{"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":121.8,"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":85.8,"fontSize":22,"fontFamily":1,"text":"Two-Stage Retrieval:\nFast Recall → Precise\nReranking","originalText":"Two-Stage Retrieval:\nFast Recall → Precise\nReranking","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":181.8,"width":288,"height":264.8,"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":199.8,"width":248,"height":228.8,"fontSize":22,"fontFamily":1,"text":"Stage 1: Retrieval\n(fast, approximate)\nVector search +\nBM25 → top-20\ncandidates\nLatency: ~20-50 ms\nQuality: good recall,\nnoisy precision","originalText":"Stage 1: Retrieval\n(fast, approximate)\nVector search +\nBM25 → top-20\ncandidates\nLatency: ~20-50 ms\nQuality: good recall,\nnoisy precision","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":490.6,"width":288,"height":550.8000000000001,"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":508.6,"width":248,"height":514.8000000000001,"fontSize":22,"fontFamily":1,"text":"Stage 2: Reranking\n(slow, precise)\nCross-encoder model\nscores each (query,\nchunk) pair\nInput: full query\ntext + full chunk\ntext\nOutput: relevance\nscore 0-1\n→ Re-order top-20 →\nselect top-5\nLatency: ~50-100 ms\n(20 pairs × 5 ms\neach)\nQuality: much higher\nprecision than\nbi-encoder cosine","originalText":"Stage 2: Reranking\n(slow, precise)\nCross-encoder model\nscores each (query,\nchunk) pair\nInput: full query\ntext + full chunk\ntext\nOutput: relevance\nscore 0-1\n→ Re-order top-20 →\nselect top-5\nLatency: ~50-100 ms\n(20 pairs × 5 ms\neach)\nQuality: much higher\nprecision than\nbi-encoder cosine","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":1085.4,"width":288,"height":121.8,"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":1103.4,"width":248,"height":85.8,"fontSize":22,"fontFamily":1,"text":"Why cross-encoder is\nbetter than\nbi-encoder (cosine):","originalText":"Why cross-encoder is\nbetter than\nbi-encoder (cosine):","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":1251.2,"width":288,"height":522.2,"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":1269.2,"width":248,"height":486.2,"fontSize":22,"fontFamily":1,"text":"Bi-encoder\n(retrieval):\nEmbed query →\nvector_q\nEmbed chunk →\nvector_c\n(precomputed at\ningestion)\nScore =\ncosine(vector_q,\nvector_c)\nFast but: query and\nchunk encoded\nINDEPENDENTLY\n→ Can't model\nfine-grained token\ninteractions","originalText":"Bi-encoder\n(retrieval):\nEmbed query →\nvector_q\nEmbed chunk →\nvector_c\n(precomputed at\ningestion)\nScore =\ncosine(vector_q,\nvector_c)\nFast but: query and\nchunk encoded\nINDEPENDENTLY\n→ Can't model\nfine-grained token\ninteractions","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":1817.4,"width":288,"height":550.8000000000001,"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":1835.4,"width":248,"height":514.8000000000001,"fontSize":22,"fontFamily":1,"text":"Cross-encoder\n(reranking):\nInput: [CLS] query\n[SEP] chunk [SEP] →\ntransformer\nScore = model\noutput\nSlow but: query and\nchunk tokens\nATTEND TO EACH\nOTHER\n→ Understands\n\"ERR-4231\" in query\nrelates to \"error\n4231\"\nin the chunk, even\nthough embeddings\nmight miss this","originalText":"Cross-encoder\n(reranking):\nInput: [CLS] query\n[SEP] chunk [SEP] →\ntransformer\nScore = model\noutput\nSlow but: query and\nchunk tokens\nATTEND TO EACH\nOTHER\n→ Understands\n\"ERR-4231\" in query\nrelates to \"error\n4231\"\nin the chunk, even\nthough embeddings\nmight miss this","textAlign":"left","verticalAlign":"middle","containerId":"shape-10","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":6}},{"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-7"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-13"}],"updated":0,"link":null,"locked":false,"id":"shape-12","type":"rectangle","seed":917,"x":16,"y":2412.2000000000003,"width":288,"height":350.6,"customData":{"revealStep":7}},{"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-7"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-13","type":"text","seed":990,"x":36,"y":2430.2000000000003,"width":248,"height":314.6,"fontSize":22,"fontFamily":1,"text":"Models: Cohere\nRerank,\nBGE-reranker,\ncross-encoder-ms-mar\nco\nCan't use for initial\nsearch (too slow for\n5B chunks)\nBut perfect for\nre-scoring 20\ncandidates","originalText":"Models: Cohere\nRerank,\nBGE-reranker,\ncross-encoder-ms-mar\nco\nCan't use for initial\nsearch (too slow for\n5B chunks)\nBut perfect for\nre-scoring 20\ncandidates","textAlign":"left","verticalAlign":"middle","containerId":"shape-12","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":7}}],"appState":{"viewBackgroundColor":"#fbfbf8","gridSize":null},"files":{}}