Multi Step Processes easy
You have a cleanup script that needs to run every night at 3 AM to delete old temporary files. What is the standard tool to trigger this?
- A A 'while(true)' loop with a sleep timer.
- B A Cron Job (Scheduler).
- C Manually waking up to run it.
- D A database trigger.
Answer: B. A Cron Job (Scheduler).
Cron is the standard time-based job scheduler in Unix-like systems. It is robust, handles restarts, and is designed specifically for periodic tasks.
One system design question a day, with spaced repetition so the ones you miss come back.
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?
- A client app sends a 'Pay $50' request to your API. The server processes the payment but the network response is lost. The client automatically retries the request. What prevents the user from being charged $100?
- 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?