You have Cloud Functions written in Node.js that pull messages from Cloud Pub/Sub and send the data to BigQuery. You observe that the message processing rate on the Pub/Sub topic is orders of…

Question

Options

• APublisher throughput quota is too small.
• BTotal outstanding messages exceed the 10-MB maximum.
• CError handling in the subscriber code is not handling run-time errors properly.
• DThe subscriber code cannot keep up with the messages.
• EThe subscriber code does not acknowledge the messages that it pulls.

• A
  24% (14)
• B
  10% (6)
• C
  59% (34)
• D
  7% (4)

Explanation

Explanation/Reference: C, E: By not acknowleding the pulled message, this result in it be putted back in Cloud Pub/Sub, meaning the messages accumulate instead of being consumed and removed from Pub/Sub. The same thing can happen ig the subscriber maintains the lease on the message it receives in case of an error. This reduces the overall rate of processing because messages get stuck on the first subscriber. Also, errors in Cloud Function do not show up in Stackdriver Log Viewer if they are not correctly handled. A: No problem with publisher rate as the observed result is a higher number of messages and not a lower number. B: if messages exceed the 10MB maximum, they cannot be published. D: Cloud Functions automatically scales so they should be able to keep up.

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