DEA-C01 Data Store Management Practice Test 10 — 15 Questions

Question 1

Refer to the exhibit. An IAM policy is attached to a user. The user cannot upload objects to the S3 bucket 'example-bucket' using the AWS CLI. What is the most likely cause?

Accepted Answer

The user is not using HTTPS for API calls. The IAM policy explicitly denies all actions unless the request uses HTTPS (via the `aws:SecureTransport` condition key). Since the AWS CLI by default can use HTTP if not explicitly configured to use HTTPS, the user's upload attempt fails. The `s3:PutObject` action is allowed in the policy, but the condition block overrides that permission when the request is not made over HTTPS.

Answer

The policy does not allow s3:PutObject

Answer

The user is not in the same AWS region

Answer

The resource ARN does not include the bucket itself

Question 2

Refer to the exhibit. A data engineer ran the CLI command to check the configuration of an RDS instance named 'mydb'. Which statement accurately describes the current configuration?

Accepted Answer

The database is a Single-AZ deployment and is not a read replica. Option B is correct because the CLI command output shows 'DBInstanceStatus: available' and 'MultiAZ: False', indicating the database is running as a Single-AZ deployment. Additionally, the absence of a 'SourceDBInstanceIdentifier' field confirms it is not a read replica. The 'ReadReplicaSourceDBInstanceIdentifier' is not present, which would be required if it were a read replica.

Answer

The database is in the 'stopped' state

Answer

The database is a read replica of another instance

Answer

The database is a Multi-AZ deployment

Question 3

Refer to the exhibit. A DynamoDB table 'Orders' has a GSI 'CustomerDateIndex'. A developer tries to query the GSI for all orders of a customer between two dates. The query fails. What is the most likely reason?

Accepted Answer

The query uses a date format that is not lexicographically sortable as a string. Option C is correct because DynamoDB's Query operation requires the sort key to be lexicographically sortable when using comparison operators like BETWEEN. If the 'order_date' attribute is stored as a non-lexicographically sortable string format (e.g., 'MM-DD-YYYY' instead of 'YYYY-MM-DD'), the BETWEEN condition will fail to return correct results or may throw an error. The GSI's sort key must be in a format that supports string comparison for range queries to work properly.

Answer

The GSI does not include 'order_id' in the key schema

Answer

The 'customer_id' attribute is not a partition key in the GSI

Answer

The 'order_date' attribute is not a sort key in the GSI

Question 4

A company is using Amazon S3 to store critical data and needs to ensure that objects are automatically transitioned to S3 Glacier Deep Archive after 180 days to reduce costs. Which S3 lifecycle action should be configured?

Accepted Answer

Transition. Option B is correct because the S3 lifecycle 'Transition' action is specifically designed to move objects between storage classes after a specified number of days. To reduce costs by moving objects to S3 Glacier Deep Archive after 180 days, you configure a lifecycle rule with a Transition action that targets the 'DEEP_ARCHIVE' storage class at the 180-day mark.

Answer

Expiration

Answer

AbortIncompleteMultipartUpload

Answer

NoncurrentVersionTransition

Question 5

A data engineer is designing a data lake on Amazon S3. The data is accessed frequently for the first 30 days, then rarely after that. Compliance requires that data be retained for 7 years. What is the MOST cost-effective storage strategy?

Accepted Answer

Use S3 Standard for 30 days, then transition to S3 Standard-IA, then to S3 Glacier Deep Archive after 90 days.. Option D is the most cost-effective because it matches the access pattern: S3 Standard for the first 30 days of frequent access, then S3 Standard-IA for the next 60 days (reduced storage cost with a retrieval fee), and finally S3 Glacier Deep Archive for the remaining ~6.9 years to meet the 7-year retention requirement at the lowest possible storage cost. This lifecycle policy minimizes total cost by transitioning data to progressively cheaper storage tiers as access frequency drops, while still meeting compliance.

