MLS-C01 Data Engineering Practice Test 19 — 15 Questions

Question 1

The Glue job my-glue-job fails after a few successful runs. The error log shows 'Job run exceeds max concurrent runs limit'. The CloudFormation template is shown in the exhibit. What change should be made to allow multiple runs to execute concurrently?

Accepted Answer

Set the MaxConcurrentRuns property to 3. The 'MaxConcurrentRuns' is set to 1, which prevents parallel executions. Setting it to a higher value (e.g., 3) allows concurrent runs. MaxRetries is for retry count, not concurrency. Role and TempDir are not relevant.

Answer

Change the IAM role to one with more permissions

Answer

Increase the MaxRetries property to 3

Answer

Remove the --job-bookmark-option argument

Question 2

A Glue job fails with an AccessDenied error when trying to write to the S3 bucket my-data-lake. The IAM policy attached to the job role is shown in the exhibit. What is the MOST likely reason for the failure?

Accepted Answer

The job role does not have permissions to decrypt the KMS key used for server-side encryption. The policy allows s3:PutObject on the bucket, so write access seems granted. However, if the bucket is encrypted with SSE-KMS, the job also needs kms:Decrypt and kms:GenerateDataKey permissions. The policy does not include KMS actions. The bucket policy might also deny, but the most common issue is KMS encryption.

Answer

The s3:ListBucket action is missing on the bucket level

Answer

The s3:PutObject action is not sufficient; the job needs s3:PutObjectAcl

Answer

The resource ARN for s3:PutObject should include a specific prefix

Question 3

A data scientist needs to process a large volume of streaming data from IoT devices and store the results in Amazon S3 for further analysis. Which AWS service is most suitable for ingesting and processing this data in near real-time?

Accepted Answer

Amazon Kinesis Data Analytics. Amazon Kinesis Data Analytics is designed for real-time processing of streaming data. AWS Glue is for batch ETL, Amazon EMR for big data processing, and Amazon Redshift for data warehousing.

Answer

Amazon Redshift

Answer

AWS Glue

Answer

Amazon EMR

Question 4

A company is using AWS Glue to run ETL jobs that transform data from Amazon S3 to Amazon Redshift. The jobs are failing intermittently with timeouts. What is the most likely cause?

Accepted Answer

The AWS Glue job does not have enough DPUs (Data Processing Units) allocated.. Insufficient DPU allocation can cause timeouts in Glue jobs. The other options are less likely: S3 bucket policies would cause permission errors, not timeouts; Redshift maintenance would affect all jobs; compression would improve performance.

Answer

The S3 bucket policy is too restrictive.

Answer

The Amazon Redshift cluster is in maintenance mode.

Answer

The source data is not compressed.

Question 5

A company uses Amazon Kinesis Data Streams to collect clickstream data. The data is consumed by a Lambda function that writes to DynamoDB. Occasionally, the Lambda function fails due to throttling from DynamoDB. How can the company resolve this issue without losing data?

Accepted Answer

Decrease the batch size in the Lambda event source mapping.. Decreasing the batch size reduces the number of records per invocation, lowering the write load on DynamoDB. Increasing shards would increase parallelism, potentially worsening throttling. Using SQS would add latency. Removing error handling would lose data.

Answer

Ignore the throttling errors and let Lambda retry.

Answer

Increase the number of shards in the Kinesis stream.

Answer

Use an Amazon SQS queue as a buffer between Kinesis and Lambda.

Question 6

A company needs to perform complex transformations on large datasets stored in Amazon S3 using Apache Spark. They want to minimize operational overhead. Which AWS service should they use?

Accepted Answer

Amazon EMR. Amazon EMR with Spark is a managed service that reduces operational overhead. AWS Glue is for simpler ETL, not complex Spark transformations. EC2 requires manual setup. Athena is SQL-based, not Spark.

Answer

Amazon EC2 with manually configured Spark

Answer

Amazon Athena

Answer

AWS Glue

Question 7

A company is migrating its on-premises Hadoop cluster to AWS. They have a large amount of historical data stored in HDFS. Which approach is the most efficient for transferring this data to Amazon S3?

Accepted Answer

Use AWS Snowball Edge devices.. AWS Snowball Edge is ideal for large data transfers when network bandwidth is limited. AWS DataSync is for network transfers, but slower for huge datasets. S3 Transfer Acceleration improves speed but still network. Direct Connect is network-based.

Answer

Use AWS Direct Connect.

Answer

Use AWS DataSync over the internet.

Answer

Use S3 Transfer Acceleration.

