The bucket's default encryption setting (e.g., AES256) will then automatically encrypt objects at rest, enforcing encryption without requiring the header in the request.

Answer

Remove the Condition block from the Allow statement.

Answer

Change the Condition in the Allow statement to use aws:kms instead of AES256.

Answer

Set the bucket's default encryption to AES256 and keep the policy unchanged.

Question 8

A company runs a daily batch processing job on Amazon EMR that reads data from Amazon S3 and writes results back to S3. The job takes longer than expected. The engineer wants to monitor the job's resource utilization. Which AWS service should be used to collect and visualize metrics such as CPU and memory usage of the EMR cluster's nodes?

Accepted Answer

Amazon CloudWatch with the CloudWatch Agent installed on the EMR nodes.. Amazon CloudWatch with the CloudWatch Agent installed on EMR nodes can collect CPU, memory, and other system-level metrics, which can be visualized in CloudWatch dashboards. Option A is incorrect because AWS Config records configuration changes, not resource utilization. Option B is incorrect because Amazon Athena is a query service for data in S3, not a monitoring service. Option D is incorrect because AWS CloudTrail logs API calls, not performance metrics.

Answer

AWS Config to record configuration changes in the EMR cluster.

Answer

Amazon Athena to query EMR job logs stored in S3.

Answer

AWS CloudTrail to log API calls made by the EMR job.

Question 9

A marketing analytics team needs to ingest customer transaction data from an on-premises PostgreSQL database into Amazon S3 for analysis. The data volume is about 10 GB daily, and the team wants to perform full refresh daily (truncate and load) into S3 as Parquet files. The company has a Direct Connect connection to AWS. The team needs a simple, managed solution that minimizes operational overhead. What should the team use?

Accepted Answer

Use an AWS Glue ETL job with a JDBC connection to the PostgreSQL database, extract data, and write to S3 in Parquet format.. AWS Glue ETL job is the best choice for this scenario. It is a fully managed service that can connect to on-premises PostgreSQL via a JDBC connection (using an AWS Glue connection with the appropriate network configuration over Direct Connect). It can perform a full extract (truncate and load) each day and write the data directly to S3 in Parquet format, minimizing operational overhead. Option A (AWS DMS) is designed for ongoing change data capture (CDC) and continuous replication, not for daily full refreshes without incremental changes. Option B (Amazon EMR with Spark) requires managing clusters and is more complex than necessary for a simple daily load. Option D (AWS Data Pipeline) requires custom scripting and more configuration compared to Glue's built-in ETL capabilities. Therefore, option C is correct.

Answer

Set up AWS Database Migration Service (DMS) to continuously replicate data to S3 in Parquet format.

Answer

Use Amazon EMR with a Spark job that reads from PostgreSQL and writes to S3.

Answer

Use AWS Data Pipeline with a SQLActivity to extract data and copy to S3.

Question 10

A data engineer is implementing a CDC (Change Data Capture) pipeline from a relational database to Amazon S3 using AWS Database Migration Service (DMS). Which TWO configurations are required for continuous replication?

Accepted Answer

Enable binary logging on the source database.. For continuous CDC replication with AWS DMS, two key configurations are required: enabling binary logging on the source database (option B) and selecting both 'Full load' and 'Ongoing replication' in the DMS task (option D). Binary logging (e.g., binlog for MySQL) captures ongoing changes, while enabling both full load and ongoing replication ensures that the initial data load is completed before continuous change capture begins. Option A (transformation rules) is optional, not required. Option C (VPC endpoint) is not necessary because DMS can connect to the source database over the internet, VPN, or VPC peering without a VPC endpoint. Option E (pre-creating the target table in S3) is not needed because DMS can create the target table automatically or you can let DMS handle the schema.

Answer

Define transformation rules in the DMS task.

Answer

Configure a VPC endpoint for DMS.

Answer

Pre-create the target table in S3.