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Diffstat (limited to 'src/wherecode.c')
| -rw-r--r-- | src/wherecode.c | 2768 |
1 files changed, 2768 insertions, 0 deletions
diff --git a/src/wherecode.c b/src/wherecode.c new file mode 100644 index 0000000..e36d1c9 --- /dev/null +++ b/src/wherecode.c @@ -0,0 +1,2768 @@ +/* +** 2015-06-06 +** +** 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. +** +************************************************************************* +** This module contains C code that generates VDBE code used to process +** the WHERE clause of SQL statements. +** +** This file was split off from where.c on 2015-06-06 in order to reduce the +** size of where.c and make it easier to edit. This file contains the routines +** that actually generate the bulk of the WHERE loop code. The original where.c +** file retains the code that does query planning and analysis. +*/ +#include "sqliteInt.h" +#include "whereInt.h" + +#ifndef SQLITE_OMIT_EXPLAIN + +/* +** Return the name of the i-th column of the pIdx index. +*/ +static const char *explainIndexColumnName(Index *pIdx, int i){ + i = pIdx->aiColumn[i]; + if( i==XN_EXPR ) return "<expr>"; + if( i==XN_ROWID ) return "rowid"; + return pIdx->pTable->aCol[i].zCnName; +} + +/* +** This routine is a helper for explainIndexRange() below +** +** pStr holds the text of an expression that we are building up one term +** at a time. This routine adds a new term to the end of the expression. +** Terms are separated by AND so add the "AND" text for second and subsequent +** terms only. +*/ +static void explainAppendTerm( + StrAccum *pStr, /* The text expression being built */ + Index *pIdx, /* Index to read column names from */ + int nTerm, /* Number of terms */ + int iTerm, /* Zero-based index of first term. */ + int bAnd, /* Non-zero to append " AND " */ + const char *zOp /* Name of the operator */ +){ + int i; + + assert( nTerm>=1 ); + if( bAnd ) sqlite3_str_append(pStr, " AND ", 5); + + if( nTerm>1 ) sqlite3_str_append(pStr, "(", 1); + for(i=0; i<nTerm; i++){ + if( i ) sqlite3_str_append(pStr, ",", 1); + sqlite3_str_appendall(pStr, explainIndexColumnName(pIdx, iTerm+i)); + } + if( nTerm>1 ) sqlite3_str_append(pStr, ")", 1); + + sqlite3_str_append(pStr, zOp, 1); + + if( nTerm>1 ) sqlite3_str_append(pStr, "(", 1); + for(i=0; i<nTerm; i++){ + if( i ) sqlite3_str_append(pStr, ",", 1); + sqlite3_str_append(pStr, "?", 1); + } + if( nTerm>1 ) sqlite3_str_append(pStr, ")", 1); +} + +/* +** Argument pLevel describes a strategy for scanning table pTab. This +** function appends text to pStr that describes the subset of table +** rows scanned by the strategy in the form of an SQL expression. +** +** For example, if the query: +** +** SELECT * FROM t1 WHERE a=1 AND b>2; +** +** is run and there is an index on (a, b), then this function returns a +** string similar to: +** +** "a=? AND b>?" +*/ +static void explainIndexRange(StrAccum *pStr, WhereLoop *pLoop){ + Index *pIndex = pLoop->u.btree.pIndex; + u16 nEq = pLoop->u.btree.nEq; + u16 nSkip = pLoop->nSkip; + int i, j; + + if( nEq==0 && (pLoop->wsFlags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ) return; + sqlite3_str_append(pStr, " (", 2); + for(i=0; i<nEq; i++){ + const char *z = explainIndexColumnName(pIndex, i); + if( i ) sqlite3_str_append(pStr, " AND ", 5); + sqlite3_str_appendf(pStr, i>=nSkip ? "%s=?" : "ANY(%s)", z); + } + + j = i; + if( pLoop->wsFlags&WHERE_BTM_LIMIT ){ + explainAppendTerm(pStr, pIndex, pLoop->u.btree.nBtm, j, i, ">"); + i = 1; + } + if( pLoop->wsFlags&WHERE_TOP_LIMIT ){ + explainAppendTerm(pStr, pIndex, pLoop->u.btree.nTop, j, i, "<"); + } + sqlite3_str_append(pStr, ")", 1); +} + +/* +** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN +** command, or if either SQLITE_DEBUG or SQLITE_ENABLE_STMT_SCANSTATUS was +** defined at compile-time. If it is not a no-op, a single OP_Explain opcode +** is added to the output to describe the table scan strategy in pLevel. +** +** If an OP_Explain opcode is added to the VM, its address is returned. +** Otherwise, if no OP_Explain is coded, zero is returned. +*/ +int sqlite3WhereExplainOneScan( + Parse *pParse, /* Parse context */ + SrcList *pTabList, /* Table list this loop refers to */ + WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */ + u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ +){ + int ret = 0; +#if !defined(SQLITE_DEBUG) && !defined(SQLITE_ENABLE_STMT_SCANSTATUS) + if( sqlite3ParseToplevel(pParse)->explain==2 ) +#endif + { + SrcItem *pItem = &pTabList->a[pLevel->iFrom]; + Vdbe *v = pParse->pVdbe; /* VM being constructed */ + sqlite3 *db = pParse->db; /* Database handle */ + int isSearch; /* True for a SEARCH. False for SCAN. */ + WhereLoop *pLoop; /* The controlling WhereLoop object */ + u32 flags; /* Flags that describe this loop */ + char *zMsg; /* Text to add to EQP output */ + StrAccum str; /* EQP output string */ + char zBuf[100]; /* Initial space for EQP output string */ + + pLoop = pLevel->pWLoop; + flags = pLoop->wsFlags; + if( (flags&WHERE_MULTI_OR) || (wctrlFlags&WHERE_OR_SUBCLAUSE) ) return 0; + + isSearch = (flags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 + || ((flags&WHERE_VIRTUALTABLE)==0 && (pLoop->u.btree.nEq>0)) + || (wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX)); + + sqlite3StrAccumInit(&str, db, zBuf, sizeof(zBuf), SQLITE_MAX_LENGTH); + str.printfFlags = SQLITE_PRINTF_INTERNAL; + sqlite3_str_appendf(&str, "%s %S", isSearch ? "SEARCH" : "SCAN", pItem); + if( (flags & (WHERE_IPK|WHERE_VIRTUALTABLE))==0 ){ + const char *zFmt = 0; + Index *pIdx; + + assert( pLoop->u.btree.pIndex!=0 ); + pIdx = pLoop->u.btree.pIndex; + assert( !(flags&WHERE_AUTO_INDEX) || (flags&WHERE_IDX_ONLY) ); + if( !HasRowid(pItem->pTab) && IsPrimaryKeyIndex(pIdx) ){ + if( isSearch ){ + zFmt = "PRIMARY KEY"; + } + }else if( flags & WHERE_PARTIALIDX ){ + zFmt = "AUTOMATIC PARTIAL COVERING INDEX"; + }else if( flags & WHERE_AUTO_INDEX ){ + zFmt = "AUTOMATIC COVERING INDEX"; + }else if( flags & WHERE_IDX_ONLY ){ + zFmt = "COVERING INDEX %s"; + }else{ + zFmt = "INDEX %s"; + } + if( zFmt ){ + sqlite3_str_append(&str, " USING ", 7); + sqlite3_str_appendf(&str, zFmt, pIdx->zName); + explainIndexRange(&str, pLoop); + } + }else if( (flags & WHERE_IPK)!=0 && (flags & WHERE_CONSTRAINT)!=0 ){ + char cRangeOp; +#if 0 /* Better output, but breaks many tests */ + const Table *pTab = pItem->pTab; + const char *zRowid = pTab->iPKey>=0 ? pTab->aCol[pTab->iPKey].zCnName: + "rowid"; +#else + const char *zRowid = "rowid"; +#endif + sqlite3_str_appendf(&str, " USING INTEGER PRIMARY KEY (%s", zRowid); + if( flags&(WHERE_COLUMN_EQ|WHERE_COLUMN_IN) ){ + cRangeOp = '='; + }else if( (flags&WHERE_BOTH_LIMIT)==WHERE_BOTH_LIMIT ){ + sqlite3_str_appendf(&str, ">? AND %s", zRowid); + cRangeOp = '<'; + }else if( flags&WHERE_BTM_LIMIT ){ + cRangeOp = '>'; + }else{ + assert( flags&WHERE_TOP_LIMIT); + cRangeOp = '<'; + } + sqlite3_str_appendf(&str, "%c?)", cRangeOp); + } +#ifndef SQLITE_OMIT_VIRTUALTABLE + else if( (flags & WHERE_VIRTUALTABLE)!=0 ){ + sqlite3_str_appendf(&str, " VIRTUAL TABLE INDEX %d:%s", + pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr); + } +#endif + if( pItem->fg.jointype & JT_LEFT ){ + sqlite3_str_appendf(&str, " LEFT-JOIN"); + } +#ifdef SQLITE_EXPLAIN_ESTIMATED_ROWS + if( pLoop->nOut>=10 ){ + sqlite3_str_appendf(&str, " (~%llu rows)", + sqlite3LogEstToInt(pLoop->nOut)); + }else{ + sqlite3_str_append(&str, " (~1 row)", 9); + } +#endif + zMsg = sqlite3StrAccumFinish(&str); + sqlite3ExplainBreakpoint("",zMsg); + ret = sqlite3VdbeAddOp4(v, OP_Explain, sqlite3VdbeCurrentAddr(v), + pParse->addrExplain, 0, zMsg,P4_DYNAMIC); + } + return ret; +} + +/* +** Add a single OP_Explain opcode that describes a Bloom filter. +** +** Or if not processing EXPLAIN QUERY PLAN and not in a SQLITE_DEBUG and/or +** SQLITE_ENABLE_STMT_SCANSTATUS build, then OP_Explain opcodes are not +** required and this routine is a no-op. +** +** If an OP_Explain opcode is added to the VM, its address is returned. +** Otherwise, if no OP_Explain is coded, zero is returned. +*/ +int sqlite3WhereExplainBloomFilter( + const Parse *pParse, /* Parse context */ + const WhereInfo *pWInfo, /* WHERE clause */ + const WhereLevel *pLevel /* Bloom filter on this level */ +){ + int ret = 0; + SrcItem *pItem = &pWInfo->pTabList->a[pLevel->iFrom]; + Vdbe *v = pParse->pVdbe; /* VM being constructed */ + sqlite3 *db = pParse->db; /* Database handle */ + char *zMsg; /* Text to add to EQP output */ + int i; /* Loop counter */ + WhereLoop *pLoop; /* The where loop */ + StrAccum str; /* EQP output string */ + char zBuf[100]; /* Initial space for EQP output string */ + + sqlite3StrAccumInit(&str, db, zBuf, sizeof(zBuf), SQLITE_MAX_LENGTH); + str.printfFlags = SQLITE_PRINTF_INTERNAL; + sqlite3_str_appendf(&str, "BLOOM FILTER ON %S (", pItem); + pLoop = pLevel->pWLoop; + if( pLoop->wsFlags & WHERE_IPK ){ + const Table *pTab = pItem->pTab; + if( pTab->iPKey>=0 ){ + sqlite3_str_appendf(&str, "%s=?", pTab->aCol[pTab->iPKey].zCnName); + }else{ + sqlite3_str_appendf(&str, "rowid=?"); + } + }else{ + for(i=pLoop->nSkip; i<pLoop->u.btree.nEq; i++){ + const char *z = explainIndexColumnName(pLoop->u.btree.pIndex, i); + if( i>pLoop->nSkip ) sqlite3_str_append(&str, " AND ", 5); + sqlite3_str_appendf(&str, "%s=?", z); + } + } + sqlite3_str_append(&str, ")", 1); + zMsg = sqlite3StrAccumFinish(&str); + ret = sqlite3VdbeAddOp4(v, OP_Explain, sqlite3VdbeCurrentAddr(v), + pParse->addrExplain, 0, zMsg,P4_DYNAMIC); + return ret; +} +#endif /* SQLITE_OMIT_EXPLAIN */ + +#ifdef SQLITE_ENABLE_STMT_SCANSTATUS +/* +** Configure the VM passed as the first argument with an +** sqlite3_stmt_scanstatus() entry corresponding to the scan used to +** implement level pLvl. Argument pSrclist is a pointer to the FROM +** clause that the scan reads data from. +** +** If argument addrExplain is not 0, it must be the address of an +** OP_Explain instruction that describes the same loop. +*/ +void sqlite3WhereAddScanStatus( + Vdbe *v, /* Vdbe to add scanstatus entry to */ + SrcList *pSrclist, /* FROM clause pLvl reads data from */ + WhereLevel *pLvl, /* Level to add scanstatus() entry for */ + int addrExplain /* Address of OP_Explain (or 0) */ +){ + const char *zObj = 0; + WhereLoop *pLoop = pLvl->pWLoop; + if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 && pLoop->u.btree.pIndex!=0 ){ + zObj = pLoop->u.btree.pIndex->zName; + }else{ + zObj = pSrclist->a[pLvl->iFrom].zName; + } + sqlite3VdbeScanStatus( + v, addrExplain, pLvl->addrBody, pLvl->addrVisit, pLoop->nOut, zObj + ); +} +#endif + + +/* +** Disable a term in the WHERE clause. Except, do not disable the term +** if it controls a LEFT OUTER JOIN and it did not originate in the ON +** or USING clause of that join. +** +** Consider the term t2.z='ok' in the following queries: +** +** (1) SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x WHERE t2.z='ok' +** (2) SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x AND t2.z='ok' +** (3) SELECT * FROM t1, t2 WHERE t1.a=t2.x AND t2.z='ok' +** +** The t2.z='ok' is disabled in the in (2) because it originates +** in the ON clause. The term is disabled in (3) because it is not part +** of a LEFT OUTER JOIN. In (1), the term is not disabled. +** +** Disabling a term causes that term to not be tested in the inner loop +** of the join. Disabling is an optimization. When terms are satisfied +** by indices, we disable them to prevent redundant tests in the inner +** loop. 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. +** +** If all the children of a term are disabled, then that term is also +** automatically disabled. In this way, terms get disabled if derived +** virtual terms are tested first. For example: +** +** x GLOB 'abc*' AND x>='abc' AND x<'acd' +** \___________/ \______/ \_____/ +** parent child1 child2 +** +** Only the parent term was in the original WHERE clause. The child1 +** and child2 terms were added by the LIKE optimization. If both of +** the virtual child terms are valid, then testing of the parent can be +** skipped. +** +** Usually the parent term is marked as TERM_CODED. But if the parent +** term was originally TERM_LIKE, then the parent gets TERM_LIKECOND instead. +** The TERM_LIKECOND marking indicates that the term should be coded inside +** a conditional such that is only evaluated on the second pass of a +** LIKE-optimization loop, when scanning BLOBs instead of strings. +*/ +static void disableTerm(WhereLevel *pLevel, WhereTerm *pTerm){ + int nLoop = 0; + assert( pTerm!