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Overview
Comment: | Add an implementation of BM25 to fts5func.c. Other changes to matchinfo related things. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | matchinfo |
Files: | files | file ages | folders |
SHA1: |
03f26d8c609c69e23ef2f7c74a84b0b3 |
User & Date: | dan 2013-01-02 20:01:06.507 |
Context
2013-01-03
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18:13 | Fill in more of the matchinfo functions so that the BM25 function works. check-in: 0e439483d7 user: dan tags: matchinfo | |
2013-01-02
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20:01 | Add an implementation of BM25 to fts5func.c. Other changes to matchinfo related things. check-in: 03f26d8c60 user: dan tags: matchinfo | |
2013-01-01
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19:56 | Add APIs to allow fts5 to be augmented with ranking and snippet functions. Does not work yet. check-in: a235305d42 user: dan tags: matchinfo | |
Changes
Changes to src/fts5.c.
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10 11 12 13 14 15 16 17 18 19 20 21 22 23 | ** ************************************************************************* */ #include "sqliteInt.h" #include "vdbeInt.h" /* ** Default distance value for NEAR operators. */ #define FTS5_DEFAULT_NEAR 10 /* ** Token types used by expression parser. | > > > > > > > > > > | 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | ** ************************************************************************* */ #include "sqliteInt.h" #include "vdbeInt.h" /* ** The global count record is a set of N varints, where N is one greater ** than the number of columns in the indexed table. The first varint ** contains the number of records in the table. Each subsequent varint ** contains the total number of tokens stored in each column. ** ** The key used for the global record in the KV store is the root page ** number of the FTS index followed by a single 0x00 byte. */ /* ** Default distance value for NEAR operators. */ #define FTS5_DEFAULT_NEAR 10 /* ** Token types used by expression parser. |
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169 170 171 172 173 174 175 176 | Fts5ExprNode *pRight; const u8 *aPk; /* Primary key of current entry (or null) */ int nPk; /* Size of aPk[] in bytes */ }; struct Fts5Expr { Fts5ExprNode *pRoot; int nPhrase; /* Number of Fts5Str objects in query */ | > | > > > > > | 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 | Fts5ExprNode *pRight; const u8 *aPk; /* Primary key of current entry (or null) */ int nPk; /* Size of aPk[] in bytes */ }; struct Fts5Expr { Fts5ExprNode *pRoot; int nPhrase; /* Number of Fts5Str objects in query */ Fts5Str **apPhrase; /* All Fts5Str objects */ }; /* ** FTS5 specific cursor data. */ struct Fts5Cursor { sqlite4 *db; Fts5Info *pInfo; Fts5Expr *pExpr; /* MATCH expression for this cursor */ char *zExpr; /* Full text of MATCH expression */ KVByteArray *aKey; /* Buffer for primary key */ int nKeyAlloc; /* Bytes allocated at aKey[] */ KVCursor *pCsr; /* Cursor used to retrive values */ Mem *aMem; /* Array of column values */ /* Array of nPhrase*nCol integers. See sqlite4_mi_row_count() for details. */ int *anRow; i64 *aGlobal; }; /* ** This type is used when reading (decoding) an instance-list. */ typedef struct InstanceList InstanceList; struct InstanceList { |
