| Index: third_party/sqlite/src/where.c
|
| ===================================================================
|
| --- third_party/sqlite/src/where.c (revision 56608)
|
| +++ third_party/sqlite/src/where.c (working copy)
|
| @@ -1,3948 +0,0 @@
|
| -/*
|
| -** 2001 September 15
|
| -**
|
| -** The author disclaims copyright to this source code. In place of
|
| -** a legal notice, here is a blessing:
|
| -**
|
| -** May you do good and not evil.
|
| -** May you find forgiveness for yourself and forgive others.
|
| -** May you share freely, never taking more than you give.
|
| -**
|
| -*************************************************************************
|
| -** This module contains C code that generates VDBE code used to process
|
| -** the WHERE clause of SQL statements. This module is responsible for
|
| -** generating the code that loops through a table looking for applicable
|
| -** rows. Indices are selected and used to speed the search when doing
|
| -** so is applicable. Because this module is responsible for selecting
|
| -** indices, you might also think of this module as the "query optimizer".
|
| -**
|
| -** $Id: where.c,v 1.411 2009/07/31 06:14:52 danielk1977 Exp $
|
| -*/
|
| -#include "sqliteInt.h"
|
| -
|
| -/*
|
| -** Trace output macros
|
| -*/
|
| -#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
|
| -int sqlite3WhereTrace = 0;
|
| -#endif
|
| -#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
|
| -# define WHERETRACE(X) if(sqlite3WhereTrace) sqlite3DebugPrintf X
|
| -#else
|
| -# define WHERETRACE(X)
|
| -#endif
|
| -
|
| -/* Forward reference
|
| -*/
|
| -typedef struct WhereClause WhereClause;
|
| -typedef struct WhereMaskSet WhereMaskSet;
|
| -typedef struct WhereOrInfo WhereOrInfo;
|
| -typedef struct WhereAndInfo WhereAndInfo;
|
| -typedef struct WhereCost WhereCost;
|
| -
|
| -/*
|
| -** The query generator uses an array of instances of this structure to
|
| -** help it analyze the subexpressions of the WHERE clause. Each WHERE
|
| -** clause subexpression is separated from the others by AND operators,
|
| -** usually, or sometimes subexpressions separated by OR.
|
| -**
|
| -** All WhereTerms are collected into a single WhereClause structure.
|
| -** The following identity holds:
|
| -**
|
| -** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm
|
| -**
|
| -** When a term is of the form:
|
| -**
|
| -** X <op> <expr>
|
| -**
|
| -** where X is a column name and <op> is one of certain operators,
|
| -** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the
|
| -** cursor number and column number for X. WhereTerm.eOperator records
|
| -** the <op> using a bitmask encoding defined by WO_xxx below. The
|
| -** use of a bitmask encoding for the operator allows us to search
|
| -** quickly for terms that match any of several different operators.
|
| -**
|
| -** A WhereTerm might also be two or more subterms connected by OR:
|
| -**
|
| -** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR ....
|
| -**
|
| -** In this second case, wtFlag as the TERM_ORINFO set and eOperator==WO_OR
|
| -** and the WhereTerm.u.pOrInfo field points to auxiliary information that
|
| -** is collected about the
|
| -**
|
| -** If a term in the WHERE clause does not match either of the two previous
|
| -** categories, then eOperator==0. The WhereTerm.pExpr field is still set
|
| -** to the original subexpression content and wtFlags is set up appropriately
|
| -** but no other fields in the WhereTerm object are meaningful.
|
| -**
|
| -** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers,
|
| -** but they do so indirectly. A single WhereMaskSet structure translates
|
| -** cursor number into bits and the translated bit is stored in the prereq
|
| -** fields. The translation is used in order to maximize the number of
|
| -** bits that will fit in a Bitmask. The VDBE cursor numbers might be
|
| -** spread out over the non-negative integers. For example, the cursor
|
| -** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet
|
| -** translates these sparse cursor numbers into consecutive integers
|
| -** beginning with 0 in order to make the best possible use of the available
|
| -** bits in the Bitmask. So, in the example above, the cursor numbers
|
| -** would be mapped into integers 0 through 7.
|
| -**
|
| -** The number of terms in a join is limited by the number of bits
|
| -** in prereqRight and prereqAll. The default is 64 bits, hence SQLite
|
| -** is only able to process joins with 64 or fewer tables.
|
| -*/
|
| -typedef struct WhereTerm WhereTerm;
|
| -struct WhereTerm {
|
| - Expr *pExpr; /* Pointer to the subexpression that is this term */
|
| - int iParent; /* Disable pWC->a[iParent] when this term disabled */
|
| - int leftCursor; /* Cursor number of X in "X <op> <expr>" */
|
| - union {
|
| - int leftColumn; /* Column number of X in "X <op> <expr>" */
|
| - WhereOrInfo *pOrInfo; /* Extra information if eOperator==WO_OR */
|
| - WhereAndInfo *pAndInfo; /* Extra information if eOperator==WO_AND */
|
| - } u;
|
| - u16 eOperator; /* A WO_xx value describing <op> */
|
| - u8 wtFlags; /* TERM_xxx bit flags. See below */
|
| - u8 nChild; /* Number of children that must disable us */
|
| - WhereClause *pWC; /* The clause this term is part of */
|
| - Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */
|
| - Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */
|
| -};
|
| -
|
| -/*
|
| -** Allowed values of WhereTerm.wtFlags
|
| -*/
|
| -#define TERM_DYNAMIC 0x01 /* Need to call sqlite3ExprDelete(db, pExpr) */
|
| -#define TERM_VIRTUAL 0x02 /* Added by the optimizer. Do not code */
|
| -#define TERM_CODED 0x04 /* This term is already coded */
|
| -#define TERM_COPIED 0x08 /* Has a child */
|
| -#define TERM_ORINFO 0x10 /* Need to free the WhereTerm.u.pOrInfo object */
|
| -#define TERM_ANDINFO 0x20 /* Need to free the WhereTerm.u.pAndInfo obj */
|
| -#define TERM_OR_OK 0x40 /* Used during OR-clause processing */
|
| -
|
| -/*
|
| -** An instance of the following structure holds all information about a
|
| -** WHERE clause. Mostly this is a container for one or more WhereTerms.