Answer

Use S3 Intelligent-Tiering for the entire 7 years.

Answer

Store all data in S3 Standard for 7 years.

Answer

Use S3 Standard for 30 days, then S3 One Zone-IA for 7 years.

Question 6

A company runs an Amazon RDS for PostgreSQL database. To meet disaster recovery requirements, they set up a cross-Region read replica. The replica has been lagging by several minutes. Which action is MOST effective to reduce the replica lag?

Accepted Answer

Increase the instance size (memory and CPU) of the replica.. Increasing the instance size (memory and CPU) of the cross-Region read replica is the most effective action because replica lag in Amazon RDS for PostgreSQL is often caused by the replica being unable to keep up with the volume of write-ahead log (WAL) data arriving from the primary. A larger replica instance provides more compute and memory resources to apply WAL changes faster, reducing the replay lag. This directly addresses the bottleneck at the replica side without impacting the primary database.

Answer

Enable Multi-AZ on the primary database.

Answer

Increase the instance size of the primary database.

Answer

Decrease the instance size of the replica to reduce cost.

Question 7

A company is using Amazon DynamoDB for a gaming application. They want to store player session data that expires after 24 hours. Which DynamoDB feature should be used?

Accepted Answer

Time to Live (TTL). Amazon DynamoDB Time to Live (TTL) allows you to define a per-item timestamp attribute that automatically deletes items after a specified duration. For the gaming session data that must expire after 24 hours, you can set the TTL attribute to the current time plus 24 hours, and DynamoDB will asynchronously delete expired items without any additional cost or write operations.

Answer

DynamoDB Streams

Answer

Global Tables

Answer

Point-in-Time Recovery

Question 8

A data engineer is migrating an on-premises Apache HBase workload to Amazon DynamoDB. The application requires strongly consistent reads and the ability to query by a composite key (partition key + sort key). Which DynamoDB table design should be used?

Accepted Answer

Create a table with a partition key and sort key, and use ConsistentRead parameter.. DynamoDB natively supports strongly consistent reads when you use the `ConsistentRead` parameter set to `true` on GetItem, Query, or Scan operations. By defining a table with a partition key and sort key, you can directly query by the composite key (partition key + sort key) with strong consistency, meeting both requirements without additional infrastructure.

Answer

Use a secondary index with strongly consistent reads.

Answer

Use a local secondary index (LSI) with the composite key.

Answer

Create a global secondary index (GSI) with the composite key.

Question 9

A company has an Amazon Redshift cluster that stores petabytes of data. Queries are experiencing high disk usage due to large intermediate results. The data engineer needs to improve query performance without adding more nodes. Which action should the engineer take?

Accepted Answer

Apply column compression encoding to reduce data size.. Option C is correct because compression reduces data size on disk and can improve query performance by reducing I/O. Option A is wrong because sort keys affect order, not intermediate result size. Option B is wrong because distribution keys affect data distribution, not intermediate results directly. Option D is wrong because WLM queues manage concurrency, not disk usage.

Answer

Set appropriate distribution keys to minimize data movement.

Answer

Configure workload management (WLM) queues to limit concurrency.

Answer

Define sort keys on all columns used in WHERE clauses.

Question 10

A company is using Amazon S3 to store sensitive data. They need to ensure that all objects are encrypted at rest. Which combination of actions should be taken? (Choose TWO.)

Accepted Answer

Use a bucket policy to deny PutObject requests that do not include the x-amz-server-side-encryption header.. Option D is correct because a bucket policy that denies PutObject requests lacking the `x-amz-server-side-encryption` header enforces encryption at the time of upload, ensuring that any object written without explicit encryption headers is rejected. Option E is correct because enabling default encryption on the S3 bucket automatically applies server-side encryption (SSE-S3 or SSE-KMS) to any object uploaded without specifying encryption headers, providing a fallback that covers all objects. Together, these actions ensure that every object stored in the bucket is encrypted at rest, either by explicit client request or by default bucket settings.