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1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 | typedef struct TokenizeCtx TokenizeCtx; typedef struct TokenizeTerm TokenizeTerm; struct TokenizeCtx { int rc; int iCol; sqlite4 *db; int nMax; Hash hash; }; struct TokenizeTerm { int iWeight; /* Weight of previous entry */ int iCol; /* Column containing previous entry */ int iOff; /* Token offset of previous entry */ int nToken; /* Size of token in bytes */ | > | 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 | typedef struct TokenizeCtx TokenizeCtx; typedef struct TokenizeTerm TokenizeTerm; struct TokenizeCtx { int rc; int iCol; sqlite4 *db; int nMax; int *aSz; /* Number of tokens in each column */ Hash hash; }; struct TokenizeTerm { int iWeight; /* Weight of previous entry */ int iCol; /* Column containing previous entry */ int iOff; /* Token offset of previous entry */ int nToken; /* Size of token in bytes */ |
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1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 | int nSrc ){ TokenizeCtx *p = (TokenizeCtx *)pCtx; TokenizeTerm *pTerm = 0; TokenizeTerm *pOrig = 0; if( nToken>p->nMax ) p->nMax = nToken; pTerm = (TokenizeTerm *)sqlite4HashFind(&p->hash, zToken, nToken); if( pTerm==0 ){ /* Size the initial allocation so that it fits in the lookaside buffer */ int nAlloc = sizeof(TokenizeTerm) + nToken + 32; pTerm = sqlite4DbMallocZero(p->db, nAlloc); | > | 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 | int nSrc ){ TokenizeCtx *p = (TokenizeCtx *)pCtx; TokenizeTerm *pTerm = 0; TokenizeTerm *pOrig = 0; if( nToken>p->nMax ) p->nMax = nToken; p->aSz[p->iCol]++; pTerm = (TokenizeTerm *)sqlite4HashFind(&p->hash, zToken, nToken); if( pTerm==0 ){ /* Size the initial allocation so that it fits in the lookaside buffer */ int nAlloc = sizeof(TokenizeTerm) + nToken + 32; pTerm = sqlite4DbMallocZero(p->db, nAlloc); |
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1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 | if( !pTerm ){ p->rc = SQLITE4_NOMEM; return 1; } return 0; } /* ** Update an fts index. */ int sqlite4Fts5Update( sqlite4 *db, /* Database handle */ Fts5Info *pInfo, /* Description of fts index to update */ | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 | if( !pTerm ){ p->rc = SQLITE4_NOMEM; return 1; } return 0; } static int fts5LoadGlobal(sqlite4 *db, Fts5Info *pInfo, i64 *aVal){ int rc; int nVal = pInfo->nCol + 1; u8 aKey[10]; /* Global record key */ int nKey; /* Bytes in key aKey */ KVCursor *pCsr = 0; /* Cursor used to read global record */ nKey = putVarint32(aKey, pInfo->iRoot); aKey[nKey++] = 0x00; rc = sqlite4KVStoreOpenCursor(db->aDb[pInfo->iDb].pKV, &pCsr); if( rc==SQLITE4_OK ){ rc = sqlite4KVCursorSeek(pCsr, aKey, nKey, 0); if( rc==SQLITE4_NOTFOUND ){ rc = SQLITE4_OK; memset(aVal, 0, sizeof(i64)*nVal); }else if( rc==SQLITE4_OK ){ const u8 *aData = 0; int nData = 0; rc = sqlite4KVCursorData(pCsr, 0, -1, &aData, &nData); if( rc==SQLITE4_OK ){ int i; int iOff = 0; for(i=0; i<nVal; i++){ iOff += sqlite4GetVarint(&aData[iOff], (u64 *)&aVal[i]); } } } sqlite4KVCursorClose(pCsr); } return rc; } static int fts5CsrLoadGlobal(Fts5Cursor *pCsr){ int rc = SQLITE4_OK; if( pCsr->aGlobal==0 ){ int nByte = sizeof(i64) * (pCsr->pInfo->nCol + 1); pCsr->aGlobal = (i64 *)sqlite4DbMallocZero(pCsr->db, nByte); if( pCsr->aGlobal==0 ){ rc = SQLITE4_NOMEM; }else{ rc = fts5LoadGlobal(pCsr->db, pCsr->pInfo, pCsr->aGlobal); } } return rc; } /* ** Update an fts index. */ int sqlite4Fts5Update( sqlite4 *db, /* Database handle */ Fts5Info *pInfo, /* Description of fts index to update */ |