|
| -*/
|
| -struct WhereClause {
|
| - Parse *pParse; /* The parser context */
|
| - WhereMaskSet *pMaskSet; /* Mapping of table cursor numbers to bitmasks */
|
| - Bitmask vmask; /* Bitmask identifying virtual table cursors */
|
| - u8 op; /* Split operator. TK_AND or TK_OR */
|
| - int nTerm; /* Number of terms */
|
| - int nSlot; /* Number of entries in a[] */
|
| - WhereTerm *a; /* Each a[] describes a term of the WHERE cluase */
|
| -#if defined(SQLITE_SMALL_STACK)
|
| - WhereTerm aStatic[1]; /* Initial static space for a[] */
|
| -#else
|
| - WhereTerm aStatic[8]; /* Initial static space for a[] */
|
| -#endif
|
| -};
|
| -
|
| -/*
|
| -** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to
|
| -** a dynamically allocated instance of the following structure.
|
| -*/
|
| -struct WhereOrInfo {
|
| - WhereClause wc; /* Decomposition into subterms */
|
| - Bitmask indexable; /* Bitmask of all indexable tables in the clause */
|
| -};
|
| -
|
| -/*
|
| -** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to
|
| -** a dynamically allocated instance of the following structure.
|
| -*/
|
| -struct WhereAndInfo {
|
| - WhereClause wc; /* The subexpression broken out */
|
| -};
|
| -
|
| -/*
|
| -** An instance of the following structure keeps track of a mapping
|
| -** between VDBE cursor numbers and bits of the bitmasks in WhereTerm.
|
| -**
|
| -** The VDBE cursor numbers are small integers contained in
|
| -** SrcList_item.iCursor and Expr.iTable fields. For any given WHERE
|
| -** clause, the cursor numbers might not begin with 0 and they might
|
| -** contain gaps in the numbering sequence. But we want to make maximum
|
| -** use of the bits in our bitmasks. This structure provides a mapping
|
| -** from the sparse cursor numbers into consecutive integers beginning
|
| -** with 0.
|
| -**
|
| -** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask
|
| -** corresponds VDBE cursor number B. The A-th bit of a bitmask is 1<<A.
|
| -**
|
| -** For example, if the WHERE clause expression used these VDBE
|
| -** cursors: 4, 5, 8, 29, 57, 73. Then the WhereMaskSet structure
|
| -** would map those cursor numbers into bits 0 through 5.
|
| -**
|
| -** Note that the mapping is not necessarily ordered. In the example
|
| -** above, the mapping might go like this: 4->3, 5->1, 8->2, 29->0,
|
| -** 57->5, 73->4. Or one of 719 other combinations might be used. It
|
| -** does not really matter. What is important is that sparse cursor
|
| -** numbers all get mapped into bit numbers that begin with 0 and contain
|
| -** no gaps.
|
| -*/
|
| -struct WhereMaskSet {
|
| - int n; /* Number of assigned cursor values */
|
| - int ix[BMS]; /* Cursor assigned to each bit */
|
| -};
|
| -
|
| -/*
|
| -** A WhereCost object records a lookup strategy and the estimated
|
| -** cost of pursuing that strategy.
|
| -*/
|
| -struct WhereCost {
|
| - WherePlan plan; /* The lookup strategy */
|
| - double rCost; /* Overall cost of pursuing this search strategy */
|
| - double nRow; /* Estimated number of output rows */
|
| - Bitmask used; /* Bitmask of cursors used by this plan */
|
| -};
|
| -
|
| -/*
|
| -** Bitmasks for the operators that indices are able to exploit. An
|
| -** OR-ed combination of these values can be used when searching for
|
| -** terms in the where clause.
|
| -*/
|
| -#define WO_IN 0x001
|
| -#define WO_EQ 0x002
|
| -#define WO_LT (WO_EQ<<(TK_LT-TK_EQ))
|
| -#define WO_LE (WO_EQ<<(TK_LE-TK_EQ))
|
| -#define WO_GT (WO_EQ<<(TK_GT-TK_EQ))
|
| -#define WO_GE (WO_EQ<<(TK_GE-TK_EQ))
|
| -#define WO_MATCH 0x040
|
| -#define WO_ISNULL 0x080
|
| -#define WO_OR 0x100 /* Two or more OR-connected terms */
|
| -#define WO_AND 0x200 /* Two or more AND-connected terms */
|
| -
|
| -#define WO_ALL 0xfff /* Mask of all possible WO_* values */
|
| -#define WO_SINGLE 0x0ff /* Mask of all non-compound WO_* values */
|
| -
|
| -/*
|
| -** Value for wsFlags returned by bestIndex() and stored in
|
| -** WhereLevel.wsFlags. These flags determine which search
|
| -** strategies are appropriate.
|
| -**
|
| -** The least significant 12 bits is reserved as a mask for WO_ values above.
|
| -** The WhereLevel.wsFlags field is usually set to WO_IN|WO_EQ|WO_ISNULL.
|
| -** But if the table is the right table of a left join, WhereLevel.wsFlags
|
| -** is set to WO_IN|WO_EQ. The WhereLevel.wsFlags field can then be used as
|
| -** the "op" parameter to findTerm when we are resolving equality constraints.
|
| -** ISNULL constraints will then not be used on the right table of a left
|
| -** join. Tickets #2177 and #2189.
