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Overview
| Comment: | Improve the performance of the ANALYZE command by taking advantage of UNIQUE constraints on indices. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
114dcf33670fd98a1ebbac0e44f66b2d |
| User & Date: | drh 2014-07-24 23:23:26 |
Context
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2014-07-25
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| 18:01 | Add constraints (enforced only when SQLITE_DEBUG is enabled) on the use of OP_Next and OP_Prev. check-in: 2230c74f user: drh tags: trunk | |
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2014-07-24
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| 23:23 | Improve the performance of the ANALYZE command by taking advantage of UNIQUE constraints on indices. check-in: 114dcf33 user: drh tags: trunk | |
| 22:41 | Fix a bug in the whereRangeSkipScanEst() procedure (added by check-in [d09ca6d5efad3e4cfa]) where it fails to consider the possibility of a ROWID column when computing the affinity of a table column. check-in: 6aea2258 user: drh tags: trunk | |
| 20:25 | Avoid trying to allocation zero bytes when analyzing a unique non-null index. Closed-Leaf check-in: 85e2bade user: drh tags: faster-analyze | |
Changes
Changes to src/analyze.c.
367 367 #endif 368 368 sqlite3DbFree(p->db, p); 369 369 } 370 370 371 371 /* 372 372 ** Implementation of the stat_init(N,K,C) SQL function. The three parameters 373 373 ** are: 374 -** N: The number of columns in the index including the rowid/pk 375 -** K: The number of columns in the index excluding the rowid/pk 376 -** C: The number of rows in the index 374 +** N: The number of columns in the index including the rowid/pk (note 1) 375 +** K: The number of columns in the index excluding the rowid/pk. 376 +** C: The number of rows in the index (note 2) 377 377 ** 378 -** C is only used for STAT3 and STAT4. 378 +** Note 1: In the special case of the covering index that implements a 379 +** WITHOUT ROWID table, N is the number of PRIMARY KEY columns, not the 380 +** total number of columns in the table. 379 381 ** 380 -** For ordinary rowid tables, N==K+1. But for WITHOUT ROWID tables, 381 -** N=K+P where P is the number of columns in the primary key. For the 382 -** covering index that implements the original WITHOUT ROWID table, N==K. 382 +** Note 2: C is only used for STAT3 and STAT4. 383 +** 384 +** For indexes on ordinary rowid tables, N==K+1. But for indexes on 385 +** WITHOUT ROWID tables, N=K+P where P is the number of columns in the 386 +** PRIMARY KEY of the table. The covering index that implements the 387 +** original WITHOUT ROWID table as N==K as a special case. 383 388 ** 384 389 ** This routine allocates the Stat4Accum object in heap memory. The return 385 390 ** value is a pointer to the the Stat4Accum object encoded as a blob (i.e. 386 391 ** the size of the blob is sizeof(void*) bytes). 387 392 */ 388 393 static void statInit( 389 394 sqlite3_context *context, ................................................................................ 685 690 ** Arguments: 686 691 ** 687 692 ** P Pointer to the Stat4Accum object created by stat_init() 688 693 ** C Index of left-most column to differ from previous row 689 694 ** R Rowid for the current row. Might be a key record for 690 695 ** WITHOUT ROWID tables. 