=0 ); + while( (pTerm->wtFlags & TERM_CODED)==0 + && (pLevel->iLeftJoin==0 || ExprHasProperty(pTerm->pExpr, EP_OuterON)) + && (pLevel->notReady & pTerm->prereqAll)==0 + ){ + if( nLoop && (pTerm->wtFlags & TERM_LIKE)!=0 ){ + pTerm->wtFlags |= TERM_LIKECOND; + }else{ + pTerm->wtFlags |= TERM_CODED; + } +#ifdef WHERETRACE_ENABLED + if( sqlite3WhereTrace & 0x20000 ){ + sqlite3DebugPrintf("DISABLE-"); + sqlite3WhereTermPrint(pTerm, (int)(pTerm - (pTerm->pWC->a))); + } +#endif + if( pTerm->iParent<0 ) break; + pTerm = &pTerm->pWC->a[pTerm->iParent]; + assert( pTerm!=0 ); + pTerm->nChild--; + if( pTerm->nChild!=0 ) break; + nLoop++; + } +} + +/* +** Code an OP_Affinity opcode to apply the column affinity string zAff +** to the n registers starting at base. +** +** As an optimization, SQLITE_AFF_BLOB and SQLITE_AFF_NONE entries (which +** are no-ops) at the beginning and end of zAff are ignored. If all entries +** in zAff are SQLITE_AFF_BLOB or SQLITE_AFF_NONE, then no code gets generated. +** +** This routine makes its own copy of zAff so that the caller is free +** to modify zAff after this routine returns. +*/ +static void codeApplyAffinity(Parse *pParse, int base, int n, char *zAff){ + Vdbe *v = pParse->pVdbe; + if( zAff==0 ){ + assert( pParse->db->mallocFailed ); + return; + } + assert( v!=0 ); + + /* Adjust base and n to skip over SQLITE_AFF_BLOB and SQLITE_AFF_NONE + ** entries at the beginning and end of the affinity string. + */ + assert( SQLITE_AFF_NONE<SQLITE_AFF_BLOB ); + while( n>0 && zAff[0]<=SQLITE_AFF_BLOB ){ + n--; + base++; + zAff++; + } + while( n>1 && zAff[n-1]<=SQLITE_AFF_BLOB ){ + n--; + } + + /* Code the OP_Affinity opcode if there is anything left to do. */ + if( n>0 ){ + sqlite3VdbeAddOp4(v, OP_Affinity, base, n, 0, zAff, n); + } +} + +/* +** Expression pRight, which is the RHS of a comparison operation, is +** either a vector of n elements or, if n==1, a scalar expression. +** Before the comparison operation, affinity zAff is to be applied +** to the pRight values. This function modifies characters within the +** affinity string to SQLITE_AFF_BLOB if either: +** +** * the comparison will be performed with no affinity, or +** * the affinity change in zAff is guaranteed not to change the value. +*/ +static void updateRangeAffinityStr( + Expr *pRight, /* RHS of comparison */ + int n, /* Number of vector elements in comparison */ + char *zAff /* Affinity string to modify */ +){ + int i; + for(i=0; i<n; i++){ + Expr *p = sqlite3VectorFieldSubexpr(pRight, i); + if( sqlite3CompareAffinity(p, zAff[i])==SQLITE_AFF_BLOB + || sqlite3ExprNeedsNoAffinityChange(p, zAff[i]) + ){ + zAff[i] = SQLITE_AFF_BLOB; + } + } +} + + +/* +** pX is an expression of the form: (vector) IN (SELECT ...) +** In other words, it is a vector IN operator with a SELECT clause on the +** LHS. But not all terms in the vector are indexable and the terms might +** not be in the correct order for indexing. +** +** This routine makes a copy of the input pX expression and then adjusts +** the vector on the LHS with corresponding changes to the SELECT so that +** the vector contains only index terms and those terms are in the correct +** order. The modified IN expression is returned. The caller is responsible +** for deleting the returned expression. +** +** Example: +** +** CREATE TABLE t1(a,b,c,d,e,f); +** CREATE INDEX t1x1 ON t1(e,c); +** SELECT * FROM t1 WHERE (a,b,c,d,e) IN (SELECT v,w,x,y,z FROM t2) +** \_______________________________________/ +** The pX expression +** +** Since only columns e and c can be used with the index, in that order, +** the modified IN expression that is returned will be: +** +** (e,c) IN (SELECT z,x FROM t2) +** +** The reduced pX is different from the original (obviously) and thus is +** only used for indexing, to improve performance. The original unaltered +** IN expression must also be run on each output row for correctness. +*/ +static Expr *removeUnindexableInClauseTerms( + Parse *pParse, /* The parsing context */ + int iEq, /* Look at loop terms starting here */ + WhereLoop *pLoop, /* The current loop */ + Expr *pX /* The IN expression to be reduced */ +){ + sqlite3 *db = pParse->db; + Expr *pNew; + pNew = sqlite3ExprDup(db, pX, 0); + if( db->mallocFailed==0 ){ + ExprList *pOrigRhs; /* Original unmodified RHS */ + ExprList *pOrigLhs; /* Original unmodified LHS */ + ExprList *pRhs = 0; /* New RHS after modifications */ + ExprList *pLhs = 0; /* New LHS after mods */ + int i; /* Loop counter */ + Select *pSelect; /* Pointer to the SELECT on the RHS */ + + assert( ExprUseXSelect(pNew) ); + pOrigRhs = pNew->x.pSelect->pEList; + assert( pNew->pLeft!=0 ); + assert( ExprUseXList(pNew->pLeft) ); + pOrigLhs = pNew->pLeft->x.pList; + for(i=iEq; i<pLoop->nLTerm; i++){ + if( pLoop->aLTerm[i]->pExpr==pX ){ + int iField; + assert( (pLoop->aLTerm[i]->eOperator & (WO_OR|WO_AND))==0 ); + iField = pLoop->aLTerm[i]->u.x.iField - 1; + if( pOrigRhs->a[iField].pExpr==0 ) continue; /* Duplicate PK column */ + pRhs = sqlite3ExprListAppend(pParse, pRhs, pOrigRhs->a[iField].pExpr); + pOrigRhs->a[iField].pExpr = 0; + assert( pOrigLhs->a[iField].pExpr!=0 ); + pLhs = sqlite3ExprListAppend(pParse, pLhs, pOrigLhs->a[iField].pExpr); + pOrigLhs->a[iField].pExpr = 0; + } + } + sqlite3ExprListDelete(db, pOrigRhs); + sqlite3ExprListDelete(db, pOrigLhs); + pNew->pLeft->x.pList = pLhs; + pNew->x.pSelect->pEList = pRhs; + if( pLhs && pLhs->nExpr==1 ){ + /* Take care here not to generate a TK_VECTOR containing only a + ** single value. Since the parser never creates such a vector, some + ** of the subroutines do not handle this case. */ + Expr *p = pLhs->a[0].pExpr; + pLhs->a[0].pExpr = 0; + sqlite3ExprDelete(db, pNew->pLeft); + pNew->pLeft = p; + } + pSelect = pNew->x.pSelect; + if( pSelect->pOrderBy ){ + /* If the SELECT statement has an ORDER BY clause, zero the + ** iOrderByCol variables. These are set to non-zero when an + ** ORDER BY term exactly matches one of the terms of the + ** result-set. Since the result-set of the SELECT statement may + ** have been modified or reordered, these variables are no longer + ** set correctly. Since setting them is just an optimization, + ** it's easiest just to zero them here. */ + ExprList *pOrderBy = pSelect->pOrderBy; + for(i=0; i<pOrderBy->nExpr; i++){ + pOrderBy->a[i].u.x.iOrderByCol = 0; + } + } + +#if 0 + printf("For indexing, change the IN expr:\n"); + sqlite3TreeViewExpr(0, pX, 0); + printf("Into:\n"); + sqlite3TreeViewExpr(0, pNew, 0); +#endif + } + return pNew; +} + + +/* +** Generate code for a single equality term of the WHERE clause. An equality +** term can be either X=expr or X IN (...). pTerm is the term to be +** coded. +** +** The current value for the constraint is left in a register, the index +** of which is returned. An attempt is made store the result in iTarget but +** this is only guaranteed for TK_ISNULL and TK_IN constraints. If the +** constraint is a TK_EQ or TK_IS, then the current value might be left in +** some other register and it is the caller's responsibility to compensate. +** +** For a constraint of the form X=expr, the expression is evaluated in +** straight-line code. For constraints of the form X IN (...) +** this routine sets up a loop that will iterate over all values of X. +*/ +static int codeEqualityTerm( + Parse *pParse, /* The parsing context */ + WhereTerm *pTerm, /* The term of the WHERE clause to be coded */ + WhereLevel *pLevel, /* The level of the FROM clause we are working on */ + int iEq, /* Index of the equality term within this level */ + int bRev, /* True for reverse-order IN operations */ + int iTarget /* Attempt to leave results in this register */ +){ + Expr *pX = pTerm->pExpr; + Vdbe *v = pParse->pVdbe; + int iReg; /* Register holding results */ + + assert( pLevel->pWLoop->aLTerm[iEq]==pTerm ); + assert( iTarget>0 ); + if( pX->op==TK_EQ || pX->op==TK_IS ){ + iReg = sqlite3ExprCodeTarget(pParse, pX->pRight, iTarget); + }else if( pX->op==TK_ISNULL ){ + iReg = iTarget; + sqlite3VdbeAddOp2(v, OP_Null, 0, iReg); +#ifndef SQLITE_OMIT_SUBQUERY + }else{ + int eType = IN_INDEX_NOOP; + int iTab; + struct InLoop *pIn; + WhereLoop *pLoop = pLevel->pWLoop; + int i; + int nEq = 0; + int *aiMap = 0; + + if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 + && pLoop->u.btree.pIndex!=0 + && pLoop->u.btree.pIndex->aSortOrder[iEq] + ){ + testcase( iEq==0 ); + testcase( bRev ); + bRev = !bRev; + } + assert( pX->op==TK_IN ); + iReg = iTarget; + + for(i=0; i<iEq; i++){ + if( pLoop->aLTerm[i] && pLoop->aLTerm[i]->pExpr==pX ){ + disableTerm(pLevel, pTerm); + return iTarget; + } + } + for(i=iEq;i<pLoop->nLTerm; i++){ + assert( pLoop->aLTerm[i]!=0 ); + if( pLoop->aLTerm[i]->pExpr==pX ) nEq++; + } + + iTab = 0; + if( !ExprUseXSelect(pX) || pX->x.pSelect->pEList->nExpr==1 ){ + eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, 0, &iTab); + }else{ + Expr *pExpr = pTerm->pExpr; + if( pExpr->iTable==0 || !ExprHasProperty(pExpr, EP_Subrtn) ){ + sqlite3 *db = pParse->db; + pX = removeUnindexableInClauseTerms(pParse, iEq, pLoop, pX); + if( !db->mallocFailed ){ + aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*nEq); + eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap,&iTab); + pExpr->iTable = iTab; + } + sqlite3ExprDelete(db, pX); + }else{ + int n = sqlite3ExprVectorSize(pX->pLeft); + aiMap = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*MAX(nEq,n)); + eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0, aiMap, &iTab); + } + pX = pExpr; + } + + if( eType==IN_INDEX_INDEX_DESC ){ + testcase( bRev ); + bRev = !bRev; + } + sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iTab, 0); + VdbeCoverageIf(v, bRev); + VdbeCoverageIf(v, !bRev); + + assert( (pLoop->wsFlags & WHERE_MULTI_OR)==0 ); + pLoop->wsFlags |= WHERE_IN_ABLE; + if( pLevel->u.in.nIn==0 ){ + pLevel->addrNxt = sqlite3VdbeMakeLabel(pParse); + } + if( iEq>0 && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0 ){ + pLoop->wsFlags |= WHERE_IN_EARLYOUT; + } + + i = pLevel->u.in.nIn; + pLevel->u.in.nIn += nEq; + pLevel->u.in.aInLoop = + sqlite3WhereRealloc(pTerm->pWC->pWInfo, + pLevel->u.in.aInLoop, + sizeof(pLevel->u.in.aInLoop[0])*pLevel->u.in.nIn); + pIn = pLevel->u.in.aInLoop; + if( pIn ){ + int iMap = 0; /* Index in aiMap[] */ + pIn += i; + for(i=iEq;i<pLoop->nLTerm; i++){ + if( pLoop->aLTerm[i]->pExpr==pX ){ + int iOut = iReg + i - iEq; + if( eType==IN_INDEX_ROWID ){ + pIn->addrInTop = sqlite3VdbeAddOp2(v, OP_Rowid, iTab, iOut); + }else{ + int iCol = aiMap ? aiMap[iMap++] : 0; + pIn->addrInTop = sqlite3VdbeAddOp3(v,OP_Column,iTab, iCol, iOut); + } + sqlite3VdbeAddOp1(v, OP_IsNull, iOut); VdbeCoverage(v); + if( i==iEq ){ + pIn->iCur = iTab; + pIn->eEndLoopOp = bRev ? OP_Prev : OP_Next; + if( iEq>0 ){ + pIn->iBase = iReg - i; + pIn->nPrefix = i; + }else{ + pIn->nPrefix = 0; + } + }else{ + pIn->eEndLoopOp = OP_Noop; + } + pIn++; + } + } + testcase( iEq>0 + && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)==0 + && (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ); + if( iEq>0 + && (pLoop->wsFlags & (WHERE_IN_SEEKSCAN|WHERE_VIRTUALTABLE))==0 + ){ + sqlite3VdbeAddOp3(v, OP_SeekHit, pLevel->iIdxCur, 0, iEq); + } + }else{ + pLevel->u.in.nIn = 0; + } + sqlite3DbFree(pParse->db, aiMap); +#endif + } + + /* As an optimization, try to disable the WHERE clause term that is + ** driving the index as it will always be true. The correct answer is + ** obtained regardless, but we might get the answer with fewer CPU cycles + ** by omitting the term. + ** + ** But do not disable the term unless we are certain that the term is + ** not a transitive constraint. For an example of where that does not + ** work, see https://sqlite.org/forum/forumpost/eb8613976a (2021-05-04) + */ + if( (pLevel->pWLoop->wsFlags & WHERE_TRANSCONS)==0 + || (pTerm->eOperator & WO_EQUIV)==0 + ){ + disableTerm(pLevel, pTerm); + } + + return iReg; +} + +/* +** Generate code that will evaluate all == and IN constraints for an +** index scan. +** +** For example, consider table t1(a,b,c,d,e,f) with index i1(a,b,c). +** Suppose the WHERE clause is this: a==5 AND b IN (1,2,3) AND c>5 AND c<10 +** The index has as many as three equality constraints, but in this +** example, the third "c" value is an inequality. So only two +** constraints are coded. This routine will generate code to evaluate +** a==5 and b IN (1,2,3). The current values for a and b will be stored +** in consecutive registers and the index of the first register is returned. +** +** In the