DEA-C01 Data Operations and Support Practice Test 9 — 15 Questions

Question 1

A company uses AWS Lake Formation to manage access to data in S3. A data analyst reports being unable to query a table in Amazon Athena, receiving an 'Access Denied' error. The analyst has SELECT permission on the table in Lake Formation. What additional configuration is MOST likely causing the issue?

Accepted Answer

The IAM role used by Athena does not have S3 GetObject permission on the underlying data. Option D is correct because Lake Formation enforces access at the S3 level via IAM; if the IAM role lacks S3 permissions, access is denied. Option A is wrong because the table is registered. Option B is wrong because the analyst has SELECT permission. Option C is wrong because Athena permissions are typically granted via Lake Formation.

Answer

Athena does not have permission to access the Glue Data Catalog

Answer

The analyst does not have DESCRIBE permission

Answer

The table is not registered with Lake Formation

Question 2

A data engineer is troubleshooting an Amazon EMR cluster that has been running for several days. The cluster uses Amazon S3 as the data source and HDFS for intermediate storage. The engineer notices that some tasks fail with 'Java heap space' errors. Which TWO actions should the engineer take to resolve this issue?

Accepted Answer

Increase the maximum Java heap size for the task nodes (mapreduce.map.java.opts).. Options C and D are correct. Increasing the YARN memory overhead allows containers to allocate more memory, and increasing the maximum Java heap size reduces out-of-memory errors. Option A is wrong because increasing container count without increasing total memory may not help. Option B is wrong because reducing container count may cause resource underutilization. Option E is wrong because EMRFS consistent view does not affect memory.

Answer

Enable EMRFS consistent view for S3.

Answer

Increase the number of containers per node.

Answer

Decrease the YARN container size.

Question 3

A company uses Amazon Redshift for data warehousing. They notice that query performance has degraded over time. Which maintenance operation should be performed to improve performance?

Accepted Answer

Run the VACUUM command. Option B is correct because VACUUM re-sorts rows and reclaims space, improving performance. Option A is wrong because ANALYZE updates statistics but does not physically reorganize data. Option C is wrong because REINDEX rebuilds indexes, but Redshift uses sort keys, not indexes. Option D is wrong because DROP TABLE deletes data.

Answer

Drop and recreate the table

Answer

Run the REINDEX command

Answer

Run the ANALYZE command

Question 4

Refer to the exhibit. An AWS Glue job is failing with 'AccessDenied' when trying to write to the 'data-lake-bucket' which is encrypted with an AWS KMS key. The IAM role used by the Glue job has the attached policy shown. What is the MOST likely cause of the failure?

Accepted Answer

The policy does not include kms:GenerateDataKey or kms:Encrypt permission.. Option C is correct because the policy allows s3:PutObject but does not allow kms:GenerateDataKey or kms:Encrypt, which are needed to write to an SSE-KMS encrypted bucket. Option A is wrong because ListBucket is allowed. Option B is wrong because GetObject is allowed. Option D is wrong because the key ARN is correct.

Answer

The policy does not include s3:ListBucket permission.

Answer

The policy does not include s3:GetObject permission.

Answer

The KMS key ARN in the policy is incorrect.

Question 5

A company uses Amazon DynamoDB as the primary data store for a web application. The application experiences high read latency. Which TWO actions can improve read performance?

Accepted Answer

Enable DynamoDB Global Tables. Option B is correct because DynamoDB Accelerator (DAX) provides in-memory caching, reducing read latency. Option D is correct because Global Tables provide local read replicas, reducing latency for global users. Option A is wrong because GSI adds secondary indexes but does not reduce read latency for primary key lookups. Option C is wrong because increasing write capacity does not affect read performance. Option E is wrong because DynamoDB Streams is for change capture, not reducing latency.

Answer

Add a Global Secondary Index (GSI)

Answer

Enable DynamoDB Streams

Answer

Increase the write capacity units

Question 6

Refer to the exhibit. A data engineer is troubleshooting an AWS Lambda function that processes data from Amazon S3. The function is triggered by S3 events, but no logs appear in CloudWatch Logs. The engineer runs the AWS CLI command shown. What is the MOST likely reason for the missing logs?

Accepted Answer

The Lambda execution role does not have permissions to create log groups and write logs.. Option B is correct because the log group shows 'storedBytes': 0, indicating no logs have been written. The most common cause is that the Lambda execution role lacks permission to create log streams and put logs. Option A is wrong because the log group exists. Option C is wrong because retention does not prevent logs from being written. Option D is wrong because the CLI command shows the log group exists.

Answer

The Lambda function is configured to log to a different log group.

Answer

The Lambda function is not being invoked by S3 events.

Answer

The log retention policy is set to 7 days, causing logs to expire immediately.

Question 7

A data engineer is designing a data pipeline that ingests data from multiple sources into Amazon S3, then processes it with AWS Glue and loads it into Amazon Redshift. Which THREE practices should be implemented to ensure data quality?

Accepted Answer

Implement data validation checks at the ingestion stage. Option A is correct because data validation at ingestion catches issues early. Option C is correct because schema enforcement prevents data type mismatches. Option E is correct because monitoring with CloudWatch allows proactive detection of failures. Option B is wrong because manual sampling is not scalable. Option D is wrong because compressing data does not ensure quality.

Answer

Compress data files to reduce storage costs

Answer

Use manual sampling to check data quality periodically

Question 8

Refer to the exhibit. A data engineer runs the command on an Amazon S3 bucket used for data lake storage. The engineer is concerned about accidental overwrites of objects. What does the output indicate?

Accepted Answer

Versioning is enabled, so previous versions of objects are preserved.. Option A is correct because the Status 'Enabled' means versioning is turned on for the bucket. Option B is wrong because MFA Delete is not required for versioning. Option C is wrong because versioning does not automatically expire old versions. Option D is wrong because versioning does not encrypt objects.

