GUIDED PRACTICE

Quiz: Dealing with Contention

Five scenario questions with explanations and a visual checkpoint.

A AceYourInterviews editorial · 8 min study

Visual checkpoint

Use this diagram to locate the state and failure boundaries tested by the questions. Answer all five questions before revealing feedback; the result is a study checkpoint rather than a certification.

Concurrent callers → Atomic state owner (conditional change); Atomic state owner → Winner (predicate matches); Atomic state owner → Conflict response (predicate fails); Lease epoch → Fenced destination (current token); Winner → Fenced destination (authorized effect) — Scroll to inspect the diagram, or open it at full size.

Figure — Concurrent callers → Atomic state owner (conditional change); Atomic state owner → Winner (predicate matches); Atomic state owner → Conflict response (predicate fails); Lease epoch → Fenced destination (current token); Winner → Fenced destination (authorized effect)

Review your reasoning

After checking answers, identify the incorrect assumption behind each missed question. Rewrite it as a rule with a concrete exception or failure case, then return to the lesson.

Why does adding a distributed lock with a 30-second expiry not guarantee only one worker writes a result?

8:00Self-guided practice timer

The timer resets when you leave this page. Save your design separately.

Your challenge

Why does adding a distributed lock with a 30-second expiry not guarantee only one worker writes a result?

Your design draft

Clarify assumptions, explain your approach, and test the difficult cases. Save your draft, then compare it with the study notes.

Read study notes

Self-review checklist

I clarified the requirements and constraints.I explained why the approach works.I considered failures, boundaries, and alternatives.I identified one improvement for my next attempt.

Self-guided practice. Automated AI feedback and code execution are not connected.