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Overview
Comment: | Refactoring of the query optimizer in advance of adding better optimization. (CVS 2551) |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
57c6bd3760163c174be4a2ece58f414e |
User & Date: | drh 2005-07-19 17:38:23.000 |
Context
2005-07-19
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22:22 | More refactoring in where.c. (CVS 2552) (check-in: a35bd50af8 user: drh tags: trunk) | |
17:38 | Refactoring of the query optimizer in advance of adding better optimization. (CVS 2551) (check-in: 57c6bd3760 user: drh tags: trunk) | |
2005-07-16
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13:33 | Allow an unlimited number of terms in the WHERE clause. The old limit was 100. (CVS 2550) (check-in: ca69f36832 user: drh tags: trunk) | |
Changes
Changes to src/sqliteInt.h.
1 2 3 4 5 6 7 8 9 10 11 12 13 | /* ** 2001 September 15 ** ** 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. ** ************************************************************************* ** Internal interface definitions for SQLite. ** | | | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | /* ** 2001 September 15 ** ** 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. ** ************************************************************************* ** Internal interface definitions for SQLite. ** ** @(#) $Id: sqliteInt.h,v 1.394 2005/07/19 17:38:23 drh Exp $ */ #ifndef _SQLITEINT_H_ #define _SQLITEINT_H_ /* ** These #defines should enable >2GB file support on Posix if the ** underlying operating system supports it. If the OS lacks |
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841 842 843 844 845 846 847 | */ #define EP_FromJoin 0x01 /* Originated in ON or USING clause of a join */ #define EP_Agg 0x02 /* Contains one or more aggregate functions */ #define EP_Resolved 0x04 /* IDs have been resolved to COLUMNs */ #define EP_Error 0x08 /* Expression contains one or more errors */ #define EP_Not 0x10 /* Operator preceeded by NOT */ #define EP_VarSelect 0x20 /* pSelect is correlated, not constant */ | < | 841 842 843 844 845 846 847 848 849 850 851 852 853 854 | */ #define EP_FromJoin 0x01 /* Originated in ON or USING clause of a join */ #define EP_Agg 0x02 /* Contains one or more aggregate functions */ #define EP_Resolved 0x04 /* IDs have been resolved to COLUMNs */ #define EP_Error 0x08 /* Expression contains one or more errors */ #define EP_Not 0x10 /* Operator preceeded by NOT */ #define EP_VarSelect 0x20 /* pSelect is correlated, not constant */ /* ** These macros can be used to test, set, or clear bits in the ** Expr.flags field. */ #define ExprHasProperty(E,P) (((E)->flags&(P))==(P)) #define ExprHasAnyProperty(E,P) (((E)->flags&(P))!=0) |
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Changes to src/where.c.
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12 13 14 15 16 17 18 | ** This module contains C code that generates VDBE code used to process ** the WHERE clause of SQL statements. This module is reponsible for ** generating the code that loops through a table looking for applicable ** rows. Indices are selected and used to speed the search when doing ** so is applicable. Because this module is responsible for selecting ** indices, you might also think of this module as the "query optimizer". ** | | > > > | | > | < | > > > > > | < | < < < < < < < < < < < < < < < < | > > | < | < | < | > < | 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 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 | ** This module contains C code that generates VDBE code used to process ** the WHERE clause of SQL statements. This module is reponsible for ** generating