{"type":"excalidraw","version":2,"source":"https://AwesomeSystemDesign.dev","elements":[{"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-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":16,"y":16,"width":288,"height":93.2,"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":36,"y":34,"width":248,"height":57.2,"fontSize":22,"fontFamily":1,"text":"Cache Invalidation\nApproaches","originalText":"Cache Invalidation\nApproaches","textAlign":"left","verticalAlign":"middle","containerId":"shape-0","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":1}},{"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-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":16,"y":153.2,"width":288,"height":350.6,"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":36,"y":171.2,"width":248,"height":314.6,"fontSize":22,"fontFamily":1,"text":"Option A: TTL-Based\nExpiration\nCache-Control:\nmax-age=86400\nSimple, no\ninfrastructure\nneeded\nContent can be stale\nup to TTL duration\nShort TTLs reduce\ncache hit ratio","originalText":"Option A: TTL-Based\nExpiration\nCache-Control:\nmax-age=86400\nSimple, no\ninfrastructure\nneeded\nContent can be stale\nup to TTL duration\nShort TTLs reduce\ncache hit ratio","textAlign":"left","verticalAlign":"middle","containerId":"shape-2","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":2}},{"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-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":16,"y":547.8,"width":288,"height":407.8,"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":36,"y":565.8,"width":248,"height":371.8,"fontSize":22,"fontFamily":1,"text":"Option B: Purge API\n(Active Invalidation)\nPOST /invalidate →\nfanout to all 250\nPoPs\nImmediate freshness\nwhen needed\nInfrastructure to\npropagate purge\nglobally in < 5s\nCan overwhelm origin\nif purge + thundering\nherd","originalText":"Option B: Purge API\n(Active Invalidation)\nPOST /invalidate →\nfanout to all 250\nPoPs\nImmediate freshness\nwhen needed\nInfrastructure to\npropagate purge\nglobally in < 5s\nCan overwhelm origin\nif purge + thundering\nherd","textAlign":"left","verticalAlign":"middle","containerId":"shape-4","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":3}},{"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-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":16,"y":999.5999999999999,"width":288,"height":522.2,"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":36,"y":1017.5999999999999,"width":248,"height":486.2,"fontSize":22,"fontFamily":1,"text":"Option C:\nStale-While-Revalidat\ne (Best of Both)\nCache-Control:\nmax-age=60,\nstale-while-revalidate\n=86400\n→ Serve stale\ncontent instantly\nwhile revalidating in\nbg\nUser always gets\nfast response\nOrigin fetched lazily,\nnot on critical path\nContent can be stale\nfor one request cycle","originalText":"Option C:\nStale-While-Revalidat\ne (Best of Both)\nCache-Control:\nmax-age=60,\nstale-while-revalidate\n=86400\n→ Serve stale\ncontent instantly\nwhile revalidating in\nbg\nUser always gets\nfast response\nOrigin fetched lazily,\nnot on critical path\nContent can be stale\nfor one request cycle","textAlign":"left","verticalAlign":"middle","containerId":"shape-6","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":4}},{"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-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":16,"y":1565.8,"width":288,"height":550.8000000000001,"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":36,"y":1583.8,"width":248,"height":514.8000000000001,"fontSize":22,"fontFamily":1,"text":"Option D: Surrogate\nKeys / Cache Tags\nTag cached content:\nSurrogate-Key:\nproduct-123\nhomepage\nPurge by tag:\nPURGE\n/tag/product-123\n→ Invalidates all\nobjects tagged\n\"product-123\"\nGranular invalidation\nwithout knowing\nexact URLs\nRequires tag\ntracking per cached\nobject","originalText":"Option D: Surrogate\nKeys / Cache Tags\nTag cached content:\nSurrogate-Key:\nproduct-123\nhomepage\nPurge by tag:\nPURGE\n/tag/product-123\n→ Invalidates all\nobjects tagged\n\"product-123\"\nGranular invalidation\nwithout knowing\nexact URLs\nRequires tag\ntracking per cached\nobject","textAlign":"left","verticalAlign":"middle","containerId":"shape-8","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":5}},{"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-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":16,"y":2160.6,"width":288,"height":350.6,"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":36,"y":2178.6,"width":248,"height":314.6,"fontSize":22,"fontFamily":1,"text":"Recommendation: TTL\n+\nStale-While-Revalidat\ne + Surrogate Keys\n→ Short TTL for\nfreshness boundary\n→ SWR for\nzero-latency impact\n→ Tags for surgical\ninvalidation of\nrelated content","originalText":"Recommendation: TTL\n+\nStale-While-Revalidat\ne + Surrogate Keys\n→ Short TTL for\nfreshness boundary\n→ SWR for\nzero-latency impact\n→ Tags for surgical\ninvalidation of\nrelated content","textAlign":"left","verticalAlign":"middle","containerId":"shape-10","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":6}}],"appState":{"viewBackgroundColor":"#fbfbf8","gridSize":null},"files":{}}