Microsoft Microsoft Certified: Azure Cosmos DB Developer Specialty DP-420 Questions & Answers

• Question 81:

  HOTSPOT

  You have three containers in an Azure Cosmos DB Core (SQL) API account as shown in the following table.

  

  You have the following Azure functions:

  1.

  A function named Fn1 that reads the change feed of cn1

  2.

  A function named Fn2 that reads the change feed of cn2

  3.

  A function named Fn3 that reads the change feed of cn3 You perform the following actions:

  1.

  Delete an item named item1 from cn1.

  2.

  Update an item named item2 in cn2.

  3.

  For an item named item3 in cn3, update the item time to live to 3,600 seconds.

  For each of the following statements, select Yes if the statement is true. Otherwise, select No.

  NOTE: Each correct selection is worth one point.

  Hot Area:

  

  Correct Answer:

  

  Box 1: No

  Azure Cosmos DB's change feed is a great choice as a central data store in event sourcing architectures where all data ingestion is modeled as writes (no updates or deletes).

  Note: The change feed does not capture deletes. If you delete an item from your container, it is also removed from the change feed. The most common method of handling this is adding a soft marker on the items that are being deleted. You

  can add a property called "deleted" and set it to "true" at the time of deletion. This document update will show up in the change feed. You can set a TTL on this item so that it can be automatically deleted later.

  Box 2: No

  The _etag format is internal and you should not take dependency on it, because it can change anytime.

  Box 3: Yes

  Change feed support in Azure Cosmos DB works by listening to an Azure Cosmos container for any changes.

  Reference:

  https://docs.microsoft.com/en-us/azure/cosmos-db/sql/change-feed-design-patterns

  https://docs.microsoft.com/en-us/azure/cosmos-db/change-feed

• Question 82:

  HOTSPOT

  You configure Azure Cognitive Search to index a container in an Azure Cosmos DB Core (SQL) API account as shown in the following exhibit.

  

  Use the drop-down menus to select the answer choice that completes each statement based on the information presented in the graphic.

  NOTE: Each correct selection is worth one point.

  Hot Area:

  

  Correct Answer:

  

  Box 1: country

  The country field is filterable.

  Note: filterable: Indicates whether to enable the field to be referenced in $filter queries. Filterable differs from searchable in how strings are handled. Fields of type Edm.String or Collection(Edm.String) that are filterable do not undergo lexical

  analysis, so comparisons are for exact matches only.

  Box 2: name

  The name field is not Retrievable.

  Retrievable: Indicates whether the field can be returned in a search result. Set this attribute to false if you want to use a field (for example, margin) as a filter, sorting, or scoring mechanism but do not want the field to be visible to the end user.

  Note: searchable: Indicates whether the field is full-text searchable and can be referenced in search queries.

  Reference:

  https://docs.microsoft.com/en-us/rest/api/searchservice/create-index

• Question 83:

  HOTSPOT

  You have an Azure Cosmos DB Core (SQL) API account named storage1 that uses provisioned throughput capacity mode.

  The storage1 account contains the databases shown in the following table.

  

  The databases contain the containers shown in the following table.

  

  For each of the following statements, select Yes if the statement is true. Otherwise, select No.

  NOTE: Each correct selection is worth one point.

  Hot Area:

  

  Correct Answer:

  

  Box 1: No

  Four containers with 1000 RU/s each.

  Box 2: No

  Max 8000 RU/s for db2. 8 containers, so 1000 RU/s for each container.

  Box 3: Yes

  Max 8000 RU/s for db2. 8 containers, so 1000 RU/s for each container. Can very well add an additional container.

  Reference:

  https://docs.microsoft.com/en-us/azure/cosmos-db/plan-manage-costs

  https://azure.microsoft.com/en-us/pricing/details/cosmos-db/

• Question 84:

  HOTSPOT

  You have a database named telemetry in an Azure Cosmos DB Core (SQL) API account that stores IoT data. The database contains two containers named readings and devices.

  Documents in readings have the following structure.

  1.

  id

  2.

  deviceid

  3.

  timestamp

  4.

  ownerid

  5.

  measures (array)

  -type

  -value

  -metricid

  Documents in devices have the following structure.

  id deviceid owner

  - ownerid

  -emailaddress

  -name brand model

  For each of the following statements, select Yes if the statement is true. Otherwise, select No.

  NOTE: Each correct selection is worth one point.

  Hot Area:

  

  Correct Answer:

  

  Box 1: Yes

  Need to join readings and devices.

  Box 2: No

  Only readings is required. All required fields are in readings.

  Box 3: No

  Only devices is required. All required fields are in devices.

• Question 85:

  You are troubleshooting the current issues caused by the application updates.

  Which action can address the application updates issue without affecting the functionality of the application?

