DEA-C01 Data Operations and Support Practice Test 21 — 15 Questions

Question 1

A data engineer is monitoring an Amazon Kinesis Data Streams application that processes real-time events. The application uses a Kinesis Client Library (KCL) consumer. The engineer notices that the consumer is lagging behind the producer, and the lag is increasing over time. The stream has 10 shards. Which action will MOST effectively reduce the lag?

Accepted Answer

Increase the number of shards in the Kinesis data stream.. Option C is correct because increasing the number of shards increases the stream's capacity and allows more parallel processing. Option A is wrong because reducing the number of records per shard per second would decrease throughput. Option B is wrong because using a single worker per shard is the default; adding more workers per shard is not recommended. Option D is wrong because decreasing the number of shards reduces capacity, worsening lag.

Answer

Use multiple KCL workers per shard to increase processing capacity.

Answer

Decrease the number of records per shard per second.

Answer

Decrease the number of shards in the Kinesis data stream.

Question 2

A data engineer needs to set up a data catalog for a new data lake in AWS Glue. The data resides in S3 in Parquet format. The engineer wants to ensure that the schema is automatically detected and updated when new columns are added to the data. Which configuration should the engineer use?

Accepted Answer

Configure the crawler's 'Schema updates' option to 'Update the table schema'.. Option D is correct because Glue crawlers can be configured to update the table schema when new columns are detected. Option A is wrong because partition indexing does not update schema. Option B is wrong because the crawler's output is a table, not a database. Option C is wrong because adding partition indexes does not update schema.

Answer

Add a partition index to the Glue Data Catalog table.

Answer

Set the crawler's 'Database' output to a new database.

Answer

Enable partition indexing on the table.

Question 3

A data engineer has set up an AWS Lambda function that processes files uploaded to an S3 bucket. The function is triggered by S3 event notifications. However, the function is not being invoked when a file is uploaded. The engineer checks the Lambda function's CloudWatch Logs and finds no execution logs. What should the engineer check FIRST?

Accepted Answer

Verify that the S3 bucket has an event notification configured for the Lambda function.. Option A is correct because the S3 bucket must have an event notification configured to trigger the Lambda function. Option B is wrong because function code errors would appear in logs after invocation. Option C is wrong because the IAM role affects execution, not invocation trigger. Option D is wrong because VPC configuration affects network access, not whether the function is triggered.

Answer

Check the Lambda function's code for errors.

Answer

Verify that the Lambda function's IAM role has permissions to read from S3.

Answer

Check if the Lambda function is attached to a VPC.

Question 4

A company uses Amazon EMR to run Spark jobs on a transient cluster. The jobs are submitted via a step in the cluster. The cluster is configured to auto-terminate after the last step completes. However, the cluster is not terminating even though the step shows as 'COMPLETED'. What could be the cause?

Accepted Answer

The step's 'ActionOnFailure' parameter is set to 'CONTINUE' and 'KeepClusterAliveOnFailure' is true.. Option B is correct because if KeepClusterAliveOnFailure is set to true for a step, the cluster will not terminate even if the step succeeds. Option A is wrong because 'COMPLETED' indicates success. Option C is wrong because the root volume size does not affect termination. Option D is wrong because cluster is transient, not long-running.

Answer

The cluster's root device size is too large.

Answer

The step failed with an error, but the status shows 'COMPLETED' due to a reporting bug.

Answer

The cluster is configured as a long-running cluster.

Question 5

A data engineer is designing a data pipeline that ingests streaming data from an IoT device fleet. The data must be processed in near real-time and stored in Amazon S3 for long-term analytics. Which TWO AWS services should the engineer use together to achieve this?

Accepted Answer

Amazon Kinesis Data Firehose. Option A is correct because Kinesis Data Streams ingests streaming data. Option C is correct because Kinesis Data Firehose can deliver data from the stream to S3. Option B is wrong because SQS is for message queues, not real-time streaming. Option D is wrong because Glue is for batch ETL, not real-time. Option E is wrong because Athena is a query service, not a delivery service.

Answer

Amazon Athena

Answer

AWS Glue

Answer

Amazon Simple Queue Service (SQS)

Question 6

A data engineer is monitoring an Amazon Redshift cluster and notices that the disk space usage is increasing rapidly. The engineer wants to reclaim space from deleted rows. Which command should the engineer run?

Accepted Answer

VACUUM. Option D is correct because VACUUM reclaims space from deleted rows. Option A is wrong because ANALYZE updates statistics. Option B is wrong because COPY loads data. Option C is wrong because UNLOAD exports data.

Answer

ANALYZE

Answer

UNLOAD

Answer

COPY

Question 7

A data engineer is troubleshooting a slow-running Amazon Redshift query. The query joins several large tables and performs aggregations. The engineer runs EXPLAIN and sees a 'DS_DIST_ALL' step. Which TWO actions will MOST likely improve query performance? (Choose TWO.)

Accepted Answer

Change the distribution style of the tables to DISTSTYLE KEY on the join columns.. Option A is correct because DS_DIST_ALL indicates a cross-node redistribution; using DISTSTYLE KEY on the join columns can reduce data movement. Option C is correct because SORTKEY can speed up joins and aggregations by reducing data scans. Option B is wrong because increasing node count may help but is not a targeted fix. Option D is wrong because VACUUM reclaims space and sorts, but does not address distribution issues. Option E is wrong because CNAME is a DNS concept, not a Redshift feature.

Answer

Run the VACUUM command on all tables.

Answer

Use the CNAME command to rename the tables.

