Interview room
Explain backpressure when downstream cannot keep up: scale, Kafka buffer, signals, shedding.
Basics
Backpressure = intentional slowdown/drop. Kafka lag is bounded buffer. Infinite memory queues are delayed OOM. Layer scale/buffer/signal/shed/priority.
Prompt
Define; Kafka semantics; scale vs shed; protect critical paths.
Good
Sink bottleneck story; four strategies; lag SLO; droppable classes.
Clarify/scope
Droppable?; max lag; critical event types.
Scoring lens: Backpressure in Streaming Pipeline
Interviewers reward incident-first teaching, a clear control loop, and named owners. Tool logos without that loop score poorly.
Weak vs strong answers on Backpressure in Streaming Pipeline
Weak: list products. Strong: tell the failure story, define the mechanism, draw the path, state rollout and monitors.
Scope control
Say what is out of scope for v1. Come back only if follow-ups demand it. This is a seniority signal for Backpressure in Streaming Pipeline.
Clarifying then committing
Ask a few high-use questions about SLAs, owners, and scale, then sketch. Endless questions without a diagram look evasive.
Priority topic design
events.payments and events.debug are different products. Different lag SLOs and shed policies. Putting everything on one topic forces bad global decisions.
Catch-up capacity
Buffers only help if sink rate can exceed steady state after a spike. Say the catch-up math. Otherwise retention merely delays the outage.
Tenant fairness under shed
Shed or throttle the noisy tenant first on shared platforms. Global random drops punish the innocent.
Interview framing detail 1
For lb-sd-32, spend the first minutes making the problem concrete: who gets hurt when this fails, what SLA is implied, and what is explicitly out of scope. Then teach the prerequisite concept before proposing boxes. A candidate who names vendors first usually loses the plot. Write two clarifying questions on the board and answer them with assumptions if the interviewer shrugs. Keep the first diagram small enough to redraw when a follow-up changes a constraint.
Interview framing detail 2
For lb-sd-32, spend the first minutes making the problem concrete: who gets hurt when this fails, what SLA is implied, and what is explicitly out of scope. Then teach the prerequisite concept before proposing boxes. A candidate who names vendors first usually loses the plot. Write two clarifying questions on the board and answer them with assumptions if the interviewer shrugs. Keep the first diagram small enough to redraw when a follow-up changes a constraint.
Interview framing detail 3
For lb-sd-32, spend the first minutes making the problem concrete: who gets hurt when this fails, what SLA is implied, and what is explicitly out of scope. Then teach the prerequisite concept before proposing boxes. A candidate who names vendors first usually loses the plot. Write two clarifying questions on the board and answer them with assumptions if the interviewer shrugs. Keep the first diagram small enough to redraw when a follow-up changes a constraint.
Interview framing detail 4
For lb-sd-32, spend the first minutes making the problem concrete: who gets hurt when this fails, what SLA is implied, and what is explicitly out of scope. Then teach the prerequisite concept before proposing boxes. A candidate who names vendors first usually loses the plot. Write two clarifying questions on the board and answer them with assumptions if the interviewer shrugs. Keep the first diagram small enough to redraw when a follow-up changes a constraint.
Interview framing detail 5
For lb-sd-32, spend the first minutes making the problem concrete: who gets hurt when this fails, what SLA is implied, and what is explicitly out of scope. Then teach the prerequisite concept before proposing boxes. A candidate who names vendors first usually loses the plot. Write two clarifying questions on the board and answer them with assumptions if the interviewer shrugs. Keep the first diagram small enough to redraw when a follow-up changes a constraint.
Interview framing detail 6
For lb-sd-32, spend the first minutes making the problem concrete: who gets hurt when this fails, what SLA is implied, and what is explicitly out of scope. Then teach the prerequisite concept before proposing boxes. A candidate who names vendors first usually loses the plot. Write two clarifying questions on the board and answer them with assumptions if the interviewer shrugs. Keep the first diagram small enough to redraw when a follow-up changes a constraint.