the code that loops through a table looking for applicable ** rows. Indices are selected and used to speed the search when doing ** so is applicable. Because this module is responsible for selecting ** indices, you might also think of this module as the "query optimizer". ** ** $Id: where.c,v 1.146 2005/07/19 17:38:23 drh Exp $ */ #include "sqliteInt.h" /* ** The number of bits in a Bitmask. "BMS" means "BitMask Size". */ #define BMS (sizeof(Bitmask)*8-1) /* ** Determine the number of elements in an array. */ #define ARRAYSIZE(X) (sizeof(X)/sizeof(X[0])) /* Forward reference */ typedef struct WhereClause WhereClause; /* ** The query generator uses an array of instances of this structure to ** help it analyze the subexpressions of the WHERE clause. Each WHERE ** clause subexpression is separated from the others by an AND operator. ** ** All WhereTerms are collected into a single WhereClause structure. ** The following identity holds: ** ** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm ** ** When a term is of the form: ** ** X <op> <expr> ** ** where X is a column name and <op> is one of certain operators, ** then WhereTerm.leftCursor and WhereTerm.leftColumn record the ** cursor number and column number for X. ** ** prereqRight and prereqAll record sets of cursor numbers, ** but they do so indirectly. A single ExprMaskSet structure translates ** cursor number into bits and the translated bit is stored in the prereq ** fields. The translation is used in order to maximize the number of ** bits that will fit in a Bitmask. The VDBE cursor numbers might be ** spread out over the non-negative integers. For example, the cursor ** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The ExprMaskSet ** translates these sparse cursor numbers into consecutive integers ** beginning with 0 in order to make the best possible use of the available ** bits in the Bitmask. So, in the example above, the cursor numbers ** would be mapped into integers 0 through 7. */ typedef struct WhereTerm WhereTerm; struct WhereTerm { Expr *pExpr; /* Pointer to the subexpression */ u16 idx; /* Index of this term in pWC->a[] */ i16 iPartner; /* Disable pWC->a[iPartner] when this term disabled */ u16 flags; /* Bit flags. See below */ i16 leftCursor; /* Cursor number of X in "X <op> <expr>" */ i16 leftColumn; /* Column number of X in "X <op> <expr>" */ WhereClause *pWC; /* The clause this term is part of */ Bitmask prereqRight; /* Bitmask of tables used by pRight */ Bitmask prereqAll; /* Bitmask of tables referenced by p */ }; /* ** Allowed values of WhereTerm.flags */ #define TERM_DYNAMIC 0x0001 /* Need to call sqlite3ExprDelete(p) */ #define TERM_VIRTUAL 0x0002 /* Added by the optimizer. Do not code */ #define TERM_CODED 0x0004 /* This term is already coded */ /* ** An instance of the following structure holds all information about a ** WHERE clause. Mostly this is a container for one or more WhereTerms. */ struct WhereClause { int nTerm; /* Number of terms */ int nSlot; /* Number of entries in a[] */ WhereTerm *a; /* Pointer to an array of terms */ WhereTerm aStatic[10]; /* Initial static space for the terms */ }; |
