Queues and Async Processing

Format: Determine which operations should be synchronous and which should be asynchronous.

Scenario: A user publishes a post in your app. Which of the following operations should be synchronous, and which asynchronous?

Operation	Sync or Async?	Your Reasoning
Save post to database	?
Return "published successfully" to user	?
Send push notifications to followers	?
Generate post thumbnail	?
Update user's post count	?
AI content moderation of the post	?
Update search index	?
Send data to analytics system	?

Core Principle:

• Synchronous: Operations where the user is waiting for the result (save data, return response)
• Asynchronous: Operations where the user doesn't need to see the result immediately (notifications, analytics, post-processing)

Analogy: In a restaurant, "placing your order" is synchronous (you need confirmation), but "the kitchen cooking your food" is asynchronous (you don't need to stand in the kitchen and watch).