DEA-C01 Data Store Management Practice Test 11 — 15 Questions

Question 1

A data engineer sees this AWS Glue table definition in the Data Catalog. The engineer wants to query this table with Amazon Athena, but the query returns zero rows. What is the MOST likely cause?

Accepted Answer

The data files are not in the specified S3 location.. The most likely cause is that the data files are not in the specified S3 location. When an AWS Glue table is defined in the Data Catalog, Athena reads the table's metadata (including the S3 location) and then attempts to read the underlying data files from that exact path. If the files are missing, misnamed, or in a different prefix, Athena returns zero rows because there is no data to scan. This is a common misconfiguration when the S3 path in the table definition does not match the actual data storage.

Answer

The SerDe library is incorrect for CSV files.

Answer

The table format CSV is not supported by Athena.

Answer

Athena cannot read tables from the Glue Data Catalog.

Question 2

A CloudFormation template includes this IAM policy for a cross-account S3 upload use case. What is the purpose of the condition?

Accepted Answer

To ensure that uploaded objects grant full control to the bucket owner.. The condition in the IAM policy uses the `s3:x-amz-acl` key with a value of `bucket-owner-full-control`. This ensures that any object uploaded to the S3 bucket explicitly grants the bucket owner full control over the object, overriding the default behavior where the uploading account retains ownership. This is critical in cross-account uploads to prevent the uploading account from retaining exclusive access to the objects.

Answer

To enforce server-side encryption with KMS.

Answer

To limit the size of objects that can be uploaded.

Answer

To restrict uploads to only a specific AWS account.

Question 3

A company is using Amazon RDS for MySQL and needs to automate backups with a retention period of 35 days. They also want to be able to restore to any point within the retention period. Which configuration should be used?

Accepted Answer

Set the backup retention period to 35 days and enable automatic backups.. Amazon RDS for MySQL supports automated backups with a configurable retention period of up to 35 days. By setting the backup retention period to 35 days and enabling automatic backups, RDS automatically performs daily snapshots and transaction log backups, enabling point-in-time recovery (PITR) to any second within the retention window. This meets the requirement for both a 35-day retention and full PITR capability without manual intervention.

Answer

Enable manual snapshots daily and retain for 35 days.

Answer

Set the backup retention period to 7 days and create daily manual snapshots.

Answer

Disable automated backups and rely on Multi-AZ for recovery.

Question 4

A company is storing sensitive user data in an Amazon S3 bucket. The security team requires that all data be encrypted at rest using a customer-managed key stored in AWS KMS. The bucket policy must deny any PUT request that does not include the appropriate encryption header. Which bucket policy condition key should be used?

Accepted Answer

s3:x-amz-server-side-encryption-aws-kms-key-id. Option A is correct because the `s3:x-amz-server-side-encryption-aws-kms-key-id` condition key allows the bucket policy to enforce that PUT requests include a specific customer-managed KMS key ID in the `x-amz-server-side-encryption-aws-kms-key-id` header, ensuring encryption at rest with the required key. This directly meets the security team's requirement to deny PUT requests that lack the appropriate encryption header tied to a customer-managed KMS key.

Answer

s3:x-amz-server-side-encryption

Answer

s3:x-amz-acl

Answer

aws:SourceArn

Question 5

A data engineer needs to set up a new Amazon RDS for MySQL database for a web application. The application experiences variable read traffic and requires low read latency. The engineer needs to minimize downtime during maintenance and provide read scalability. Which configuration meets these requirements?

Accepted Answer

Multi-AZ db.r5.large instance with two Read Replicas. Option A is correct because a Multi-AZ deployment provides high availability and automatic failover to minimize downtime during maintenance, while adding two Read Replicas offloads read traffic from the primary instance, reducing read latency and enabling read scalability. The db.r5.large instance size is sufficient for the variable read workload, and Read Replicas can be promoted to standalone instances if needed.

