4.1 Integrating Applications with Data and Storage Services PROFESSIONAL-CLOUD-DEVELOPER Practice Questions (Page 3)

Questions 11–15

1. 11application · medium

   A mobile app backend writes user activity events to Firestore. The team notices that writes are slow and sometimes fail with 'resource exhausted' errors during peak usage. They want to improve write performance and reduce contention. What should they do?

   • AUse batched writes to group multiple operations into a single commit
   • BIncrease the Firestore quota by contacting support
   • CUse a random or distributed document ID to spread writes across the keyspace
   • DUse a monotonically increasing counter as the document ID to ensure unique writes
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2. 12foundation · easy

   When publishing a message to Pub/Sub, what is the recommended way to handle transient errors such as network timeouts?

   • ASwitch to a different topic and publish there
   • BIgnore the error and continue with the next message
   • CLog the error and terminate the application
   • DRetry the publish operation with exponential backoff
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4. 13application · medium

   A company has a Pub/Sub topic that receives messages from multiple producers. The messages are JSON payloads. They want to ensure that messages are not lost if the publishing application crashes after sending the message. What should they do?

   • AUse the Pub/Sub client library's built-in retry mechanism and ensure the publish is acknowledged
   • BUse a synchronous publish call and wait for the response
   • CUse a retry policy and if it fails, store the message in a local file
   • DUse a transactional outbox pattern: write the message to a database table and then publish it, and have a separate process publish pending messages
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5. 14application · medium

   A team has a Pub/Sub subscription that receives messages from a topic. The subscriber processes each message and then acknowledges it. They notice that some messages are being delivered multiple times. What is the most likely cause?

   • AThe topic has multiple subscriptions, and each subscription receives a copy
   • BThe subscriber is taking longer than the acknowledgment deadline to process messages
   • CThe subscriber is acknowledging messages before processing is complete
   • DThe subscriber is using the synchronous pull method instead of asynchronous pull
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6. 15application · medium

   A data analytics team needs to read a 10 TB dataset stored in Cloud Storage and load it into BigQuery for analysis. The data is in CSV format and resides in a single bucket. They want to minimize data transfer costs and maximize throughput. What is the best approach?

   • AUse the BigQuery Storage API to read the data directly from Cloud Storage
   • BDownload the files to a local server and then upload them to BigQuery using the client library
   • CUse a Cloud Dataflow pipeline to read the files and write them to BigQuery
   • DCreate a BigQuery load job that references the Cloud Storage bucket and uses wildcard URIs to load all CSV files
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