Multi Step Processes medium
In a distributed trace visualization (like Jaeger or Zipkin), what does a 'Span' represent?
- A The network latency.
- B The entire request lifecycle.
- C A single logical unit of work (e.g., a DB query) with a start time and duration.
- D An error log.
Answer: C. A single logical unit of work (e.g., a DB query) with a start time and duration.
A Trace is a tree of Spans. The Trace tracks the user's request; each Span tracks a specific step (Database Call, Auth Check, Downstream API call) within that request.
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Get the appRelated questions
- A user registration process involves two steps: inserting a row into the 'Users' database table and inserting a row into the 'Profiles' table. If the first insert succeeds but the second fails, the database is left in an inconsistent state. What mechanism prevents this?
- In a multi-step workflow across different services (Order Service -> Payment Service), you cannot use a single database transaction. If the Payment fails after the Order was created, how do you fix the Order state?
- You are writing a script to process 10,000 images. The script runs on a server that might restart unexpectedly. To ensure you don't have to start over from image #1 after a crash, what should you implement?
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- A user uploads a large video file that needs to be transcoded (converted), which takes 5 minutes. Why is it bad practice to keep the HTTP connection open while the server processes the video?
- How does CDC (reading the database transaction log) solve the 'Dual Write' problem better than the Application-level Outbox pattern?