Amazon Web Services pass4future aws Certified Database Dbs-c01 New Questions by Arley q81 vce pdf

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Exam Name:	AWS Certified Database - Specialty
Exam Code:	DBS-C01 Dumps
Vendor:	Amazon Web Services	Certification:	AWS Certified Database
Questions:	324 Q&A's	Shared By:	arley

Question 88

A development team at an international gaming company is experimenting with Amazon DynamoDB to store in-game events for three mobile games. The most popular game hosts a maximum of 500,000 concurrent users, and the least popular game hosts a maximum of 10,000 concurrent users. The average size of an event is 20 KB, and the average user session produces one event each second. Each event is tagged with a time in milliseconds and a globally unique identifier.

The lead developer created a single DynamoDB table for the events with the following schema:

Partition key: game name
Sort key: event identifier
Local secondary index: player identifier
Event time

The tests were successful in a small-scale development environment. However, when deployed to production, new events stopped being added to the table and the logs show DynamoDB failures with the ItemCollectionSizeLimitExceededException error code.

Which design change should a database specialist recommend to the development team?

Options:

Use the player identifier as the partition key. Use the event time as the sort key. Add a global secondary index with the game name as the partition key and the event time as the sort key.

Create two tables. Use the game name as the partition key in both tables. Use the event time as the sort key for the first table. Use the player identifier as the sort key for the second table.

Replace the sort key with a compound value consisting of the player identifier collated with the event time, separated by a dash. Add a local secondary index with the player identifier as the sort key.

Create one table for each game. Use the player identifier as the partition key. Use the event time as the sort key.

Discussion

Answer:

Explanation:

Explanation:

The correct answer is D. Create one table for each game. Use the player identifier as the partition key. Use the event time as the sort key.

The explanation is as follows:

The ItemCollectionSizeLimitExceededException error occurs when an item collection exceeds the 10 GB limit1. An item collection is a group of items that have the same partition key value but different sort key values2. In this case, the item collection is based on the game name, which has only three possible values. This means that all events for each game are stored in the same item collection, which can easily exceed the 10 GB limit given the high volume and size of events.
To avoid this error, a database specialist should recommend a design change that distributes the events across more partitions and reduces the size of each item collection. Option D achieves this by creating one table for each game, and using the player identifier as the partition key. This way, each event is stored in a separate partition based on the player identifier, and sorted by the event time. This design also supports efficient queries by game, player, and time range.
Option A is incorrect because it still uses a single table for all events, which can cause hot partitions and throttling due to uneven access patterns across games. Also, using the player identifier as the partition key can result in many small partitions that are underutilized and waste provisioned capacity. Adding a global secondary index with the game name as the partition key and the event time as the sort key does not solve the problem of item collection size limit, because global secondary indexes have their own item collections that are subject to the same limit3.
Option B is incorrect because it creates two tables with redundant data and increases storage costs. Also, using the game name as the partition key in both tables does not solve the problem of item collection size limit, as explained above.
Option C is incorrect because it still uses a single table for all events, which can cause hot partitions and throttling due to uneven access patterns across games. Also, replacing the sort key with a compound value consisting of the player identifier collated with the event time does not reduce the size of each item collection, because each event still has a unique sort key value. Adding a local secondary index with the player identifier as the sort key does not solve the problem of item collection size limit, because local secondary indexes share the same item collections as their base table4.

References: 1: ItemCollectionSizeLimitExceededException (AWS SDK for Java - 1.12.547) 2: Best practices for designing and using partition keys effectively - Amazon DynamoDB 3: Global Secondary Indexes - Amazon DynamoDB 4: Local Secondary Indexes - Amazon DynamoDB

Question 89

A worldwide digital advertising corporation collects browser information in order to provide targeted visitors with contextually relevant pictures, websites, and connections. A single page load may create many events, each of which must be kept separately. A single event may have a maximum size of 200 KB and an average size of 10 KB. Each page load requires a query of the user's browsing history in order to deliver suggestions for targeted advertising. The advertising corporation anticipates daily page views of more than 1 billion from people in the United States, Europe, Hong Kong, and India. The information structure differs according to the event. Additionally, browsing information must be written and read with a very low latency to guarantee that consumers have a positive viewing experience.

Which database solution satisfies these criteria?

Options:

Amazon DocumentDB

Amazon RDS Multi-AZ deployment

Amazon DynamoDB global table

Amazon Aurora Global Database

Discussion

Question 90

A pharmaceutical company uses Amazon Quantum Ledger Database (Amazon QLDB) to store its clinical trial data records. The company has an application that runs as AWS Lambda functions. The application is hosted in the private subnet in a VPC.

The application does not have internet access and needs to read some of the clinical data records. The company is concerned that traffic between the QLDB ledger and the VPC could leave the AWS network. The company needs to secure access to the QLDB ledger and allow the VPC traffic to have read-only access.

Which security strategy should a database specialist implement to meet these requirements?

Options:

Move the QLDB ledger into a private database subnet inside the VPC. Run the Lambda functions inside the same VPC in an application private subnet. Ensure that the VPC route table allows read-only flow from the application subnet to the database subnet.

Create an AWS PrivateLink VPC endpoint for the QLDB ledger. Attach a VPC policy to the VPC endpoint to allow read-only traffic for the Lambda functions that run inside the VPC.

Add a security group to the QLDB ledger to allow access from the private subnets inside the VPC where the Lambda functions that access the QLDB ledger are running.

Create a VPN connection to ensure pairing of the private subnet where the Lambda functions are running with the private subnet where the QLDB ledger is deployed.

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Question 91

A company is running an Amazon RDS for MySQL Multi-AZ DB instance for a business-critical workload. RDS encryption for the DB instance is disabled. A recent security audit concluded that all business-critical applications must encrypt data at rest. The company has asked its database specialist to formulate a plan to accomplish this for the DB instance.

Which process should the database specialist recommend?

Options:

Create an encrypted snapshot of the unencrypted DB instance. Copy the encrypted snapshot to Amazon S3. Restore the DB instance from the encrypted snapshot using Amazon S3.

Create a new RDS for MySQL DB instance with encryption enabled. Restore the unencrypted snapshot to this DB instance.

Create a snapshot of the unencrypted DB instance. Create an encrypted copy of the snapshot. Restore the DB instance from the encrypted snapshot.

Temporarily shut down the unencrypted DB instance. Enable AWS KMS encryption in the AWS Management Console using an AWS managed CMK. Restart the DB instance in an encrypted state.