example above nEq==2. But this subroutine works for any value +** of nEq including 0. If nEq==0, this routine is nearly a no-op. +** The only thing it does is allocate the pLevel->iMem memory cell and +** compute the affinity string. +** +** The nExtraReg parameter is 0 or 1. It is 0 if all WHERE clause constraints +** are == or IN and are covered by the nEq. nExtraReg is 1 if there is +** an inequality constraint (such as the "c>=5 AND c<10" in the example) that +** occurs after the nEq quality constraints. +** +** This routine allocates a range of nEq+nExtraReg memory cells and returns +** the index of the first memory cell in that range. The code that +** calls this routine will use that memory range to store keys for +** start and termination conditions of the loop. +** key value of the loop. If one or more IN operators appear, then +** this routine allocates an additional nEq memory cells for internal +** use. +** +** Before returning, *pzAff is set to point to a buffer containing a +** copy of the column affinity string of the index allocated using +** sqlite3DbMalloc(). Except, entries in the copy of the string associated +** with equality constraints that use BLOB or NONE affinity are set to +** SQLITE_AFF_BLOB. This is to deal with SQL such as the following: +** +** CREATE TABLE t1(a TEXT PRIMARY KEY, b); +** SELECT ... FROM t1 AS t2, t1 WHERE t1.a = t2.b; +** +** In the example above, the index on t1(a) has TEXT affinity. But since +** the right hand side of the equality constraint (t2.b) has BLOB/NONE affinity, +** no conversion should be attempted before using a t2.b value as part of +** a key to search the index. Hence the first byte in the returned affinity +** string in this example would be set to SQLITE_AFF_BLOB. +*/ +static int codeAllEqualityTerms( + Parse *pParse, /* Parsing context */ + WhereLevel *pLevel, /* Which nested loop of the FROM we are coding */ + int bRev, /* Reverse the order of IN operators */ + int nExtraReg, /* Number of extra registers to allocate */ + char **pzAff /* OUT: Set to point to affinity string */ +){ + u16 nEq; /* The number of == or IN constraints to code */ + u16 nSkip; /* Number of left-most columns to skip */ + Vdbe *v = pParse->pVdbe; /* The vm under construction */ + Index *pIdx; /* The index being used for this loop */ + WhereTerm *pTerm; /* A single constraint term */ + WhereLoop *pLoop; /* The WhereLoop object */ + int j; /* Loop counter */ + int regBase; /* Base register */ + int nReg; /* Number of registers to allocate */ + char *zAff; /* Affinity string to return */ + + /* This module is only called on query plans that use an index. */ + pLoop = pLevel->pWLoop; + assert( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 ); + nEq = pLoop->u.btree.nEq; + nSkip = pLoop->nSkip; + pIdx = pLoop->u.btree.pIndex; + assert( pIdx!=0 ); + + /* Figure out how many memory cells we will need then allocate them. + */ + regBase = pParse->nMem + 1; + nReg = pLoop->u.btree.nEq + nExtraReg; + pParse->nMem += nReg; + + zAff = sqlite3DbStrDup(pParse->db,sqlite3IndexAffinityStr(pParse->db,pIdx)); + assert( zAff!=0 || pParse->db->mallocFailed ); + + if( nSkip ){ + int iIdxCur = pLevel->iIdxCur; + sqlite3VdbeAddOp3(v, OP_Null, 0, regBase, regBase+nSkip-1); + sqlite3VdbeAddOp1(v, (bRev?OP_Last:OP_Rewind), iIdxCur); + VdbeCoverageIf(v, bRev==0); + VdbeCoverageIf(v, bRev!=0); + VdbeComment((v, "begin skip-scan on %s", pIdx->zName)); + j = sqlite3VdbeAddOp0(v, OP_Goto); + assert( pLevel->addrSkip==0 ); + pLevel->addrSkip = sqlite3VdbeAddOp4Int(v, (bRev?OP_SeekLT:OP_SeekGT), + iIdxCur, 0, regBase, nSkip); + VdbeCoverageIf(v, bRev==0); + VdbeCoverageIf(v, bRev!=0); + sqlite3VdbeJumpHere(v, j); + for(j=0; j<nSkip; j++){ + sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, j, regBase+j); + testcase( pIdx->aiColumn[j]==XN_EXPR ); + VdbeComment((v, "%s", explainIndexColumnName(pIdx, j))); + } + } + + /* Evaluate the equality constraints + */ + assert( zAff==0 || (int)strlen(zAff)>=nEq ); + for(j=nSkip; j<nEq; j++){ + int r1; + pTerm = pLoop->aLTerm[j]; + assert( pTerm!=0 ); + /* The following testcase is true for indices with redundant columns. + ** Ex: CREATE INDEX i1 ON t1(a,b,a); SELECT * FROM t1 WHERE a=0 AND b=0; */ + testcase( (pTerm->wtFlags & TERM_CODED)!=0 ); + testcase( pTerm->wtFlags & TERM_VIRTUAL ); + r1 = codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, regBase+j); + if( r1!=regBase+j ){ + if( nReg==1 ){ + sqlite3ReleaseTempReg(pParse, regBase); + regBase = r1; + }else{ + sqlite3VdbeAddOp2(v, OP_Copy, r1, regBase+j); + } + } + } + for(j=nSkip; j<nEq; j++){ + pTerm = pLoop->aLTerm[j]; + if( pTerm->eOperator & WO_IN ){ + if( pTerm->pExpr->flags & EP_xIsSelect ){ + /* No affinity ever needs to be (or should be) applied to a value + ** from the RHS of an "? IN (SELECT ...)" expression. The + ** sqlite3FindInIndex() routine has already ensured that the + ** affinity of the comparison has been applied to the value. */ + if( zAff ) zAff[j] = SQLITE_AFF_BLOB; + } + }else if( (pTerm->eOperator & WO_ISNULL)==0 ){ + Expr *pRight = pTerm->pExpr->pRight; + if( (pTerm->wtFlags & TERM_IS)==0 && sqlite3ExprCanBeNull(pRight) ){ + sqlite3VdbeAddOp2(v, OP_IsNull, regBase+j, pLevel->addrBrk); + VdbeCoverage(v); + } + if( pParse->nErr==0 ){ + assert( pParse->db->mallocFailed==0 ); + if( sqlite3CompareAffinity(pRight, zAff[j])==SQLITE_AFF_BLOB ){ + zAff[j] = SQLITE_AFF_BLOB; + } + if( sqlite3ExprNeedsNoAffinityChange(pRight, zAff[j]) ){ + zAff[j] = SQLITE_AFF_BLOB; + } + } + } + } + *pzAff = zAff; + return regBase; +} + +#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS +/* +** If the most recently coded instruction is a constant range constraint +** (a string literal) that originated from the LIKE optimization, then +** set P3 and P5 on the OP_String opcode so that the string will be cast +** to a BLOB at appropriate times. +** +** The LIKE optimization trys to evaluate "x LIKE 'abc%'" as a range +** expression: "x>='ABC' AND x<'abd'". But this requires that the range +** scan loop run twice, once for strings and a second time for BLOBs. +** The OP_String opcodes on the second pass convert the upper and lower +** bound string constants to blobs. This routine makes the necessary changes +** to the OP_String opcodes for that to happen. +** +** Except, of course, if SQLITE_LIKE_DOESNT_MATCH_BLOBS is defined, then +** only the one pass through the string space is required, so this routine +** becomes a no-op. +*/ +static void whereLikeOptimizationStringFixup( + Vdbe *v, /* prepared statement under construction */ + WhereLevel *pLevel, /* The loop that contains the LIKE operator */ + WhereTerm *pTerm /* The upper or lower bound just coded */ +){ + if( pTerm->wtFlags & TERM_LIKEOPT ){ + VdbeOp *pOp; + assert( pLevel->iLikeRepCntr>0 ); + pOp = sqlite3VdbeGetLastOp(v); + assert( pOp!=0 ); + assert( pOp->opcode==OP_String8 + || pTerm->pWC->pWInfo->pParse->db->mallocFailed ); + pOp->p3 = (int)(pLevel->iLikeRepCntr>>1); /* Register holding counter */ + pOp->p5 = (u8)(pLevel->iLikeRepCntr&1); /* ASC or DESC */ + } +} +#else +# define whereLikeOptimizationStringFixup(A,B,C) +#endif + +#ifdef SQLITE_ENABLE_CURSOR_HINTS +/* +** Information is passed from codeCursorHint() down to individual nodes of +** the expression tree (by sqlite3WalkExpr()) using an instance of this +** structure. +*/ +struct CCurHint { + int iTabCur; /* Cursor for the main table */ + int iIdxCur; /* Cursor for the index, if pIdx!=0. Unused otherwise */ + Index *pIdx; /* The index used to access the table */ +}; + +/* +** This function is called for every node of an expression that is a candidate +** for a cursor hint on an index cursor. For TK_COLUMN nodes that reference +** the table CCurHint.iTabCur, verify that the same column can be +** accessed through the index. If it cannot, then set pWalker->eCode to 1. +*/ +static int codeCursorHintCheckExpr(Walker *pWalker, Expr *pExpr){ + struct CCurHint *pHint = pWalker->u.pCCurHint; + assert( pHint->pIdx!=0 ); + if( pExpr->op==TK_COLUMN + && pExpr->iTable==pHint->iTabCur + && sqlite3TableColumnToIndex(pHint->pIdx, pExpr->iColumn)<0 + ){ + pWalker->eCode = 1; + } + return WRC_Continue; +} + +/* +** Test whether or not expression pExpr, which was part of a WHERE clause, +** should be included in the cursor-hint for a table that is on the rhs +** of a LEFT JOIN. Set Walker.eCode to non-zero before returning if the +** expression is not suitable. +** +** An expression is unsuitable if it might evaluate to non NULL even if +** a TK_COLUMN node that does affect the value of the expression is set +** to NULL. For example: +** +** col IS NULL +** col IS NOT NULL +** coalesce(col, 1) +** CASE WHEN col THEN 0 ELSE 1 END +*/ +static int codeCursorHintIsOrFunction(Walker *pWalker, Expr *pExpr){ + if( pExpr->op==TK_IS + || pExpr->op==TK_ISNULL || pExpr->op==TK_ISNOT + || pExpr->op==TK_NOTNULL || pExpr->op==TK_CASE + ){ + pWalker->eCode = 1; + }else if( pExpr->op==TK_FUNCTION ){ + int d1; + char d2[4]; + if( 0==sqlite3IsLikeFunction(pWalker->pParse->db, pExpr, &d1, d2) ){ + pWalker->eCode = 1; + } + } + + return WRC_Continue; +} + + +/* +** This function is called on every node of an expression tree used as an +** argument to the OP_CursorHint instruction. If the node is a TK_COLUMN +** that accesses any table other than the one identified by +** CCurHint.iTabCur, then do the following: +** +** 1) allocate a register and code an OP_Column instruction to read +** the specified column into the new register, and +** +** 2) transform the expression node to a TK_REGISTER node that reads +** from the newly populated register. +** +** Also, if the node is a TK_COLUMN that does access the table idenified +** by pCCurHint.iTabCur, and an index is being used (which we will +** know because CCurHint.pIdx!=0) then transform the TK_COLUMN into +** an access of the index rather than the original table. +*/ +static int codeCursorHintFixExpr(Walker *pWalker, Expr *pExpr){ + int rc = WRC_Continue; + struct CCurHint *pHint = pWalker->u.pCCurHint; + if( pExpr->op==TK_COLUMN ){ + if( pExpr->iTable!=pHint->iTabCur ){ + int reg = ++pWalker->pParse->nMem; /* Register for column value */ + sqlite3ExprCode(pWalker->pParse, pExpr, reg); + pExpr->op = TK_REGISTER; + pExpr->iTable = reg; + }else if( pHint->pIdx!=0 ){ + pExpr->iTable = pHint->iIdxCur; + pExpr->iColumn = sqlite3TableColumnToIndex(pHint->pIdx, pExpr->iColumn); + assert( pExpr->iColumn>=0 ); + } + }else if( pExpr->op==TK_AGG_FUNCTION ){ + /* An aggregate function in the WHERE clause of a query means this must + ** be a correlated sub-query, and expression pExpr is an aggregate from + ** the parent context. Do not walk the function arguments in this case. + ** + ** todo: It should be possible to replace this node with a TK_REGISTER + ** expression, as the result of the expression must be stored in a + ** register at this point. The same holds for TK_AGG_COLUMN nodes. */ + rc = WRC_Prune; + } + return rc; +} + +/* +** Insert an OP_CursorHint instruction if it is appropriate to do so. +*/ +static void codeCursorHint( + SrcItem *pTabItem, /* FROM clause item */ + WhereInfo *pWInfo, /* The where clause */ + WhereLevel *pLevel, /* Which loop to provide hints for */ + WhereTerm *pEndRange /* Hint this end-of-scan boundary term if not NULL */ +){ + Parse *pParse = pWInfo->pParse; + sqlite3 *db = pParse->db; + Vdbe *v = pParse->pVdbe; + Expr *pExpr = 0; + WhereLoop *pLoop = pLevel->pWLoop; + int iCur; + WhereClause *pWC; + WhereTerm *pTerm; + int i, j; + struct CCurHint sHint; + Walker sWalker; + + if( OptimizationDisabled(db, SQLITE_CursorHints) ) return; + iCur = pLevel->iTabCur; + assert( iCur==pWInfo->pTabList->a[pLevel->iFrom].iCursor ); + sHint.iTabCur = iCur; + sHint.iIdxCur = pLevel->iIdxCur; + sHint.pIdx = pLoop->u.btree.pIndex; + memset(&sWalker, 0, sizeof(sWalker)); + sWalker.pParse = pParse; + sWalker.u.pCCurHint = &sHint; + pWC = &pWInfo->sWC; + for(i=0; i<pWC->nBase; i++){ + pTerm = &pWC->a[i]; + if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue; + if( pTerm->prereqAll & pLevel->notReady ) continue; + + /* Any terms specified as part of the ON(...) clause for any LEFT + ** JOIN for which the current table is not the rhs are omitted + ** from the cursor-hint. + ** + ** If this table is the rhs of a LEFT JOIN, "IS" or "IS NULL" terms + ** that were specified as part of the WHERE clause must be excluded. + ** This is to address the following: + ** + ** SELECT ... t1 LEFT JOIN t2 ON (t1.a=t2.b) WHERE t2.c IS NULL; + ** + ** Say there is a single row in t2 that matches (t1.a=t2.b), but its + ** t2.c values is not NULL. If the (t2.c IS NULL) constraint is + ** pushed down to the cursor, this row is filtered out, causing + ** SQLite to synthesize a row of NULL values. Which does match the + ** WHERE clause, and so the query returns a row. Which is incorrect. + ** + ** For the same reason, WHERE terms such as: + ** + ** WHERE 1 = (t2.c IS NULL) + ** + ** are also excluded. See codeCursorHintIsOrFunction() for details. + */ + if( pTabItem->fg.jointype & JT_LEFT ){ + Expr *pExpr = pTerm->pExpr; + if( !ExprHasProperty(pExpr, EP_OuterON) + || pExpr->w.iJoin!