You recently developed an application that monitors a large number of stock prices. You need to configure Pub/Sub to receive messages and update the current stock price in an in-memory database. A…

Question

Options

• ACreate a push subscription with exactly-once delivery enabled.
• BCreate a pull subscription with both ordering and exactly-once delivery turned off.
• CCreate a pull subscription with ordering enabled, using the stock symbol as the ordering key.
• DCreate a push subscription with both ordering and exactly-once delivery turned off.

• A
  78% (29)
• B
  14% (5)
• C
  3% (1)
• D
  5% (2)

Explanation

A push subscription with exactly-once delivery ensures each stock price update is processed exactly once with no duplicate messages, which is critical for financial data accuracy. Push delivery gives low-latency, real-time message delivery to the service updating the in-memory database. Since each message already carries a timestamp, the application can use that field to discard out-of-order updates at the application level - only updating the database when the incoming message's timestamp is newer than the stored one. Option C (pull with ordering by stock symbol) would guarantee per-symbol ordering but can deliver duplicates and adds pull-loop complexity. Options B and D disable both ordering and exactly-once, risking stale or duplicate prices in the in-memory store.

No community discussion yet for this question.