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152 153 154 155 156 157 158 | ** itself is not freed. This routine is the inverse of whereClauseInit(). */ static void whereClauseClear(WhereClause *pWC){ int i; WhereTerm *a; for(i=pWC->nTerm-1, a=pWC->a; i>=0; i--, a++){ if( a->flags & TERM_DYNAMIC ){ | | | | | > > | > > > | 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 | ** itself is not freed. This routine is the inverse of whereClauseInit(). */ static void whereClauseClear(WhereClause *pWC){ int i; WhereTerm *a; for(i=pWC->nTerm-1, a=pWC->a; i>=0; i--, a++){ if( a->flags & TERM_DYNAMIC ){ sqlite3ExprDelete(a->pExpr); } } if( pWC->a!=pWC->aStatic ){ sqliteFree(pWC->a); } } /* ** Add a new entries to the WhereClause structure. Increase the allocated ** space as necessary. */ static WhereTerm *whereClauseInsert(WhereClause *pWC, Expr *p, int flags){ WhereTerm *pTerm; if( pWC->nTerm>=pWC->nSlot ){ WhereTerm *pOld = pWC->a; pWC->a = sqliteMalloc( sizeof(pWC->a[0])*pWC->nSlot*2 ); if( pWC->a==0 ) return 0; memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm); if( pOld!=pWC->aStatic ){ sqliteFree(pOld); } pWC->nSlot *= 2; } pTerm = &pWC->a[pWC->nTerm]; pTerm->idx = pWC->nTerm; pWC->nTerm++; pTerm->pExpr = p; pTerm->flags = flags; pTerm->pWC = pWC; pTerm->iPartner = -1; return pTerm; } /* ** This routine identifies subexpressions in the WHERE clause where ** each subexpression is separate by the AND operator. aSlot is ** filled with pointers to the subexpressions. For example: ** |
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229 230 231 232 233 234 235 236 237 | } } return 0; } /* ** Create a new mask for cursor iCursor. */ static void createMask(ExprMaskSet *pMaskSet, int iCursor){ | > > > > > | | < | 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 | } } return 0; } /* ** Create a new mask for cursor iCursor. ** ** There is one cursor per table in the FROM clause. The number of ** tables in the FROM clause is limited by a test early in the ** sqlite3WhereBegin() routien. So we know that the pMaskSet->ix[] ** array will never overflow. */ static void createMask(ExprMaskSet *pMaskSet, int iCursor){ assert( pMaskSet->n < ARRAYSIZE(pMaskSet->ix) ); pMaskSet->ix[pMaskSet->n++] = iCursor; } /* ** Destroy an expression mask set */ #define freeMaskSet(P) /* NO-OP */ |
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301 302 303 304 305 306 307 | /* ** Swap two objects of type T. */ #define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;} /* | | < < | < < < | | > > > > > | | > > | > > > > > > < | > > > > | | < | < < | < < < < < < < < < < < < < < < | < > | | < > > | | | | | > > > | | > > > | > > | | | > > > > | < > | | | | 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 | /* ** Swap two objects of type T. */ #define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;} /* ** Commute a comparision operator. Expressions of the form "X op Y" ** are converted into "Y op X". */ static void exprCommute(Expr *pExpr){ assert( pExpr->op==TK_EQ || pExpr->op==TK_NE || pExpr->op==TK_LT || pExpr->op==TK_LE || pExpr->op==TK_GT || pExpr->op==TK_GE ); SWAP(CollSeq*,pExpr->pRight->pColl,pExpr->pLeft->pColl); SWAP(Expr*,pExpr->pRight,pExpr->pLeft); if( pExpr->op>=TK_GT ){ assert( TK_LT==TK_GT+2 ); assert( TK_GE==TK_LE+2 ); assert( TK_GT>TK_EQ ); assert( TK_GT<TK_LE ); assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE ); pExpr->op = ((pExpr->op-TK_GT)^2)+TK_GT; } } /* ** The input to this routine is an WhereTerm structure with only the ** "p" field filled in. The job of this routine is to analyze the ** subexpression and populate all the other fields of the WhereTerm ** structure. */ static void exprAnalyze( SrcList *pSrc, /* the FROM clause */ ExprMaskSet *pMaskSet, /* table masks */ WhereTerm *pTerm /* the WHERE clause term to be analyzed */ ){ Expr *pExpr = pTerm->pExpr; Bitmask prereqLeft; Bitmask prereqAll; int idxRight; prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft); pTerm->prereqRight = exprTableUsage(pMaskSet, pExpr->pRight); pTerm->prereqAll = prereqAll = exprTableUsage(pMaskSet, pExpr); pTerm->leftCursor = -1; pTerm->iPartner = -1; idxRight = -1; if( allowedOp(pExpr->op) && (pTerm->prereqRight & prereqLeft)==0 ){ Expr *pLeft = pExpr->pLeft; Expr *pRight = pExpr->pRight; if( pLeft->op==TK_COLUMN ){ pTerm->leftCursor = pLeft->iTable; pTerm->leftColumn = pLeft->iColumn; } if( pRight && pRight->op==TK_COLUMN ){ WhereTerm *pNew; Expr *pDup; if( pTerm->leftCursor>=0 ){ pDup = sqlite3ExprDup(pExpr); pNew = whereClauseInsert(pTerm->pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC); if( pNew==0 ) return; pNew->iPartner = pTerm->idx; }else{ pDup = pExpr; pNew = pTerm; } exprCommute(pDup); pLeft = pDup->pLeft; pNew->leftCursor = pLeft->iTable; pNew->leftColumn = pLeft->iColumn; pNew->prereqRight = prereqLeft; pNew->prereqAll = prereqAll; } } } /* ** This routine decides if pIdx can be used to satisfy the ORDER BY ** clause. If it can, it returns 1. If pIdx cannot satisfy the ** ORDER BY clause, this routine returns 0. ** ** pOrderBy is an ORDER BY clause from a SELECT statement. pTab is the |
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511 512 513 514 515 516 517 | ** Disabling a term causes that term to not be tested in the inner loop ** of the join. Disabling is an optimization. We would get the correct ** results if nothing were ever disabled, but joins might run a little ** slower. The trick is to disable as much as we can without disabling ** too much. If we disabled in (1), we'd get the wrong answer. ** See ticket #813. */ | | | > | > | > > > | 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 | ** Disabling a term causes that term to not be tested in the inner loop ** of the join. Disabling is an optimization. We would get the correct ** results if nothing were ever disabled, but joins might run a little ** slower. The trick is to disable as much as we can without disabling ** too much. If we disabled in (1), we'd get the wrong answer. ** See ticket #813. */ static void disableTerm(WhereLevel *pLevel, WhereTerm *pTerm){ if( pTerm && (pTerm->flags & TERM_CODED)==0 && (pLevel->iLeftJoin==0 || ExprHasProperty(pTerm->pExpr, EP_FromJoin)) ){ pTerm->flags |= TERM_CODED; if( pTerm->iPartner>=0 ){ disableTerm(pLevel, &pTerm->pWC->a[pTerm->iPartner]); } } } /* ** Generate code that builds a probe for an index. Details: ** ** * Check the top nColumn entries on the stack. If any |
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547 548 549 550 551 552 553 | */ static void codeEqualityTerm( Parse *pParse, /* The parsing context */ WhereTerm *pTerm, /* The term of the WHERE clause to be coded */ int brk, /* Jump here to abandon the loop */ WhereLevel *pLevel /* When level of the FROM clause we are working on */ ){ | | | | 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 | */ static void codeEqualityTerm( Parse *pParse, /* The parsing context */ WhereTerm *pTerm, /* The term of the WHERE clause to be coded */ int brk, /* Jump here to abandon the loop */ WhereLevel *pLevel /* When level of the FROM clause we are working on */ ){ Expr *pX = pTerm->pExpr; if( pX->op!=TK_IN ){ assert( pX->op==TK_EQ ); sqlite3ExprCode(pParse, pX->pRight); #ifndef SQLITE_OMIT_SUBQUERY }else{ int iTab; Vdbe *v = pParse->pVdbe; sqlite3CodeSubselect(pParse, pX); iTab = pX->iTable; sqlite3VdbeAddOp(v, OP_Rewind, iTab, brk); VdbeComment((v, "# %.*s", pX->span.n, pX->span.z)); pLevel->inP2 = sqlite3VdbeAddOp(v, OP_Column, iTab, 0); pLevel->inOp = OP_Next; pLevel->inP1 = iTab; #endif } disableTerm(pLevel, pTerm); } #ifdef SQLITE_TEST /* ** The following variable holds a text description of query plan generated ** by the most recent call to sqlite3WhereBegin(). Each call to WhereBegin ** overwrites the previous. This information is used for testing and |