=pTabItem->iCursor + ){ + sWalker.eCode = 0; + sWalker.xExprCallback = codeCursorHintIsOrFunction; + sqlite3WalkExpr(&sWalker, pTerm->pExpr); + if( sWalker.eCode ) continue; + } + }else{ + if( ExprHasProperty(pTerm->pExpr, EP_OuterON) ) continue; + } + + /* All terms in pWLoop->aLTerm[] except pEndRange are used to initialize + ** the cursor. These terms are not needed as hints for a pure range + ** scan (that has no == terms) so omit them. */ + if( pLoop->u.btree.nEq==0 && pTerm!=pEndRange ){ + for(j=0; j<pLoop->nLTerm && pLoop->aLTerm[j]!=pTerm; j++){} + if( j<pLoop->nLTerm ) continue; + } + + /* No subqueries or non-deterministic functions allowed */ + if( sqlite3ExprContainsSubquery(pTerm->pExpr) ) continue; + + /* For an index scan, make sure referenced columns are actually in + ** the index. */ + if( sHint.pIdx!=0 ){ + sWalker.eCode = 0; + sWalker.xExprCallback = codeCursorHintCheckExpr; + sqlite3WalkExpr(&sWalker, pTerm->pExpr); + if( sWalker.eCode ) continue; + } + + /* If we survive all prior tests, that means this term is worth hinting */ + pExpr = sqlite3ExprAnd(pParse, pExpr, sqlite3ExprDup(db, pTerm->pExpr, 0)); + } + if( pExpr!=0 ){ + sWalker.xExprCallback = codeCursorHintFixExpr; + sqlite3WalkExpr(&sWalker, pExpr); + sqlite3VdbeAddOp4(v, OP_CursorHint, + (sHint.pIdx ? sHint.iIdxCur : sHint.iTabCur), 0, 0, + (const char*)pExpr, P4_EXPR); + } +} +#else +# define codeCursorHint(A,B,C,D) /* No-op */ +#endif /* SQLITE_ENABLE_CURSOR_HINTS */ + +/* +** Cursor iCur is open on an intkey b-tree (a table). Register iRowid contains +** a rowid value just read from cursor iIdxCur, open on index pIdx. This +** function generates code to do a deferred seek of cursor iCur to the +** rowid stored in register iRowid. +** +** Normally, this is just: +** +** OP_DeferredSeek $iCur $iRowid +** +** Which causes a seek on $iCur to the row with rowid $iRowid. +** +** However, if the scan currently being coded is a branch of an OR-loop and +** the statement currently being coded is a SELECT, then additional information +** is added that might allow OP_Column to omit the seek and instead do its +** lookup on the index, thus avoiding an expensive seek operation. To +** enable this optimization, the P3 of OP_DeferredSeek is set to iIdxCur +** and P4 is set to an array of integers containing one entry for each column +** in the table. For each table column, if the column is the i'th +** column of the index, then the corresponding array entry is set to (i+1). +** If the column does not appear in the index at all, the array entry is set +** to 0. The OP_Column opcode can check this array to see if the column it +** wants is in the index and if it is, it will substitute the index cursor +** and column number and continue with those new values, rather than seeking +** the table cursor. +*/ +static void codeDeferredSeek( + WhereInfo *pWInfo, /* Where clause context */ + Index *pIdx, /* Index scan is using */ + int iCur, /* Cursor for IPK b-tree */ + int iIdxCur /* Index cursor */ +){ + Parse *pParse = pWInfo->pParse; /* Parse context */ + Vdbe *v = pParse->pVdbe; /* Vdbe to generate code within */ + + assert( iIdxCur>0 ); + assert( pIdx->aiColumn[pIdx->nColumn-1]==-1 ); + + pWInfo->bDeferredSeek = 1; + sqlite3VdbeAddOp3(v, OP_DeferredSeek, iIdxCur, 0, iCur); + if( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN)) + && DbMaskAllZero(sqlite3ParseToplevel(pParse)->writeMask) + ){ + int i; + Table *pTab = pIdx->pTable; + u32 *ai = (u32*)sqlite3DbMallocZero(pParse->db, sizeof(u32)*(pTab->nCol+1)); + if( ai ){ + ai[0] = pTab->nCol; + for(i=0; i<pIdx->nColumn-1; i++){ + int x1, x2; + assert( pIdx->aiColumn[i]<pTab->nCol ); + x1 = pIdx->aiColumn[i]; + x2 = sqlite3TableColumnToStorage(pTab, x1); + testcase( x1!=x2 ); + if( x1>=0 ) ai[x2+1] = i+1; + } + sqlite3VdbeChangeP4(v, -1, (char*)ai, P4_INTARRAY); + } + } +} + +/* +** If the expression passed as the second argument is a vector, generate +** code to write the first nReg elements of the vector into an array +** of registers starting with iReg. +** +** If the expression is not a vector, then nReg must be passed 1. In +** this case, generate code to evaluate the expression and leave the +** result in register iReg. +*/ +static void codeExprOrVector(Parse *pParse, Expr *p, int iReg, int nReg){ + assert( nReg>0 ); + if( p && sqlite3ExprIsVector(p) ){ +#ifndef SQLITE_OMIT_SUBQUERY + if( ExprUseXSelect(p) ){ + Vdbe *v = pParse->pVdbe; + int iSelect; + assert( p->op==TK_SELECT ); + iSelect = sqlite3CodeSubselect(pParse, p); + sqlite3VdbeAddOp3(v, OP_Copy, iSelect, iReg, nReg-1); + }else +#endif + { + int i; + const ExprList *pList; + assert( ExprUseXList(p) ); + pList = p->x.pList; + assert( nReg<=pList->nExpr ); + for(i=0; i<nReg; i++){ + sqlite3ExprCode(pParse, pList->a[i].pExpr, iReg+i); + } + } + }else{ + assert( nReg==1 || pParse->nErr ); + sqlite3ExprCode(pParse, p, iReg); + } +} + +/* +** The pTruth expression is always true because it is the WHERE clause +** a partial index that is driving a query loop. Look through all of the +** WHERE clause terms on the query, and if any of those terms must be +** true because pTruth is true, then mark those WHERE clause terms as +** coded. +*/ +static void whereApplyPartialIndexConstraints( + Expr *pTruth, + int iTabCur, + WhereClause *pWC +){ + int i; + WhereTerm *pTerm; + while( pTruth->op==TK_AND ){ + whereApplyPartialIndexConstraints(pTruth->pLeft, iTabCur, pWC); + pTruth = pTruth->pRight; + } + for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){ + Expr *pExpr; + if( pTerm->wtFlags & TERM_CODED ) continue; + pExpr = pTerm->pExpr; + if( sqlite3ExprCompare(0, pExpr, pTruth, iTabCur)==0 ){ + pTerm->wtFlags |= TERM_CODED; + } + } +} + +/* +** This routine is called right after An OP_Filter has been generated and +** before the corresponding index search has been performed. This routine +** checks to see if there are additional Bloom filters in inner loops that +** can be checked prior to doing the index lookup. If there are available +** inner-loop Bloom filters, then evaluate those filters now, before the +** index lookup. The idea is that a Bloom filter check is way faster than +** an index lookup, and the Bloom filter might return false, meaning that +** the index lookup can be skipped. +** +** We know that an inner loop uses a Bloom filter because it has the +** WhereLevel.regFilter set. If an inner-loop Bloom filter is checked, +** then clear the WhereLevel.regFilter value to prevent the Bloom filter +** from being checked a second time when the inner loop is evaluated. +*/ +static SQLITE_NOINLINE void filterPullDown( + Parse *pParse, /* Parsing context */ + WhereInfo *pWInfo, /* Complete information about the WHERE clause */ + int iLevel, /* Which level of pWInfo->a[] should be coded */ + int addrNxt, /* Jump here to bypass inner loops */ + Bitmask notReady /* Loops that are not ready */ +){ + while( ++iLevel < pWInfo->nLevel ){ + WhereLevel *pLevel = &pWInfo->a[iLevel]; + WhereLoop *pLoop = pLevel->pWLoop; + if( pLevel->regFilter==0 ) continue; + if( pLevel->pWLoop->nSkip ) continue; + /* ,--- Because sqlite3ConstructBloomFilter() has will not have set + ** vvvvv--' pLevel->regFilter if this were true. */ + if( NEVER(pLoop->prereq & notReady) ) continue; + assert( pLevel->addrBrk==0 ); + pLevel->addrBrk = addrNxt; + if( pLoop->wsFlags & WHERE_IPK ){ + WhereTerm *pTerm = pLoop->aLTerm[0]; + int regRowid; + assert( pTerm!=0 ); + assert( pTerm->pExpr!=0 ); + testcase( pTerm->wtFlags & TERM_VIRTUAL ); + regRowid = sqlite3GetTempReg(pParse); + regRowid = codeEqualityTerm(pParse, pTerm, pLevel, 0, 0, regRowid); + sqlite3VdbeAddOp2(pParse->pVdbe, OP_MustBeInt, regRowid, addrNxt); + VdbeCoverage(pParse->pVdbe); + sqlite3VdbeAddOp4Int(pParse->pVdbe, OP_Filter, pLevel->regFilter, + addrNxt, regRowid, 1); + VdbeCoverage(pParse->pVdbe); + }else{ + u16 nEq = pLoop->u.btree.nEq; + int r1; + char *zStartAff; + + assert( pLoop->wsFlags & WHERE_INDEXED ); + assert( (pLoop->wsFlags & WHERE_COLUMN_IN)==0 ); + r1 = codeAllEqualityTerms(pParse,pLevel,0,0,&zStartAff); + codeApplyAffinity(pParse, r1, nEq, zStartAff); + sqlite3DbFree(pParse->db, zStartAff); + sqlite3VdbeAddOp4Int(pParse->pVdbe, OP_Filter, pLevel->regFilter, + addrNxt, r1, nEq); + VdbeCoverage(pParse->pVdbe); + } + pLevel->regFilter = 0; + pLevel->addrBrk = 0; + } +} + +/* +** Generate code for the start of the iLevel-th loop in the WHERE clause +** implementation described by pWInfo. +*/ +Bitmask sqlite3WhereCodeOneLoopStart( + Parse *pParse, /* Parsing context */ + Vdbe *v, /* Prepared statement under construction */ + WhereInfo *pWInfo, /* Complete information about the WHERE clause */ + int iLevel, /* Which level of pWInfo->a[] should be coded */ + WhereLevel *pLevel, /* The current level pointer */ + Bitmask notReady /* Which tables are currently available */ +){ + int j, k; /* Loop counters */ + int iCur; /* The VDBE cursor for the table */ + int addrNxt; /* Where to jump to continue with the next IN case */ + int bRev; /* True if we need to scan in reverse order */ + WhereLoop *pLoop; /* The WhereLoop object being coded */ + WhereClause *pWC; /* Decomposition of the entire WHERE clause */ + WhereTerm *pTerm; /* A WHERE clause term */ + sqlite3 *db; /* Database connection */ + SrcItem *pTabItem; /* FROM clause term being coded */ + int addrBrk; /* Jump here to break out of the loop */ + int addrHalt; /* addrBrk for the outermost loop */ + int addrCont; /* Jump here to continue with next cycle */ + int iRowidReg = 0; /* Rowid is stored in this register, if not zero */ + int iReleaseReg = 0; /* Temp register to free before returning */ + Index *pIdx = 0; /* Index used by loop (if any) */ + int iLoop; /* Iteration of constraint generator loop */ + + pWC = &pWInfo->sWC; + db = pParse->db; + pLoop = pLevel->pWLoop; + pTabItem = &pWInfo->pTabList->a[pLevel->iFrom]; + iCur = pTabItem->iCursor; + pLevel->notReady = notReady & ~sqlite3WhereGetMask(&pWInfo->sMaskSet, iCur); + bRev = (pWInfo->revMask>>iLevel)&1; + VdbeModuleComment((v, "Begin WHERE-loop%d: %s",iLevel,pTabItem->pTab->zName)); +#if WHERETRACE_ENABLED /* 0x20800 */ + if( sqlite3WhereTrace & 0x800 ){ + sqlite3DebugPrintf("Coding level %d of %d: notReady=%llx iFrom=%d\n", + iLevel, pWInfo->nLevel, (u64)notReady, pLevel->iFrom); + sqlite3WhereLoopPrint(pLoop, pWC); + } + if( sqlite3WhereTrace & 0x20000 ){ + if( iLevel==0 ){ + sqlite3DebugPrintf("WHERE clause being coded:\n"); + sqlite3TreeViewExpr(0, pWInfo->pWhere, 0); + } + sqlite3DebugPrintf("All WHERE-clause terms before coding:\n"); + sqlite3WhereClausePrint(pWC); + } +#endif + + /* Create labels for the "break" and "continue" instructions + ** for the current loop. Jump to addrBrk to break out of a loop. + ** Jump to cont to go immediately to the next iteration of the + ** loop. + ** + ** When there is an IN operator, we also have a "addrNxt" label that + ** means to continue with the next IN value combination. When + ** there are no IN operators in the constraints, the "addrNxt" label + ** is the same as "addrBrk". + */ + addrBrk = pLevel->addrBrk = pLevel->addrNxt = sqlite3VdbeMakeLabel(pParse); + addrCont = pLevel->addrCont = sqlite3VdbeMakeLabel(pParse); + + /* If this is the right table of a LEFT OUTER JOIN, allocate and + ** initialize a memory cell that records if this table matches any + ** row of the left table of the join. + */ + assert( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN)) + || pLevel->iFrom>0 || (pTabItem[0].fg.jointype & JT_LEFT)==0 + ); + if( pLevel->iFrom>0 && (pTabItem[0].fg.jointype & JT_LEFT)!