Layer 3 · Go deeper · 6 min
Go deeper
Size it, build it, then make the calls an interviewer will push you on.
Build-up · 4 steps
Two subscribers miss five minutes
A publisher keeps sending while two subscribers restart from 10:00 to 10:05. One subscription is ephemeral, the other durable.
Step 1 of 4
The publisher keeps going
The publisher sends m1 to m6 over eight minutes. It neither knows nor cares who is listening.
4 interview moments
You’re the candidate
The interviewer pushes on the hard parts. Pick an approach and see how it holds up.
Deep dive 1 of 4
Interviewer
“Checkout must tell the kitchen, rider, SMS, loyalty, fraud and analytics services about every order. How do you wire it?”
Your move. Pick an approach:
Deep dive 2 of 4
Interviewer
“A high-volume, bursty analytics consumer joins the order-events topic. Should the broker push to it, or should it pull?”
Your move. Pick an approach:
Deep dive 3 of 4
Interviewer
“Six subscribers react to OrderPlaced at 5,000 events a second. Should the event carry just the order ID?”
Your move. Pick an approach:
Deep dive 4 of 4
Interviewer
“A chat app wants one Pub/Sub subscription per user to deliver messages. Good idea?”
Your move. Pick an approach:
Build-up · 5 steps
Kafka, pub/sub across groups
One orders topic with four partitions, read by two consumer groups.
Step 1 of 5
One topic, four partitions
Records keyed by order ID land in partitions P0 to P3. Reading doesn’t delete anything.