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674 675 676 677 678 679 680 | Expr *pWhere, /* The WHERE clause */ ExprList **ppOrderBy /* An ORDER BY clause, or NULL */ ){ int i; /* Loop counter */ WhereInfo *pWInfo; /* Will become the return value of this function */ Vdbe *v = pParse->pVdbe; /* The virtual database engine */ int brk, cont = 0; /* Addresses used during code generation */ | | | 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 | Expr *pWhere, /* The WHERE clause */ ExprList **ppOrderBy /* An ORDER BY clause, or NULL */ ){ int i; /* Loop counter */ WhereInfo *pWInfo; /* Will become the return value of this function */ Vdbe *v = pParse->pVdbe; /* The virtual database engine */ int brk, cont = 0; /* Addresses used during code generation */ Bitmask loopMask; /* One bit cleared for each outer loop */ WhereTerm *pTerm; /* A single term in the WHERE clause */ ExprMaskSet maskSet; /* The expression mask set */ int iDirectEq[BMS]; /* Term of the form ROWID==X for the N-th table */ int iDirectLt[BMS]; /* Term of the form ROWID<X or ROWID<=X */ int iDirectGt[BMS]; /* Term of the form ROWID>X or ROWID>=X */ WhereClause wc; /* The WHERE clause is divided into these terms */ struct SrcList_item *pTabItem; /* A single entry from pTabList */ |
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728 729 730 731 732 733 734 | } /* Analyze all of the subexpressions. */ for(i=0; i<pTabList->nSrc; i++){ createMask(&maskSet, pTabList->a[i].iCursor); } | | | | | 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 | } /* Analyze all of the subexpressions. */ for(i=0; i<pTabList->nSrc; i++){ createMask(&maskSet, pTabList->a[i].iCursor); } for(i=wc.nTerm-1; i>=0; i--){ exprAnalyze(pTabList, &maskSet, &wc.a[i]); } /* Figure out what index to use (if any) for each nested loop. ** Make pWInfo->a[i].pIdx point to the index to use for the i-th nested ** loop where i==0 is the outer loop and i==pTabList->nSrc-1 is the inner ** loop. ** ** If terms exist that use the ROWID of any table, then set the ** iDirectEq[], iDirectLt[], or iDirectGt[] elements for that table ** to the index of the term containing the ROWID. We always prefer ** to use a ROWID which can directly access a table rather than an ** index which requires reading an index first to get the rowid then ** doing a second read of the actual database table. ** ** Actually, if there are more than 32 tables in the join, only the ** first 32 tables are candidates for indices. This is (again) due ** to the limit of 32 bits in an integer bitmask. */ loopMask = ~(Bitmask)0; pTabItem = pTabList->a; pLevel = pWInfo->a; for(i=0; i<pTabList->nSrc && i<ARRAYSIZE(iDirectEq); i++,pTabItem++,pLevel++){ int j; int iCur = pTabItem->iCursor; /* The cursor for this table */ Bitmask mask = getMask(&maskSet, iCur); /* Cursor mask for this table */ Table *pTab = pTabItem->pTab; |
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774 775 776 777 778 779 780 | ** (Added:) Treat ROWID IN expr like ROWID=expr. */ pLevel->iIdxCur = -1; iDirectEq[i] = -1; iDirectLt[i] = -1; iDirectGt[i] = -1; for(pTerm=wc.a, j=0; j<wc.nTerm; j++, pTerm++){ | | < | | | | 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 | ** (Added:) Treat ROWID IN expr like ROWID=expr. */ pLevel->iIdxCur = -1; iDirectEq[i] = -1; iDirectLt[i] = -1; iDirectGt[i] = -1; for(pTerm=wc.a, j=0; j<wc.nTerm; j++, pTerm++){ if( pTerm->leftCursor==iCur && pTerm->leftColumn<0 && (pTerm->prereqRight & loopMask)==0 ){ switch( pTerm->pExpr->op ){ case TK_IN: case TK_EQ: iDirectEq[i] = j; break; case TK_LE: case TK_LT: iDirectLt[i] = j; break; case TK_GE: case TK_GT: iDirectGt[i] = j; break; } } } /* If we found a term that tests ROWID with == or IN, that term ** will be used to locate the rows in the database table. There ** is no need to continue into the code below that looks for ** an index. We will always use the ROWID over an index. */ if( iDirectEq[i]>=0 ){ loopMask &= ~mask; pLevel->pIdx = 0; continue; } /* Do a search for usable indices. Leave pBestIdx pointing to ** the "best" index. pBestIdx is left set to NULL if no indices ** are usable. |