Answer

Old versions will be automatically deleted after a retention period.

Answer

Objects are encrypted at rest by default.

Answer

MFA Delete is disabled, meaning anyone can delete objects permanently.

Question 9

A company is using AWS Glue to process data stored in Amazon S3. The Glue job runs successfully but takes longer than expected. Which TWO actions can reduce the job runtime?

Accepted Answer

Increase the number of DPUs allocated to the job. Option B is correct because increasing worker capacity speeds up processing. Option D is correct because partitioning data reduces the amount scanned. Option A is wrong because the job type (Spark vs Python) is not specified as the bottleneck. Option C is wrong because reducing worker count would increase runtime. Option E is wrong because disabling job bookmarking might affect incremental processing but not runtime significantly.

Answer

Disable job bookmarking

Answer

Reduce the number of workers

Answer

Change the job type from Spark to Python shell

Question 10

A data engineering team uses AWS Glue ETL jobs to process data from Amazon S3. The jobs recently started failing with 'Access Denied' errors when writing to the output S3 bucket. What is the most likely cause?

Accepted Answer

The S3 bucket policy was modified to deny write access to the Glue job's IAM role.. Option C is correct because AWS Glue ETL jobs require an IAM role with permissions to write to the S3 bucket. If the bucket policy was inadvertently changed to deny access to that role, the job would fail. Option A is wrong because insufficient memory would cause out-of-memory errors, not access denied. Option B is wrong because separate encryption permissions are not the primary cause; S3 access permissions are. Option D is wrong because KMS key permissions would cause encryption-related errors, not general access denied.

Answer

The KMS key used for server-side encryption is not accessible to the Glue job.

Answer

The S3 bucket does not have default encryption enabled.

Answer

The job ran out of memory due to large data volume.

Question 11

Refer to the exhibit. A data engineer sees this output from the AWS CLI for a failed Glue job. The job uses 10 workers of Standard type. What is the MOST appropriate action to resolve the OutOfMemoryError?

Accepted Answer

Increase MaxCapacity to 20. Option B is correct because increasing the number of workers adds more parallelism but does not increase memory per worker; the error is heap space per worker. Option A is wrong because G.1X has less memory. Option C is correct: increasing MaxCapacity (DPUs) per worker increases memory per worker. Option D is wrong because reducing workers exacerbates the issue.

Answer

Increase NumberOfWorkers to 20

Answer

Reduce NumberOfWorkers to 5

Answer

Change WorkerType to G.1X

Question 12

A data engineer needs to monitor the number of records processed by a Kinesis Data Firehose delivery stream and set an alarm if the count drops below a threshold. Which CloudWatch metric should be used?

Accepted Answer

IncomingRecords. Option A is correct because 'IncomingRecords' counts records received by Firehose, which directly indicates processing volume. Option B is wrong because 'IncomingBytes' measures bytes, not records. Option C is wrong because 'DeliveryToS3.Success' is a success metric but measures successful deliveries, not record count. Option D is wrong because 'PutRecord.Success' is a per-API call metric for Kinesis Data Streams, not Firehose.

Answer

PutRecord.Success

Answer

DeliveryToS3.Success

Answer

IncomingBytes

Question 13

A company runs a Redshift cluster for analytics. The data engineering team notices that COPY commands from S3 are failing for large files (>1 GB) with the error 'S3ServiceException: SlowDown'. What is the most effective solution?

Accepted Answer

Split the large files into smaller parts (e.g., 100 MB each) and use parallel COPY.. Option D is correct because the SlowDown error indicates throttling from S3. Splitting large files into smaller parts increases parallelism and reduces the chance of throttling per object. Option A is wrong because increasing node count does not directly address S3 throttling. Option B is wrong because enabling automatic compression is for compression, not throttling. Option C is wrong because using spectrum queries is for querying external tables, not direct COPY.

Answer

Use Redshift Spectrum to query the data directly in S3.

Answer

Enable automatic compression on the target tables.

Answer

Increase the number of Redshift nodes to distribute the load.

Question 14

Refer to the exhibit. This IAM policy is attached to a user who is trying to read the object s3://data-bucket/confidential/report.csv. The user's principal tag 'role' is set to 'analyst'. What will happen when the user attempts to read the object?

Accepted Answer

Denied because the condition in the Deny statement evaluates to true. Option C is correct because the Deny statement applies when the role tag is not 'admin'. The user's tag is 'analyst', so the condition matches and access is denied. Option A is wrong because the Allow statement is overridden by the explicit Deny. Option B is wrong because the Deny applies to all actions in the confidential prefix. Option D is wrong because Deny overrides Allow.

Answer

Denied because the Deny statement covers all actions under confidential

Answer

Allowed because there is an explicit Allow and no explicit Deny that matches

Answer

Allowed because of the Allow statement for s3:GetObject

Question 15

A data engineer is troubleshooting a step function that orchestrates ETL jobs. The state machine fails with 'State Machine Execution Throttled' error. What should the engineer do to resolve this?

Accepted Answer

Request a service quota increase for concurrent executions.. Option C is correct because the throttling is likely due to exceeding the default concurrent execution limit. Requesting a limit increase from AWS Support is the proper solution. Option A is wrong because reducing the number of steps does not affect concurrent execution limits. Option B is wrong because CloudWatch alarms only monitor, not resolve throttling. Option D is wrong because the error is about execution throttling, not API throttling, so adjusting API rate limits is not relevant.

Answer

Reduce the number of steps in the state machine.

Answer

Set up a CloudWatch alarm to detect throttling and retry.

Answer

Adjust the API rate limits in the state machine definition.