691 696 ** 692 -** The SQL function always returns NULL. 697 +** This SQL function always returns NULL. It's purpose it to accumulate 698 +** statistical data and/or samples in the Stat4Accum object about the 699 +** index being analyzed. The stat_get() SQL function will later be used to 700 +** extract relevant information for constructing the sqlite_statN tables. 693 701 ** 694 702 ** The R parameter is only used for STAT3 and STAT4 695 703 */ 696 704 static void statPush( 697 705 sqlite3_context *context, 698 706 int argc, 699 707 sqlite3_value **argv ................................................................................ 779 787 #define STAT_GET_ROWID 1 /* "rowid" column of stat[34] entry */ 780 788 #define STAT_GET_NEQ 2 /* "neq" column of stat[34] entry */ 781 789 #define STAT_GET_NLT 3 /* "nlt" column of stat[34] entry */ 782 790 #define STAT_GET_NDLT 4 /* "ndlt" column of stat[34] entry */ 783 791 784 792 /* 785 793 ** Implementation of the stat_get(P,J) SQL function. This routine is 786 -** used to query the results. Content is returned for parameter J 794 +** used to query statistical information that has been gathered into 795 +** the Stat4Accum object by prior calls to stat_push(). The P parameter 796 +** is a BLOB which is decoded into a pointer to the Stat4Accum objects. 797 +** The content to returned is determined by the parameter J 787 798 ** which is one of the STAT_GET_xxxx values defined above. 788 799 ** 789 800 ** If neither STAT3 nor STAT4 are enabled, then J is always 790 801 ** STAT_GET_STAT1 and is hence omitted and this routine becomes 791 802 ** a one-parameter function, stat_get(P), that always returns the 792 803 ** stat1 table entry information. 793 804 */ ................................................................................ 998 1009 iTabCur = iTab++; 999 1010 iIdxCur = iTab++; 1000 1011 pParse->nTab = MAX(pParse->nTab, iTab); 1001 1012 sqlite3OpenTable(pParse, iTabCur, iDb, pTab, OP_OpenRead); 1002 1013 sqlite3VdbeAddOp4(v, OP_String8, 0, regTabname, 0, pTab->zName, 0); 1003 1014 1004 1015 for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ 1005 - int nCol; /* Number of columns indexed by pIdx */ 1006 - int *aGotoChng; /* Array of jump instruction addresses */ 1016 + int nCol; /* Number of columns in pIdx. "N" */ 1007 1017 int addrRewind; /* Address of "OP_Rewind iIdxCur" */ 1008 - int addrGotoChng0; /* Address of "Goto addr_chng_0" */ 1009 1018 int addrNextRow; /* Address of "next_row:" */ 1010 1019 const char *zIdxName; /* Name of the index */ 1020 + int nColTest; /* Number of columns to test for changes */ 1011 1021 1012 1022 if( pOnlyIdx && pOnlyIdx!=pIdx ) continue; 1013 1023 if( pIdx->pPartIdxWhere==0 ) needTableCnt = 0; 1014 1024 if( !HasRowid(pTab) && IsPrimaryKeyIndex(pIdx) ){ 1015 1025 nCol = pIdx->nKeyCol; 1016 1026 zIdxName = pTab->zName; 1027 + nColTest = nCol - 1; 1017 1028 }else{ 1018 1029 nCol = pIdx->nColumn; 1019 1030 zIdxName = pIdx->zName; 1031 + nColTest = pIdx->uniqNotNull ? pIdx->nKeyCol-1 : nCol-1; 1020 1032 } 1021 - aGotoChng = sqlite3DbMallocRaw(db, sizeof(int)*(nCol+1)); 1022 - if( aGotoChng==0 ) continue; 1023 1033 1024 1034 /* Populate the register containing the index name. */ 1025 1035 sqlite3VdbeAddOp4(v, OP_String8, 0, regIdxname, 0, zIdxName, 0); 1026 1036 VdbeComment((v, "Analysis for %s.%s", pTab->zName, zIdxName)); 1027 1037 1028 1038 /* 1029 1039 ** Pseudo-code for loop that calls stat_push(): ................................................................................ 