[Solved] Given this pseudocode for an Outbox processor, what will be the output if the Outbox table has 3 unprocessed events?... db.update("UPDATE outbox SET processed = true WHERE id = ?", event.id); | Microservices

Microservices - Advanced Patterns

Given this pseudocode for an Outbox processor, what will be the output if the Outbox table has 3 unprocessed events?

events = db.query("SELECT * FROM outbox WHERE processed = false");
for event in events:
    publish(event);
    db.update("UPDATE outbox SET processed = true WHERE id = ?", event.id);
print("Processed events count:", len(events))

AProcessed events count: 1

BProcessed events count: 0

CProcessed events count: 3

DError: Cannot update processed flag

Step-by-Step Solution

Solution:

Step 1: Analyze event selection
The query selects all 3 unprocessed events from the Outbox table.
Step 2: Understand processing loop
Each event is published and marked processed, so all 3 are handled.
Final Answer:
Processed events count: 3 -> Option C
Quick Check:
Processed events count = 3 [OK]

Quick Trick: Loop processes all unprocessed events before printing count [OK]

Common Mistakes:

Assuming only one event is processed
Thinking processed count is zero before update
Expecting an error without reason

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More Microservices Quizzes

Given this pseudocode for an Outbox processor, what will be the output if the Outbox table has 3 unprocessed events?

Step 1: Analyze event selection

Step 2: Understand processing loop

Final Answer:

Quick Check:

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