Question 8

A data engineer needs to automate the transformation of CSV files to Parquet format as soon as they are uploaded to an S3 bucket. The transformed files should be stored in another S3 bucket. Which solution is the most cost-effective and requires the least maintenance?

Accepted Answer

Configure an S3 event notification to invoke a Lambda function.. S3 Event Notification to Lambda is serverless and cost-effective. Glue jobs have a minimum billing of 1 minute. EMR is overkill. EC2 requires management.

Answer

Configure an S3 event notification to invoke an AWS Glue job.

Answer

Run an Amazon EMR cluster continuously to watch for new files.

Answer

Set up an EC2 instance with a cron job to poll the S3 bucket.

Question 9

A company uses Amazon Kinesis Data Firehose to deliver streaming data to Amazon S3. They notice that the data is delivered in 5-minute intervals even though they set the buffer interval to 60 seconds. What could be the cause?

Accepted Answer

The buffer size is set to a value larger than the incoming data rate.. Firehose has a minimum buffer interval of 60 seconds and a maximum of 900 seconds. The actual delivery interval is controlled by both buffer size and interval; if the buffer size is not reached, Firehose waits up to the maximum interval. The default buffer size is 5 MB. If data rate is low, Firehose will wait 5 minutes (default max interval) unless the buffer size is lowered.

Answer

The source Kinesis stream has insufficient shards.

Answer

The S3 bucket is in a different region.

Answer

The IAM role does not have permission to write to S3.

Question 10

A company needs to process sensitive data from multiple sources. They want to use AWS Glue to catalog and transform the data. Which feature should they use to ensure that sensitive columns are masked before the data is available for querying?

Accepted Answer

AWS Glue DataBrew. Glue DataBrew provides data masking and cleansing capabilities. Glue Studio is for building ETL jobs, but masking requires custom code. Lake Formation is for fine-grained access control, not masking. Macie is for discovering sensitive data, not masking.

Answer

AWS Glue Studio

Answer

AWS Lake Formation

Answer

Amazon Macie

Question 11

A company runs a critical ETL job using AWS Glue that writes to an Amazon Redshift cluster. The job occasionally fails due to insufficient disk space on the Redshift cluster. How can the company automate the process to prevent this failure?

Accepted Answer

Use a CloudWatch alarm to trigger a Lambda function that resizes the cluster.. Using Amazon CloudWatch to monitor disk space and automatically resize the cluster is the best automated solution. Reserving nodes does not address space. Using RA3 nodes with managed storage is a good proactive step but does not automate resizing. The correct answer is to monitor and auto-resize.

Answer

Use RA3 node types with managed storage.

Answer

Increase the number of slices in the Redshift cluster.

Answer

Reserve additional nodes for the Redshift cluster.

Question 12

Which TWO AWS services are suitable for real-time stream processing?

Accepted Answer

Amazon Kinesis Data Analytics. Amazon Kinesis Data Analytics and AWS Lambda can process streams in real-time. AWS Glue is batch-oriented, Amazon EMR can process streams but is more batch, and Amazon Athena is for ad-hoc SQL queries on S3.

Answer

Amazon Athena

Answer

AWS Glue

Answer

Amazon EMR

Question 13

Which TWO data formats are columnar and optimized for analytics queries in Amazon S3?

Accepted Answer

ORC. Parquet and ORC are columnar storage formats. JSON and CSV are row-oriented. Avro is row-oriented.

Answer

CSV

Answer

JSON

Answer

Avro

Question 14

Which THREE considerations are important when designing a data lake on Amazon S3?

Accepted Answer

Setting up S3 Lifecycle policies to transition data to colder storage. Organizing data with partitioning, encrypting data at rest, and setting up lifecycle policies are key. Single Availability Zone is not an S3 consideration (S3 is regional). Using Provisioned IOPS is for block storage.

Answer

Using Provisioned IOPS for S3

Answer

Using a single Availability Zone for data storage

Question 15

An IAM policy attached to an AWS Glue job allows reading and writing to an S3 bucket and accessing Glue Data Catalog. The job fails with an access denied error when trying to create a table in the Data Catalog. What is the likely issue?

Accepted Answer

The policy does not include the glue:CreateTable action.. The policy allows GetTable and GetDatabase actions, but not CreateTable. The job needs glue:CreateTable permission. The S3 actions are sufficient. The error is specifically about creating a table.

Answer

The Glue Data Catalog is not enabled for the account.

Answer

The job does not have permission to write to the S3 bucket.

Answer

The S3 bucket is encrypted with a KMS key that the job cannot access.

MLS-C01 Data Engineering Practice Test 19 — 15 Questions

Exhibit

MLS-C01 Data Engineering Practice Test 19 — 15 Questions

Exhibit