Answer

Enable S3 Versioning on the bucket.

Answer

Enable MFA Delete on the bucket.

Answer

Configure S3 Access Points with network policies.

Question 11

A company uses Amazon Redshift for analytics. They notice that some queries are slow due to data redistribution. The data engineer wants to minimize data movement across nodes. Which table design strategy should be used? (Choose TWO.)

Accepted Answer

Choose a distribution key that matches the join key for large tables.. Option C is correct because when large tables are joined on their distribution keys, Redshift can perform a collocated join, meaning the matching rows are already on the same node slice, eliminating the need to redistribute data across the network. This directly minimizes data movement and speeds up query execution.

Answer

Set the distribution style to AUTO for all tables.

Answer

Define compound sort keys on frequently filtered columns.

Answer

Use EVEN distribution for all tables.

Question 12

A company is using Amazon S3 for data lake storage. They need to query the data directly using SQL without loading it into a database. Which AWS service should be used?

Accepted Answer

Amazon Athena. Amazon Athena is the correct choice because it is a serverless, interactive query service that allows you to analyze data directly in Amazon S3 using standard SQL, without needing to load or transform the data into a database. Athena uses Presto under the hood and supports querying structured, semi-structured, and unstructured data formats (e.g., CSV, JSON, Parquet, ORC) stored in S3, making it ideal for ad-hoc SQL queries on a data lake.

Answer

Amazon Redshift Spectrum

Answer

Amazon EMR

Answer

AWS Glue

Question 13

A company is using Amazon DynamoDB for an e-commerce application. The application experiences sudden spikes in traffic, causing throttling errors. The data engineer needs to handle the spikes cost-effectively. Which solution should be used?

Accepted Answer

Use DynamoDB auto scaling with a target utilization of 70%.. Option C is correct because DynamoDB auto scaling with a target utilization of 70% allows the table to dynamically adjust provisioned read/write capacity based on actual traffic patterns, handling sudden spikes without manual intervention while avoiding over-provisioning. This balances performance and cost by scaling up during spikes and scaling down during low traffic, preventing throttling errors cost-effectively.

Answer

Implement DynamoDB Accelerator (DAX) to cache reads.

Answer

Switch to DynamoDB on-demand capacity mode.

Answer

Provision high read and write capacity units to handle peak traffic.

Question 14

A data engineer reviews this IAM policy attached to an S3 bucket. What is the effect of this policy?

Accepted Answer

Allows PutObject only when the object is NOT encrypted with SSE-KMS.. Option D is correct because the IAM policy uses a `Deny` effect with a `StringNotEquals` condition on `s3:x-amz-server-side-encryption` for `aws:kms`. This means that if the encryption header is NOT `aws:kms` (i.e., SSE-KMS), the request is denied. The net effect is that `PutObject` is allowed only when the object is encrypted with SSE-KMS, as any other encryption or no encryption triggers the deny.

Answer

Denies PutObject when encryption is not SSE-KMS.

Answer

Denies all PutObject requests.

Answer

Allows PutObject only when the object is encrypted with SSE-KMS.

Question 15

A data engineer runs this CLI command. Which query is MOST efficient against this table?

Accepted Answer

Query the CustomerIndex GSI by CustomerID and OrderDate.. The CLI command likely created a global secondary index (GSI) named CustomerIndex on CustomerID and OrderDate. Querying this GSI directly is the most efficient because it uses the index's sort key to retrieve only the relevant items without scanning the entire table, minimizing read capacity consumption.

Answer

Scan the table to find all orders for a CustomerID.

Answer

Create a local secondary index on CustomerID.

Answer

Query by OrderID and filter by OrderDate.

DEA-C01 Data Store Management Practice Test 10 — 15 Questions

Exhibit

DEA-C01 Data Store Management Practice Test 10 — 15 Questions

Exhibit