=0 ){ + pLevel->iLeftJoin = ++pParse->nMem; + sqlite3VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin); + VdbeComment((v, "init LEFT JOIN no-match flag")); + } + + /* Compute a safe address to jump to if we discover that the table for + ** this loop is empty and can never contribute content. */ + for(j=iLevel; j>0; j--){ + if( pWInfo->a[j].iLeftJoin ) break; + if( pWInfo->a[j].pRJ ) break; + } + addrHalt = pWInfo->a[j].addrBrk; + + /* Special case of a FROM clause subquery implemented as a co-routine */ + if( pTabItem->fg.viaCoroutine ){ + int regYield = pTabItem->regReturn; + sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pTabItem->addrFillSub); + pLevel->p2 = sqlite3VdbeAddOp2(v, OP_Yield, regYield, addrBrk); + VdbeCoverage(v); + VdbeComment((v, "next row of %s", pTabItem->pTab->zName)); + pLevel->op = OP_Goto; + }else + +#ifndef SQLITE_OMIT_VIRTUALTABLE + if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){ + /* Case 1: The table is a virtual-table. Use the VFilter and VNext + ** to access the data. + */ + int iReg; /* P3 Value for OP_VFilter */ + int addrNotFound; + int nConstraint = pLoop->nLTerm; + + iReg = sqlite3GetTempRange(pParse, nConstraint+2); + addrNotFound = pLevel->addrBrk; + for(j=0; j<nConstraint; j++){ + int iTarget = iReg+j+2; + pTerm = pLoop->aLTerm[j]; + if( NEVER(pTerm==0) ) continue; + if( pTerm->eOperator & WO_IN ){ + if( SMASKBIT32(j) & pLoop->u.vtab.mHandleIn ){ + int iTab = pParse->nTab++; + int iCache = ++pParse->nMem; + sqlite3CodeRhsOfIN(pParse, pTerm->pExpr, iTab); + sqlite3VdbeAddOp3(v, OP_VInitIn, iTab, iTarget, iCache); + }else{ + codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, iTarget); + addrNotFound = pLevel->addrNxt; + } + }else{ + Expr *pRight = pTerm->pExpr->pRight; + codeExprOrVector(pParse, pRight, iTarget, 1); + if( pTerm->eMatchOp==SQLITE_INDEX_CONSTRAINT_OFFSET + && pLoop->u.vtab.bOmitOffset + ){ + assert( pTerm->eOperator==WO_AUX ); + assert( pWInfo->pSelect!=0 ); + assert( pWInfo->pSelect->iOffset>0 ); + sqlite3VdbeAddOp2(v, OP_Integer, 0, pWInfo->pSelect->iOffset); + VdbeComment((v,"Zero OFFSET counter")); + } + } + } + sqlite3VdbeAddOp2(v, OP_Integer, pLoop->u.vtab.idxNum, iReg); + sqlite3VdbeAddOp2(v, OP_Integer, nConstraint, iReg+1); + sqlite3VdbeAddOp4(v, OP_VFilter, iCur, addrNotFound, iReg, + pLoop->u.vtab.idxStr, + pLoop->u.vtab.needFree ? P4_DYNAMIC : P4_STATIC); + VdbeCoverage(v); + pLoop->u.vtab.needFree = 0; + /* An OOM inside of AddOp4(OP_VFilter) instruction above might have freed + ** the u.vtab.idxStr. NULL it out to prevent a use-after-free */ + if( db->mallocFailed ) pLoop->u.vtab.idxStr = 0; + pLevel->p1 = iCur; + pLevel->op = pWInfo->eOnePass ? OP_Noop : OP_VNext; + pLevel->p2 = sqlite3VdbeCurrentAddr(v); + assert( (pLoop->wsFlags & WHERE_MULTI_OR)==0 ); + + for(j=0; j<nConstraint; j++){ + pTerm = pLoop->aLTerm[j]; + if( j<16 && (pLoop->u.vtab.omitMask>>j)&1 ){ + disableTerm(pLevel, pTerm); + continue; + } + if( (pTerm->eOperator & WO_IN)!=0 + && (SMASKBIT32(j) & pLoop->u.vtab.mHandleIn)==0 + && !db->mallocFailed + ){ + Expr *pCompare; /* The comparison operator */ + Expr *pRight; /* RHS of the comparison */ + VdbeOp *pOp; /* Opcode to access the value of the IN constraint */ + int iIn; /* IN loop corresponding to the j-th constraint */ + + /* Reload the constraint value into reg[iReg+j+2]. The same value + ** was loaded into the same register prior to the OP_VFilter, but + ** the xFilter implementation might have changed the datatype or + ** encoding of the value in the register, so it *must* be reloaded. + */ + for(iIn=0; ALWAYS(iIn<pLevel->u.in.nIn); iIn++){ + pOp = sqlite3VdbeGetOp(v, pLevel->u.in.aInLoop[iIn].addrInTop); + if( (pOp->opcode==OP_Column && pOp->p3==iReg+j+2) + || (pOp->opcode==OP_Rowid && pOp->p2==iReg+j+2) + ){ + testcase( pOp->opcode==OP_Rowid ); + sqlite3VdbeAddOp3(v, pOp->opcode, pOp->p1, pOp->p2, pOp->p3); + break; + } + } + + /* Generate code that will continue to the next row if + ** the IN constraint is not satisfied + */ + pCompare = sqlite3PExpr(pParse, TK_EQ, 0, 0); + if( !db->mallocFailed ){ + int iFld = pTerm->u.x.iField; + Expr *pLeft = pTerm->pExpr->pLeft; + assert( pLeft!=0 ); + if( iFld>0 ){ + assert( pLeft->op==TK_VECTOR ); + assert( ExprUseXList(pLeft) ); + assert( iFld<=pLeft->x.pList->nExpr ); + pCompare->pLeft = pLeft->x.pList->a[iFld-1].pExpr; + }else{ + pCompare->pLeft = pLeft; + } + pCompare->pRight = pRight = sqlite3Expr(db, TK_REGISTER, 0); + if( pRight ){ + pRight->iTable = iReg+j+2; + sqlite3ExprIfFalse( + pParse, pCompare, pLevel->addrCont, SQLITE_JUMPIFNULL + ); + } + pCompare->pLeft = 0; + } + sqlite3ExprDelete(db, pCompare); + } + } + + /* These registers need to be preserved in case there is an IN operator + ** loop. So we could deallocate the registers here (and potentially + ** reuse them later) if (pLoop->wsFlags & WHERE_IN_ABLE)==0. But it seems + ** simpler and safer to simply not reuse the registers. + ** + ** sqlite3ReleaseTempRange(pParse, iReg, nConstraint+2); + */ + }else +#endif /* SQLITE_OMIT_VIRTUALTABLE */ + + if( (pLoop->wsFlags & WHERE_IPK)!=0 + && (pLoop->wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_EQ))!=0 + ){ + /* Case 2: 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( pLoop->u.btree.nEq==1 ); + pTerm = pLoop->aLTerm[0]; + assert( pTerm!=0 ); + assert( pTerm->pExpr!=0 ); + testcase( pTerm->wtFlags & TERM_VIRTUAL ); + iReleaseReg = ++pParse->nMem; + iRowidReg = codeEqualityTerm(pParse, pTerm, pLevel, 0, bRev, iReleaseReg); + if( iRowidReg!=iReleaseReg ) sqlite3ReleaseTempReg(pParse, iReleaseReg); + addrNxt = pLevel->addrNxt; + if( pLevel->regFilter ){ + sqlite3VdbeAddOp2(v, OP_MustBeInt, iRowidReg, addrNxt); + VdbeCoverage(v); + sqlite3VdbeAddOp4Int(v, OP_Filter, pLevel->regFilter, addrNxt, + iRowidReg, 1); + VdbeCoverage(v); + filterPullDown(pParse, pWInfo, iLevel, addrNxt, notReady); + } + sqlite3VdbeAddOp3(v, OP_SeekRowid, iCur, addrNxt, iRowidReg); + VdbeCoverage(v); + pLevel->op = OP_Noop; + }else if( (pLoop->wsFlags & WHERE_IPK)!=0 + && (pLoop->wsFlags & WHERE_COLUMN_RANGE)!=0 + ){ + /* Case 3: We have an inequality comparison against the ROWID field. + */ + int testOp = OP_Noop; + int start; + int memEndValue = 0; + WhereTerm *pStart, *pEnd; + + j = 0; + pStart = pEnd = 0; + if( pLoop->wsFlags & WHERE_BTM_LIMIT ) pStart = pLoop->aLTerm[j++]; + if( pLoop->wsFlags & WHERE_TOP_LIMIT ) pEnd = pLoop->aLTerm[j++]; + assert( pStart!=0 || pEnd!=0 ); + if( bRev ){ + pTerm = pStart; + pStart = pEnd; + pEnd = pTerm; + } + codeCursorHint(pTabItem, pWInfo, pLevel, pEnd); + if( pStart ){ + Expr *pX; /* The expression that defines the start bound */ + int r1, rTemp; /* Registers for holding the start boundary */ + int op; /* Cursor seek operation */ + + /* The following constant maps TK_xx codes into corresponding + ** seek opcodes. It depends on a particular ordering of TK_xx + */ + const u8 aMoveOp[] = { + /* TK_GT */ OP_SeekGT, + /* TK_LE */ OP_SeekLE, + /* TK_LT */ OP_SeekLT, + /* TK_GE */ OP_SeekGE + }; + assert( TK_LE==TK_GT+1 ); /* Make sure the ordering.. */ + assert( TK_LT==TK_GT+2 ); /* ... of the TK_xx values... */ + assert( TK_GE==TK_GT+3 ); /* ... is correcct. */ + + assert( (pStart->wtFlags & TERM_VNULL)==0 ); + testcase( pStart->wtFlags & TERM_VIRTUAL ); + pX = pStart->pExpr; + assert( pX!=0 ); + testcase( pStart->leftCursor!=iCur ); /* transitive constraints */ + if( sqlite3ExprIsVector(pX->pRight) ){ + r1 = rTemp = sqlite3GetTempReg(pParse); + codeExprOrVector(pParse, pX->pRight, r1, 1); + testcase( pX->op==TK_GT ); + testcase( pX->op==TK_GE ); + testcase( pX->op==TK_LT ); + testcase( pX->op==TK_LE ); + op = aMoveOp[((pX->op - TK_GT - 1) & 0x3) | 0x1]; + assert( pX->op!=TK_GT || op==OP_SeekGE ); + assert( pX->op!=TK_GE || op==OP_SeekGE ); + assert( pX->op!=TK_LT || op==OP_SeekLE ); + assert( pX->op!=TK_LE || op==OP_SeekLE ); + }else{ + r1 = sqlite3ExprCodeTemp(pParse, pX->pRight, &rTemp); + disableTerm(pLevel, pStart); + op = aMoveOp[(pX->op - TK_GT)]; + } + sqlite3VdbeAddOp3(v, op, iCur, addrBrk, r1); + VdbeComment((v, "pk")); + VdbeCoverageIf(v, pX->op==TK_GT); + VdbeCoverageIf(v, pX->op==TK_LE); + VdbeCoverageIf(v, pX->op==TK_LT); + VdbeCoverageIf(v, pX->op==TK_GE); + sqlite3ReleaseTempReg(pParse, rTemp); + }else{ + sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, addrHalt); + VdbeCoverageIf(v, bRev==0); + VdbeCoverageIf(v, bRev!=0); + } + if( pEnd ){ + Expr *pX; + pX = pEnd->pExpr; + assert( pX!=0 ); + assert( (pEnd->wtFlags & TERM_VNULL)==0 ); + testcase( pEnd->leftCursor!=iCur ); /* Transitive constraints */ + testcase( pEnd->wtFlags & TERM_VIRTUAL ); + memEndValue = ++pParse->nMem; + codeExprOrVector(pParse, pX->pRight, memEndValue, 1); + if( 0==sqlite3ExprIsVector(pX->pRight) + && (pX->op==TK_LT || pX->op==TK_GT) + ){ + testOp = bRev ? OP_Le : OP_Ge; + }else{ + testOp = bRev ? OP_Lt : OP_Gt; + } + if( 0==sqlite3ExprIsVector(pX->pRight) ){ + disableTerm(pLevel, pEnd); + } + } + start = sqlite3VdbeCurrentAddr(v); + pLevel->op = bRev ? OP_Prev : OP_Next; + pLevel->p1 = iCur; + pLevel->p2 = start; + assert( pLevel->p5==0 ); + if( testOp!=OP_Noop ){ + iRowidReg = ++pParse->nMem; + sqlite3VdbeAddOp2(v, OP_Rowid, iCur, iRowidReg); + sqlite3VdbeAddOp3(v, testOp, memEndValue, addrBrk, iRowidReg); + VdbeCoverageIf(v, testOp==OP_Le); + VdbeCoverageIf(v, testOp==OP_Lt); + VdbeCoverageIf(v, testOp==OP_Ge); + VdbeCoverageIf(v, testOp==OP_Gt); + sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC | SQLITE_JUMPIFNULL); + } + }else if( pLoop->wsFlags & WHERE_INDEXED ){ + /* Case 4: A scan using an index. + ** + ** The WHERE clause may contain zero or more equality + ** terms ("==" or "IN" operators) that refer to the N + ** left-most columns of the index. It may also contain + ** inequality constraints (>, <, >= or <=) on the indexed + ** column that immediately follows the N equalities. Only + ** the right-most column can be an inequality - the rest must + ** use the "==" and "IN" operators. For example, if the + ** index is on (x,y,z), then the following clauses are all + ** optimized: + ** + ** x=5 + ** x=5 AND y=10 + ** x=5 AND y<10 + ** x=5 AND y>5 AND y<10 + ** x=5 AND y=5 AND z<=10 + ** + ** The z<10 term of the following cannot be used, only + ** the x=5 term: + ** + ** x=5 AND z<10 + ** + ** N may be zero if there are inequality constraints. + ** If there are no inequality constraints, then N is at + ** least one. + ** + ** This case is also used when there are no WHERE clause + ** constraints but an index is selected anyway, in order + ** to force the output order to conform to an ORDER BY. + */ + static const u8 aStartOp[] = { + 0, + 0, + OP_Rewind, /* 2: (!start_constraints && startEq && !bRev) */ + OP_Last, /* 3: (!start_constraints && startEq && bRev) */ + OP_SeekGT, /* 4: (start_constraints && !startEq && !bRev) */ + OP_SeekLT, /* 5: (start_constraints && !startEq && bRev) */ + OP_SeekGE, /* 6: (start_constraints && startEq && !bRev) */ + OP_SeekLE /* 7: (start_constraints && startEq && bRev) */ + }; + static const u8 aEndOp[] = { + OP_IdxGE, /* 0: (end_constraints && !bRev && !endEq) */ + OP_IdxGT, /* 1: (end_constraints && !bRev && endEq) */ + OP_IdxLE, /* 2: (end_constraints && bRev && !endEq) */ + OP_IdxLT, /* 3: (end_constraints && bRev && endEq) */ + }; + u16 nEq = pLoop->u.btree.nEq; /* Number of == or IN terms */ + u16 nBtm = pLoop->u.btree.nBtm; /* Length of BTM vector */ + u16 nTop = pLoop->u.btree.nTop; /* Length of TOP vector */ + int regBase; /* Base register holding constraint values */ + WhereTerm *pRangeStart = 0; /* Inequality constraint at range start */ + WhereTerm *pRangeEnd = 0; /* Inequality constraint at range end */ + int startEq; /* True if range start uses ==, >= or <= */ + int endEq; /* True if range end uses ==, >= or <= */ + int start_constraints; /* Start of range is constrained */ + int nConstraint; /* Number of constraint terms */ + int iIdxCur; /* The VDBE cursor for the index */ + int nExtraReg = 0; /* Number of extra registers needed */ + int op; /* Instruction opcode */ + char *zStartAff; /* Affinity for start of range constraint */ + char *zEndAff = 0; /* Affinity for end of range constraint */ + u8 bSeekPastNull = 0; /* True to seek past initial nulls */ + u8 bStopAtNull = 0; /* Add condition to terminate at NULLs */ + int omitTable; /* True if we use the index only */ + int regBignull = 0; /* big-null flag register */ + int addrSeekScan = 0; /* Opcode of the OP_SeekScan, if any */ + + pIdx = pLoop->u.btree.pIndex; + iIdxCur = pLevel->iIdxCur; + assert( nEq>=pLoop->nSkip ); + + /* Find any inequality constraint terms for the start and end + ** of the range. + */ + j = nEq; + if( pLoop->wsFlags & WHERE_BTM_LIMIT ){ + pRangeStart = pLoop->aLTerm[j++]; + nExtraReg = MAX(nExtraReg, pLoop->u.btree.nBtm); + /* Like optimization range constraints always occur in pairs */ + assert( (pRangeStart->wtFlags & TERM_LIKEOPT)==0 || + (pLoop->wsFlags & WHERE_TOP_LIMIT)!