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1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 | pPK = (const u8 *)sqlite4_value_blob(pKey); nPK = sqlite4_value_bytes(pKey); nTnum = getVarint32(pPK, dummy); nPK -= nTnum; pPK += nTnum; for(i=0; rc==SQLITE4_OK && i<pInfo->nCol; i++){ sqlite4_value *pArg = (sqlite4_value *)(&aArg[i]); if( pArg->flags & MEM_Str ){ const char *zText; int nText; zText = (const char *)sqlite4_value_text(pArg); | > > > | > | | 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 | pPK = (const u8 *)sqlite4_value_blob(pKey); nPK = sqlite4_value_bytes(pKey); nTnum = getVarint32(pPK, dummy); nPK -= nTnum; pPK += nTnum; sCtx.aSz = (int *)sqlite4DbMallocZero(db, pInfo->nCol * sizeof(int)); if( sCtx.aSz==0 ) rc = SQLITE4_NOMEM; for(i=0; rc==SQLITE4_OK && i<pInfo->nCol; i++){ sqlite4_value *pArg = (sqlite4_value *)(&aArg[i]); if( pArg->flags & MEM_Str ){ const char *zText; int nText; zText = (const char *)sqlite4_value_text(pArg); nText = sqlite4_value_bytes(pArg); sCtx.iCol = i; rc = pInfo->pTokenizer->xTokenize( &sCtx, pInfo->p, zText, nText, fts5TokenizeCb ); } } nKey = sqlite4VarintLen(pInfo->iRoot)+2+sCtx.nMax+nPK + 10*(pInfo->nCol+1); aKey = sqlite4DbMallocRaw(db, nKey); if( aKey==0 ) rc = SQLITE4_NOMEM; for(pElem=sqliteHashFirst(&sCtx.hash); pElem; pElem=sqliteHashNext(pElem)){ TokenizeTerm *pTerm = (TokenizeTerm *)sqliteHashData(pElem); if( rc==SQLITE4_OK ){ int nToken = sqliteHashKeysize(pElem); |
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1276 1277 1278 1279 1280 1281 1282 | const KVByteArray *aData = (const KVByteArray *)&pTerm[1]; aData += pTerm->nToken; rc = sqlite4KVStoreReplace(pStore, aKey, nKey, aData, pTerm->nData); } } sqlite4DbFree(db, pTerm); } | | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 | const KVByteArray *aData = (const KVByteArray *)&pTerm[1]; aData += pTerm->nToken; rc = sqlite4KVStoreReplace(pStore, aKey, nKey, aData, pTerm->nData); } } sqlite4DbFree(db, pTerm); } /* Write the "sizes" record into the db */ if( rc==SQLITE4_OK ){ nKey = putVarint32(aKey, pInfo->iRoot); aKey[nKey++] = 0x00; memcpy(&aKey[nKey], pPK, nPK); nKey += nPK; if( bDel ){ rc = sqlite4KVStoreReplace(pStore, aKey, nKey, 0, -1); }else{ u8 *aData = &aKey[nKey]; int nData = 0; for(i=0; i<pInfo->nCol; i++){ nData += putVarint32(&aData[nData], sCtx.aSz[i]); } rc = sqlite4KVStoreReplace(pStore, aKey, nKey, aData, nData); } } /* Update the global record */ if( rc==SQLITE4_OK ){ i64 *aGlobal = (i64 *)aKey; u8 *aData = (u8 *)&aGlobal[pInfo->nCol+1]; int nData = 0; rc = fts5LoadGlobal(db, pInfo, aGlobal); if( rc==SQLITE4_OK ){ u8 aDbKey[10]; int nDbKey; nDbKey = putVarint32(aDbKey, pInfo->iRoot); aDbKey[nDbKey++] = 0x00; nData += sqlite4PutVarint(&aData[nData], aGlobal[0] + (bDel?-1:1)); for(i=0; i<pInfo->nCol; i++){ i64 iNew = aGlobal[i+1] + (i64)sCtx.aSz[i] * (bDel?-1:1); nData += sqlite4PutVarint(&aData[nData], iNew); } rc = sqlite4KVStoreReplace(pStore, aDbKey, nDbKey, aData, nData); } } sqlite4DbFree(db, aKey); sqlite4DbFree(db, sCtx.aSz); sqlite4HashClear(&sCtx.hash); return rc; } static Fts5Info *fts5InfoCreate(Parse *pParse, Index *pIdx, int bCol){ sqlite4 *db = pParse->db; Fts5Info *pInfo; /* p4 argument for FtsUpdate opcode */ |
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1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 | return fts5OpenExprCursors(db, pInfo, pCsr->pExpr->pRoot); } void sqlite4Fts5Close(sqlite4 *db, Fts5Cursor *pCsr){ if( pCsr ){ fts5ExpressionFree(db, pCsr->pExpr); sqlite4DbFree(db, pCsr->aKey); sqlite4DbFree(db, pCsr); } } static int fts5TokenAdvanceToMatch( InstanceList *p, InstanceList *pFirst, | > | 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 | return fts5OpenExprCursors(db, pInfo, pCsr->pExpr->pRoot); } void sqlite4Fts5Close(sqlite4 *db, Fts5Cursor *pCsr){ if( pCsr ){ fts5ExpressionFree(db, pCsr->pExpr); sqlite4DbFree(db, pCsr->aKey); sqlite4DbFree(db, pCsr->anRow); sqlite4DbFree(db, pCsr); } } static int fts5TokenAdvanceToMatch( InstanceList *p, InstanceList *pFirst, |