|
| -*/
|
| -#define WHERE_ROWID_EQ 0x00001000 /* rowid=EXPR or rowid IN (...) */
|
| -#define WHERE_ROWID_RANGE 0x00002000 /* rowid<EXPR and/or rowid>EXPR */
|
| -#define WHERE_COLUMN_EQ 0x00010000 /* x=EXPR or x IN (...) or x IS NULL */
|
| -#define WHERE_COLUMN_RANGE 0x00020000 /* x<EXPR and/or x>EXPR */
|
| -#define WHERE_COLUMN_IN 0x00040000 /* x IN (...) */
|
| -#define WHERE_COLUMN_NULL 0x00080000 /* x IS NULL */
|
| -#define WHERE_INDEXED 0x000f0000 /* Anything that uses an index */
|
| -#define WHERE_IN_ABLE 0x000f1000 /* Able to support an IN operator */
|
| -#define WHERE_TOP_LIMIT 0x00100000 /* x<EXPR or x<=EXPR constraint */
|
| -#define WHERE_BTM_LIMIT 0x00200000 /* x>EXPR or x>=EXPR constraint */
|
| -#define WHERE_IDX_ONLY 0x00800000 /* Use index only - omit table */
|
| -#define WHERE_ORDERBY 0x01000000 /* Output will appear in correct order */
|
| -#define WHERE_REVERSE 0x02000000 /* Scan in reverse order */
|
| -#define WHERE_UNIQUE 0x04000000 /* Selects no more than one row */
|
| -#define WHERE_VIRTUALTABLE 0x08000000 /* Use virtual-table processing */
|
| -#define WHERE_MULTI_OR 0x10000000 /* OR using multiple indices */
|
| -
|
| -/*
|
| -** Initialize a preallocated WhereClause structure.
|
| -*/
|
| -static void whereClauseInit(
|
| - WhereClause *pWC, /* The WhereClause to be initialized */
|
| - Parse *pParse, /* The parsing context */
|
| - WhereMaskSet *pMaskSet /* Mapping from table cursor numbers to bitmasks */
|
| -){
|
| - pWC->pParse = pParse;
|
| - pWC->pMaskSet = pMaskSet;
|
| - pWC->nTerm = 0;
|
| - pWC->nSlot = ArraySize(pWC->aStatic);
|
| - pWC->a = pWC->aStatic;
|
| - pWC->vmask = 0;
|
| -}
|
| -
|
| -/* Forward reference */
|
| -static void whereClauseClear(WhereClause*);
|
| -
|
| -/*
|
| -** Deallocate all memory associated with a WhereOrInfo object.
|
| -*/
|
| -static void whereOrInfoDelete(sqlite3 *db, WhereOrInfo *p){
|
| - whereClauseClear(&p->wc);
|
| - sqlite3DbFree(db, p);
|
| -}
|
| -
|
| -/*
|
| -** Deallocate all memory associated with a WhereAndInfo object.
|
| -*/
|
| -static void whereAndInfoDelete(sqlite3 *db, WhereAndInfo *p){
|
| - whereClauseClear(&p->wc);
|
| - sqlite3DbFree(db, p);
|
| -}
|
| -
|
| -/*
|
| -** Deallocate a WhereClause structure. The WhereClause structure
|
| -** itself is not freed. This routine is the inverse of whereClauseInit().
|
| -*/
|
| -static void whereClauseClear(WhereClause *pWC){
|
| - int i;
|
| - WhereTerm *a;
|
| - sqlite3 *db = pWC->pParse->db;
|
| - for(i=pWC->nTerm-1, a=pWC->a; i>=0; i--, a++){
|
| - if( a->wtFlags & TERM_DYNAMIC ){
|
| - sqlite3ExprDelete(db, a->pExpr);
|
| - }
|
| - if( a->wtFlags & TERM_ORINFO ){
|
| - whereOrInfoDelete(db, a->u.pOrInfo);
|
| - }else if( a->wtFlags & TERM_ANDINFO ){
|
| - whereAndInfoDelete(db, a->u.pAndInfo);
|
| - }
|
| - }
|
| - if( pWC->a!=pWC->aStatic ){
|
| - sqlite3DbFree(db, pWC->a);
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** Add a single new WhereTerm entry to the WhereClause object pWC.
|
| -** The new WhereTerm object is constructed from Expr p and with wtFlags.
|
| -** The index in pWC->a[] of the new WhereTerm is returned on success.
|
| -** 0 is returned if the new WhereTerm could not be added due to a memory
|
| -** allocation error. The memory allocation failure will be recorded in
|
| -** the db->mallocFailed flag so that higher-level functions can detect it.
|
| -**
|
| -** This routine will increase the size of the pWC->a[] array as necessary.
|
| -**
|
| -** If the wtFlags argument includes TERM_DYNAMIC, then responsibility
|
| -** for freeing the expression p is assumed by the WhereClause object pWC.
|
| -** This is true even if this routine fails to allocate a new WhereTerm.
|
| -**
|
| -** WARNING: This routine might reallocate the space used to store
|
| -** WhereTerms. All pointers to WhereTerms should be invalidated after
|
| -** calling this routine. Such pointers may be reinitialized by referencing
|
| -** the pWC->a[] array.
|
| -*/
|
| -static int whereClauseInsert(WhereClause *pWC, Expr *p, u8 wtFlags){
|
| - WhereTerm *pTerm;
|
| - int idx;
|
| - if( pWC->nTerm>=pWC->nSlot ){
|
| - WhereTerm *pOld = pWC->a;
|
| - sqlite3 *db = pWC->pParse->db;
|
| - pWC->a = sqlite3DbMallocRaw(db, sizeof(pWC->a[0])*pWC->nSlot*2 );
|
| - if( pWC->a==0 ){
|
| - if( wtFlags & TERM_DYNAMIC ){
|
| - sqlite3ExprDelete(db, p);
|
| - }
|
| - pWC->a = pOld;
|
| - return 0;
|
| - }
|
| - memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm);
|
| - if( pOld!=pWC->aStatic ){
|
| - sqlite3DbFree(db, pOld);
|
| - }
|
| - pWC->nSlot = sqlite3DbMallocSize(db, pWC->a)/sizeof(pWC->a[0]);
|
| - }
|
| - pTerm = &pWC->a[idx = pWC->nTerm++];
|
| - pTerm->pExpr = p;
|
| - pTerm->wtFlags = wtFlags;
|
| - pTerm->pWC = pWC;
|
| - pTerm->iParent = -1;
|
| - return idx;
|
| -}
|
| -
|
| -/*
|
| -** This routine identifies subexpressions in the WHERE clause where
|
| -** each subexpression is separated by the AND operator or some other
|
| -** operator specified in the op parameter. The WhereClause structure
|
| -** is filled with pointers to subexpressions. For example:
|
| -**
|
| -** WHERE a=='hello' AND coalesce(b,11)<10 AND (c+12!=d OR c==22)
|
| -** \________/ \_______________/ \________________/
|
| -** slot[0] slot[1] slot[2]
|
| -**
|
| -** The original WHERE clause in pExpr is unaltered. All this routine
|
| -** does is make slot[] entries point to substructure within pExpr.
