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Knowledge catalogChoose core direction and segmented content
Practice 33AdvancedImplementationAbout 18 minutes

Corresponding knowledge: Atomic intent and duplicate delivery with the outbox pattern

The task has been written to the database, but the message has not been sent to the queue. How to avoid permanent loss of the task?

Examine double-write issues, transaction outboxes, duplicate deliveries, and recovery scans.

Learn corresponding knowledgeInterview questions · Answer independently →
Outboxmessage queueReliable delivery

Knowledge content check2026-10-03 · Check the source of the original question2026-10-02

The knowledge corresponding to this exercise:

Atomic intent and duplicate delivery with the outbox pattern · Principle explanation →
Knowledge unit directory

LEARN · PRACTICE · REFLECT

Knowledge exercises·Independent answers

My notes and review ↗

Principles and Solutions have been collapsed. Explain the core mechanism, boundaries and verification methods in your own words, and then compare them.

Answers and personal notes

Each modified commit will be kept as an independent history. Your level of mastery is up to you to evaluate yourself against the standards.

Explain in your own words first

The core principles, analysis, Q&A and migration cases have been closed. When you are ready, unfold it and compare it with the content to find any omissions.

Hands-on verificationComplete on demand · Suggestions15 minutes

Draw the transaction boundaries of task submission, Outbox delivery and consumption, and mark recurrence points.

Expand acceptance requirements and checkpoints
  • Tasks and events live and die together
  • Duplicate messages have defined handling
  • Lost deliveries can be detected by scanning

Key inspections

  • Identify database and queue double-write windows
  • Write Outbox with the same transaction
  • Process at least one delivery and recovery scan