MLS-C01 Practice Test 38 — 15 Questions

Question 1

A data pipeline uses AWS Glue to transform data from Amazon RDS to Amazon S3. The team wants to ensure that only new or updated records are processed in each run, minimizing cost and time. Which AWS Glue feature should be used?

Accepted Answer

Enable Glue Job Bookmarks.. Option D is correct because Job Bookmarks track processed data and enable incremental processing. Option A is wrong because Partitioning organizes data but doesn't track changes. Option B is wrong because Crawlers discover schema but don't process incrementally. Option C is wrong because Triggers schedule jobs but don't enable incremental processing.

Answer

Use Glue triggers to run the job on a schedule.

Answer

Use Glue partition pruning to filter data.

Answer

Use Glue crawlers to detect new data.

Question 2

A data engineer needs to transform and move 2 TB of data from an Amazon RDS for PostgreSQL instance to Amazon S3 daily. The transformation includes filtering, joining with data in S3, and aggregating. Which AWS services can be used together to accomplish this with minimal operational overhead? (Choose THREE.)

Accepted Answer

Amazon S3. Option A (Glue) is the ETL service, Option C (S3) is the target, and Option D (Glue Data Catalog) manages metadata. Option B (EMR) adds overhead, Option E (Redshift) is a warehouse, not needed.

Answer

Amazon EMR

Answer

Amazon Redshift

Question 3

A company wants to build a data lake on Amazon S3. The data lake should support both batch and real-time data ingestion. Which AWS services should be used for data ingestion? (Choose TWO.)

Accepted Answer

AWS Glue. Option B (Kinesis Firehose) is for real-time ingestion, Option D (AWS Glue) is for batch ETL. Option A (Athena) is for querying, Option C (Redshift) is a warehouse, Option E (SQS) is not for ingestion into S3.

Answer

Amazon Redshift

Answer

Amazon Athena

Answer

Amazon SQS

Question 4

A data engineer wants to stream clickstream data from a web application to Amazon S3 for near-real-time analytics. Which AWS service should be used to ingest and buffer the data before landing in S3?

Accepted Answer

Amazon Kinesis Data Firehose. Amazon Kinesis Data Firehose is the correct service for loading streaming data into S3 without custom code. Option A is wrong because Kinesis Data Streams requires a consumer to write to S3. Option C is wrong because AppFlow is for SaaS integrations. Option D is wrong because Glue is for ETL, not real-time streaming.

Answer

Amazon AppFlow

Answer

Amazon Kinesis Data Streams

Answer

AWS Glue

Question 5

A company is designing a data pipeline to ingest data from multiple sources into an Amazon S3 data lake. The data must be encrypted at rest and in transit. Which TWO actions should be taken to meet these requirements?

Accepted Answer

Enable Server-Side Encryption on the S3 bucket. Server-Side Encryption (SSE-S3 or KMS) encrypts data at rest in S3. Using HTTPS (SSL/TLS) for all API calls encrypts data in transit. Client-side encryption is an alternative but not the standard AWS approach. VPC endpoints and CloudFront do not encrypt in transit by themselves.

Answer

Enable S3 Transfer Acceleration

Answer

Use client-side encryption before uploading

Answer

Use S3 VPC Endpoint

Question 6

An IAM policy attached to a SageMaker notebook role is shown. The data engineer tries to run an Athena query on a table in the 'my_database' Glue database. The query fails with an access denied error. What is the MOST likely cause?

Accepted Answer

The policy does not allow athena:StartQueryExecution on the Athena workgroup.. Option D is correct because the policy does not grant permission to the Athena workgroup. Athena requires workgroup permissions for StartQueryExecution. Option A is wrong because the policy allows GetObject. Option B is wrong because the policy allows GetTable and GetDatabase. Option C is wrong because S3 actions are allowed on the bucket.

Answer

The policy does not allow s3:PutObject on the query results location.

Answer

The policy does not allow glue:GetTable on the specific database.

Answer

The policy does not allow s3:ListBucket on the bucket.

Question 7

A data engineer needs to run a one-time ETL job to transform 500 GB of data from Amazon RDS to Amazon S3. The job should be cost-effective and require minimal infrastructure management. Which AWS service should be used?

Accepted Answer

AWS Glue. Option B is correct because AWS Glue is serverless and suitable for one-time ETL jobs. Option A is wrong because EMR requires cluster management and is more expensive for one-time jobs. Option C is wrong because Data Pipeline is a managed service but still requires provisioning. Option D is wrong because Athena is for querying, not ETL.

Answer

Amazon EMR

Answer

Amazon Athena

Answer

AWS Data Pipeline

Question 8

A company uses Amazon Kinesis Data Analytics for real-time anomaly detection on a stream of IoT sensor data. The application is experiencing high latency. The data volume has doubled. Which action would MOST effectively reduce latency?

Accepted Answer

Increase the Parallelism setting of the Kinesis Data Analytics application. Increasing the parallelism (number of KPUs) in Kinesis Data Analytics allows processing more data in parallel, reducing latency. Changing record format may help but not as much as scaling. Reducing retention is not relevant. Using Lambda adds overhead.

Answer

Change the record format from JSON to Avro

Answer

Decrease the retention period of the source stream

Answer

Increase the number of shards in the source Kinesis stream

Question 9

A data engineer needs to ingest streaming data from an on-premises Kafka cluster into Amazon S3 with minimal operational overhead. Which AWS service should be used to stream the data into S3 without managing servers?

