{"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":"Hybrid Two-Layer\nApproach","originalText":"Hybrid Two-Layer\nApproach","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":379.2,"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":343.2,"fontSize":22,"fontFamily":1,"text":"Hold Phase (high\ncontention,\ntemporary):\n→ Redis SET NX EX\n— atomic, fast,\nauto-expiring\n→ Source of truth\nfor \"who is currently\nholding this seat\"\n→ 100K+\noperations/sec for\none event","originalText":"Hold Phase (high\ncontention,\ntemporary):\n→ Redis SET NX EX\n— atomic, fast,\nauto-expiring\n→ Source of truth\nfor \"who is currently\nholding this seat\"\n→ 100K+\noperations/sec for\none event","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":576.4,"width":288,"height":436.40000000000003,"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":594.4,"width":248,"height":400.40000000000003,"fontSize":22,"fontFamily":1,"text":"Book Phase\n(permanent, must be\ndurable):\n→ PostgreSQL\nUPDATE (CAS on\nversion) — ACID,\ndurable\n→ Source of truth\nfor \"who owns this\nseat\"\n→ Only ~1K-5K\nbookings/sec per\nevent (much lower\ncontention)","originalText":"Book Phase\n(permanent, must be\ndurable):\n→ PostgreSQL\nUPDATE (CAS on\nversion) — ACID,\ndurable\n→ Source of truth\nfor \"who owns this\nseat\"\n→ Only ~1K-5K\nbookings/sec per\nevent (much lower\ncontention)","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":1056.8,"width":288,"height":350.6,"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":1074.8,"width":248,"height":314.6,"fontSize":22,"fontFamily":1,"text":"Why this works:\nThe hold phase\nabsorbs all the\ncontention (100K\nusers fighting\nfor seats). Only the\nwinners proceed to\nbooking (much smaller\npool). The booking\nphase has low\ncontention by design.","originalText":"Why this works:\nThe hold phase\nabsorbs all the\ncontention (100K\nusers fighting\nfor seats). Only the\nwinners proceed to\nbooking (much smaller\npool). The booking\nphase has low\ncontention by design.","textAlign":"left","verticalAlign":"middle","containerId":"shape-6","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":4}}],"appState":{"viewBackgroundColor":"#fbfbf8","gridSize":null},"files":{}}