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845 846 847 848 849 850 851 | Bitmask m; int nEq, score, bRev = 0; if( pIdx->nColumn>sizeof(eqMask)*8 ){ continue; /* Ignore indices with too many columns to analyze */ } for(pTerm=wc.a, j=0; j<wc.nTerm; j++, pTerm++){ | | < | | | 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 | Bitmask m; int nEq, score, bRev = 0; if( pIdx->nColumn>sizeof(eqMask)*8 ){ continue; /* Ignore indices with too many columns to analyze */ } for(pTerm=wc.a, j=0; j<wc.nTerm; j++, pTerm++){ Expr *pX = pTerm->pExpr; CollSeq *pColl = sqlite3ExprCollSeq(pParse, pX->pLeft); if( !pColl && pX->pRight ){ pColl = sqlite3ExprCollSeq(pParse, pX->pRight); } if( !pColl ){ pColl = pParse->db->pDfltColl; } if( pTerm->leftCursor==iCur && (pTerm->prereqRight & loopMask)==0 ){ int iColumn = pTerm->leftColumn; int k; char idxaff = iColumn>=0 ? pIdx->pTable->aCol[iColumn].affinity : 0; for(k=0; k<pIdx->nColumn; k++){ /* If the collating sequences or affinities don't match, ** ignore this index. */ if( pColl!=pIdx->keyInfo.aColl[k] ) continue; if( !sqlite3IndexAffinityOk(pX, idxaff) ) continue; |
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948 949 950 951 952 953 954 | bestScore = score; bestRev = bRev; } } pLevel->pIdx = pBestIdx; pLevel->score = bestScore; pLevel->bRev = bestRev; | | | 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 | bestScore = score; bestRev = bRev; } } pLevel->pIdx = pBestIdx; pLevel->score = bestScore; pLevel->bRev = bestRev; loopMask &= ~mask; if( pBestIdx ){ pLevel->iIdxCur = pParse->nTab++; } } /* Check to see if the ORDER BY clause is or can be satisfied by the ** use of an index on the first table. |
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1066 1067 1068 1069 1070 1071 1072 | } sqlite3_query_plan[nQPlan] = 0; nQPlan = 0; #endif /* Generate the code to do the search */ | | | 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 | } sqlite3_query_plan[nQPlan] = 0; nQPlan = 0; #endif /* Generate the code to do the search */ loopMask = ~(Bitmask)0; pLevel = pWInfo->a; pTabItem = pTabList->a; for(i=0; i<pTabList->nSrc; i++, pTabItem++, pLevel++){ int j, k; int iCur = pTabItem->iCursor; /* The VDBE cursor for the table */ Index *pIdx; /* The index we will be using */ int iIdxCur; /* The VDBE cursor for the index */ |
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1105 1106 1107 1108 1109 1110 1111 | /* Case 1: We can directly reference a single row using an ** equality comparison against the ROWID field. Or ** we reference multiple rows using a "rowid IN (...)" ** construct. */ assert( k<wc.nTerm ); pTerm = &wc.a[k]; | | | | 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 | /* Case 1: We can directly reference a single row using an ** equality comparison against the ROWID field. Or ** we reference multiple rows using a "rowid IN (...)" ** construct. */ assert( k<wc.nTerm ); pTerm = &wc.a[k]; assert( pTerm->pExpr!=0 ); assert( pTerm->leftCursor==iCur ); assert( omitTable==0 ); brk = pLevel->brk = sqlite3VdbeMakeLabel(v); codeEqualityTerm(pParse, pTerm, brk, pLevel); cont = pLevel->cont = sqlite3VdbeMakeLabel(v); sqlite3VdbeAddOp(v, OP_MustBeInt, 1, brk); sqlite3VdbeAddOp(v, OP_NotExists, iCur, brk); VdbeComment((v, "pk")); |