Answer

Multi-AZ db.r5.large instance

Answer

Single-AZ db.r5.large instance

Answer

Single-AZ db.r5.xlarge instance

Question 6

A data engineer is designing a data lake on Amazon S3. The data is partitioned by year, month, day, and hour. The engineer needs to ensure that queries using Amazon Athena are cost-effective and performant. The data is written in Parquet format, and the total volume is 50 TB. Which approach minimizes query costs?

Accepted Answer

Partition the data by year, month, day, and hour. Option C is correct because partitioning by year, month, day, and hour allows Athena to use partition pruning, reading only the relevant S3 prefixes instead of scanning the entire 50 TB dataset. This drastically reduces the amount of data scanned per query, which directly lowers query costs (Athena charges per TB scanned). The existing Parquet format further optimizes performance through columnar storage and compression.

Answer

Use AWS Glue Data Catalog to catalog the data

Answer

Convert data to CSV format

Answer

Use S3 Intelligent-Tiering storage class

Question 7

An e-commerce company uses Amazon DynamoDB as the primary data store for its product catalog. The table has a simple primary key (ProductID) and handles 10,000 writes per second during peak hours. Recently, the engineering team noticed increased write latency and throttled requests during peak times. The table's provisioned write capacity is set to 12,000 WCU. What is the most likely cause of the throttling?

Accepted Answer

Write traffic is unevenly distributed across partitions. Option C is correct because DynamoDB partitions data by the primary key's hash value. If write traffic is unevenly distributed across partitions (e.g., a few ProductIDs receive most writes), those hot partitions can exceed their individual throughput limits (3,000 WCU per partition for provisioned tables), causing throttling even when the table's total provisioned WCU of 12,000 is not fully utilized.

Answer

The table has reached the maximum number of partitions

Answer

DynamoDB Accelerator (DAX) is not configured

Answer

A global secondary index is consuming write capacity

Question 8

A data engineer needs to store semi-structured JSON logs from multiple microservices in a cost-effective manner for later analysis using Amazon Athena. The logs are generated continuously, and the total volume is about 1 TB per day. The data must be queryable within minutes of arrival. Which storage solution is most appropriate?

Accepted Answer

Amazon S3 bucket with partitioned folders. Amazon S3 with partitioned folders is the most appropriate solution because it provides a cost-effective, scalable storage layer for semi-structured JSON logs, and integrates natively with Amazon Athena for serverless querying. By partitioning the data by time (e.g., year/month/day/hour), Athena can use partition pruning to minimize scanned data, enabling queries within minutes of arrival. S3's low cost per GB and lifecycle policies further optimize storage for the 1 TB/day volume.

Answer

Amazon DynamoDB table with JSON attribute

Answer

Amazon RDS for PostgreSQL table with JSON column

Answer

Amazon Redshift cluster with JSON ingestion

Question 9

A data engineer ran the command shown in the exhibit on the bucket 'my-data-lake'. The engineer then tries to delete an object version but receives an 'AccessDenied' error. The engineer has full S3 permissions via IAM. What is the most likely reason for the error?

Accepted Answer

MFA Delete is enabled, requiring multi-factor authentication. The command shown in the exhibit (likely `aws s3api put-bucket-versioning --bucket my-data-lake --versioning-configuration Status=Enabled,MFADelete=Enabled`) enables both versioning and MFA Delete on the bucket. When MFA Delete is enabled, any operation that permanently deletes an object version or changes the versioning state requires the request to include a multi-factor authentication token. Even though the engineer has full S3 permissions via IAM, the missing MFA token causes the 'AccessDenied' error. This is a bucket-level setting that overrides IAM permissions for these specific operations.

Answer

Versioning is suspended on the bucket

Answer

The bucket policy denies s3:DeleteObjectVersion

Answer

An S3 Object Lock retention policy is in effect

Question 10

A company is migrating its on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB in size and has a 24-hour maintenance window. The migration must have minimal downtime. Which AWS service should be used for the migration?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is the correct choice because it supports heterogeneous migrations (Oracle to RDS for Oracle) with minimal downtime using ongoing replication via Oracle LogMiner or binary reader. DMS can perform a full load of the 2 TB database and then continuously replicate changes from the source to the target during the 24-hour maintenance window, allowing a final cutover with only seconds of downtime.

