HLD-307·Caching & Consistency
Hard · 1,500 ptsLive Gaming Leaderboard & Rank Aggregator
Design a global esports leaderboard handling tens of thousands of concurrent match score increments per second while serving real-time Top-100 and player percentile lookups.
Max p99
≤ 55 ms
Availability
≥ 99.5%
Budget
≤ $6,000
Functional Requirements
- FR-1POST /leaderboards/{tournament_id}/score — Records a player match score delta.
- FR-2GET /leaderboards/{tournament_id}/top — Returns sorted top-K standings and caller rank.
- FR-3PATCH & DELETE /leaderboards/{tournament_id}/score — Updates, cancels, or deletes tournament_id records and immediately invalidates or updates cached state (read-after-write).
- FR-4Players must immediately see their updated score reflected after match completion (read-after-write).
Workload Profile
Baseline Matches50,000 Rank Read RPS / 14,000 Score Write RPS
Finals Burst130,000 Read RPS / 38,000 Write RPS
Active Working Set28 GB sorted rank sets & player scores
Contention ProfileHigh skew on flagship global tournament_id
Consistency Model
Read-after-write rank accuracy required (write-through sorted cache or immediate cache invalidation + durable backing store).
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Design Write-up
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