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1128 1129 1130 1131 1132 1133 1134 | brk = pLevel->brk = sqlite3VdbeMakeLabel(v); /* For each column of the index, find the term of the WHERE clause that ** constraints that column. If the WHERE clause term is X=expr, then ** generate code to evaluate expr and leave the result on the stack */ for(j=0; j<nColumn; j++){ for(pTerm=wc.a, k=0; k<wc.nTerm; k++, pTerm++){ | | | | | | | > | 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 | brk = pLevel->brk = sqlite3VdbeMakeLabel(v); /* For each column of the index, find the term of the WHERE clause that ** constraints that column. If the WHERE clause term is X=expr, then ** generate code to evaluate expr and leave the result on the stack */ for(j=0; j<nColumn; j++){ for(pTerm=wc.a, k=0; k<wc.nTerm; k++, pTerm++){ Expr *pX = pTerm->pExpr; assert( pX ); if( pTerm->leftCursor==iCur && (pTerm->prereqRight & loopMask)==0 && pTerm->leftColumn==pIdx->aiColumn[j] && (pX->op==TK_EQ || pX->op==TK_IN) ){ char idxaff = pIdx->pTable->aCol[pTerm->leftColumn].affinity; assert( (pTerm->flags & TERM_CODED)==0 ); if( sqlite3IndexAffinityOk(pX, idxaff) ){ codeEqualityTerm(pParse, pTerm, brk, pLevel); break; } } } } |
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1194 1195 1196 1197 1198 1199 1200 | iDirectLt[i] = t; } if( iDirectGt[i]>=0 ){ Expr *pX; k = iDirectGt[i]; assert( k<wc.nTerm ); pTerm = &wc.a[k]; | | | | | | | | 1203 1204 1205 1206 1207 1208 1209 1210 1211 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 | iDirectLt[i] = t; } if( iDirectGt[i]>=0 ){ Expr *pX; k = iDirectGt[i]; assert( k<wc.nTerm ); pTerm = &wc.a[k]; pX = pTerm->pExpr; assert( pX!=0 ); assert( pTerm->leftCursor==iCur ); sqlite3ExprCode(pParse, pX->pRight); sqlite3VdbeAddOp(v, OP_ForceInt, pX->op==TK_LE || pX->op==TK_GT, brk); sqlite3VdbeAddOp(v, bRev ? OP_MoveLt : OP_MoveGe, iCur, brk); VdbeComment((v, "pk")); disableTerm(pLevel, pTerm); }else{ sqlite3VdbeAddOp(v, bRev ? OP_Last : OP_Rewind, iCur, brk); } if( iDirectLt[i]>=0 ){ Expr *pX; k = iDirectLt[i]; assert( k<wc.nTerm ); pTerm = &wc.a[k]; pX = pTerm->pExpr; assert( pX!=0 ); assert( pTerm->leftCursor==iCur ); sqlite3ExprCode(pParse, pX->pRight); pLevel->iMem = pParse->nMem++; sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1); if( pX->op==TK_LT || pX->op==TK_GT ){ testOp = bRev ? OP_Le : OP_Ge; }else{ testOp = bRev ? OP_Lt : OP_Gt; } disableTerm(pLevel, pTerm); } start = sqlite3VdbeCurrentAddr(v); pLevel->op = bRev ? OP_Prev : OP_Next; pLevel->p1 = iCur; pLevel->p2 = start; if( testOp!=OP_Noop ){ sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0); |
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1276 1277 1278 1279 1280 1281 1282 | int testOp; /* Evaluate the equality constraints */ for(j=0; j<nEqColumn; j++){ int iIdxCol = pIdx->aiColumn[j]; for(pTerm=wc.a, k=0; k<wc.nTerm; k++, pTerm++){ | | | | | | < > | > | 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 | int testOp; /* Evaluate the equality constraints */ for(j=0; j<nEqColumn; j++){ int iIdxCol = pIdx->aiColumn[j]; for(pTerm=wc.a, k=0; k<wc.nTerm; k++, pTerm++){ Expr *pX; if( pTerm->leftCursor==iCur && pTerm->leftColumn==iIdxCol && (pX = pTerm->pExpr)->op==TK_EQ && (pTerm->prereqRight & loopMask)==0 ){ assert( (pTerm->flags & TERM_CODED)==0 ); sqlite3ExprCode(pParse, pX->pRight); disableTerm(pLevel, pTerm); break; } } assert( k<wc.nTerm ); } /* Duplicate the equality term values because they will all be ** used twice: once to make the termination key and once to make the ** start key. */ for(j=0; j<nEqColumn; j++){ |