=0 ); + } + if( pLoop->wsFlags & WHERE_TOP_LIMIT ){ + pRangeEnd = pLoop->aLTerm[j++]; + nExtraReg = MAX(nExtraReg, pLoop->u.btree.nTop); +#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS + if( (pRangeEnd->wtFlags & TERM_LIKEOPT)!=0 ){ + assert( pRangeStart!=0 ); /* LIKE opt constraints */ + assert( pRangeStart->wtFlags & TERM_LIKEOPT ); /* occur in pairs */ + pLevel->iLikeRepCntr = (u32)++pParse->nMem; + sqlite3VdbeAddOp2(v, OP_Integer, 1, (int)pLevel->iLikeRepCntr); + VdbeComment((v, "LIKE loop counter")); + pLevel->addrLikeRep = sqlite3VdbeCurrentAddr(v); + /* iLikeRepCntr actually stores 2x the counter register number. The + ** bottom bit indicates whether the search order is ASC or DESC. */ + testcase( bRev ); + testcase( pIdx->aSortOrder[nEq]==SQLITE_SO_DESC ); + assert( (bRev & ~1)==0 ); + pLevel->iLikeRepCntr <<=1; + pLevel->iLikeRepCntr |= bRev ^ (pIdx->aSortOrder[nEq]==SQLITE_SO_DESC); + } +#endif + if( pRangeStart==0 ){ + j = pIdx->aiColumn[nEq]; + if( (j>=0 && pIdx->pTable->aCol[j].notNull==0) || j==XN_EXPR ){ + bSeekPastNull = 1; + } + } + } + assert( pRangeEnd==0 || (pRangeEnd->wtFlags & TERM_VNULL)==0 ); + + /* If the WHERE_BIGNULL_SORT flag is set, then index column nEq uses + ** a non-default "big-null" sort (either ASC NULLS LAST or DESC NULLS + ** FIRST). In both cases separate ordered scans are made of those + ** index entries for which the column is null and for those for which + ** it is not. For an ASC sort, the non-NULL entries are scanned first. + ** For DESC, NULL entries are scanned first. + */ + if( (pLoop->wsFlags & (WHERE_TOP_LIMIT|WHERE_BTM_LIMIT))==0 + && (pLoop->wsFlags & WHERE_BIGNULL_SORT)!=0 + ){ + assert( bSeekPastNull==0 && nExtraReg==0 && nBtm==0 && nTop==0 ); + assert( pRangeEnd==0 && pRangeStart==0 ); + testcase( pLoop->nSkip>0 ); + nExtraReg = 1; + bSeekPastNull = 1; + pLevel->regBignull = regBignull = ++pParse->nMem; + if( pLevel->iLeftJoin ){ + sqlite3VdbeAddOp2(v, OP_Integer, 0, regBignull); + } + pLevel->addrBignull = sqlite3VdbeMakeLabel(pParse); + } + + /* If we are doing a reverse order scan on an ascending index, or + ** a forward order scan on a descending index, interchange the + ** start and end terms (pRangeStart and pRangeEnd). + */ + if( (nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC)) ){ + SWAP(WhereTerm *, pRangeEnd, pRangeStart); + SWAP(u8, bSeekPastNull, bStopAtNull); + SWAP(u8, nBtm, nTop); + } + + if( iLevel>0 && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)!=0 ){ + /* In case OP_SeekScan is used, ensure that the index cursor does not + ** point to a valid row for the first iteration of this loop. */ + sqlite3VdbeAddOp1(v, OP_NullRow, iIdxCur); + } + + /* Generate code to evaluate all constraint terms using == or IN + ** and store the values of those terms in an array of registers + ** starting at regBase. + */ + codeCursorHint(pTabItem, pWInfo, pLevel, pRangeEnd); + regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff); + assert( zStartAff==0 || sqlite3Strlen30(zStartAff)>=nEq ); + if( zStartAff && nTop ){ + zEndAff = sqlite3DbStrDup(db, &zStartAff[nEq]); + } + addrNxt = (regBignull ? pLevel->addrBignull : pLevel->addrNxt); + + testcase( pRangeStart && (pRangeStart->eOperator & WO_LE)!=0 ); + testcase( pRangeStart && (pRangeStart->eOperator & WO_GE)!=0 ); + testcase( pRangeEnd && (pRangeEnd->eOperator & WO_LE)!=0 ); + testcase( pRangeEnd && (pRangeEnd->eOperator & WO_GE)!=0 ); + startEq = !pRangeStart || pRangeStart->eOperator & (WO_LE|WO_GE); + endEq = !pRangeEnd || pRangeEnd->eOperator & (WO_LE|WO_GE); + start_constraints = pRangeStart || nEq>0; + + /* Seek the index cursor to the start of the range. */ + nConstraint = nEq; + if( pRangeStart ){ + Expr *pRight = pRangeStart->pExpr->pRight; + codeExprOrVector(pParse, pRight, regBase+nEq, nBtm); + whereLikeOptimizationStringFixup(v, pLevel, pRangeStart); + if( (pRangeStart->wtFlags & TERM_VNULL)==0 + && sqlite3ExprCanBeNull(pRight) + ){ + sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt); + VdbeCoverage(v); + } + if( zStartAff ){ + updateRangeAffinityStr(pRight, nBtm, &zStartAff[nEq]); + } + nConstraint += nBtm; + testcase( pRangeStart->wtFlags & TERM_VIRTUAL ); + if( sqlite3ExprIsVector(pRight)==0 ){ + disableTerm(pLevel, pRangeStart); + }else{ + startEq = 1; + } + bSeekPastNull = 0; + }else if( bSeekPastNull ){ + startEq = 0; + sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq); + start_constraints = 1; + nConstraint++; + }else if( regBignull ){ + sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq); + start_constraints = 1; + nConstraint++; + } + codeApplyAffinity(pParse, regBase, nConstraint - bSeekPastNull, zStartAff); + if( pLoop->nSkip>0 && nConstraint==pLoop->nSkip ){ + /* The skip-scan logic inside the call to codeAllEqualityConstraints() + ** above has already left the cursor sitting on the correct row, + ** so no further seeking is needed */ + }else{ + if( regBignull ){ + sqlite3VdbeAddOp2(v, OP_Integer, 1, regBignull); + VdbeComment((v, "NULL-scan pass ctr")); + } + if( pLevel->regFilter ){ + sqlite3VdbeAddOp4Int(v, OP_Filter, pLevel->regFilter, addrNxt, + regBase, nEq); + VdbeCoverage(v); + filterPullDown(pParse, pWInfo, iLevel, addrNxt, notReady); + } + + op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev]; + assert( op!=0 ); + if( (pLoop->wsFlags & WHERE_IN_SEEKSCAN)!=0 && op==OP_SeekGE ){ + assert( regBignull==0 ); + /* TUNING: The OP_SeekScan opcode seeks to reduce the number + ** of expensive seek operations by replacing a single seek with + ** 1 or more step operations. The question is, how many steps + ** should we try before giving up and going with a seek. The cost + ** of a seek is proportional to the logarithm of the of the number + ** of entries in the tree, so basing the number of steps to try + ** on the estimated number of rows in the btree seems like a good + ** guess. */ + addrSeekScan = sqlite3VdbeAddOp1(v, OP_SeekScan, + (pIdx->aiRowLogEst[0]+9)/10); + if( pRangeStart ){ + sqlite3VdbeChangeP5(v, 1); + sqlite3VdbeChangeP2(v, addrSeekScan, sqlite3VdbeCurrentAddr(v)+1); + addrSeekScan = 0; + } + VdbeCoverage(v); + } + sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint); + VdbeCoverage(v); + VdbeCoverageIf(v, op==OP_Rewind); testcase( op==OP_Rewind ); + VdbeCoverageIf(v, op==OP_Last); testcase( op==OP_Last ); + VdbeCoverageIf(v, op==OP_SeekGT); testcase( op==OP_SeekGT ); + VdbeCoverageIf(v, op==OP_SeekGE); testcase( op==OP_SeekGE ); + VdbeCoverageIf(v, op==OP_SeekLE); testcase( op==OP_SeekLE ); + VdbeCoverageIf(v, op==OP_SeekLT); testcase( op==OP_SeekLT ); + + assert( bSeekPastNull==0 || bStopAtNull==0 ); + if( regBignull ){ + assert( bSeekPastNull==1 || bStopAtNull==1 ); + assert( bSeekPastNull==!bStopAtNull ); + assert( bStopAtNull==startEq ); + sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+2); + op = aStartOp[(nConstraint>1)*4 + 2 + bRev]; + sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, + nConstraint-startEq); + VdbeCoverage(v); + VdbeCoverageIf(v, op==OP_Rewind); testcase( op==OP_Rewind ); + VdbeCoverageIf(v, op==OP_Last); testcase( op==OP_Last ); + VdbeCoverageIf(v, op==OP_SeekGE); testcase( op==OP_SeekGE ); + VdbeCoverageIf(v, op==OP_SeekLE); testcase( op==OP_SeekLE ); + assert( op==OP_Rewind || op==OP_Last || op==OP_SeekGE || op==OP_SeekLE); + } + } + + /* Load the value for the inequality constraint at the end of the + ** range (if any). + */ + nConstraint = nEq; + assert( pLevel->p2==0 ); + if( pRangeEnd ){ + Expr *pRight = pRangeEnd->pExpr->pRight; + if( addrSeekScan ){ + /* For a seek-scan that has a range on the lowest term of the index, + ** we have to make the top of the loop be code that sets the end + ** condition of the range. Otherwise, the OP_SeekScan might jump + ** over that initialization, leaving the range-end value set to the + ** range-start value, resulting in a wrong answer. + ** See ticket 5981a8c041a3c2f3 (2021-11-02). + */ + pLevel->p2 = sqlite3VdbeCurrentAddr(v); + } + codeExprOrVector(pParse, pRight, regBase+nEq, nTop); + whereLikeOptimizationStringFixup(v, pLevel, pRangeEnd); + if( (pRangeEnd->wtFlags & TERM_VNULL)==0 + && sqlite3ExprCanBeNull(pRight) + ){ + sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt); + VdbeCoverage(v); + } + if( zEndAff ){ + updateRangeAffinityStr(pRight, nTop, zEndAff); + codeApplyAffinity(pParse, regBase+nEq, nTop, zEndAff); + }else{ + assert( pParse->db->mallocFailed ); + } + nConstraint += nTop; + testcase( pRangeEnd->wtFlags & TERM_VIRTUAL ); + + if( sqlite3ExprIsVector(pRight)==0 ){ + disableTerm(pLevel, pRangeEnd); + }else{ + endEq = 1; + } + }else if( bStopAtNull ){ + if( regBignull==0 ){ + sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq); + endEq = 0; + } + nConstraint++; + } + if( zStartAff ) sqlite3DbNNFreeNN(db, zStartAff); + if( zEndAff ) sqlite3DbNNFreeNN(db, zEndAff); + + /* Top of the loop body */ + if( pLevel->p2==0 ) pLevel->p2 = sqlite3VdbeCurrentAddr(v); + + /* Check if the index cursor is past the end of the range. */ + if( nConstraint ){ + if( regBignull ){ + /* Except, skip the end-of-range check while doing the NULL-scan */ + sqlite3VdbeAddOp2(v, OP_IfNot, regBignull, sqlite3VdbeCurrentAddr(v)+3); + VdbeComment((v, "If NULL-scan 2nd pass")); + VdbeCoverage(v); + } + op = aEndOp[bRev*2 + endEq]; + sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint); + testcase( op==OP_IdxGT ); VdbeCoverageIf(v, op==OP_IdxGT ); + testcase( op==OP_IdxGE ); VdbeCoverageIf(v, op==OP_IdxGE ); + testcase( op==OP_IdxLT ); VdbeCoverageIf(v, op==OP_IdxLT ); + testcase( op==OP_IdxLE ); VdbeCoverageIf(v, op==OP_IdxLE ); + if( addrSeekScan ) sqlite3VdbeJumpHere(v, addrSeekScan); + } + if( regBignull ){ + /* During a NULL-scan, check to see if we have reached the end of + ** the NULLs */ + assert( bSeekPastNull==!bStopAtNull ); + assert( bSeekPastNull+bStopAtNull==1 ); + assert( nConstraint+bSeekPastNull>0 ); + sqlite3VdbeAddOp2(v, OP_If, regBignull, sqlite3VdbeCurrentAddr(v)+2); + VdbeComment((v, "If NULL-scan 1st pass")); + VdbeCoverage(v); + op = aEndOp[bRev*2 + bSeekPastNull]; + sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, + nConstraint+bSeekPastNull); + testcase( op==OP_IdxGT ); VdbeCoverageIf(v, op==OP_IdxGT ); + testcase( op==OP_IdxGE ); VdbeCoverageIf(v, op==OP_IdxGE ); + testcase( op==OP_IdxLT ); VdbeCoverageIf(v, op==OP_IdxLT ); + testcase( op==OP_IdxLE ); VdbeCoverageIf(v, op==OP_IdxLE ); + } + + if( (pLoop->wsFlags & WHERE_IN_EARLYOUT)!=0 ){ + sqlite3VdbeAddOp3(v, OP_SeekHit, iIdxCur, nEq, nEq); + } + + /* Seek the table cursor, if required */ + omitTable = (pLoop->wsFlags & WHERE_IDX_ONLY)!=0 + && (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))==0; + if( omitTable ){ + /* pIdx is a covering index. No need to access the main table. */ + }else if( HasRowid(pIdx->pTable) ){ + codeDeferredSeek(pWInfo, pIdx, iCur, iIdxCur); + }else if( iCur!=iIdxCur ){ + Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable); + iRowidReg = sqlite3GetTempRange(pParse, pPk->nKeyCol); + for(j=0; j<pPk->nKeyCol; j++){ + k = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[j]); + sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, k, iRowidReg+j); + } + sqlite3VdbeAddOp4Int(v, OP_NotFound, iCur, addrCont, + iRowidReg, pPk->nKeyCol); VdbeCoverage(v); + } + + if( pLevel->iLeftJoin==0 ){ + /* If a partial index is driving the loop, try to eliminate WHERE clause + ** terms from the query that must be true due to the WHERE clause of + ** the partial index. + ** + ** 2019-11-02 ticket 623eff57e76d45f6: This optimization does not work + ** for a LEFT JOIN. + */ + if( pIdx->pPartIdxWhere ){ + whereApplyPartialIndexConstraints(pIdx->pPartIdxWhere, iCur, pWC); + } + }else{ + testcase( pIdx->pPartIdxWhere ); + /* The following assert() is not a requirement, merely an observation: + ** The OR-optimization doesn't work for the right hand table of + ** a LEFT JOIN: */ + assert( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))==0 ); + } + + /* Record the instruction used to terminate the loop. */ + if( pLoop->wsFlags & WHERE_ONEROW ){ + pLevel->op = OP_Noop; + }else if( bRev ){ + pLevel->op = OP_Prev; + }else{ + pLevel->op = OP_Next; + } + pLevel->p1 = iIdxCur; + pLevel->p3 = (pLoop->wsFlags&WHERE_UNQ_WANTED)!=0 ? 