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2238 2239 2240 2241 2242 2243 2244 2245 | const char *zMatch, /* Match expression */ int bDesc, /* True to iterate in desc. order of PK */ Fts5Cursor **ppCsr, /* OUT: New FTS cursor object */ char **pzErr /* OUT: Error message */ ){ int rc = SQLITE4_OK; Fts5Cursor *pCsr; | > | > > > | 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 | const char *zMatch, /* Match expression */ int bDesc, /* True to iterate in desc. order of PK */ Fts5Cursor **ppCsr, /* OUT: New FTS cursor object */ char **pzErr /* OUT: Error message */ ){ int rc = SQLITE4_OK; Fts5Cursor *pCsr; int nMatch = sqlite4Strlen30(zMatch); pCsr = sqlite4DbMallocZero(db, sizeof(Fts5Cursor) + nMatch + 1); if( !pCsr ){ rc = SQLITE4_NOMEM; }else{ pCsr->zExpr = (char *)&pCsr[1]; memcpy(pCsr->zExpr, nMatch, zMatch); pCsr->pInfo = pInfo; pCsr->db = db; rc = fts5ParseExpression(db, pInfo->pTokenizer, pInfo->p, pInfo->iRoot, pInfo->azCol, pInfo->nCol, zMatch, &pCsr->pExpr, pzErr ); } |
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2368 2369 2370 2371 2372 2373 2374 | int iPhrase, int iMatch, int *piOff ){ } int sqlite4_mi_total_match_count( | | | | | | > > > > > | > > > > > > > > > > | > > > > > > > > > > > > > > > > > > > > > > > > > > | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 | int iPhrase, int iMatch, int *piOff ){ } int sqlite4_mi_total_match_count( sqlite4_context *pCtx, int iCol, int iPhrase, int *pnMatch, int *pnDoc, int *pnRelevant ){ } int sqlite4_mi_total_size(sqlite4_context *pCtx, int iCol, int *pnToken){ int rc = SQLITE4_OK; if( pCtx->pFts ){ Fts5Cursor *pCsr = pCtx->pFts; int nCol = pCsr->pInfo->nCol; if( iCol>=nCol ){ rc = SQLITE4_ERROR; }else{ rc = fts5CsrLoadGlobal(pCsr); if( rc==SQLITE4_OK ){ if( iCol<0 ){ int i; int nToken = 0; for(i=0; i<nCol; i++){ nToken += pCsr->aGlobal[i+1]; } *pnToken = nToken; }else{ *pnToken = pCsr->aGlobal[iCol+1]; } } } }else{ rc = SQLITE4_MISUSE; } return rc; } static int fts5CsrLoadRowcounts(Fts5Cursor *pCsr){ if( pCsr->anRow==0 ){ Fts5Expr *pExpr = pCsr->pExpr; Fts5Info *pInfo = pCsr->pInfo; int *anRow; pCsr->anRow = anRow = (int *)sqlite4DbMallocZero(pCsr->db, pExpr->nPhrase * pInfo->nCol * sizeof(int) ); if( !anRow ) return SQLITE4_NOMEM; } } int sqlite4_mi_row_count( sqlite4_context *pCtx, /* Context object passed to mi function */ int iCol, /* Specific column (or -1) */ int iPhrase, /* Specific phrase (or -1) */ int *pnRow /* Total number of rows */ ){ int rc = SQLITE4_OK; if( pCtx->pFts ){ Fts5Cursor *pCsr = pCtx->pFts; Fts5Expr *pExpr = pCsr->pExpr; int nCol = pCsr->pInfo->nCol; int nPhrase = pExpr->nPhrase; if( iCol>=nCol || iPhrase>=nPhrase ){ rc = SQLITE4_ERROR; } else if( iPhrase>=0 ){ int iIdx = iPhrase * pCsr->pInfo->nCol; rc = fts5CsrLoadRowcounts(pCsr); if( rc==SQLITE4_OK ){ if( iCol>0 ){ *pnRow = pCsr->anRow[iIdx + iCol]; }else{ int i; int nRow = 0; for(i=0; i<pCsr->pInfo->nCol; i++){ nRow += pCsr->anRow[iIdx + i]; } *pnRow = nRow; } } }else{ /* Total number of rows in table... */ rc = fts5CsrLoadGlobal(pCsr); if( rc==SQLITE4_OK ){ *pnRow = (int)pCsr->aGlobal[0]; } } }else{ rc = SQLITE4_MISUSE; } return rc; } /************************************************************************** *************************************************************************** ** Below this point is test code. */ #ifdef SQLITE4_TEST |
