General

Question 1

Write through vs. write back

Answer 1

Write through: write to both cache and DB synchronously

Write back: write to cache only, write to DB when cache item is going to be removed

Question 2

What is sticky-session?

Answer 2

The solution to route the requests for a particular session to the same physical machine that serviced the first request for that session

Question 3

List out programming principles:

Answer 3

1. Single responsibility
2. Unix philosophy: Make each program do one thing well.
3. DRY principle: Don’t repeat yourself
4. KISS: Keep it simple, stupid

Question 4

What is signed URL?

Answer 4

URL with token and expiry time e.g. 1h to allow users with URL can download content.
AWS S3 use this

Question 5

What is signed cookies?

Answer 5

To allow 1 user to access multiple files

Question 6

Rules

Answer 6

1. Stop Fixing the Symptoms…Find the Root Cause Instead