1044 1054 ** 1045 1055 ** chng_addr_0: 1046 1056 ** regPrev(0) = idx(0) 1047 1057 ** chng_addr_1: 1048 1058 ** regPrev(1) = idx(1) 1049 1059 ** ... 1050 1060 ** 1051 - ** chng_addr_N: 1061 + ** endDistinctTest: 1052 1062 ** regRowid = idx(rowid) 1053 1063 ** stat_push(P, regChng, regRowid) 1054 1064 ** Next csr 1055 1065 ** if !eof(csr) goto next_row; 1056 1066 ** 1057 1067 ** end_of_scan: 1058 1068 */ 1059 1069 1060 1070 /* Make sure there are enough memory cells allocated to accommodate 1061 1071 ** the regPrev array and a trailing rowid (the rowid slot is required 1062 1072 ** when building a record to insert into the sample column of 1063 1073 ** the sqlite_stat4 table. */ 1064 - pParse->nMem = MAX(pParse->nMem, regPrev+nCol); 1074 + pParse->nMem = MAX(pParse->nMem, regPrev+nColTest); 1065 1075 1066 1076 /* Open a read-only cursor on the index being analyzed. */ 1067 1077 assert( iDb==sqlite3SchemaToIndex(db, pIdx->pSchema) ); 1068 1078 sqlite3VdbeAddOp3(v, OP_OpenRead, iIdxCur, pIdx->tnum, iDb); 1069 1079 sqlite3VdbeSetP4KeyInfo(pParse, pIdx); 1070 1080 VdbeComment((v, "%s", pIdx->zName)); 1071 1081 1072 1082 /* Invoke the stat_init() function. The arguments are: 1073 1083 ** 1074 - ** (1) the number of columns in the index including the rowid, 1075 - ** (2) the number of rows in the index, 1084 + ** (1) the number of columns in the index including the rowid 1085 + ** (or for a WITHOUT ROWID table, the number of PK columns), 1086 + ** (2) the number of columns in the key without the rowid/pk 1087 + ** (3) the number of rows in the index, 1088 + ** 1076 1089 ** 1077 - ** The second argument is only used for STAT3 and STAT4 1090 + ** The third argument is only used for STAT3 and STAT4 1078 1091 */ 1079 1092 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 1080 1093 sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regStat4+3); 1081 1094 #endif 1082 1095 sqlite3VdbeAddOp2(v, OP_Integer, nCol, regStat4+1); 1083 1096 sqlite3VdbeAddOp2(v, OP_Integer, pIdx->nKeyCol, regStat4+2); 1084 1097 sqlite3VdbeAddOp3(v, OP_Function, 0, regStat4+1, regStat4); ................................................................................ 1092 1105 ** regChng = 0 1093 1106 ** goto next_push_0; 1094 1107 ** 1095 1108 */ 1096 1109 addrRewind = sqlite3VdbeAddOp1(v, OP_Rewind, iIdxCur); 1097 1110 VdbeCoverage(v); 1098 1111 sqlite3VdbeAddOp2(v, OP_Integer, 0, regChng); 1099 - addrGotoChng0 = sqlite3VdbeAddOp0(v, OP_Goto); 1100 - 1101 - /* 1102 - ** next_row: 1103 - ** regChng = 0 1104 - ** if( idx(0) != regPrev(0) ) goto chng_addr_0 1105 - ** regChng = 1 1106 - ** if( idx(1) != regPrev(1) ) goto chng_addr_1 1107 - ** ... 1108 - ** regChng = N 1109 - ** goto chng_addr_N 1110 - */ 1111 1112 addrNextRow = sqlite3VdbeCurrentAddr(v); 1112 - for(i=0; i<nCol-1; i++){ 1113 - char *pColl = (char*)sqlite3LocateCollSeq(pParse, pIdx->azColl[i]); 1114 - sqlite3VdbeAddOp2(v, OP_Integer, i, regChng); 1115 - sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regTemp); 1116 - aGotoChng[i] = 1117 - sqlite3VdbeAddOp4(v, OP_Ne, regTemp, 0, regPrev+i, pColl, P4_COLLSEQ); 1118 - sqlite3VdbeChangeP5(v, SQLITE_NULLEQ); 1119 - VdbeCoverage(v); 1120 - } 1121 - sqlite3VdbeAddOp2(v, OP_Integer, nCol-1, regChng); 1122 - aGotoChng[nCol] = sqlite3VdbeAddOp0(v, OP_Goto); 1123 - 1124 - /* 1125 - ** chng_addr_0: 1126 - ** regPrev(0) = idx(0) 1127 - ** chng_addr_1: 1128 - ** regPrev(1) = idx(1) 1129 - ** ... 