|
| -**
|
| -** In the previous sentence and in the diagram, "slot[]" refers to
|
| -** the WhereClause.a[] array. The slot[] array grows as needed to contain
|
| -** all terms of the WHERE clause.
|
| -*/
|
| -static void whereSplit(WhereClause *pWC, Expr *pExpr, int op){
|
| - pWC->op = (u8)op;
|
| - if( pExpr==0 ) return;
|
| - if( pExpr->op!=op ){
|
| - whereClauseInsert(pWC, pExpr, 0);
|
| - }else{
|
| - whereSplit(pWC, pExpr->pLeft, op);
|
| - whereSplit(pWC, pExpr->pRight, op);
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** Initialize an expression mask set (a WhereMaskSet object)
|
| -*/
|
| -#define initMaskSet(P) memset(P, 0, sizeof(*P))
|
| -
|
| -/*
|
| -** Return the bitmask for the given cursor number. Return 0 if
|
| -** iCursor is not in the set.
|
| -*/
|
| -static Bitmask getMask(WhereMaskSet *pMaskSet, int iCursor){
|
| - int i;
|
| - assert( pMaskSet->n<=sizeof(Bitmask)*8 );
|
| - for(i=0; i<pMaskSet->n; i++){
|
| - if( pMaskSet->ix[i]==iCursor ){
|
| - return ((Bitmask)1)<<i;
|
| - }
|
| - }
|
| - return 0;
|
| -}
|
| -
|
| -/*
|
| -** Create a new mask for cursor iCursor.
|
| -**
|
| -** There is one cursor per table in the FROM clause. The number of
|
| -** tables in the FROM clause is limited by a test early in the
|
| -** sqlite3WhereBegin() routine. So we know that the pMaskSet->ix[]
|
| -** array will never overflow.
|
| -*/
|
| -static void createMask(WhereMaskSet *pMaskSet, int iCursor){
|
| - assert( pMaskSet->n < ArraySize(pMaskSet->ix) );
|
| - pMaskSet->ix[pMaskSet->n++] = iCursor;
|
| -}
|
| -
|
| -/*
|
| -** This routine walks (recursively) an expression tree and generates
|
| -** a bitmask indicating which tables are used in that expression
|
| -** tree.
|
| -**
|
| -** In order for this routine to work, the calling function must have
|
| -** previously invoked sqlite3ResolveExprNames() on the expression. See
|
| -** the header comment on that routine for additional information.
|
| -** The sqlite3ResolveExprNames() routines looks for column names and
|
| -** sets their opcodes to TK_COLUMN and their Expr.iTable fields to
|
| -** the VDBE cursor number of the table. This routine just has to
|
| -** translate the cursor numbers into bitmask values and OR all
|
| -** the bitmasks together.
|
| -*/
|
| -static Bitmask exprListTableUsage(WhereMaskSet*, ExprList*);
|
| -static Bitmask exprSelectTableUsage(WhereMaskSet*, Select*);
|
| -static Bitmask exprTableUsage(WhereMaskSet *pMaskSet, Expr *p){
|
| - Bitmask mask = 0;
|
| - if( p==0 ) return 0;
|
| - if( p->op==TK_COLUMN ){
|
| - mask = getMask(pMaskSet, p->iTable);
|
| - return mask;
|
| - }
|
| - mask = exprTableUsage(pMaskSet, p->pRight);
|
| - mask |= exprTableUsage(pMaskSet, p->pLeft);
|
| - if( ExprHasProperty(p, EP_xIsSelect) ){
|
| - mask |= exprSelectTableUsage(pMaskSet, p->x.pSelect);
|
| - }else{
|
| - mask |= exprListTableUsage(pMaskSet, p->x.pList);
|
| - }
|
| - return mask;
|
| -}
|
| -static Bitmask exprListTableUsage(WhereMaskSet *pMaskSet, ExprList *pList){
|
| - int i;
|
| - Bitmask mask = 0;
|
| - if( pList ){
|
| - for(i=0; i<pList->nExpr; i++){
|
| - mask |= exprTableUsage(pMaskSet, pList->a[i].pExpr);
|
| - }
|
| - }
|
| - return mask;
|
| -}
|
| -static Bitmask exprSelectTableUsage(WhereMaskSet *pMaskSet, Select *pS){
|
| - Bitmask mask = 0;
|
| - while( pS ){
|
| - mask |= exprListTableUsage(pMaskSet, pS->pEList);
|
| - mask |= exprListTableUsage(pMaskSet, pS->pGroupBy);
|
| - mask |= exprListTableUsage(pMaskSet, pS->pOrderBy);
|
| - mask |= exprTableUsage(pMaskSet, pS->pWhere);
|
| - mask |= exprTableUsage(pMaskSet, pS->pHaving);
|
| - pS = pS->pPrior;
|
| - }
|
| - return mask;
|
| -}
|
| -
|
| -/*
|
| -** Return TRUE if the given operator is one of the operators that is
|
| -** allowed for an indexable WHERE clause term. The allowed operators are
|
| -** "=", "<", ">", "<=", ">=", and "IN".
|
| -*/
|
| -static int allowedOp(int op){
|
| - assert( TK_GT>TK_EQ && TK_GT<TK_GE );
|
| - assert( TK_LT>TK_EQ && TK_LT<TK_GE );
|
| - assert( TK_LE>TK_EQ && TK_LE<TK_GE );
|
| - assert( TK_GE==TK_EQ+4 );
|
| - return op==TK_IN || (op>=TK_EQ && op<=TK_GE) || op==TK_ISNULL;
|
| -}
|
| -
|
| -/*
|
| -** Swap two objects of type TYPE.
