diff options
Diffstat (limited to 'lib/libsqlite3/src/wherecode.c')
| -rw-r--r-- | lib/libsqlite3/src/wherecode.c | 1514 |
1 files changed, 0 insertions, 1514 deletions
diff --git a/lib/libsqlite3/src/wherecode.c b/lib/libsqlite3/src/wherecode.c deleted file mode 100644 index 910ff34e02d..00000000000 --- a/lib/libsqlite3/src/wherecode.c +++ /dev/null @@ -1,1514 +0,0 @@ -/* -** 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 -/* -** 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 */ - int iTerm, /* Index of this term. First is zero */ - const char *zColumn, /* Name of the column */ - const char *zOp /* Name of the operator */ -){ - if( iTerm ) sqlite3StrAccumAppend(pStr, " AND ", 5); - sqlite3StrAccumAppendAll(pStr, zColumn); - sqlite3StrAccumAppend(pStr, zOp, 1); - sqlite3StrAccumAppend(pStr, "?", 1); -} - -/* -** 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].zName; -} - -/* -** 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; - sqlite3StrAccumAppend(pStr, " (", 2); - for(i=0; i<nEq; i++){ - const char *z = explainIndexColumnName(pIndex, i); - if( i ) sqlite3StrAccumAppend(pStr, " AND ", 5); - sqlite3XPrintf(pStr, 0, i>=nSkip ? "%s=?" : "ANY(%s)", z); - } - - j = i; - if( pLoop->wsFlags&WHERE_BTM_LIMIT ){ - const char *z = explainIndexColumnName(pIndex, i); - explainAppendTerm(pStr, i++, z, ">"); - } - if( pLoop->wsFlags&WHERE_TOP_LIMIT ){ - const char *z = explainIndexColumnName(pIndex, j); - explainAppendTerm(pStr, i, z, "<"); - } - sqlite3StrAccumAppend(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 */ - int iLevel, /* Value for "level" column of output */ - int iFrom, /* Value for "from" column of output */ - u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ -){ - int ret = 0; -#if !defined(SQLITE_DEBUG) && !defined(SQLITE_ENABLE_STMT_SCANSTATUS) - if( pParse->explain==2 ) -#endif - { - struct SrcList_item *pItem = &pTabList->a[pLevel->iFrom]; - Vdbe *v = pParse->pVdbe; /* VM being constructed */ - sqlite3 *db = pParse->db; /* Database handle */ - int iId = pParse->iSelectId; /* Select id (left-most output column) */ - 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_ONETABLE_ONLY) ) 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); - sqlite3StrAccumAppendAll(&str, isSearch ? "SEARCH" : "SCAN"); - if( pItem->pSelect ){ - sqlite3XPrintf(&str, 0, " SUBQUERY %d", pItem->iSelectId); - }else{ - sqlite3XPrintf(&str, 0, " TABLE %s", pItem->zName); - } - - if( pItem->zAlias ){ - sqlite3XPrintf(&str, 0, " AS %s", pItem->zAlias); - } - 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 ){ - sqlite3StrAccumAppend(&str, " USING ", 7); - sqlite3XPrintf(&str, 0, zFmt, pIdx->zName); - explainIndexRange(&str, pLoop); - } - }else if( (flags & WHERE_IPK)!=0 && (flags & WHERE_CONSTRAINT)!=0 ){ - const char *zRangeOp; - if( flags&(WHERE_COLUMN_EQ|WHERE_COLUMN_IN) ){ - zRangeOp = "="; - }else if( (flags&WHERE_BOTH_LIMIT)==WHERE_BOTH_LIMIT ){ - zRangeOp = ">? AND rowid<"; - }else if( flags&WHERE_BTM_LIMIT ){ - zRangeOp = ">"; - }else{ - assert( flags&WHERE_TOP_LIMIT); - zRangeOp = "<"; - } - sqlite3XPrintf(&str, 0, " USING INTEGER PRIMARY KEY (rowid%s?)",zRangeOp); - } -#ifndef SQLITE_OMIT_VIRTUALTABLE - else if( (flags & WHERE_VIRTUALTABLE)!=0 ){ - sqlite3XPrintf(&str, 0, " VIRTUAL TABLE INDEX %d:%s", - pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr); - } -#endif -#ifdef SQLITE_EXPLAIN_ESTIMATED_ROWS - if( pLoop->nOut>=10 ){ - sqlite3XPrintf(&str, 0, " (~%llu rows)", sqlite3LogEstToInt(pLoop->nOut)); - }else{ - sqlite3StrAccumAppend(&str, " (~1 row)", 9); - } -#endif - zMsg = sqlite3StrAccumFinish(&str); - ret = sqlite3VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, 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; - while( pTerm - && (pTerm->wtFlags & TERM_CODED)==0 - && (pLevel->iLeftJoin==0 || ExprHasProperty(pTerm->pExpr, EP_FromJoin)) - && (pLevel->notReady & pTerm->prereqAll)==0 - ){ - if( nLoop && (pTerm->wtFlags & TERM_LIKE)!