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Unified Diff: third_party/sqlite/sqlite-src-3100200/src/wherecode.c

Issue 2846743003: [sql] Remove SQLite 3.10.2 reference directory. (Closed)
Patch Set: Created 3 years, 8 months ago
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Index: third_party/sqlite/sqlite-src-3100200/src/wherecode.c
diff --git a/third_party/sqlite/sqlite-src-3100200/src/wherecode.c b/third_party/sqlite/sqlite-src-3100200/src/wherecode.c
deleted file mode 100644
index bc72e0ac7d2819e416d7866fa16b6fa99ce7d802..0000000000000000000000000000000000000000
--- a/third_party/sqlite/sqlite-src-3100200/src/wherecode.c
+++ /dev/null
@@ -1,1675 +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;
-}
-
-#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
-/*
-** 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.
-**
-** 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 = sqlite3VdbeGetOp(v, -1);
- assert( pOp!=0 );
- assert( pOp->opcode==OP_String8
- || pTerm->pWC->pWInfo->pParse->db->mallocFailed );
- pOp->p3 = pLevel->iLikeRepCntr;
- pOp->p5 = 1;
- }
-}
-#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
- && sqlite3ColumnOfIndex(pHint->pIdx, pExpr->iColumn)<0
- ){
- 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 ){
- Vdbe *v = pWalker->pParse->pVdbe;
- int reg = ++pWalker->pParse->nMem; /* Register for column value */
- sqlite3ExprCodeGetColumnOfTable(
- v, pExpr->pTab, pExpr->iTable, pExpr->iColumn, reg
- );
- pExpr->op = TK_REGISTER;
- pExpr->iTable = reg;
- }else if( pHint->pIdx!=0 ){
- pExpr->iTable = pHint->iIdxCur;
- pExpr->iColumn = sqlite3ColumnOfIndex(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(
- 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->nTerm; i++){
- pTerm = &pWC->a[i];
- if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
- if( pTerm->prereqAll & pLevel->notReady ) continue;
- if( ExprHasProperty(pTerm->pExpr, EP_FromJoin) ) 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(db, 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) /* No-op */
-#endif /* SQLITE_ENABLE_CURSOR_HINTS */
-
-/*
-** 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;
- }
- codeCursorHint(pWInfo, pLevel, pEnd);
- 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;
-#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 = ++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);
- }
-#endif
- if( pRangeStart==0
- && (j = pIdx->aiColumn[nEq])>=0
- && pIdx->pTable->aCol[j].notNull==0
- ){
- bSeekPastNull = 1;
- }
- }
- assert( pRangeEnd==0 || (pRangeEnd->wtFlags & TERM_VNULL)==0 );
-
- /* 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);
- }
-
- /* 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(pWInfo, pLevel, pRangeEnd);
- regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff);
- assert( zStartAff==0 || sqlite3Strlen30(zStartAff)>=nEq );
- if( zStartAff ) cEndAff = zStartAff[nEq];
- addrNxt = 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;
- 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|TKFLG_DONTFOLD, 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];
- sqlite3ExprCodeGetColumnToReg(pParse, pTab, iCol, iCur, 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{
- codeCursorHint(pWInfo, pLevel, 0);
- 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 ){
-#ifdef SQLITE_LIKE_DOESNT_MATCH_BLOBS
- continue;
-#else
- assert( pLevel->iLikeRepCntr>0 );
- skipLikeAddr = sqlite3VdbeAddOp1(v, OP_IfNot, pLevel->iLikeRepCntr);
- VdbeCoverage(v);
-#endif
- }
- 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;
-}
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