1130 - */ 1131 - sqlite3VdbeJumpHere(v, addrGotoChng0); 1132 - for(i=0; i<nCol-1; i++){ 1133 - sqlite3VdbeJumpHere(v, aGotoChng[i]); 1134 - sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regPrev+i); 1135 - } 1136 - 1113 + 1114 + if( nColTest>0 ){ 1115 + int endDistinctTest = sqlite3VdbeMakeLabel(v); 1116 + int *aGotoChng; /* Array of jump instruction addresses */ 1117 + aGotoChng = sqlite3DbMallocRaw(db, sizeof(int)*nColTest); 1118 + if( aGotoChng==0 ) continue; 1119 + 1120 + /* 1121 + ** next_row: 1122 + ** regChng = 0 1123 + ** if( idx(0) != regPrev(0) ) goto chng_addr_0 1124 + ** regChng = 1 1125 + ** if( idx(1) != regPrev(1) ) goto chng_addr_1 1126 + ** ... 1127 + ** regChng = N 1128 + ** goto endDistinctTest 1129 + */ 1130 + sqlite3VdbeAddOp0(v, OP_Goto); 1131 + addrNextRow = sqlite3VdbeCurrentAddr(v); 1132 + if( nColTest==1 && pIdx->nKeyCol==1 && pIdx->onError!=OE_None ){ 1133 + /* For a single-column UNIQUE index, once we have found a non-NULL 1134 + ** row, we know that all the rest will be distinct, so skip 1135 + ** subsequent distinctness tests. */ 1136 + sqlite3VdbeAddOp2(v, OP_NotNull, regPrev, endDistinctTest); 1137 + VdbeCoverage(v); 1138 + } 1139 + for(i=0; i<nColTest; i++){ 1140 + char *pColl = (char*)sqlite3LocateCollSeq(pParse, pIdx->azColl[i]); 1141 + sqlite3VdbeAddOp2(v, OP_Integer, i, regChng); 1142 + sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regTemp); 1143 + aGotoChng[i] = 1144 + sqlite3VdbeAddOp4(v, OP_Ne, regTemp, 0, regPrev+i, pColl, P4_COLLSEQ); 1145 + sqlite3VdbeChangeP5(v, SQLITE_NULLEQ); 1146 + VdbeCoverage(v); 1147 + } 1148 + sqlite3VdbeAddOp2(v, OP_Integer, nColTest, regChng); 1149 + sqlite3VdbeAddOp2(v, OP_Goto, 0, endDistinctTest); 1150 + 1151 + 1152 + /* 1153 + ** chng_addr_0: 1154 + ** regPrev(0) = idx(0) 1155 + ** chng_addr_1: 1156 + ** regPrev(1) = idx(1) 1157 + ** ... 1158 + */ 1159 + sqlite3VdbeJumpHere(v, addrNextRow-1); 1160 + for(i=0; i<nColTest; i++){ 1161 + sqlite3VdbeJumpHere(v, aGotoChng[i]); 1162 + sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regPrev+i); 1163 + } 1164 + sqlite3VdbeResolveLabel(v, endDistinctTest); 1165 + sqlite3DbFree(db, aGotoChng); 1166 + } 1167 + 1137 1168 /* 1138 1169 ** chng_addr_N: 1139 1170 ** regRowid = idx(rowid) // STAT34 only 1140 1171 ** stat_push(P, regChng, regRowid) // 3rd parameter STAT34 only 1141 1172 ** Next csr 1142 1173 ** if !eof(csr) goto next_row; 1143 1174 */ 1144 - sqlite3VdbeJumpHere(v, aGotoChng[nCol]); 1145 1175 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 1146 1176 assert( regRowid==(regStat4+2) ); 1147 1177 if( HasRowid(pTab) ){ 1148 1178 sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, regRowid); 1149 1179 }else{ 1150 1180 Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable); 1151 1181 int j, k, regKey; ................................................................................ 1215 1245 sqlite3VdbeAddOp2(v, OP_Goto, 1, addrNext); /* P1==1 for end-of-loop */ 1216 1246 sqlite3VdbeJumpHere(v, addrIsNull); 1217 1247 } 1218 1248 #endif /* SQLITE_ENABLE_STAT3_OR_STAT4 */ 1219 1249 1220 1250 /* End of analysis */ 1221 1251 sqlite3VdbeJumpHere(v, addrRewind); 1222 - sqlite3DbFree(db, aGotoChng); 1223 1252 } 1224 1253 1225 1254 1226 1255 /* Create a single sqlite_stat1 entry containing NULL as the index 1227 1256 ** name and the row count as the content. 1228 1257 */ 1229 1258 if( pOnlyIdx==0 && needTableCnt ){