|
| -*/
|
| -#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}
|
| -
|
| -/*
|
| -** Commute a comparison operator. Expressions of the form "X op Y"
|
| -** are converted into "Y op X".
|
| -**
|
| -** If a collation sequence is associated with either the left or right
|
| -** side of the comparison, it remains associated with the same side after
|
| -** the commutation. So "Y collate NOCASE op X" becomes
|
| -** "X collate NOCASE op Y". This is because any collation sequence on
|
| -** the left hand side of a comparison overrides any collation sequence
|
| -** attached to the right. For the same reason the EP_ExpCollate flag
|
| -** is not commuted.
|
| -*/
|
| -static void exprCommute(Parse *pParse, Expr *pExpr){
|
| - u16 expRight = (pExpr->pRight->flags & EP_ExpCollate);
|
| - u16 expLeft = (pExpr->pLeft->flags & EP_ExpCollate);
|
| - assert( allowedOp(pExpr->op) && pExpr->op!=TK_IN );
|
| - pExpr->pRight->pColl = sqlite3ExprCollSeq(pParse, pExpr->pRight);
|
| - pExpr->pLeft->pColl = sqlite3ExprCollSeq(pParse, pExpr->pLeft);
|
| - SWAP(CollSeq*,pExpr->pRight->pColl,pExpr->pLeft->pColl);
|
| - pExpr->pRight->flags = (pExpr->pRight->flags & ~EP_ExpCollate) | expLeft;
|
| - pExpr->pLeft->flags = (pExpr->pLeft->flags & ~EP_ExpCollate) | expRight;
|
| - SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
|
| - if( pExpr->op>=TK_GT ){
|
| - assert( TK_LT==TK_GT+2 );
|
| - assert( TK_GE==TK_LE+2 );
|
| - assert( TK_GT>TK_EQ );
|
| - assert( TK_GT<TK_LE );
|
| - assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );
|
| - pExpr->op = ((pExpr->op-TK_GT)^2)+TK_GT;
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** Translate from TK_xx operator to WO_xx bitmask.
|
| -*/
|
| -static u16 operatorMask(int op){
|
| - u16 c;
|
| - assert( allowedOp(op) );
|
| - if( op==TK_IN ){
|
| - c = WO_IN;
|
| - }else if( op==TK_ISNULL ){
|
| - c = WO_ISNULL;
|
| - }else{
|
| - assert( (WO_EQ<<(op-TK_EQ)) < 0x7fff );
|
| - c = (u16)(WO_EQ<<(op-TK_EQ));
|
| - }
|
| - assert( op!=TK_ISNULL || c==WO_ISNULL );
|
| - assert( op!=TK_IN || c==WO_IN );
|
| - assert( op!=TK_EQ || c==WO_EQ );
|
| - assert( op!=TK_LT || c==WO_LT );
|
| - assert( op!=TK_LE || c==WO_LE );
|
| - assert( op!=TK_GT || c==WO_GT );
|
| - assert( op!=TK_GE || c==WO_GE );
|
| - return c;
|
| -}
|
| -
|
| -/*
|
| -** Search for a term in the WHERE clause that is of the form "X <op> <expr>"
|
| -** where X is a reference to the iColumn of table iCur and <op> is one of
|
| -** the WO_xx operator codes specified by the op parameter.
|
| -** Return a pointer to the term. Return 0 if not found.
|
| -*/
|
| -static WhereTerm *findTerm(
|
| - WhereClause *pWC, /* The WHERE clause to be searched */
|
| - int iCur, /* Cursor number of LHS */
|
| - int iColumn, /* Column number of LHS */
|
| - Bitmask notReady, /* RHS must not overlap with this mask */
|
| - u32 op, /* Mask of WO_xx values describing operator */
|
| - Index *pIdx /* Must be compatible with this index, if not NULL */
|
| -){
|
| - WhereTerm *pTerm;
|
| - int k;
|
| - assert( iCur>=0 );
|
| - op &= WO_ALL;
|
| - for(pTerm=pWC->a, k=pWC->nTerm; k; k--, pTerm++){
|
| - if( pTerm->leftCursor==iCur
|
| - && (pTerm->prereqRight & notReady)==0
|
| - && pTerm->u.leftColumn==iColumn
|
| - && (pTerm->eOperator & op)!=0
|
| - ){
|
| - if( pIdx && pTerm->eOperator!=WO_ISNULL ){
|
| - Expr *pX = pTerm->pExpr;
|
| - CollSeq *pColl;
|
| - char idxaff;
|
| - int j;
|
| - Parse *pParse = pWC->pParse;
|
| -
|
| - idxaff = pIdx->pTable->aCol[iColumn].affinity;
|
| - if( !sqlite3IndexAffinityOk(pX, idxaff) ) continue;
|
| -
|
| - /* Figure out the collation sequence required from an index for
|
| - ** it to be useful for optimising expression pX. Store this
|
| - ** value in variable pColl.
|
| - */
|
| - assert(pX->pLeft);
|
| - pColl = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
|
| - assert(pColl || pParse->nErr);
|
| -
|
| - for(j=0; pIdx->aiColumn[j]!=iColumn; j++){
|
| - if( NEVER(j>=pIdx->nColumn) ) return 0;
|
| - }
|
| - if( pColl && sqlite3StrICmp(pColl->zName, pIdx->azColl[j]) ) continue;
|
| - }
|
| - return pTerm;
|
| - }
|
| - }
|
| - return 0;
|
| -}
|
| -
|
| -/* Forward reference */
|
| -static void exprAnalyze(SrcList*, WhereClause*, int);
|
| -
|
| -/*
|
| -** Call exprAnalyze on all terms in a WHERE clause.
|
| -**
|
| -**
|
| -*/
|
| -static void exprAnalyzeAll(
|
| - SrcList *pTabList, /* the FROM clause */
|
| - WhereClause *pWC /* the WHERE clause to be analyzed */
|
| -){
|
| - int i;
|
| - for(i=pWC->nTerm-1; i>=0; i--){
|
| - exprAnalyze(pTabList, pWC, i);
|
| - }
|
| -}
|
| -
|
| -#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
|
| -/*
|
| -** Check to see if the given expression is a LIKE or GLOB operator that
|
| -** can be optimized using inequality constraints. Return TRUE if it is
|
| -** so and false if not.
