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Exam Professional Cloud Architect topic 1 question 64 discussion

Actual exam question from Google's Professional Cloud Architect

Question #: 64
Topic #: 1

[All Professional Cloud Architect Questions]

You are creating an App Engine application that uses Cloud Datastore as its persistence layer. You need to retrieve several root entities for which you have the identifiers. You want to minimize the overhead in operations performed by Cloud Datastore. What should you do?

A. Create the Key object for each Entity and run a batch get operation
B. Create the Key object for each Entity and run multiple get operations, one operation for each entity
C. Use the identifiers to create a query filter and run a batch query operation
D. Use the identifiers to create a query filter and run multiple query operations, one operation for each entity

Show Suggested Answer

Suggested Answer: A 🗳️

by Eroc at Oct. 26, 2019, 6:05 p.m.

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shashu07

Highly Voted 4 years, 7 months ago

Correct Answer: A Create the Key object for each Entity and run a batch get operation https://cloud.google.com/datastore/docs/best-practices Use batch operations for your reads, writes, and deletes instead of single operations. Batch operations are more efficient because they perform multiple operations with the same overhead as a single operation. Firestore in Datastore mode supports batch versions of the operations which allow it to operate on multiple objects in a single Datastore mode call. Such batch calls are faster than making separate calls for each individual entity because they incur the overhead for only one service call. If multiple entity groups are involved, the work for all the groups is performed in parallel on the server side.

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AzureDP900

2 years, 3 months ago

works fine .. A is right

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AWS56

Highly Voted 5 years ago

Agree A

upvoted 7 times

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halifax

Most Recent 5 months, 1 week ago

Selected Answer: A

An old question, no more datastore. in 2025 you can use Firestore in datastore mode.

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de1001c

8 months, 1 week ago

Keep in mind that datastore is discontinued, Firestore being the recommended alternative.

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don_v

1 year ago

According to "A. Create the Key object for each Entity and run a batch get operation" which is wrong as the key is already created for each entity whenever it's persisted. I believe the correct answer is C, -- to use a bulk query (a.k.a. "batch" in their terms). You need a query with a criteria anyway to find a resultset, and not just a fetch by "get" operation to load by surrogate keys.

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vamgcp

2 years ago

By using the "lookup by key" API of Cloud Datastore, you can minimize the overhead in operations performed by Cloud Datastore and optimize the performance of your App Engine application. from google.cloud import datastore client = datastore.Client() keys = [client.key('EntityKind', id) for id in entity_ids] entities = client.get_multi(keys)

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omermahgoub

2 years, 1 month ago

A. Create the Key object for each Entity and run a batch get operation To minimize the overhead in operations performed by Cloud Datastore, you should use the batch get operation to retrieve multiple entities in a single API call. To do this, you should create a Key object for each entity that you want to retrieve, then pass the Key objects to the batch get operation. This will allow you to retrieve multiple entities in a single API call, reducing the number of operations performed by Cloud Datastore and improving the efficiency of your application.

upvoted 6 times

omermahgoub

2 years, 1 month ago

Option B, running multiple get operations, one operation for each entity, would not be an efficient way to retrieve the entities because it would require multiple API calls to Cloud Datastore, which would increase the overhead and decrease the efficiency of the application. Option C, using the identifiers to create a query filter and running a batch query operation, would not be an efficient way to retrieve the entities because it would require performing a query operation, which is generally more expensive than a get operation. Option D, using the identifiers to create a query filter and running multiple query operations, one operation for each entity, would not be an efficient way to retrieve the entities because it would require performing multiple query operations, which are generally more expensive than get operations.

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megumin

2 years, 2 months ago

Selected Answer: A

A is ok

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Mahmoud_E

2 years, 3 months ago

Selected Answer: A

A is correct https://cloud.google.com/datastore/docs/best-practices#api_calls

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RitwickKumar

2 years, 5 months ago

Selected Answer: A

https://cloud.google.com/datastore/docs/concepts/entities#datastore-datastore-batch-lookup-python

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haroldbenites

3 years, 1 month ago

go for A.

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vincy2202

3 years, 2 months ago

A is the right answer

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joe2211

3 years, 2 months ago

Selected Answer: A

vote A

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MaxNRG

3 years, 3 months ago

A – create a key object for each entity, and run a batch get operations. See Batch Operations section here: https://cloud.google.com/datastore/docs/concepts/entities var keys = new Key[] { _keyFactory.CreateKey(1), _keyFactory.CreateKey(2) }; var tasks = _db.Lookup(keys[0], keys[1]); 1 and 2 are identifiers of the Key. Check Key / Identifier definition on the same link (top of that page) Such batch calls are faster than making separate calls for each individual entity because they incur the overhead for only one service call.

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