1:0; + if( (pLoop->wsFlags & WHERE_CONSTRAINT)==0 ){ + pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP; + }else{ + assert( pLevel->p5==0 ); + } + if( omitTable ) pIdx = 0; + }else + +#ifndef SQLITE_OMIT_OR_OPTIMIZATION + if( pLoop->wsFlags & WHERE_MULTI_OR ){ + /* Case 5: Two or more separately indexed terms connected by OR + ** + ** Example: + ** + ** CREATE TABLE t1(a,b,c,d); + ** CREATE INDEX i1 ON t1(a); + ** CREATE INDEX i2 ON t1(b); + ** CREATE INDEX i3 ON t1(c); + ** + ** SELECT * FROM t1 WHERE a=5 OR b=7 OR (c=11 AND d=13) + ** + ** In the example, there are three indexed terms connected by OR. + ** The top of the loop looks like this: + ** + ** Null 1 # Zero the rowset in reg 1 + ** + ** Then, for each indexed term, the following. The arguments to + ** RowSetTest are such that the rowid of the current row is inserted + ** into the RowSet. If it is already present, control skips the + ** Gosub opcode and jumps straight to the code generated by WhereEnd(). + ** + ** sqlite3WhereBegin(<term>) + ** RowSetTest # Insert rowid into rowset + ** Gosub 2 A + ** sqlite3WhereEnd() + ** + ** Following the above, code to terminate the loop. Label A, the target + ** of the Gosub above, jumps to the instruction right after the Goto. + ** + ** Null 1 # Zero the rowset in reg 1 + ** Goto B # The loop is finished. + ** + ** A: <loop body> # Return data, whatever. + ** + ** Return 2 # Jump back to the Gosub + ** + ** B: <after the loop> + ** + ** Added 2014-05-26: If the table is a WITHOUT ROWID table, then + ** use an ephemeral index instead of a RowSet to record the primary + ** keys of the rows we have already seen. + ** + */ + WhereClause *pOrWc; /* The OR-clause broken out into subterms */ + SrcList *pOrTab; /* Shortened table list or OR-clause generation */ + Index *pCov = 0; /* Potential covering index (or NULL) */ + int iCovCur = pParse->nTab++; /* Cursor used for index scans (if any) */ + + int regReturn = ++pParse->nMem; /* Register used with OP_Gosub */ + int regRowset = 0; /* Register for RowSet object */ + int regRowid = 0; /* Register holding rowid */ + int iLoopBody = sqlite3VdbeMakeLabel(pParse);/* Start of loop body */ + int iRetInit; /* Address of regReturn init */ + int untestedTerms = 0; /* Some terms not completely tested */ + int ii; /* Loop counter */ + Expr *pAndExpr = 0; /* An ".. AND (...)" expression */ + Table *pTab = pTabItem->pTab; + + pTerm = pLoop->aLTerm[0]; + assert( pTerm!=0 ); + assert( pTerm->eOperator & WO_OR ); + assert( (pTerm->wtFlags & TERM_ORINFO)!=0 ); + pOrWc = &pTerm->u.pOrInfo->wc; + pLevel->op = OP_Return; + pLevel->p1 = regReturn; + + /* Set up a new SrcList in pOrTab containing the table being scanned + ** by this loop in the a[0] slot and all notReady tables in a[1..] slots. + ** This becomes the SrcList in the recursive call to sqlite3WhereBegin(). + */ + if( pWInfo->nLevel>1 ){ + int nNotReady; /* The number of notReady tables */ + SrcItem *origSrc; /* Original list of tables */ + nNotReady = pWInfo->nLevel - iLevel - 1; + pOrTab = sqlite3DbMallocRawNN(db, + sizeof(*pOrTab)+ nNotReady*sizeof(pOrTab->a[0])); + if( pOrTab==0 ) return notReady; + pOrTab->nAlloc = (u8)(nNotReady + 1); + pOrTab->nSrc = pOrTab->nAlloc; + memcpy(pOrTab->a, pTabItem, sizeof(*pTabItem)); + origSrc = pWInfo->pTabList->a; + for(k=1; k<=nNotReady; k++){ + memcpy(&pOrTab->a[k], &origSrc[pLevel[k].iFrom], sizeof(pOrTab->a[k])); + } + }else{ + pOrTab = pWInfo->pTabList; + } + + /* Initialize the rowset register to contain NULL. An SQL NULL is + ** equivalent to an empty rowset. Or, create an ephemeral index + ** capable of holding primary keys in the case of a WITHOUT ROWID. + ** + ** Also initialize regReturn to contain the address of the instruction + ** immediately following the OP_Return at the bottom of the loop. This + ** is required in a few obscure LEFT JOIN cases where control jumps + ** over the top of the loop into the body of it. In this case the + ** correct response for the end-of-loop code (the OP_Return) is to + ** fall through to the next instruction, just as an OP_Next does if + ** called on an uninitialized cursor. + */ + if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){ + if( HasRowid(pTab) ){ + regRowset = ++pParse->nMem; + sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset); + }else{ + Index *pPk = sqlite3PrimaryKeyIndex(pTab); + regRowset = pParse->nTab++; + sqlite3VdbeAddOp2(v, OP_OpenEphemeral, regRowset, pPk->nKeyCol); + sqlite3VdbeSetP4KeyInfo(pParse, pPk); + } + regRowid = ++pParse->nMem; + } + iRetInit = sqlite3VdbeAddOp2(v, OP_Integer, 0, regReturn); + + /* If the original WHERE clause is z of the form: (x1 OR x2 OR ...) AND y + ** Then for every term xN, evaluate as the subexpression: xN AND y + ** That way, terms in y that are factored into the disjunction will + ** be picked up by the recursive calls to sqlite3WhereBegin() below. + ** + ** Actually, each subexpression is converted to "xN AND w" where w is + ** the "interesting" terms of z - terms that did not originate in the + ** ON or USING clause of a LEFT JOIN, and terms that are usable as + ** indices. + ** + ** This optimization also only applies if the (x1 OR x2 OR ...) term + ** is not contained in the ON clause of a LEFT JOIN. + ** See ticket http://www.sqlite.org/src/info/f2369304e4 + ** + ** 2022-02-04: Do not push down slices of a row-value comparison. + ** In other words, "w" or "y" may not be a slice of a vector. Otherwise, + ** the initialization of the right-hand operand of the vector comparison + ** might not occur, or might occur only in an OR branch that is not + ** taken. dbsqlfuzz 80a9fade844b4fb43564efc972bcb2c68270f5d1. + ** + ** 2022-03-03: Do not push down expressions that involve subqueries. + ** The subquery might get coded as a subroutine. Any table-references + ** in the subquery might be resolved to index-references for the index on + ** the OR branch in which the subroutine is coded. But if the subroutine + ** is invoked from a different OR branch that uses a different index, such + ** index-references will not work. tag-20220303a + ** https://sqlite.org/forum/forumpost/36937b197273d403 + */ + if( pWC->nTerm>1 ){ + int iTerm; + for(iTerm=0; iTerm<pWC->nTerm; iTerm++){ + Expr *pExpr = pWC->a[iTerm].pExpr; + if( &pWC->a[iTerm] == pTerm ) continue; + testcase( pWC->a[iTerm].wtFlags & TERM_VIRTUAL ); + testcase( pWC->a[iTerm].wtFlags & TERM_CODED ); + testcase( pWC->a[iTerm].wtFlags & TERM_SLICE ); + if( (pWC->a[iTerm].wtFlags & (TERM_VIRTUAL|TERM_CODED|TERM_SLICE))!=0 ){ + continue; + } + if( (pWC->a[iTerm].eOperator & WO_ALL)==0 ) continue; + if( ExprHasProperty(pExpr, EP_Subquery) ) continue; /* tag-20220303a */ + pExpr = sqlite3ExprDup(db, pExpr, 0); + pAndExpr = sqlite3ExprAnd(pParse, pAndExpr, pExpr); + } + if( pAndExpr ){ + /* The extra 0x10000 bit on the opcode is masked off and does not + ** become part of the new Expr.op. However, it does make the + ** op==TK_AND comparison inside of sqlite3PExpr() false, and this + ** prevents sqlite3PExpr() from applying the AND short-circuit + ** optimization, which we do not want here. */ + pAndExpr = sqlite3PExpr(pParse, TK_AND|0x10000, 0, pAndExpr); + } + } + + /* Run a separate WHERE clause for each term of the OR clause. After + ** eliminating duplicates from other WHERE clauses, the action for each + ** sub-WHERE clause is to to invoke the main loop body as a subroutine. + */ + ExplainQueryPlan((pParse, 1, "MULTI-INDEX OR")); + for(ii=0; ii<pOrWc->nTerm; ii++){ + WhereTerm *pOrTerm = &pOrWc->a[ii]; + if( pOrTerm->leftCursor==iCur || (pOrTerm->eOperator & WO_AND)!=0 ){ + WhereInfo *pSubWInfo; /* Info for single OR-term scan */ + Expr *pOrExpr = pOrTerm->pExpr; /* Current OR clause term */ + Expr *pDelete; /* Local copy of OR clause term */ + int jmp1 = 0; /* Address of jump operation */ + testcase( (pTabItem[0].fg.jointype & JT_LEFT)!=0 + && !ExprHasProperty(pOrExpr, EP_OuterON) + ); /* See TH3 vtab25.400 and ticket 614b25314c766238 */ + pDelete = pOrExpr = sqlite3ExprDup(db, pOrExpr, 0); + if( db->mallocFailed ){ + sqlite3ExprDelete(db, pDelete); + continue; + } + if( pAndExpr ){ + pAndExpr->pLeft = pOrExpr; + pOrExpr = pAndExpr; + } + /* Loop through table entries that match term pOrTerm. */ + ExplainQueryPlan((pParse, 1, "INDEX %d", ii+1)); + WHERETRACE(0xffff, ("Subplan for OR-clause:\n")); + pSubWInfo = sqlite3WhereBegin(pParse, pOrTab, pOrExpr, 0, 0, 0, + WHERE_OR_SUBCLAUSE, iCovCur); + assert( pSubWInfo || pParse->nErr ); + if( pSubWInfo ){ + WhereLoop *pSubLoop; + int addrExplain = sqlite3WhereExplainOneScan( + pParse, pOrTab, &pSubWInfo->a[0], 0 + ); + sqlite3WhereAddScanStatus(v, pOrTab, &pSubWInfo->a[0], addrExplain); + + /* This is the sub-WHERE clause body. First skip over + ** duplicate rows from prior sub-WHERE clauses, and record the + ** rowid (or PRIMARY KEY) for the current row so that the same + ** row will be skipped in subsequent sub-WHERE clauses. + */ + if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){ + int iSet = ((ii==pOrWc->nTerm-1)?-1:ii); + if( HasRowid(pTab) ){ + sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, -1, regRowid); + jmp1 = sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset, 0, + regRowid, iSet); + VdbeCoverage(v); + }else{ + Index *pPk = sqlite3PrimaryKeyIndex(pTab); + int nPk = pPk->nKeyCol; + int iPk; + int r; + + /* Read the PK into an array of temp registers. */ + r = sqlite3GetTempRange(pParse, nPk); + for(iPk=0; iPk<nPk; iPk++){ + int iCol = pPk->aiColumn[iPk]; + sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol,r+iPk); + } + + /* Check if the temp table already contains this key. If so, + ** the row has already been included in the result set and + ** can be ignored (by jumping past the Gosub below). Otherwise, + ** insert the key into the temp table and proceed with processing + ** the row. + ** + ** Use some of the same optimizations as OP_RowSetTest: If iSet + ** is zero, assume that the key cannot already be present in + ** the temp table. And if iSet is -1, assume that there is no + ** need to insert the key into the temp table, as it will never + ** be tested for. */ + if( iSet ){ + jmp1 = sqlite3VdbeAddOp4Int(v, OP_Found, regRowset, 0, r, nPk); + VdbeCoverage(v); + } + if( iSet>=0 ){ + sqlite3VdbeAddOp3(v, OP_MakeRecord, r, nPk, regRowid); + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, regRowset, regRowid, + r, nPk); + if( iSet ) sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT); + } + + /* Release the array of temp registers */ + sqlite3ReleaseTempRange(pParse, r, nPk); + } + } + + /* Invoke the main loop body as a subroutine */ + sqlite3VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody); + + /* Jump here (skipping the main loop body subroutine) if the + ** current sub-WHERE row is a duplicate from prior sub-WHEREs. */ + if( jmp1 ) sqlite3VdbeJumpHere(v, jmp1); + + /* The pSubWInfo->untestedTerms flag means that this OR term + ** contained one or more AND term from a notReady table. The + ** terms from the notReady table could not be tested and will + ** need to be tested later. + */ + if( pSubWInfo->untestedTerms ) untestedTerms = 1; + + /* If all of the OR-connected terms are optimized using the same + ** index, and the index is opened using the same cursor number + ** by each call to sqlite3WhereBegin() made by this loop, it may + ** be possible to use that index as a covering index. + ** + ** If the call to sqlite3WhereBegin() above resulted in a scan that + ** uses an index, and this is either the first OR-connected term + ** processed or the index is the same as that used by all previous + ** terms, set pCov to the candidate covering index. Otherwise, set + ** pCov to NULL to indicate that no candidate covering index will + ** be available. + */ + pSubLoop = pSubWInfo->a[0].pWLoop; + assert( (pSubLoop->wsFlags & WHERE_AUTO_INDEX)==0 ); + if( (pSubLoop->wsFlags & WHERE_INDEXED)!=0 + && (ii==0 || pSubLoop->u.btree.pIndex==pCov) + && (HasRowid(pTab) || !IsPrimaryKeyIndex(pSubLoop->u.btree.pIndex)) + ){ + assert( pSubWInfo->a[0].iIdxCur==iCovCur ); + pCov = pSubLoop->u.btree.pIndex; + }else{ + pCov = 0; + } + if( sqlite3WhereUsesDeferredSeek(pSubWInfo) ){ + pWInfo->bDeferredSeek = 1; + } + + /* Finish the loop through table entries that match term pOrTerm. */ + sqlite3WhereEnd(pSubWInfo); + ExplainQueryPlanPop(pParse); + } + sqlite3ExprDelete(db, pDelete); + } + } + ExplainQueryPlanPop(pParse); + assert( pLevel->pWLoop==pLoop ); + assert( (pLoop->wsFlags & WHERE_MULTI_OR)!