Latency budget на собеседовании системного аналитика
Содержание:
Что такое latency budget
Total latency SLA broken down между components.
Total p99 budget: 500ms.
- Auth check: 50ms.
- DB query: 200ms.
- Business logic: 50ms.
- External API call: 150ms.
- Serialization / network: 50ms.Каждый owner свою долю.
Breakdown по components
Trace request through system. Allocate budget proportionally к expected work.
Caveats:
- Network roundtrips often underestimated.
- Cache misses должны быть в budget.
- Retries — extra latency.
Sequential vs parallel
Sequential calls — sum latencies.
A → B (50ms) → C (100ms) → D (50ms) = 200ms.Parallel — max.
A → [B, C, D] in parallel → max(50, 100, 50) = 100ms.Parallelize where possible.
Slow chains
Long sync RPC chains compound.
Service A → B → C → D → E
50ms each → 250ms total.Plus retries / failures.
Solution. Async events для chains, или aggregate в parallel.
Optimization strategies
Caching. Avoid hot path computation.
Async. Move work из synchronous path.
Batching. Combine multiple ops в one round-trip.
Connection pooling. Reuse connections.
Compression. Less network bytes.
Edge / CDN. Closer к user.
Read replicas. Distribute read load.
Pre-computation. Materialized views, pre-aggregated tables.
Связанные темы
- SLA SLO SLI для SA
- Cache strategies для SA
- Capacity planning для SA
- Circuit Breaker для SA
- Подготовка к собесу системного аналитика
FAQ
Это официальная информация?
Нет. Статья основана на индустриальных performance practices.
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