Accepted Answer

Amazon Kinesis Data Firehose. Amazon Kinesis Data Firehose is the correct service for loading streaming data into S3 without managing servers. Option A (Amazon Kinesis Data Streams) requires a consumer to process data; Option B (Amazon MSK) is a managed Kafka service but still requires management; Option D (AWS Glue) is for ETL jobs, not real-time streaming.

Answer

Amazon Kinesis Data Streams

Answer

AWS Glue

Answer

Amazon Managed Streaming for Apache Kafka (Amazon MSK)

Question 10

A company needs to transfer 10 TB of data from an on-premises data center to Amazon S3. The network bandwidth is limited to 100 Mbps, and the transfer must complete within 5 days. Which TWO options are viable? (Choose TWO.)

Accepted Answer

Use AWS Snowball Edge device to ship the data. AWS Snowball Edge is a physical device for large data transfers over slow networks. AWS DataSync can be used if there is some bandwidth, but with 100 Mbps, it would take ~10 days, exceeding the 5-day window. Option B (S3 Transfer Acceleration) uses existing internet, which is still limited. Option C (Direct Connect) would require setup time and may not meet the window. Option E (S3 Multipart Upload) is for uploading files, not for bulk transfer over slow link.

Answer

Use S3 Transfer Acceleration to speed up the transfer

Answer

Use S3 Multipart Upload to upload files in parallel

Answer

Use AWS DataSync over the existing internet connection

Answer

Use AWS Direct Connect to establish a dedicated network connection

Question 11

A company is using Amazon Redshift for data warehousing. The data engineering team notices that queries are slow and the system is frequently writing to disk due to insufficient memory. Which type of workload management (WLM) configuration change would help reduce disk writes?

Accepted Answer

Increase the memory percentage allocated to the WLM queue.. If queries spill to disk, they need more memory. Increasing the memory percentage allocated to the queue reduces disk spills. Option A is wrong because concurrency slots increase parallelism but may reduce memory per query. Option C is wrong because query monitoring rules only flag issues, not fix them. Option D is wrong because short query acceleration is for short queries, not memory issues.

Answer

Increase the number of query concurrency slots.

Answer

Enable query monitoring rules to abort queries that spill to disk.

Answer

Enable short query acceleration (SQA).

Question 12

A data pipeline uses Amazon Kinesis Data Streams to ingest event data. The data is consumed by an AWS Lambda function, which writes to Amazon DynamoDB. The Lambda function is experiencing throttling errors, and the DynamoDB write capacity is underutilized. The events must be processed in order per shard. Which solution most effectively addresses the throttling?

Accepted Answer

Increase the number of shards in the Kinesis Data Stream. Adding more shards to the Kinesis stream increases the number of concurrent Lambda invocations, spreading the load. Option B (increasing DynamoDB write capacity) does not address Lambda throttling. Option C (using SQS FIFO) would decouple but may cause duplicates. Option D (increasing Lambda reserved concurrency) alone may not help if Lambda is throttled due to concurrency limits; adding shards is more effective.

Answer

Use an SQS FIFO queue between Kinesis and Lambda to buffer

Answer

Increase the Lambda function's reserved concurrency

Answer

Increase the write capacity units of the DynamoDB table

Question 13

A data engineer runs the AWS CLI command above to inspect a file in S3. They need to determine if the file was modified after a Glue ETL job processed it. What additional information could they obtain from this command?

Accepted Answer

The object's last modified timestamp.. Option D is correct because the LastModified timestamp is provided, which can be used to compare with job completion time. Option A is wrong because head-object does not show object size. Option B is wrong because ContentLength is shown. Option C is wrong because ETag is shown.

Answer

The object's content type.

Answer

The object's storage class.

Answer

The object's ETag.

Question 14

A company uses Amazon DynamoDB as the primary data store for a real-time application. The data science team wants to analyze the data using Amazon Athena. What is the most efficient way to make the DynamoDB data available for Athena queries?

Accepted Answer

Use DynamoDB Streams to invoke an AWS Lambda function that writes data to Amazon S3 in Parquet format. Then query the data in S3 using Athena.. Option A is correct because DynamoDB Streams can trigger a Lambda function to write to S3, and Athena can query S3. Option B is wrong because EMR can query DynamoDB directly but is more complex. Option C is wrong because Glue can extract data but adds latency. Option D is wrong because Redshift Spectrum uses S3, not DynamoDB directly.

Answer

Use AWS Glue to extract data from DynamoDB and load into S3 on a schedule.

Answer

Use Amazon Redshift Spectrum to query DynamoDB directly.

Answer

Use Amazon EMR to read directly from DynamoDB and run Hive queries.

Question 15

A data engineer needs to transfer 50 TB of historical data from an on-premises HDFS cluster to Amazon S3. The company has a 1 Gbps internet connection. Which service would complete the transfer in the shortest time?

Accepted Answer

AWS Snowball. AWS Snowball is a physical device that can transfer large amounts of data faster than internet due to bandwidth limitations. DataSync is for network transfers. Direct Connect helps but still limited by bandwidth. S3 Transfer Acceleration speeds up internet transfers but cannot match physical shipment for 50 TB.

Answer

Amazon S3 Transfer Acceleration

Answer

AWS Direct Connect

Answer

AWS DataSync