Patterns

35 items

System Design Pattern

Rate Managementbackpressureflow-controlreactiveproducer-consumeroverflowintermediate

Backpressure Pattern

Flow control when downstream is overwhelmed

Used in: Stream Processing, Message Queues, Reactive Systems|20 min read

Key Takeaways

Alternative to Unbounded Buffering

Without backpressure, slow consumer + fast producer = unbounded queue = OOM crash. Backpressure bounds the queue by slowing producers.

Propagates Through System

Service A slows down, A applies backpressure to B, B applies to C. Propagates to source. Whole system finds sustainable rate.

Explicit vs Implicit

Explicit: NACK, 429, flow control frames. Implicit: Slow responses cause timeouts upstream, effectively slowing callers.

Key Takeaways

Alternative to Unbounded Buffering

Without backpressure, slow consumer + fast producer = unbounded queue = OOM crash. Backpressure bounds the queue by slowing producers.

Propagates Through System

Service A slows down, A applies backpressure to B, B applies to C. Propagates to source. Whole system finds sustainable rate.

Explicit vs Implicit

Explicit: NACK, 429, flow control frames. Implicit: Slow responses cause timeouts upstream, effectively slowing callers.

Reactive Streams

Reactive Streams spec (Java, JS, etc.) builds in backpressure. Subscriber requests N items, publisher sends only N. Built-in flow control.

TCP Has Backpressure

TCP flow control is backpressure - receiver advertises window, sender respects it. But application-level backpressure often needed too.

Aspect	Advantage	Disadvantage

Patterns

Horizontal Scaling Pattern

Retry with Backoff Pattern

Replication Pattern

Caching Strategies Pattern

Persistent Connections Pattern

Load Balancing Pattern

Fan-out Pattern

Fan-in Pattern

Circuit Breaker Pattern

Eventual Consistency Pattern

Queue-based Load Leveling Pattern

Bloom Filters Pattern

Time-Series Storage Pattern

Bulkhead Pattern

Batch Processing Pattern

Write-Ahead Log Pattern

API Gateway Pattern

Backend for Frontend Pattern

Sidecar Pattern

Idempotency Pattern

Rate Limiting Pattern