|
| -**
|
| -** In order for the operator to be optimizible, the RHS must be a string
|
| -** literal that does not begin with a wildcard.
|
| -*/
|
| -static int isLikeOrGlob(
|
| - Parse *pParse, /* Parsing and code generating context */
|
| - Expr *pExpr, /* Test this expression */
|
| - int *pnPattern, /* Number of non-wildcard prefix characters */
|
| - int *pisComplete, /* True if the only wildcard is % in the last character */
|
| - int *pnoCase /* True if uppercase is equivalent to lowercase */
|
| -){
|
| - const char *z; /* String on RHS of LIKE operator */
|
| - Expr *pRight, *pLeft; /* Right and left size of LIKE operator */
|
| - ExprList *pList; /* List of operands to the LIKE operator */
|
| - int c; /* One character in z[] */
|
| - int cnt; /* Number of non-wildcard prefix characters */
|
| - char wc[3]; /* Wildcard characters */
|
| - CollSeq *pColl; /* Collating sequence for LHS */
|
| - sqlite3 *db = pParse->db; /* Database connection */
|
| -
|
| - if( !sqlite3IsLikeFunction(db, pExpr, pnoCase, wc) ){
|
| - return 0;
|
| - }
|
| -#ifdef SQLITE_EBCDIC
|
| - if( *pnoCase ) return 0;
|
| -#endif
|
| - pList = pExpr->x.pList;
|
| - pRight = pList->a[0].pExpr;
|
| - if( pRight->op!=TK_STRING ){
|
| - return 0;
|
| - }
|
| - pLeft = pList->a[1].pExpr;
|
| - if( pLeft->op!=TK_COLUMN ){
|
| - return 0;
|
| - }
|
| - pColl = sqlite3ExprCollSeq(pParse, pLeft);
|
| - assert( pColl!=0 || pLeft->iColumn==-1 );
|
| - if( pColl==0 ) return 0;
|
| - if( (pColl->type!=SQLITE_COLL_BINARY || *pnoCase) &&
|
| - (pColl->type!=SQLITE_COLL_NOCASE || !*pnoCase) ){
|
| - return 0;
|
| - }
|
| - if( sqlite3ExprAffinity(pLeft)!=SQLITE_AFF_TEXT ) return 0;
|
| - z = pRight->u.zToken;
|
| - if( ALWAYS(z) ){
|
| - cnt = 0;
|
| - while( (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2] ){
|
| - cnt++;
|
| - }
|
| - if( cnt!=0 && c!=0 && 255!=(u8)z[cnt-1] ){
|
| - *pisComplete = z[cnt]==wc[0] && z[cnt+1]==0;
|
| - *pnPattern = cnt;
|
| - return 1;
|
| - }
|
| - }
|
| - return 0;
|
| -}
|
| -#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
|
| -
|
| -
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| -/*
|
| -** Check to see if the given expression is of the form
|
| -**
|
| -** column MATCH expr
|
| -**
|
| -** If it is then return TRUE. If not, return FALSE.
|
| -*/
|
| -static int isMatchOfColumn(
|
| - Expr *pExpr /* Test this expression */
|
| -){
|
| - ExprList *pList;
|
| -
|
| - if( pExpr->op!=TK_FUNCTION ){
|
| - return 0;
|
| - }
|
| - if( sqlite3StrICmp(pExpr->u.zToken,"match")!=0 ){
|
| - return 0;
|
| - }
|
| - pList = pExpr->x.pList;
|
| - if( pList->nExpr!=2 ){
|
| - return 0;
|
| - }
|
| - if( pList->a[1].pExpr->op != TK_COLUMN ){
|
| - return 0;
|
| - }
|
| - return 1;
|
| -}
|
| -#endif /* SQLITE_OMIT_VIRTUALTABLE */
|
| -
|
| -/*
|
| -** If the pBase expression originated in the ON or USING clause of
|
| -** a join, then transfer the appropriate markings over to derived.
|
| -*/
|
| -static void transferJoinMarkings(Expr *pDerived, Expr *pBase){
|
| - pDerived->flags |= pBase->flags & EP_FromJoin;
|
| - pDerived->iRightJoinTable = pBase->iRightJoinTable;
|
| -}
|
| -
|
| -#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
|
| -/*
|
| -** Analyze a term that consists of two or more OR-connected
|
| -** subterms. So in:
|
| -**
|
| -** ... WHERE (a=5) AND (b=7 OR c=9 OR d=13) AND (d=13)
|
| -** ^^^^^^^^^^^^^^^^^^^^
|
| -**
|
| -** This routine analyzes terms such as the middle term in the above example.
|
| -** A WhereOrTerm object is computed and attached to the term under
|
| -** analysis, regardless of the outcome of the analysis. Hence:
|
| -**
|
| -** WhereTerm.wtFlags |= TERM_ORINFO
|
| -** WhereTerm.u.pOrInfo = a dynamically allocated WhereOrTerm object
|
| -**
|
| -** The term being analyzed must have two or more of OR-connected subterms.
|
| -** A single subterm might be a set of AND-connected sub-subterms.
|
| -** Examples of terms under analysis:
|
| -**
|
| -** (A) t1.x=t2.y OR t1.x=t2.z OR t1.y=15 OR t1.z=t3.a+5
|
| -** (B) x=expr1 OR expr2=x OR x=expr3
|
| -** (C) t1.x=t2.y OR (t1.x=t2.z AND t1.y=15)
|
| -** (D) x=expr1 OR (y>11 AND y<22 AND z LIKE '*hello*')
|
| -** (E) (p.a=1 AND q.b=2 AND r.c=3) OR (p.x=4 AND q.y=5 AND r.z=6)
|
| -**
|
| -** CASE 1:
|
| -**
|
| -** If all subterms are of the form T.C=expr for some single column of C
|
| -** a single table T (as shown in example B above) then create a new virtual
|
| -** term that is an equivalent IN expression. In other words, if the term
|
| -** being analyzed is:
|
| -**
|
| -** x = expr1 OR expr2 = x OR x = expr3
|
| -**
|
| -** then create a new virtual term like this:
|
| -**
|
| -** x IN (expr1,expr2,expr3)
|
| -**
|
| -** CASE 2:
|
| -**
|
| -** If all subterms are indexable by a single table T, then set
|
| -**
|
| -** WhereTerm.eOperator = WO_OR
|
| -** WhereTerm.u.pOrInfo->indexable |= the cursor number for table T
|
| -**
|
| -** A subterm is "indexable" if it is of the form
|
| -** "T.C <op> <expr>" where C is any column of table T and
|
| -** <op> is one of "=", "<", "<=", ">", ">=", "IS NULL", or "IN".