=0 ){ - pTerm->wtFlags |= TERM_LIKECOND; - }else{ - pTerm->wtFlags |= TERM_CODED; - } - if( pTerm->iParent<0 ) break; - pTerm = &pTerm->pWC->a[pTerm->iParent]; - 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 entries (which are no-ops) at the -** beginning and end of zAff are ignored. If all entries in zAff are -** SQLITE_AFF_BLOB, 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 entries at the beginning - ** and end of the affinity string. - */ - 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 ){ - sqlite3VdbeAddOp2(v, OP_Affinity, base, n); - sqlite3VdbeChangeP4(v, -1, zAff, n); - sqlite3ExprCacheAffinityChange(pParse, base, n); - } -} - - -/* -** 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 register iReg. -** -** For a constraint of the form X=expr, the expression is evaluated and its -** result is left on the stack. 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( 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; - int iTab; - struct InLoop *pIn; - WhereLoop *pLoop = pLevel->pWLoop; - - 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; - eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0); - if( eType==IN_INDEX_INDEX_DESC ){ - testcase( bRev ); - bRev = !bRev; - } - iTab = pX->iTable; - 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(v); - } - pLevel->u.in.nIn++; - pLevel->u.in.aInLoop = - sqlite3DbReallocOrFree(pParse->db, pLevel->u.in.aInLoop, - sizeof(pLevel->u.in.aInLoop[0])*pLevel->u.in.nIn); - pIn = pLevel->u.in.aInLoop; - if( pIn ){ - pIn += pLevel->u.in.nIn - 1; - pIn->iCur = iTab; - if( eType==IN_INDEX_ROWID ){ - pIn->addrInTop = sqlite3VdbeAddOp2(v, OP_Rowid, iTab, iReg); - }else{ - pIn->addrInTop = sqlite3VdbeAddOp3(v, OP_Column, iTab, 0, iReg); - } - pIn->eEndLoopOp = bRev ? OP_PrevIfOpen : OP_NextIfOpen; - sqlite3VdbeAddOp1(v, OP_IsNull, iReg); VdbeCoverage(v); - }else{ - pLevel->u.in.nIn = 0; - } -#endif - } - 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)); - if( !zAff ){ - pParse->db->mallocFailed = 1; - } - - if( nSkip ){ - int iIdxCur = pLevel->iIdxCur; - 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); - 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_SCopy, r1, regBase+j); - } - } - testcase( pTerm->eOperator & WO_ISNULL ); - testcase( pTerm->eOperator & WO_IN ); - if( (pTerm->eOperator & (WO_ISNULL|WO_IN))==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( zAff ){ - 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; -} - -/* -** If the most recently coded instruction is a constant range contraint -** that originated from the LIKE optimization, then change the P3 to be -** pLoop->iLikeRepCntr and set P5. -** -** 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 contants to blobs. This routine makes the necessary changes -** to the OP_String opcodes for that to happen. -*/ -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 = sqlite3VdbeGetOp(v, -1); - assert( pOp!