Answer

Amazon RDS native backup and restore

Answer

Amazon S3 Transfer Acceleration

Answer

AWS Snowball Edge

Question 11

A data engineer created the IAM policy shown in the exhibit. The engineer then attempts to upload an object to 'my-bucket' using the AWS CLI with the command: aws s3 cp file.txt s3://my-bucket/ --sse aws:kms. The upload fails with an 'AccessDenied' error. What is the most likely cause?

Accepted Answer

The policy requires SSE-S3 (AES256), but the command uses SSE-KMS. The IAM policy in the exhibit requires the `s3:x-amz-server-side-encryption` header to be set to `AES256`, which corresponds to SSE-S3. The AWS CLI command uses `--sse aws:kms`, which sets the header to `aws:kms` for SSE-KMS. This mismatch causes the request to fail the `s3:PutObject` condition check in the policy, resulting in an 'AccessDenied' error.

Answer

The policy resource is incorrect

Answer

The policy does not allow the s3:PutObject action

Answer

The command is missing the --sse-customer-algorithm parameter

Question 12

A data engineer is configuring an Amazon S3 lifecycle policy to transition objects to S3 Glacier Deep Archive after 90 days. The bucket receives new objects daily. The engineer wants to ensure that objects are not deleted before 90 days. Which lifecycle action should be used?

Accepted Answer

Transition. Option B (Transition) is correct because the S3 Lifecycle Transition action moves objects between storage classes over time. To ensure objects are moved to S3 Glacier Deep Archive after 90 days without deletion, a Transition rule is configured to specify the target storage class and the number of days from object creation.

Answer

Expiration

Answer

NoncurrentVersionTransition

Answer

AbortIncompleteMultipartUpload

Question 13

A financial services company is designing a data store for transaction records that must be immutable and auditable. The data must be stored for 7 years. Which AWS services can be combined to meet these requirements? (Choose TWO.)

Accepted Answer

Amazon S3 Glacier Deep Archive. Amazon S3 Glacier Deep Archive is correct because it provides the lowest-cost storage for long-term retention of immutable data, with a 7-year lifecycle meeting compliance requirements. Amazon S3 with Object Lock enabled is correct because it enforces a write-once-read-many (WORM) model, preventing records from being deleted or overwritten for a specified retention period, ensuring immutability and auditability.

Answer

Amazon EBS volume with snapshots

Answer

Amazon RDS with automated backups

Answer

Amazon DynamoDB with point-in-time recovery

Question 14

A data engineer is troubleshooting slow query performance on an Amazon Redshift cluster. The cluster has 10 nodes and is using automatic distribution style. The engineer suspects that data distribution is causing excessive data movement. Which steps should the engineer take to diagnose and resolve the issue? (Choose THREE.)

Accepted Answer

Choose appropriate distribution keys for large tables. Option A is correct because choosing appropriate distribution keys for large tables ensures that data is evenly distributed across the cluster slices, minimizing the need for data redistribution during joins and aggregations. Automatic distribution style may not always select the optimal key, leading to excessive data movement and slow query performance.

Answer

Run the VACUUM command to reclaim space

Answer

Increase the number of nodes in the cluster

Question 15

A company uses Amazon DynamoDB for a gaming leaderboard. The table has a primary key of GameId (partition key) and Score (sort key). The application needs to retrieve the top 10 scores for a given game. Which strategies can improve query performance? (Choose TWO.)

Accepted Answer

Create a global secondary index with Score as sort key. Option B is correct because creating a global secondary index (GSI) with Score as the sort key allows efficient range queries on scores for a given GameId. DynamoDB can then use the GSI to retrieve the top 10 scores in sorted order without scanning the entire table, leveraging the index's sort key to fetch only the highest values.

Answer

Change the primary key to a single attribute

Answer

Use a Scan operation with a limit

Answer

Increase the write capacity units

DEA-C01 Data Store Management Practice Test 11 — 15 Questions

Exhibit

DEA-C01 Data Store Management Practice Test 11 — 15 Questions

Exhibit