|
| -** A subterm is also indexable if it is an AND of two or more
|
| -** subsubterms at least one of which is indexable. Indexable AND
|
| -** subterms have their eOperator set to WO_AND and they have
|
| -** u.pAndInfo set to a dynamically allocated WhereAndTerm object.
|
| -**
|
| -** From another point of view, "indexable" means that the subterm could
|
| -** potentially be used with an index if an appropriate index exists.
|
| -** This analysis does not consider whether or not the index exists; that
|
| -** is something the bestIndex() routine will determine. This analysis
|
| -** only looks at whether subterms appropriate for indexing exist.
|
| -**
|
| -** All examples A through E above all satisfy case 2. But if a term
|
| -** also statisfies case 1 (such as B) we know that the optimizer will
|
| -** always prefer case 1, so in that case we pretend that case 2 is not
|
| -** satisfied.
|
| -**
|
| -** It might be the case that multiple tables are indexable. For example,
|
| -** (E) above is indexable on tables P, Q, and R.
|
| -**
|
| -** Terms that satisfy case 2 are candidates for lookup by using
|
| -** separate indices to find rowids for each subterm and composing
|
| -** the union of all rowids using a RowSet object. This is similar
|
| -** to "bitmap indices" in other database engines.
|
| -**
|
| -** OTHERWISE:
|
| -**
|
| -** If neither case 1 nor case 2 apply, then leave the eOperator set to
|
| -** zero. This term is not useful for search.
|
| -*/
|
| -static void exprAnalyzeOrTerm(
|
| - SrcList *pSrc, /* the FROM clause */
|
| - WhereClause *pWC, /* the complete WHERE clause */
|
| - int idxTerm /* Index of the OR-term to be analyzed */
|
| -){
|
| - Parse *pParse = pWC->pParse; /* Parser context */
|
| - sqlite3 *db = pParse->db; /* Database connection */
|
| - WhereTerm *pTerm = &pWC->a[idxTerm]; /* The term to be analyzed */
|
| - Expr *pExpr = pTerm->pExpr; /* The expression of the term */
|
| - WhereMaskSet *pMaskSet = pWC->pMaskSet; /* Table use masks */
|
| - int i; /* Loop counters */
|
| - WhereClause *pOrWc; /* Breakup of pTerm into subterms */
|
| - WhereTerm *pOrTerm; /* A Sub-term within the pOrWc */
|
| - WhereOrInfo *pOrInfo; /* Additional information associated with pTerm */
|
| - Bitmask chngToIN; /* Tables that might satisfy case 1 */
|
| - Bitmask indexable; /* Tables that are indexable, satisfying case 2 */
|
| -
|
| - /*
|
| - ** Break the OR clause into its separate subterms. The subterms are
|
| - ** stored in a WhereClause structure containing within the WhereOrInfo
|
| - ** object that is attached to the original OR clause term.
|
| - */
|
| - assert( (pTerm->wtFlags & (TERM_DYNAMIC|TERM_ORINFO|TERM_ANDINFO))==0 );
|
| - assert( pExpr->op==TK_OR );
|
| - pTerm->u.pOrInfo = pOrInfo = sqlite3DbMallocZero(db, sizeof(*pOrInfo));
|
| - if( pOrInfo==0 ) return;
|
| - pTerm->wtFlags |= TERM_ORINFO;
|
| - pOrWc = &pOrInfo->wc;
|
| - whereClauseInit(pOrWc, pWC->pParse, pMaskSet);
|
| - whereSplit(pOrWc, pExpr, TK_OR);
|
| - exprAnalyzeAll(pSrc, pOrWc);
|
| - if( db->mallocFailed ) return;
|
| - assert( pOrWc->nTerm>=2 );
|
| -
|
| - /*
|
| - ** Compute the set of tables that might satisfy cases 1 or 2.
|
| - */
|
| - indexable = ~(Bitmask)0;
|
| - chngToIN = ~(pWC->vmask);
|
| - for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){
|
| - if( (pOrTerm->eOperator & WO_SINGLE)==0 ){
|
| - WhereAndInfo *pAndInfo;
|
| - assert( pOrTerm->eOperator==0 );
|
| - assert( (pOrTerm->wtFlags & (TERM_ANDINFO|TERM_ORINFO))==0 );
|
| - chngToIN = 0;
|
| - pAndInfo = sqlite3DbMallocRaw(db, sizeof(*pAndInfo));
|
| - if( pAndInfo ){
|
| - WhereClause *pAndWC;
|
| - WhereTerm *pAndTerm;
|
| - int j;
|
| - Bitmask b = 0;
|
| - pOrTerm->u.pAndInfo = pAndInfo;
|
| - pOrTerm->wtFlags |= TERM_ANDINFO;
|
| - pOrTerm->eOperator = WO_AND;
|
| - pAndWC = &pAndInfo->wc;
|
| - whereClauseInit(pAndWC, pWC->pParse, pMaskSet);
|
| - whereSplit(pAndWC, pOrTerm->pExpr, TK_AND);
|
| - exprAnalyzeAll(pSrc, pAndWC);
|
| - testcase( db->mallocFailed );
|
| - if( !db->mallocFailed ){
|
| - for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){
|
| - assert( pAndTerm->pExpr );
|
| - if( allowedOp(pAndTerm->pExpr->op) ){
|
| - b |= getMask(pMaskSet, pAndTerm->leftCursor);
|
| - }
|
| - }
|
| - }
|
| - indexable &= b;
|
| - }
|
| - }else if( pOrTerm->wtFlags & TERM_COPIED ){
|
| - /* Skip this term for now. We revisit it when we process the
|
| - ** corresponding TERM_VIRTUAL term */
|
| - }else{
|
| - Bitmask b;
|
| - b = getMask(pMaskSet, pOrTerm->leftCursor);
|
| - if( pOrTerm->wtFlags & TERM_VIRTUAL ){
|
| - WhereTerm *pOther = &pOrWc->a[pOrTerm->iParent];
|
| - b |= getMask(pMaskSet, pOther->leftCursor);
|
| - }
|
| - indexable &= b;
|
| - if( pOrTerm->eOperator!=WO_EQ ){
|
| - chngToIN = 0;
|
| - }else{
|
| - chngToIN &= b;
|
| - }
|
| - }
|
| - }
|
| -
|
| - /*
|
| - ** Record the set of tables that satisfy case 2. The set might be
|
| - ** empty.
