Problems / AI systems, medium

RAG support assistant

40 questions/s, 4,000-token prompts, a 6M tokens/min quota and a 25% answer-cache hit rate.

Free to open. Runs in your browser, no sign-up.

Your goals

Success ≥ 99% and time to first token p99 ≤ 1.5 s. Adding replicas will not lift a provider quota.

The traffic

40 requests a second for 60 seconds: 100% question (reads).

The system

What each component does in this design, and what calls it. The simulator mimics each one from these settings.

ComponentIts job hereSettings
Load balancerLoad balancerTraffic enters here.Calls AI gateway.Layer 4 balancers route by IP and port; layer 7 balancers read HTTP and can route by path or header.–
AI gatewayApp serviceLoad balancer forwards to it.Calls Semantic cache (checked first), Embedding model, Vector DB, LLM endpoint.Little's law: throughput ≈ concurrency ÷ latency. 200 slots at 50 ms serve about 4,000 req/s.3 replicas × 200 slots · timeout 30 s
Semantic cacheSemantic cacheAI gateway checks it first.A semantic cache matches questions by meaning using embeddings, not exact text.25% hit rate
Embedding modelEmbedding modelAI gateway calls it.Embeddings turn text into vectors where similar meanings sit close together.–
Vector DBVector DBAI gateway calls it.Approximate indexes like HNSW trade a little recall for much faster search.–
LLM endpointLLM endpointAI gateway calls it.Latency has two parts: time to the first token, then a steady stream of tokens per second.300 streams · 6M input tokens/min

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