=0 ); - assert( pOp->opcode==OP_String8 - || pTerm->pWC->pWInfo->pParse->db->mallocFailed ); - pOp->p3 = pLevel->iLikeRepCntr; - pOp->p5 = 1; - } -} - - -/* -** Generate code for the start of the iLevel-th loop in the WHERE clause -** implementation described by pWInfo. -*/ -Bitmask sqlite3WhereCodeOneLoopStart( - WhereInfo *pWInfo, /* Complete information about the WHERE clause */ - int iLevel, /* Which level of pWInfo->a[] should be coded */ - 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 omitTable; /* True if we use the index only */ - int bRev; /* True if we need to scan in reverse order */ - WhereLevel *pLevel; /* The where level to be coded */ - WhereLoop *pLoop; /* The WhereLoop object being coded */ - WhereClause *pWC; /* Decomposition of the entire WHERE clause */ - WhereTerm *pTerm; /* A WHERE clause term */ - Parse *pParse; /* Parsing context */ - sqlite3 *db; /* Database connection */ - Vdbe *v; /* The prepared stmt under constructions */ - struct SrcList_item *pTabItem; /* FROM clause term being coded */ - int addrBrk; /* Jump here to break out of the 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 */ - - pParse = pWInfo->pParse; - v = pParse->pVdbe; - pWC = &pWInfo->sWC; - db = pParse->db; - pLevel = &pWInfo->a[iLevel]; - pLoop = pLevel->pWLoop; - pTabItem = &pWInfo->pTabList->a[pLevel->iFrom]; - iCur = pTabItem->iCursor; - pLevel->notReady = notReady & ~sqlite3WhereGetMask(&pWInfo->sMaskSet, iCur); - bRev = (pWInfo->revMask>>iLevel)&1; - omitTable = (pLoop->wsFlags & WHERE_IDX_ONLY)!=0 - && (pWInfo->wctrlFlags & WHERE_FORCE_TABLE)==0; - VdbeModuleComment((v, "Begin WHERE-loop%d: %s",iLevel,pTabItem->pTab->zName)); - - /* 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(v); - addrCont = pLevel->addrCont = sqlite3VdbeMakeLabel(v); - - /* 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. - */ - 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")); - } - - /* 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; - - sqlite3ExprCachePush(pParse); - iReg = sqlite3GetTempRange(pParse, nConstraint+2); - addrNotFound = pLevel->addrBrk; - for(j=0; j<nConstraint; j++){ - int iTarget = iReg+j+2; - pTerm = pLoop->aLTerm[j]; - if( pTerm==0 ) continue; - if( pTerm->eOperator & WO_IN ){ - codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, iTarget); - addrNotFound = pLevel->addrNxt; - }else{ - sqlite3ExprCode(pParse, pTerm->pExpr->pRight, iTarget); - } - } - 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_MPRINTF : P4_STATIC); - VdbeCoverage(v); - pLoop->u.vtab.needFree = 0; - for(j=0; j<nConstraint && j<16; j++){ - if( (pLoop->u.vtab.omitMask>>j)&1 ){ - disableTerm(pLevel, pLoop->aLTerm[j]); - } - } - pLevel->p1 = iCur; - pLevel->op = pWInfo->eOnePass ? OP_Noop : OP_VNext; - pLevel->p2 = sqlite3VdbeCurrentAddr(v); - sqlite3ReleaseTempRange(pParse, iReg, nConstraint+2); - sqlite3ExprCachePop(pParse); - }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 ); - assert( omitTable==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; - sqlite3VdbeAddOp2(v, OP_MustBeInt, iRowidReg, addrNxt); VdbeCoverage(v); - sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addrNxt, iRowidReg); - VdbeCoverage(v); - sqlite3ExprCacheAffinityChange(pParse, iRowidReg, 1); - sqlite3ExprCacheStore(pParse, iCur, -1, iRowidReg); - VdbeComment((v, "pk")); - 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; - - assert( omitTable==0 ); - 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; - } - if( pStart ){ - Expr *pX; /* The expression that defines the start bound */ - int r1, rTemp; /* Registers for holding the start boundary */ - - /* 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 */ - r1 = sqlite3ExprCodeTemp(pParse, pX->pRight, &rTemp); - sqlite3VdbeAddOp3(v, aMoveOp[pX->op-TK_GT], 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); - sqlite3ExprCacheAffinityChange(pParse, r1, 1); - sqlite3ReleaseTempReg(pParse, rTemp); - disableTerm(pLevel, pStart); - }else{ - sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, addrBrk); - 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; - sqlite3ExprCode(pParse, pX->pRight, memEndValue); - if( pX->op==TK_LT || pX->op==TK_GT ){ - testOp = bRev ? OP_Le : OP_Ge; - }else{ - testOp = bRev ? OP_Lt : OP_Gt; - } - 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); - sqlite3ExprCacheStore(pParse, iCur, -1, 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 */ - 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 */ - Index *pIdx; /* The index we will be using */ - 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 cEndAff = 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 */ - - pIdx = pLoop->u.btree.pIndex; - iIdxCur = pLevel->iIdxCur; - assert( nEq>=pLoop->nSkip ); - - /* If this loop satisfies a sort order (pOrderBy) request that - ** was passed to this function to implement a "SELECT min(x) ..." - ** query, then the caller will only allow the loop to run for - ** a single iteration. This means that the first row returned - ** should not have a NULL value stored in 'x'. If column 'x' is - ** the first one after the nEq equality constraints in the index, - ** this requires some special handling. - */ - assert( pWInfo->pOrderBy==0 - || pWInfo->pOrderBy->nExpr==1 - || (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0 ); - if( (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)!=0 - && pWInfo->nOBSat>0 - && (pIdx->nKeyCol>nEq) - ){ - assert( pLoop->nSkip==0 ); - bSeekPastNull = 1; - nExtraReg = 1; - } - - /* 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 = 1; - /* 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 = 1; - if( (pRangeEnd->wtFlags & TERM_LIKEOPT)!=0 ){ - assert( pRangeStart!=0 ); /* LIKE opt constraints */ - assert( pRangeStart->wtFlags & TERM_LIKEOPT ); /* occur in pairs */ - pLevel->iLikeRepCntr = ++pParse->nMem; - testcase( bRev ); - testcase( pIdx->aSortOrder[nEq]==SQLITE_SO_DESC ); - sqlite3VdbeAddOp2(v, OP_Integer, - bRev ^ (pIdx->aSortOrder[nEq]==SQLITE_SO_DESC), - pLevel->iLikeRepCntr); - VdbeComment((v, "LIKE loop counter")); - pLevel->addrLikeRep = sqlite3VdbeCurrentAddr(v); - } - if( pRangeStart==0 - && (j = pIdx->aiColumn[nEq])>=0 - && pIdx->pTable->aCol[j].notNull==0 - ){ - bSeekPastNull = 1; - } - } - assert( pRangeEnd==0 || (pRangeEnd->wtFlags & TERM_VNULL)==0 ); - - /* 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. - */ - regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff); - assert( zStartAff==0 || sqlite3Strlen30(zStartAff)>=nEq ); - if( zStartAff ) cEndAff = zStartAff[nEq]; - addrNxt = pLevel->addrNxt; - - /* 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->nKeyCol && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC)) - || (bRev && pIdx->nKeyCol==nEq) - ){ - SWAP(WhereTerm *, pRangeEnd, pRangeStart); - SWAP(u8, bSeekPastNull, bStopAtNull); - } - - 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; - sqlite3ExprCode(pParse, pRight, regBase+nEq); - whereLikeOptimizationStringFixup(v, pLevel, pRangeStart); - if( (pRangeStart->wtFlags & TERM_VNULL)==0 - && sqlite3ExprCanBeNull(pRight) - ){ - sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt); - VdbeCoverage(v); - } - if( zStartAff ){ - if( sqlite3CompareAffinity(pRight, zStartAff[nEq])==SQLITE_AFF_BLOB){ - /* Since the comparison is to be performed with no conversions - ** applied to the operands, set the affinity to apply to pRight to - ** SQLITE_AFF_BLOB. */ - zStartAff[nEq] = SQLITE_AFF_BLOB; - } - if( sqlite3ExprNeedsNoAffinityChange(pRight, zStartAff[nEq]) ){ - zStartAff[nEq] = SQLITE_AFF_BLOB; - } - } - nConstraint++; - testcase( pRangeStart->wtFlags & TERM_VIRTUAL ); - }else if( bSeekPastNull ){ - sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq); - nConstraint++; - startEq = 0; - start_constraints = 1; - } - codeApplyAffinity(pParse, regBase, nConstraint - bSeekPastNull, zStartAff); - op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev]; - assert( op!