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1312 1313 1314 1315 1316 1317 1318 | ** are no equality terms and no "X<..." term. ** ** 2002-Dec-04: On a reverse-order scan, the so-called "termination" ** key computed here really ends up being the start key. */ if( (score & 4)!=0 ){ for(pTerm=wc.a, k=0; k<wc.nTerm; k++, pTerm++){ | | | | | | > | > | 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 | ** are no equality terms and no "X<..." term. ** ** 2002-Dec-04: On a reverse-order scan, the so-called "termination" ** key computed here really ends up being the start key. */ if( (score & 4)!=0 ){ for(pTerm=wc.a, k=0; k<wc.nTerm; k++, pTerm++){ Expr *pX = pTerm->pExpr; assert( pX ); if( pTerm->leftCursor==iCur && (pX->op==TK_LT || pX->op==TK_LE) && (pTerm->prereqRight & loopMask)==0 && pTerm->leftColumn==pIdx->aiColumn[j] ){ assert( (pTerm->flags & TERM_CODED)==0 ); sqlite3ExprCode(pParse, pX->pRight); leFlag = pX->op==TK_LE; disableTerm(pLevel, pTerm); break; } } assert( k<wc.nTerm ); testOp = OP_IdxGE; }else{ testOp = nEqColumn>0 ? OP_IdxGE : OP_Noop; leFlag = 1; } if( testOp!=OP_Noop ){ int nCol = nEqColumn + ((score & 4)!=0); |
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1355 1356 1357 1358 1359 1360 1361 | ** start key search. ** ** 2002-Dec-04: In the case of a reverse-order search, the so-called ** "start" key really ends up being used as the termination key. */ if( (score & 8)!=0 ){ for(pTerm=wc.a, k=0; k<wc.nTerm; k++, pTerm++){ | | | | | | > | | 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 | ** start key search. ** ** 2002-Dec-04: In the case of a reverse-order search, the so-called ** "start" key really ends up being used as the termination key. */ if( (score & 8)!=0 ){ for(pTerm=wc.a, k=0; k<wc.nTerm; k++, pTerm++){ Expr *pX = pTerm->pExpr; assert( pX ); if( pTerm->leftCursor==iCur && (pX->op==TK_GT || pX->op==TK_GE) && (pTerm->prereqRight & loopMask)==0 && pTerm->leftColumn==pIdx->aiColumn[j] ){ assert( (pTerm->flags & TERM_CODED)==0 ); sqlite3ExprCode(pParse, pX->pRight); geFlag = pX->op==TK_GE; disableTerm(pLevel, pTerm); break; } } }else{ geFlag = 1; } if( nEqColumn>0 || (score&8)!=0 ){ |
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1413 1414 1415 1416 1417 1418 1419 | /* Record the instruction used to terminate the loop. */ pLevel->op = pLevel->bRev ? OP_Prev : OP_Next; pLevel->p1 = iIdxCur; pLevel->p2 = start; } | | | | | | > > | < | | > | | | 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 | /* Record the instruction used to terminate the loop. */ pLevel->op = pLevel->bRev ? OP_Prev : OP_Next; pLevel->p1 = iIdxCur; pLevel->p2 = start; } loopMask &= ~getMask(&maskSet, iCur); /* Insert code to test every subexpression that can be completely ** computed using the current set of tables. */ for(pTerm=wc.a, j=wc.nTerm; j>0; j--, pTerm++){ Expr *pE; if( pTerm->flags & (TERM_VIRTUAL|TERM_CODED) ) continue; if( (pTerm->prereqAll & loopMask)!=0 ) continue; pE = pTerm->pExpr; assert( pE!=0 ); if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){ continue; } sqlite3ExprIfFalse(pParse, pE, cont, 1); pTerm->flags |= TERM_CODED; } brk = cont; /* For a LEFT OUTER JOIN, generate code that will record the fact that ** at least one row of the right table has matched the left table. */ if( pLevel->iLeftJoin ){ pLevel->top = sqlite3VdbeCurrentAddr(v); sqlite3VdbeAddOp(v, OP_Integer, 1, 0); sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1); VdbeComment((v, "# record LEFT JOIN hit")); for(pTerm=wc.a, j=0; j<wc.nTerm; j++, pTerm++){ if( pTerm->flags & (TERM_VIRTUAL|TERM_CODED) ) continue; if( (pTerm->prereqAll & loopMask)!=0 ) continue; assert( pTerm->pExpr ); sqlite3ExprIfFalse(pParse, pTerm->pExpr, cont, 1); pTerm->flags |= TERM_CODED; } } } pWInfo->iContinue = cont; freeMaskSet(&maskSet); whereClauseClear(&wc); return pWInfo; |
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