=0 ); + assert( (pLoop->wsFlags & WHERE_IN_ABLE)==0 ); + pLevel->u.pCoveringIdx = pCov; + if( pCov ) pLevel->iIdxCur = iCovCur; + if( pAndExpr ){ + pAndExpr->pLeft = 0; + sqlite3ExprDelete(db, pAndExpr); + } + sqlite3VdbeChangeP1(v, iRetInit, sqlite3VdbeCurrentAddr(v)); + sqlite3VdbeGoto(v, pLevel->addrBrk); + sqlite3VdbeResolveLabel(v, iLoopBody); + + /* Set the P2 operand of the OP_Return opcode that will end the current + ** loop to point to this spot, which is the top of the next containing + ** loop. The byte-code formatter will use that P2 value as a hint to + ** indent everything in between the this point and the final OP_Return. + ** See tag-20220407a in vdbe.c and shell.c */ + assert( pLevel->op==OP_Return ); + pLevel->p2 = sqlite3VdbeCurrentAddr(v); + + if( pWInfo->nLevel>1 ){ sqlite3DbFreeNN(db, pOrTab); } + if( !untestedTerms ) disableTerm(pLevel, pTerm); + }else +#endif /* SQLITE_OMIT_OR_OPTIMIZATION */ + + { + /* Case 6: There is no usable index. We must do a complete + ** scan of the entire table. + */ + static const u8 aStep[] = { OP_Next, OP_Prev }; + static const u8 aStart[] = { OP_Rewind, OP_Last }; + assert( bRev==0 || bRev==1 ); + if( pTabItem->fg.isRecursive ){ + /* Tables marked isRecursive have only a single row that is stored in + ** a pseudo-cursor. No need to Rewind or Next such cursors. */ + pLevel->op = OP_Noop; + }else{ + codeCursorHint(pTabItem, pWInfo, pLevel, 0); + pLevel->op = aStep[bRev]; + pLevel->p1 = iCur; + pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrHalt); + VdbeCoverageIf(v, bRev==0); + VdbeCoverageIf(v, bRev!=0); + pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP; + } + } + +#ifdef SQLITE_ENABLE_STMT_SCANSTATUS + pLevel->addrVisit = sqlite3VdbeCurrentAddr(v); +#endif + + /* Insert code to test every subexpression that can be completely + ** computed using the current set of tables. + ** + ** This loop may run between one and three times, depending on the + ** constraints to be generated. The value of stack variable iLoop + ** determines the constraints coded by each iteration, as follows: + ** + ** iLoop==1: Code only expressions that are entirely covered by pIdx. + ** iLoop==2: Code remaining expressions that do not contain correlated + ** sub-queries. + ** iLoop==3: Code all remaining expressions. + ** + ** An effort is made to skip unnecessary iterations of the loop. + */ + iLoop = (pIdx ? 1 : 2); + do{ + int iNext = 0; /* Next value for iLoop */ + for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){ + Expr *pE; + int skipLikeAddr = 0; + testcase( pTerm->wtFlags & TERM_VIRTUAL ); + testcase( pTerm->wtFlags & TERM_CODED ); + if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue; + if( (pTerm->prereqAll & pLevel->notReady)!=0 ){ + testcase( pWInfo->untestedTerms==0 + && (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)!=0 ); + pWInfo->untestedTerms = 1; + continue; + } + pE = pTerm->pExpr; + assert( pE!=0 ); + if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT) ){ + if( !ExprHasProperty(pE,EP_OuterON|EP_InnerON) ){ + /* Defer processing WHERE clause constraints until after outer + ** join processing. tag-20220513a */ + continue; + }else if( (pTabItem->fg.jointype & JT_LEFT)==JT_LEFT + && !ExprHasProperty(pE,EP_OuterON) ){ + continue; + }else{ + Bitmask m = sqlite3WhereGetMask(&pWInfo->sMaskSet, pE->w.iJoin); + if( m & pLevel->notReady ){ + /* An ON clause that is not ripe */ + continue; + } + } + } + if( iLoop==1 && !sqlite3ExprCoveredByIndex(pE, pLevel->iTabCur, pIdx) ){ + iNext = 2; + continue; + } + if( iLoop<3 && (pTerm->wtFlags & TERM_VARSELECT) ){ + if( iNext==0 ) iNext = 3; + continue; + } + + if( (pTerm->wtFlags & TERM_LIKECOND)!=0 ){ + /* If the TERM_LIKECOND flag is set, that means that the range search + ** is sufficient to guarantee that the LIKE operator is true, so we + ** can skip the call to the like(A,B) function. But this only works + ** for strings. So do not skip the call to the function on the pass + ** that compares BLOBs. */ +#ifdef SQLITE_LIKE_DOESNT_MATCH_BLOBS + continue; +#else + u32 x = pLevel->iLikeRepCntr; + if( x>0 ){ + skipLikeAddr = sqlite3VdbeAddOp1(v, (x&1)?OP_IfNot:OP_If,(int)(x>>1)); + VdbeCoverageIf(v, (x&1)==1); + VdbeCoverageIf(v, (x&1)==0); + } +#endif + } +#ifdef WHERETRACE_ENABLED /* 0xffff */ + if( sqlite3WhereTrace ){ + VdbeNoopComment((v, "WhereTerm[%d] (%p) priority=%d", + pWC->nTerm-j, pTerm, iLoop)); + } + if( sqlite3WhereTrace & 0x800 ){ + sqlite3DebugPrintf("Coding auxiliary constraint:\n"); + sqlite3WhereTermPrint(pTerm, pWC->nTerm-j); + } +#endif + sqlite3ExprIfFalse(pParse, pE, addrCont, SQLITE_JUMPIFNULL); + if( skipLikeAddr ) sqlite3VdbeJumpHere(v, skipLikeAddr); + pTerm->wtFlags |= TERM_CODED; + } + iLoop = iNext; + }while( iLoop>0 ); + + /* Insert code to test for implied constraints based on transitivity + ** of the "==" operator. + ** + ** Example: If the WHERE clause contains "t1.a=t2.b" and "t2.b=123" + ** and we are coding the t1 loop and the t2 loop has not yet coded, + ** then we cannot use the "t1.a=t2.b" constraint, but we can code + ** the implied "t1.a=123" constraint. + */ + for(pTerm=pWC->a, j=pWC->nBase; j>0; j--, pTerm++){ + Expr *pE, sEAlt; + WhereTerm *pAlt; + if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue; + if( (pTerm->eOperator & (WO_EQ|WO_IS))==0 ) continue; + if( (pTerm->eOperator & WO_EQUIV)==0 ) continue; + if( pTerm->leftCursor!=iCur ) continue; + if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT) ) continue; + pE = pTerm->pExpr; +#ifdef WHERETRACE_ENABLED /* 0x800 */ + if( sqlite3WhereTrace & 0x800 ){ + sqlite3DebugPrintf("Coding transitive constraint:\n"); + sqlite3WhereTermPrint(pTerm, pWC->nTerm-j); + } +#endif + assert( !ExprHasProperty(pE, EP_OuterON) ); + assert( (pTerm->prereqRight & pLevel->notReady)!=0 ); + assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 ); + pAlt = sqlite3WhereFindTerm(pWC, iCur, pTerm->u.x.leftColumn, notReady, + WO_EQ|WO_IN|WO_IS, 0); + if( pAlt==0 ) continue; + if( pAlt->wtFlags & (TERM_CODED) ) continue; + if( (pAlt->eOperator & WO_IN) + && ExprUseXSelect(pAlt->pExpr) + && (pAlt->pExpr->x.pSelect->pEList->nExpr>1) + ){ + continue; + } + testcase( pAlt->eOperator & WO_EQ ); + testcase( pAlt->eOperator & WO_IS ); + testcase( pAlt->eOperator & WO_IN ); + VdbeModuleComment((v, "begin transitive constraint")); + sEAlt = *pAlt->pExpr; + sEAlt.pLeft = pE->pLeft; + sqlite3ExprIfFalse(pParse, &sEAlt, addrCont, SQLITE_JUMPIFNULL); + pAlt->wtFlags |= TERM_CODED; + } + + /* For a RIGHT OUTER JOIN, record the fact that the current row has + ** been matched at least once. + */ + if( pLevel->pRJ ){ + Table *pTab; + int nPk; + int r; + int jmp1 = 0; + WhereRightJoin *pRJ = pLevel->pRJ; + + /* pTab is the right-hand table of the RIGHT JOIN. Generate code that + ** will record that the current row of that table has been matched at + ** least once. This is accomplished by storing the PK for the row in + ** both the iMatch index and the regBloom Bloom filter. + */ + pTab = pWInfo->pTabList->a[pLevel->iFrom].pTab; + if( HasRowid(pTab) ){ + r = sqlite3GetTempRange(pParse, 2); + sqlite3ExprCodeGetColumnOfTable(v, pTab, pLevel->iTabCur, -1, r+1); + nPk = 1; + }else{ + int iPk; + Index *pPk = sqlite3PrimaryKeyIndex(pTab); + nPk = pPk->nKeyCol; + r = sqlite3GetTempRange(pParse, nPk+1); + for(iPk=0; iPk<nPk; iPk++){ + int iCol = pPk->aiColumn[iPk]; + sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol,r+1+iPk); + } + } + jmp1 = sqlite3VdbeAddOp4Int(v, OP_Found, pRJ->iMatch, 0, r+1, nPk); + VdbeCoverage(v); + VdbeComment((v, "match against %s", pTab->zName)); + sqlite3VdbeAddOp3(v, OP_MakeRecord, r+1, nPk, r); + sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pRJ->iMatch, r, r+1, nPk); + sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pRJ->regBloom, 0, r+1, nPk); + sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT); + sqlite3VdbeJumpHere(v, jmp1); + sqlite3ReleaseTempRange(pParse, r, nPk+1); + } + + /* 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->addrFirst = sqlite3VdbeCurrentAddr(v); + sqlite3VdbeAddOp2(v, OP_Integer, 1, pLevel->iLeftJoin); + VdbeComment((v, "record LEFT JOIN hit")); + if( pLevel->pRJ==0 ){ + goto code_outer_join_constraints; /* WHERE clause constraints */ + } + } + + if( pLevel->pRJ ){ + /* Create a subroutine used to process all interior loops and code + ** of the RIGHT JOIN. During normal operation, the subroutine will + ** be in-line with the rest of the code. But at the end, a separate + ** loop will run that invokes this subroutine for unmatched rows + ** of pTab, with all tables to left begin set to NULL. + */ + WhereRightJoin *pRJ = pLevel->pRJ; + sqlite3VdbeAddOp2(v, OP_BeginSubrtn, 0, pRJ->regReturn); + pRJ->addrSubrtn = sqlite3VdbeCurrentAddr(v); + assert( pParse->withinRJSubrtn < 255 ); + pParse->withinRJSubrtn++; + + /* WHERE clause constraints must be deferred until after outer join + ** row elimination has completed, since WHERE clause constraints apply + ** to the results of the OUTER JOIN. The following loop generates the + ** appropriate WHERE clause constraint checks. tag-20220513a. + */ + code_outer_join_constraints: + for(pTerm=pWC->a, j=0; j<pWC->nBase; j++, pTerm++){ + testcase( pTerm->wtFlags & TERM_VIRTUAL ); + testcase( pTerm->wtFlags & TERM_CODED ); + if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue; + if( (pTerm->prereqAll & pLevel->notReady)!=0 ){ + assert( pWInfo->untestedTerms ); + continue; + } + if( pTabItem->fg.jointype & JT_LTORJ ) continue; + assert( pTerm->pExpr ); + sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL); + pTerm->wtFlags |= TERM_CODED; + } + } + +#if WHERETRACE_ENABLED /* 0x20800 */ + if( sqlite3WhereTrace & 0x20000 ){ + sqlite3DebugPrintf("All WHERE-clause terms after coding level %d:\n", + iLevel); + sqlite3WhereClausePrint(pWC); + } + if( sqlite3WhereTrace & 0x800 ){ + sqlite3DebugPrintf("End Coding level %d: notReady=%llx\n", + iLevel, (u64)pLevel->notReady); + } +#endif + return pLevel->notReady; +} + +/* +** Generate the code for the loop that finds all non-matched terms +** for a RIGHT JOIN. +*/ +SQLITE_NOINLINE void sqlite3WhereRightJoinLoop( + WhereInfo *pWInfo, + int iLevel, + WhereLevel *pLevel +){ + Parse *pParse = pWInfo->pParse; + Vdbe *v = pParse->pVdbe; + WhereRightJoin *pRJ = pLevel->pRJ; + Expr *pSubWhere = 0; + WhereClause *pWC = &pWInfo->sWC; + WhereInfo *pSubWInfo; + WhereLoop *pLoop = pLevel->pWLoop; + SrcItem *pTabItem = &pWInfo->pTabList->a[pLevel->iFrom]; + SrcList sFrom; + Bitmask mAll = 0; + int k; + + ExplainQueryPlan((pParse, 1, "RIGHT-JOIN %s", pTabItem->pTab->zName)); + sqlite3VdbeNoJumpsOutsideSubrtn(v, pRJ->addrSubrtn, pRJ->endSubrtn, + pRJ->regReturn); + for(k=0; k<iLevel; k++){ + int iIdxCur; + mAll |= pWInfo->a[k].pWLoop->maskSelf; + sqlite3VdbeAddOp1(v, OP_NullRow, pWInfo->a[k].iTabCur); + iIdxCur = pWInfo->a[k].iIdxCur; + if( iIdxCur ){ + sqlite3VdbeAddOp1(v, OP_NullRow, iIdxCur); + } + } + if( (pTabItem->fg.jointype & JT_LTORJ)==0 ){ + mAll |= pLoop->maskSelf; + for(k=0; k<pWC->nTerm; k++){ + WhereTerm *pTerm = &pWC->a[k]; + if( (pTerm->wtFlags & (TERM_VIRTUAL|TERM_SLICE))!=0 + && pTerm->eOperator!=WO_ROWVAL + ){ + break; + } + if( pTerm->prereqAll & ~mAll ) continue; + if( ExprHasProperty(pTerm->pExpr, EP_OuterON|EP_InnerON) ) continue; + pSubWhere = sqlite3ExprAnd(pParse, pSubWhere, + sqlite3ExprDup(pParse->db, pTerm->pExpr, 0)); + } + } + sFrom.nSrc = 1; + sFrom.nAlloc = 1; + memcpy(&sFrom.a[0], pTabItem, sizeof(SrcItem)); + sFrom.a[0].fg.jointype = 0; + assert( pParse->withinRJSubrtn < 100 ); + pParse->withinRJSubrtn++; + pSubWInfo = sqlite3WhereBegin(pParse, &sFrom, pSubWhere, 0, 0, 0, + WHERE_RIGHT_JOIN, 0); + if( pSubWInfo ){ + int iCur = pLevel->iTabCur; + int r = ++pParse->nMem; + int nPk; + int jmp; + int addrCont = sqlite3WhereContinueLabel(pSubWInfo); + Table *pTab = pTabItem->pTab; + if( HasRowid(pTab) ){ + sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, -1, r); + nPk = 1; + }else{ + int iPk; + Index *pPk = sqlite3PrimaryKeyIndex(pTab); + nPk = pPk->nKeyCol; + pParse->nMem += nPk - 1; + for(iPk=0; iPk<nPk; iPk++){ + int iCol = pPk->aiColumn[iPk]; + sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol,r+iPk); + } + } + jmp = sqlite3VdbeAddOp4Int(v, OP_Filter, pRJ->regBloom, 0, r, nPk); + VdbeCoverage(v); + sqlite3VdbeAddOp4Int(v, OP_Found, pRJ->iMatch, addrCont, r, nPk); + VdbeCoverage(v); + sqlite3VdbeJumpHere(v, jmp); + sqlite3VdbeAddOp2(v, OP_Gosub, pRJ->regReturn, pRJ->addrSubrtn); + sqlite3WhereEnd(pSubWInfo); + } + sqlite3ExprDelete(pParse->db, pSubWhere); + ExplainQueryPlanPop(pParse); + assert( pParse->withinRJSubrtn>0 ); + pParse->withinRJSubrtn--; +} |