  A. Enable time to live for the con-product container.

  B. Set the default consistency level of account1 to strong.

  C. Set the default consistency level of account1 to bounded staleness.

  D. Add a custom indexing policy to the con-product container.

  Correct Answer: C

  Bounded staleness is frequently chosen by globally distributed applications that expect low write latencies but require total global order guarantee. Bounded staleness is great for applications featuring group collaboration and sharing, stock ticker, publish-subscribe/queueing etc.

  Scenario: Application updates in con-product frequently cause HTTP status code 429 "Too many requests". You discover that the 429 status code relates to excessive request unit (RU) consumption during the updates.

  Reference: https://docs.microsoft.com/en-us/azure/cosmos-db/consistency-levels

• Question 86:

  You need to select the partition key for con-iot1. The solution must meet the IoT telemetry requirements. What should you select?

  A. the timestamp

  B. the humidity

  C. the temperature

  D. the device ID

  Correct Answer: D

  The partition key is what will determine how data is routed in the various partitions by Cosmos DB and needs to make sense in the context of your specific scenario. The IoT Device ID is generally the "natural" partition key for IoT applications.

  Scenario: The iotdb database will contain two containers named con-iot1 and con-iot2. Ensure that Azure Cosmos DB costs for IoT-related processing are predictable.

  Reference: https://docs.microsoft.com/en-us/azure/architecture/solution-ideas/articles/iot-using-cosmos-db

• Question 87:

  You configure multi-region writes for account1.

  You need to ensure that App1 supports the new configuration for account1. The solution must meet the business requirements and the product catalog requirements.

  What should you do?

  A. Set the default consistency level of account1 to bounded staleness.

  B. Create a private endpoint connection.

  C. Modify the connection policy of App1.

  D. Increase the number of request units per second (RU/s) allocated to the con-product and con-productVendor containers.

  Correct Answer: D

  App1 queries the con-product and con-productVendor containers.

  Note: Request unit is a performance currency abstracting the system resources such as CPU, IOPS, and memory that are required to perform the database operations supported by Azure Cosmos DB.

  Scenario:

  Develop an app named App1 that will run from all locations and query the data in account1.

  Once multi-region writes are configured, maximize the performance of App1 queries against the data in account1.

  Whenever there are multiple solutions for a requirement, select the solution that provides the best performance, as long as there are no additional costs associated.

  Incorrect Answers:

  A:

  Bounded staleness relates to writes. App1 only do reads.

  Note: Bounded staleness is frequently chosen by globally distributed applications that expect low write latencies but require total global order guarantee. Bounded staleness is great for applications featuring group collaboration and sharing, stock ticker, publish-subscribe/queueing etc.

  Reference: https://docs.microsoft.com/en-us/azure/cosmos-db/consistency-levels

• Question 88:

  You need to provide a solution for the Azure Functions notifications following updates to con-product. The solution must meet the business requirements and the product catalog requirements. Which two actions should you perform? Each correct answer presents part of the solution. NOTE: Each correct selection is worth one point.

  A. Configure the trigger for each function to use a different leaseCollectionPrefix

  B. Configure the trigger for each function to use the same leaseCollectionName

  C. Configure the trigger for each function to use a different leaseCollectionName

  D. Configure the trigger for each function to use the same leaseCollectionPrefix

  Correct Answer: AB

  leaseCollectionPrefix: when set, the value is added as a prefix to the leases created in the Lease collection for this Function. Using a prefix allows two separate Azure Functions to share the same Lease collection by using different prefixes.

  Scenario: Use Azure Functions to send notifications about product updates to different recipients.

  Trigger the execution of two Azure functions following every update to any document in the con-product container.

  Reference:

  https://docs.microsoft.com/en-us/azure/azure-functions/functions-bindings-cosmosdb-v2-trigger

• Question 89:

  You need to identify which connectivity mode to use when implementing App2. The solution must support the planned changes and meet the business requirements. Which connectivity mode should you identify?

  A. Direct mode over HTTPS

  B. Gateway mode (using HTTPS)

  C. Direct mode over TCP

  Correct Answer: C

  Scenario: Develop an app named App2 that will run from the retail stores and query the data in account2. App2 must be limited to a single DNS endpoint when accessing account2.

  By using Azure Private Link, you can connect to an Azure Cosmos account via a private endpoint. The private endpoint is a set of private IP addresses in a subnet within your virtual network.

  When you're using Private Link with an Azure Cosmos account through a direct mode connection, you can use only the TCP protocol. The HTTP protocol is not currently supported.

  Reference:

  https://docs.microsoft.com/en-us/azure/cosmos-db/how-to-configure-private-endpoints

• Question 90:

  You need to implement a solution to meet the product catalog requirements. What should you do to implement the conflict resolution policy.

  A. Remove frequently changed field from the index policy of the con-product container.

  B. Disable indexing on all fields in the index policy of the con-product container.

  C. Set the default consistency level for account1 to eventual.

  D. Create a new container and migrate the product catalog data to the new container.

  Correct Answer: D