Answer

Increase the number of nodes in the Redshift cluster.

Question 8

Refer to the exhibit. This log snippet is from a failed AWS Glue job. The job processes a large dataset in memory. What is the MOST likely cause of the OutOfMemoryError?

Accepted Answer

The Glue job is running with insufficient DPUs or worker type.. Option B is correct because an OutOfMemoryError in Glue often indicates that the DPU (worker) allocation is insufficient for the data size. Option A is wrong because the error is not about file format. Option C is wrong because the job is not about joining; the error is heap space. Option D is wrong because the error is not about partitioning.

Answer

The input data is in an unsupported file format.

Answer

The job is attempting to join two tables with mismatched keys.

Answer

The job has too many partitions.

Question 9

A company uses Amazon S3 to store data for analytics. The data engineer needs to ensure that the S3 bucket is protected against accidental deletion of objects. Which THREE actions should the engineer take? (Choose THREE.)

Accepted Answer

Create an S3 bucket policy that explicitly denies the s3:DeleteObject action.. Option A is correct because MFA Delete adds an extra layer of protection. Option B is correct because versioning keeps multiple versions, allowing recovery. Option D is correct because a bucket policy denying s3:DeleteObject to all principals prevents any deletion. Option C is wrong because lifecycle policies delete objects automatically. Option E is wrong because server access logs are for auditing, not prevention.

Answer

Enable server access logging for the S3 bucket.

Answer

Configure a lifecycle policy to transition objects to Glacier.

Question 10

Which TWO actions are effective ways to monitor the health of an Amazon DynamoDB table? (Choose two.)

Accepted Answer

Enable DynamoDB Streams and process with Lambda to detect failures.. Options A and D are correct. CloudWatch metrics like ConsumedReadCapacityUnits and ThrottledRequests provide insight into table health. Option B is wrong because there is no 'TableHealth' metric. Option C is wrong because S3 is not for DynamoDB monitoring. Option E is wrong because EC2 is not relevant.

Answer

Use AWS S3 inventory to track table size.

Answer

Use EC2 instance status checks.

Answer

Monitor the 'TableHealth' metric in CloudWatch.

Question 11

A data engineer creates an IAM policy as shown in the exhibit. The engineer then attaches this policy to an IAM role used by an application that uploads objects to the S3 bucket 'my-bucket'. When the application uploads an object without specifying server-side encryption, what happens?

Accepted Answer

The upload fails with a 403 Access Denied error.. Option D is correct because the policy requires the s3:x-amz-server-side-encryption header to be set to AES256. If the request does not include that header, the condition is not met, and the request is denied with a 403 Access Denied error. Option A is wrong because the object is not uploaded. Option B is wrong because the condition requires AES256, not SSE-C. Option C is wrong because the condition is not met if the header is absent; the request is denied.

Answer

The object is uploaded with SSE-S3 encryption by default.

Answer

The object is uploaded without encryption.

Answer

The object is uploaded with SSE-C encryption.

Question 12

Which THREE are best practices for managing data in Amazon S3 for a data lake? (Choose three.)

Accepted Answer

Enable S3 Versioning to protect against accidental deletions.. Enabling S3 Versioning is a best practice for data lakes because it protects against accidental deletions or overwrites by preserving all versions of an object, including deletions (which are recorded as delete markers). This allows you to recover previous object states and is essential for data governance and auditability in a data lake environment.

Answer

Enable S3 Snapshot for point-in-time recovery.

Answer

Disable S3 server access logging to reduce costs.

Question 13

A data engineer runs an AWS Glue ETL job that transforms data in Amazon S3. The job fails with the error shown in the exhibit. Which action will MOST likely fix the issue?

Accepted Answer

Change the worker type from G.1X to G.2X.. Option B is correct because the error indicates an out-of-memory error in the Spark executor. Increasing the worker type (e.g., from G.1X to G.2X) provides more memory per worker. Option A is wrong because increasing the number of workers does not increase memory per worker if the worker type is unchanged. Option C is wrong because decreasing the number of workers reduces parallelism and does not help memory. Option D is wrong because the error is not related to IAM permissions.

Answer

Decrease the number of workers from 2 to 1.

Answer

Add an IAM policy that grants the Glue job permission to write to S3.

Answer

Increase the number of workers from 2 to 4.

Question 14

Which TWO are valid approaches to troubleshoot a slow Amazon Redshift query? (Choose two.)

Accepted Answer

Check for table locks using STV_LOCKS.. Options B and D are correct. Using EXPLAIN to review the query plan and checking for table locks are troubleshooting steps. Option A is wrong because VACUUM reclaims space, not directly troubleshoots slow queries. Option C is wrong because DISTSTYLE is a design choice, not a troubleshooting step. Option E is wrong because enabling encryption does not affect query performance.

Answer

Enable encryption on the cluster.

Answer

Run VACUUM on the table.

Answer

Alter the table to change DISTSTYLE to KEY.

Question 15

A data engineer uses AWS CloudTrail to investigate a security incident. The engineer runs the command shown in the exhibit. What does the output indicate?

Accepted Answer

A file was uploaded to the S3 bucket.. Option C is correct because the EventName is PutObject, and the ResourceName includes the object key 'sales_2024-07-01.csv', indicating that a file was uploaded. Option A is wrong because the event is a PutObject, not a GetObject. Option B is wrong because the event is an upload, not a deletion. Option D is wrong because the event is a single object upload, not a batch.

Answer

A file was downloaded from the S3 bucket.

Answer

A file was deleted from the S3 bucket.

Answer

A batch of files was listed from the S3 bucket.