You are updating the code for a subscriber to a Pub/Sub feed. You are concerned that upon deployment the subscriber may erroneously acknowledge messages, leading to message loss. Your subscriber is…

Question

Options

• ASet up the Pub/Sub emulator on your local machine.
• BCreate a Pub/Sub snapshot before deploying new subscriber code.
• CUse Cloud Build for your deployment. If an error occurs after deployment, use a Seek operation to locate a timestamp logged by Cloud Build at the start of the
• DEnable dead-lettering on the Pub/Sub topic to capture messages that aren't successfully acknowledged.

• A
  2% (1)
• B
  85% (40)
• C
  4% (2)
• D
  9% (4)

Explanation

Creating a Pub/Sub snapshot before deploying captures the state of all unacknowledged messages at that point in time, allowing you to use a Seek operation to roll back to that snapshot if the new subscriber code mistakenly acknowledges messages - effectively replaying those messages from the pre-deployment state.

Why the distractors fail:

• A - The Pub/Sub emulator is a local development/testing tool; it has no bearing on recovering messages in a production deployment.
• C - Cloud Build timestamps are useful for Seek, but only if you combine them with a snapshot or know the exact pre-deployment timestamp; without a snapshot, a timestamp-based Seek only works if message retention is enabled, which the question states it is not.
• D - Dead-lettering captures messages that fail acknowledgment (exceed delivery attempts), not messages that are erroneously acknowledged - once a message is acked, it's gone without a snapshot.

Memory tip: Think of a Pub/Sub snapshot like a save point in a video game - take it before you do something risky, so you can always Seek back to that checkpoint if things go wrong.

No community discussion yet for this question.