=0 ); - 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 ); - - /* Load the value for the inequality constraint at the end of the - ** range (if any). - */ - nConstraint = nEq; - if( pRangeEnd ){ - Expr *pRight = pRangeEnd->pExpr->pRight; - sqlite3ExprCacheRemove(pParse, regBase+nEq, 1); - sqlite3ExprCode(pParse, pRight, regBase+nEq); - whereLikeOptimizationStringFixup(v, pLevel, pRangeEnd); - if( (pRangeEnd->wtFlags & TERM_VNULL)==0 - && sqlite3ExprCanBeNull(pRight) - ){ - sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt); - VdbeCoverage(v); - } - if( sqlite3CompareAffinity(pRight, cEndAff)!=SQLITE_AFF_BLOB - && !sqlite3ExprNeedsNoAffinityChange(pRight, cEndAff) - ){ - codeApplyAffinity(pParse, regBase+nEq, 1, &cEndAff); - } - nConstraint++; - testcase( pRangeEnd->wtFlags & TERM_VIRTUAL ); - }else if( bStopAtNull ){ - sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq); - endEq = 0; - nConstraint++; - } - sqlite3DbFree(db, zStartAff); - - /* Top of the loop body */ - pLevel->p2 = sqlite3VdbeCurrentAddr(v); - - /* Check if the index cursor is past the end of the range. */ - if( nConstraint ){ - 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 ); - } - - /* Seek the table cursor, if required */ - disableTerm(pLevel, pRangeStart); - disableTerm(pLevel, pRangeEnd); - if( omitTable ){ - /* pIdx is a covering index. No need to access the main table. */ - }else if( HasRowid(pIdx->pTable) ){ - iRowidReg = ++pParse->nMem; - sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, iRowidReg); - sqlite3ExprCacheStore(pParse, iCur, -1, iRowidReg); - if( pWInfo->eOnePass!=ONEPASS_OFF ){ - sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, iRowidReg); - VdbeCoverage(v); - }else{ - sqlite3VdbeAddOp2(v, OP_Seek, iCur, iRowidReg); /* Deferred seek */ - } - }else if( iCur!=iIdxCur ){ - Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable); - iRowidReg = sqlite3GetTempRange(pParse, pPk->nKeyCol); - for(j=0; j<pPk->nKeyCol; j++){ - k = sqlite3ColumnOfIndex(pIdx, pPk->aiColumn[j]); - sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, k, iRowidReg+j); - } - sqlite3VdbeAddOp4Int(v, OP_NotFound, iCur, addrCont, - iRowidReg, pPk->nKeyCol); VdbeCoverage(v); - } - - /* Record the instruction used to terminate the loop. Disable - ** WHERE clause terms made redundant by the index range scan. - */ - 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 ); - } - }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(v); /* Start of loop body */ - int iRetInit; /* Address of regReturn init */ - int untestedTerms = 0; /* Some terms not completely tested */ - int ii; /* Loop counter */ - u16 wctrlFlags; /* Flags for sub-WHERE clause */ - 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 */ - struct SrcList_item *origSrc; /* Original list of tables */ - nNotReady = pWInfo->nLevel - iLevel - 1; - pOrTab = sqlite3StackAllocRaw(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 z - ** 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 - */ - 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; - if( ExprHasProperty(pExpr, EP_FromJoin) ) continue; - if( (pWC->a[iTerm].wtFlags & TERM_VIRTUAL)!=0 ) continue; - if( (pWC->a[iTerm].eOperator & WO_ALL)==0 ) continue; - testcase( pWC->a[iTerm].wtFlags & TERM_ORINFO ); - pExpr = sqlite3ExprDup(db, pExpr, 0); - pAndExpr = sqlite3ExprAnd(db, pAndExpr, pExpr); - } - if( pAndExpr ){ - pAndExpr = sqlite3PExpr(pParse, TK_AND, 0, pAndExpr, 0); - } - } - - /* 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. - */ - wctrlFlags = WHERE_OMIT_OPEN_CLOSE - | WHERE_FORCE_TABLE - | WHERE_ONETABLE_ONLY - | WHERE_NO_AUTOINDEX; - 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 */ - int jmp1 = 0; /* Address of jump operation */ - if( pAndExpr && !ExprHasProperty(pOrExpr, EP_FromJoin) ){ - pAndExpr->pLeft = pOrExpr; - pOrExpr = pAndExpr; - } - /* Loop through table entries that match term pOrTerm. */ - WHERETRACE(0xffff, ("Subplan for OR-clause:\n")); - pSubWInfo = sqlite3WhereBegin(pParse, pOrTab, pOrExpr, 0, 0, - wctrlFlags, iCovCur); - assert( pSubWInfo || pParse->nErr || db->mallocFailed ); - if( pSubWInfo ){ - WhereLoop *pSubLoop; - int addrExplain = sqlite3WhereExplainOneScan( - pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 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 r; - int iSet = ((ii==pOrWc->nTerm-1)?-1:ii); - if( HasRowid(pTab) ){ - r = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iCur, regRowid, 0); - jmp1 = sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset, 0, - r,iSet); - VdbeCoverage(v); - }else{ - Index *pPk = sqlite3PrimaryKeyIndex(pTab); - int nPk = pPk->nKeyCol; - int iPk; - - /* Read the PK into an array of temp registers. */ - r = sqlite3GetTempRange(pParse, nPk); - for(iPk=0; iPk<nPk; iPk++){ - int iCol = pPk->aiColumn[iPk]; - int rx; - rx = sqlite3ExprCodeGetColumn(pParse, pTab, iCol, iCur,r+iPk,0); - if( rx!=r+iPk ){ - sqlite3VdbeAddOp2(v, OP_SCopy, rx, 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); - sqlite3VdbeAddOp3(v, OP_IdxInsert, regRowset, regRowid, 0); - 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; - wctrlFlags |= WHERE_REOPEN_IDX; - }else{ - pCov = 0; - } - - /* Finish the loop through table entries that match term pOrTerm. */ - sqlite3WhereEnd(pSubWInfo); - } - } - } - pLevel->u.pCovidx = 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); - - if( pWInfo->nLevel>1 ) sqlite3StackFree(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{ - pLevel->op = aStep[bRev]; - pLevel->p1 = iCur; - pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrBrk); - 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. - */ - 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_ONETABLE_ONLY)!=0 ); - pWInfo->untestedTerms = 1; - continue; - } - pE = pTerm->pExpr; - assert( pE!=0 ); - if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){ - continue; - } - if( pTerm->wtFlags & TERM_LIKECOND ){ - assert( pLevel->iLikeRepCntr>0 ); - skipLikeAddr = sqlite3VdbeAddOp1(v, OP_IfNot, pLevel->iLikeRepCntr); - VdbeCoverage(v); - } - sqlite3ExprIfFalse(pParse, pE, addrCont, SQLITE_JUMPIFNULL); - if( skipLikeAddr ) sqlite3VdbeJumpHere(v, skipLikeAddr); - pTerm->wtFlags |= TERM_CODED; - } - - /* 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->nTerm; j>0; j--, pTerm++){ - Expr *pE, *pEAlt; - 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( pLevel->iLeftJoin ) continue; - pE = pTerm->pExpr; - assert( !ExprHasProperty(pE, EP_FromJoin) ); - assert( (pTerm->prereqRight & pLevel->notReady)!=0 ); - pAlt = sqlite3WhereFindTerm(pWC, iCur, pTerm->u.leftColumn, notReady, - WO_EQ|WO_IN|WO_IS, 0); - if( pAlt==0 ) continue; - if( pAlt->wtFlags & (TERM_CODED) ) continue; - testcase( pAlt->eOperator & WO_EQ ); - testcase( pAlt->eOperator & WO_IS ); - testcase( pAlt->eOperator & WO_IN ); - VdbeModuleComment((v, "begin transitive constraint")); - pEAlt = sqlite3StackAllocRaw(db, sizeof(*pEAlt)); - if( pEAlt ){ - *pEAlt = *pAlt->pExpr; - pEAlt->pLeft = pE->pLeft; - sqlite3ExprIfFalse(pParse, pEAlt, addrCont, SQLITE_JUMPIFNULL); - sqlite3StackFree(db, pEAlt); - } - } - - /* 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")); - sqlite3ExprCacheClear(pParse); - for(pTerm=pWC->a, j=0; j<pWC->nTerm; 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; - } - assert( pTerm->pExpr ); - sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL); - pTerm->wtFlags |= TERM_CODED; - } - } - - return pLevel->notReady; -} |