{"type":"excalidraw","version":2,"source":"https://AwesomeSystemDesign.dev","elements":[{"angle":0,"strokeColor":"#628572","backgroundColor":"#edf5ee","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-1"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-1"}],"updated":0,"link":null,"locked":false,"id":"shape-0","type":"rectangle","seed":41,"x":30,"y":30,"width":420,"height":68,"customData":{"revealStep":1}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-1"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-1","type":"text","seed":114,"x":50,"y":52.3,"width":380,"height":23.400000000000002,"fontSize":18,"fontFamily":1,"text":"Cache Invalidation Approaches","originalText":"Cache Invalidation Approaches","textAlign":"left","verticalAlign":"middle","containerId":"shape-0","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":1}},{"angle":0,"strokeColor":"#a68a53","backgroundColor":"#fff7e6","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-2"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-3"}],"updated":0,"link":null,"locked":false,"id":"shape-2","type":"rectangle","seed":187,"x":30,"y":123,"width":440.88988,"height":153,"customData":{"revealStep":2}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-2"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-3","type":"text","seed":260,"x":50,"y":141,"width":400.88988,"height":117,"fontSize":18,"fontFamily":1,"text":"Option A: TTL-Based Expiration\nCache-Control: max-age=86400\nSimple, no infrastructure needed\nContent can be stale up to TTL duration\nShort TTLs reduce cache hit ratio","originalText":"Option A: TTL-Based Expiration\nCache-Control: max-age=86400\nSimple, no infrastructure needed\nContent can be stale up to TTL duration\nShort TTLs reduce cache hit ratio","textAlign":"left","verticalAlign":"middle","containerId":"shape-2","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":2}},{"angle":0,"strokeColor":"#9180ac","backgroundColor":"#f4effb","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-3"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-5"}],"updated":0,"link":null,"locked":false,"id":"shape-4","type":"rectangle","seed":333,"x":30,"y":301,"width":523.25824,"height":153,"customData":{"revealStep":3}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-3"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-5","type":"text","seed":406,"x":50,"y":319,"width":483.25824,"height":117,"fontSize":18,"fontFamily":1,"text":"Option B: Purge API (Active Invalidation)\nPOST /invalidate → fanout to all 250 PoPs\nImmediate freshness when needed\nInfrastructure to propagate purge globally in < 5s\nCan overwhelm origin if purge + thundering herd","originalText":"Option B: Purge API (Active Invalidation)\nPOST /invalidate → fanout to all 250 PoPs\nImmediate freshness when needed\nInfrastructure to propagate purge globally in < 5s\nCan overwhelm origin if purge + thundering herd","textAlign":"left","verticalAlign":"middle","containerId":"shape-4","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":3}},{"angle":0,"strokeColor":"#6577aa","backgroundColor":"#eef1fc","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-4"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-7"}],"updated":0,"link":null,"locked":false,"id":"shape-6","type":"rectangle","seed":479,"x":30,"y":479,"width":588.5118400000001,"height":176.4,"customData":{"revealStep":4}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-4"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-7","type":"text","seed":552,"x":50,"y":497,"width":548.5118400000001,"height":140.4,"fontSize":18,"fontFamily":1,"text":"Option C: Stale-While-Revalidate (Best of Both)\nCache-Control: max-age=60, stale-while-revalidate=86400\n→ Serve stale content instantly while revalidating in bg\nUser always gets fast response\nOrigin fetched lazily, not on critical path\nContent can be stale for one request cycle","originalText":"Option C: Stale-While-Revalidate (Best of Both)\nCache-Control: max-age=60, stale-while-revalidate=86400\n→ Serve stale content instantly while revalidating in bg\nUser always gets fast response\nOrigin fetched lazily, not on critical path\nContent can be stale for one request cycle","textAlign":"left","verticalAlign":"middle","containerId":"shape-6","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":4}},{"angle":0,"strokeColor":"#628572","backgroundColor":"#edf5ee","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-5"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-9"}],"updated":0,"link":null,"locked":false,"id":"shape-8","type":"rectangle","seed":625,"x":30,"y":680.4,"width":593.43448,"height":176.4,"customData":{"revealStep":5}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-5"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-9","type":"text","seed":698,"x":50,"y":698.4,"width":553.43448,"height":140.4,"fontSize":18,"fontFamily":1,"text":"Option D: Surrogate Keys / Cache Tags\nTag cached content: Surrogate-Key: product-123 homepage\nPurge by tag: PURGE /tag/product-123\n→ Invalidates all objects tagged \"product-123\"\nGranular invalidation without knowing exact URLs\nRequires tag tracking per cached object","originalText":"Option D: Surrogate Keys / Cache Tags\nTag cached content: Surrogate-Key: product-123 homepage\nPurge by tag: PURGE /tag/product-123\n→ Invalidates all objects tagged \"product-123\"\nGranular invalidation without knowing exact URLs\nRequires tag tracking per cached object","textAlign":"left","verticalAlign":"middle","containerId":"shape-8","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":5}},{"angle":0,"strokeColor":"#a68a53","backgroundColor":"#fff7e6","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-6"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-11"}],"updated":0,"link":null,"locked":false,"id":"shape-10","type":"rectangle","seed":771,"x":30,"y":881.8,"width":656.8373200000001,"height":129.60000000000002,"customData":{"revealStep":6}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-6"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-11","type":"text","seed":844,"x":50,"y":899.8,"width":616.8373200000001,"height":93.60000000000001,"fontSize":18,"fontFamily":1,"text":"Recommendation: TTL + Stale-While-Revalidate + Surrogate Keys\n→ Short TTL for freshness boundary\n→ SWR for zero-latency impact\n→ Tags for surgical invalidation of related content","originalText":"Recommendation: TTL + Stale-While-Revalidate + Surrogate Keys\n→ Short TTL for freshness boundary\n→ SWR for zero-latency impact\n→ Tags for surgical invalidation of related content","textAlign":"left","verticalAlign":"middle","containerId":"shape-10","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":6}}],"appState":{"viewBackgroundColor":"#fbfbf8","gridSize":null},"files":{}}