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Changes to src/fts5func.c.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | /* ** 2012 December 17 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* */ #include "sqliteInt.h" static char fts5Tolower(char c){ if( c>='A' && c<='Z' ) c = c + ('a' - 'A'); return c; } | > > > > > > > > > > > | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 | /* ** 2012 December 17 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* */ /* ** BM25 and BM25F references: ** ** Stephen Robertson and Hugo Zaragoza: "The Probablistic Relevance ** Framework: BM25 and Beyond", 2009. ** ** http://xapian.org/docs/bm25.html ** ** http://en.wikipedia.org/wiki/Okapi_BM25 */ #include "sqliteInt.h" static char fts5Tolower(char c){ if( c>='A' && c<='Z' ) c = c + ('a' - 'A'); return c; } |
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28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 | return SQLITE4_OK; } static int fts5SimpleDestroy(sqlite4_tokenizer *p){ return SQLITE4_OK; } static void fts5Rank(sqlite4_context *pCtx, int nArg, sqlite4_value **apArg){ } static void fts5Snippet(sqlite4_context *pCtx, int nArg, sqlite4_value **apArg){ } static int fts5SimpleTokenize( void *pCtx, | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 | return SQLITE4_OK; } static int fts5SimpleDestroy(sqlite4_tokenizer *p){ return SQLITE4_OK; } typedef struct Fts5RankCtx Fts5RankCtx; struct Fts5RankCtx { sqlite4 *db; double avgdl; /* Average document size in tokens */ int nPhrase; /* Number of phrases in query */ double *aIdf; /* IDF weights for each phrase in query */ }; static void fts5RankFreeCtx(void *pCtx){ if( pCtx ){ Fts5RankCtx *p = (Fts5RankCtx *)pCtx; sqlite4DbFree(p->db, p); } } /* ** A BM25 based ranking function for fts5. ** ** This is based on the information in the Robertson/Zaragoza paper ** referenced above. As there is no way to provide relevance feedback ** IDF weights (equation 3.3 in R/Z) are used instead of RSJ for each phrase. ** The rest of the implementation is as presented in equation 3.15. ** ** R and Z observe that the experimental evidence suggests that reasonable ** values for free parameters "b" and "k1" are often in the ranges ** (0.5 < b < 0.8) and (1.2 < k1 < 2), although the optimal values depend ** on the nature of both the documents and queries. The implementation ** below sets each parameter to the midpoint of the suggested range. */ static void fts5Rank(sqlite4_context *pCtx, int nArg, sqlite4_value **apArg){ const double b = 0.65; const double k1 = 1.6; int rc = SQLITE4_OK; /* Error code */ Fts5RankCtx *p; /* Structure to store reusable values */ int i; /* Used to iterate through phrases */ double rank = 0.0; /* UDF return value */ p = sqlite4_get_auxdata(pCtx, 0); if( p==0 ){ sqlite4 *db = sqlite4_context_db_handle(pCtx); int nPhrase; /* Number of phrases in query expression */ int nByte; /* Number of bytes of data to allocate */ sqlite4_mi_phrase_count(pCtx, &nPhrase); nByte = sizeof(Fts5RankCtx) + nPhrase * sizeof(double); p = (Fts5RankCtx *)sqlite4DbMallocZero(db, nByte); sqlite4_set_auxdata(pCtx, 0, (void *)p, fts5RankFreeCtx); p = sqlite4_get_auxdata(pCtx, 0); if( !p ){ rc = SQLITE4_NOMEM; }else{ int N; /* Total number of docs in collection */ int ni; /* Number of docs with phrase i */ p->db = db; p->nPhrase = nPhrase; p->aIdf = (double *)&p[1]; /* Determine the IDF weight for each phrase in the query. */ rc = sqlite4_mi_row_count(pCtx, -1, -1, &N); for(i=0; rc==SQLITE4_OK && i<nPhrase; i++){ rc = sqlite4_mi_row_count(pCtx, -1, i, &ni); if( rc==SQLITE4_OK ){ p->aIdf[i] = log((0.5 + N - ni) / (0.5 + ni)); } } /* Determine the average document length */ if( rc==SQLITE4_OK ){ int nTotal; rc = sqlite4_mi_total_size(pCtx, -1, &nTotal); if( rc==SQLITE4_OK ){ p->avgdl = (double)nTotal / (double)N; } } } } for(i=0; rc==SQLITE4_OK && i<p->nPhrase; i++){ int tf; /* Occurences of phrase i in row (term freq.) */ int dl; /* Tokens in this row (document length) */ double L; /* Normalized document length */ double prank; /* Contribution to rank of this phrase */ /* Set variable tf to the total number of occurrences of phrase iPhrase ** in this row (within any column). And dl to the number of tokens in ** the current row (again, in any column). */ rc = sqlite4_mi_match_count(pCtx, -1, i, &tf); if( rc==SQLITE4_OK ) rc = sqlite4_mi_column_size(pCtx, -1, &dl); /* Calculate the normalized document length */ L = (double)dl / p->avgdl; /* Calculate the contribution to the rank made by this phrase. Then ** add it to variable rank. */ prank = (p->aIdf[i] * tf) / (k1 * ( (1.0 - b) + b * L) + tf); rank += prank; } if( rc==SQLITE4_OK ){ sqlite4_result_double(pCtx, rank); }else{ sqlite4_result_error_code(pCtx, rc); } } static void fts5Snippet(sqlite4_context *pCtx, int nArg, sqlite4_value **apArg){ } static int fts5SimpleTokenize( void *pCtx, |
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Changes to src/sqlite.h.in.
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4453 4454 4455 4456 4457 4458 4459 | ** of range (i.e. too large) it is not an error. In this case *piOff is ** set to -1 before returning. ** ** sqlite4_mi_total_size(): ** Set *pnToken to the total number of tokens in column iCol of all rows ** in the indexed table. ** | | > > | > > > > > > > > > > | | | < < | | 4453 4454 4455 4456 4457 4458 4459 4460 4461 4462 4463 4464 4465 4466 4467 4468 4469 4470 4471 4472 4473 4474 4475 4476 4477 4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488 4489 4490 4491 4492 4493 | ** of range (i.e. too large) it is not an error. In this case *piOff is ** set to -1 before returning. ** ** sqlite4_mi_total_size(): ** Set *pnToken to the total number of tokens in column iCol of all rows ** in the indexed table. ** ** sqlite4_mi_row_count(): ** If parameter iPhrase is negative, this function sets the output ** parameter to the total number of documents in the collection (rows ** in the indexed table). ** ** Otherwise, if iPhrase is not negative, then the output is set to the ** total number of rows that contain at least one instance of phrase iPhrase ** in column iCol, or in any column if iCol is negative. ** ** If parameter iPhrase is equal to or greater than the number of phrases ** in the current query, or if iCol is equal to or greater than the number ** of columns in the indexed table, SQLITE4_MISUSE is returned. The value ** of the output parameter is undefined in this case. */ int sqlite4_mi_column_count(sqlite4_context *, int *pnCol); int sqlite4_mi_column_size(sqlite4_context *, int iCol, int *pnToken); int sqlite4_mi_column_value(sqlite4_context *, int iCol, sqlite4_value **ppVal); int sqlite4_mi_phrase_count(sqlite4_context *, int *pnPhrase); int sqlite4_mi_match_count(sqlite4_context *, int iCol, int iPhrase, int *pn); int sqlite4_mi_match_detail(sqlite4_context *, int iCol, int iPhrase, int iMatch, int *piOff, int *piWeight ); int sqlite4_mi_total_size(sqlite4_context *, int iCol, int *pnToken); int sqlite4_mi_row_count(sqlite4_context *, int iCol, int iPhrase, int *pnRow); /* ** Undo the hack that converts floating point types to integer for ** builds on processors without floating point support. */ #ifdef SQLITE4_OMIT_FLOATING_POINT # undef double |
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