|
| - */
|
| - pOrInfo->indexable = indexable;
|
| - pTerm->eOperator = indexable==0 ? 0 : WO_OR;
|
| -
|
| - /*
|
| - ** chngToIN holds a set of tables that *might* satisfy case 1. But
|
| - ** we have to do some additional checking to see if case 1 really
|
| - ** is satisfied.
|
| - **
|
| - ** chngToIN will hold either 0, 1, or 2 bits. The 0-bit case means
|
| - ** that there is no possibility of transforming the OR clause into an
|
| - ** IN operator because one or more terms in the OR clause contain
|
| - ** something other than == on a column in the single table. The 1-bit
|
| - ** case means that every term of the OR clause is of the form
|
| - ** "table.column=expr" for some single table. The one bit that is set
|
| - ** will correspond to the common table. We still need to check to make
|
| - ** sure the same column is used on all terms. The 2-bit case is when
|
| - ** the all terms are of the form "table1.column=table2.column". It
|
| - ** might be possible to form an IN operator with either table1.column
|
| - ** or table2.column as the LHS if either is common to every term of
|
| - ** the OR clause.
|
| - **
|
| - ** Note that terms of the form "table.column1=table.column2" (the
|
| - ** same table on both sizes of the ==) cannot be optimized.
|
| - */
|
| - if( chngToIN ){
|
| - int okToChngToIN = 0; /* True if the conversion to IN is valid */
|
| - int iColumn = -1; /* Column index on lhs of IN operator */
|
| - int iCursor = -1; /* Table cursor common to all terms */
|
| - int j = 0; /* Loop counter */
|
| -
|
| - /* Search for a table and column that appears on one side or the
|
| - ** other of the == operator in every subterm. That table and column
|
| - ** will be recorded in iCursor and iColumn. There might not be any
|
| - ** such table and column. Set okToChngToIN if an appropriate table
|
| - ** and column is found but leave okToChngToIN false if not found.
|
| - */
|
| - for(j=0; j<2 && !okToChngToIN; j++){
|
| - pOrTerm = pOrWc->a;
|
| - for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){
|
| - assert( pOrTerm->eOperator==WO_EQ );
|
| - pOrTerm->wtFlags &= ~TERM_OR_OK;
|
| - if( pOrTerm->leftCursor==iCursor ){
|
| - /* This is the 2-bit case and we are on the second iteration and
|
| - ** current term is from the first iteration. So skip this term. */
|
| - assert( j==1 );
|
| - continue;
|
| - }
|
| - if( (chngToIN & getMask(pMaskSet, pOrTerm->leftCursor))==0 ){
|
| - /* This term must be of the form t1.a==t2.b where t2 is in the
|
| - ** chngToIN set but t1 is not. This term will be either preceeded
|
| - ** or follwed by an inverted copy (t2.b==t1.a). Skip this term
|
| - ** and use its inversion. */
|
| - testcase( pOrTerm->wtFlags & TERM_COPIED );
|
| - testcase( pOrTerm->wtFlags & TERM_VIRTUAL );
|
| - assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) );
|
| - continue;
|
| - }
|
| - iColumn = pOrTerm->u.leftColumn;
|
| - iCursor = pOrTerm->leftCursor;
|
| - break;
|
| - }
|
| - if( i<0 ){
|
| - /* No candidate table+column was found. This can only occur
|
| - ** on the second iteration */
|
| - assert( j==1 );
|
| - assert( (chngToIN&(chngToIN-1))==0 );
|
| - assert( chngToIN==getMask(pMaskSet, iCursor) );
|
| - break;
|
| - }
|
| - testcase( j==1 );
|
| -
|
| - /* We have found a candidate table and column. Check to see if that
|
| - ** table and column is common to every term in the OR clause */
|
| - okToChngToIN = 1;
|
| - for(; i>=0 && okToChngToIN; i--, pOrTerm++){
|
| - assert( pOrTerm->eOperator==WO_EQ );
|
| - if( pOrTerm->leftCursor!=iCursor ){
|
| - pOrTerm->wtFlags &= ~TERM_OR_OK;
|
| - }else if( pOrTerm->u.leftColumn!=iColumn ){
|
| - okToChngToIN = 0;
|
| - }else{
|
| - int affLeft, affRight;
|
| - /* If the right-hand side is also a column, then the affinities
|
| - ** of both right and left sides must be such that no type
|
| - ** conversions are required on the right. (Ticket #2249)
|
| - */
|
| - affRight = sqlite3ExprAffinity(pOrTerm->pExpr->pRight);
|
| - affLeft = sqlite3ExprAffinity(pOrTerm->pExpr->pLeft);
|
| - if( affRight!=0 && affRight!=affLeft ){
|
| - okToChngToIN = 0;
|
| - }else{
|
| - pOrTerm->wtFlags |= TERM_OR_OK;
|
| - }
|
| - }
|
| - }
|
| - }
|
| -
|
| - /* At this point, okToChngToIN is true if original pTerm satisfies
|
| - ** case 1. In that case, construct a new virtual term that is
|
| - ** pTerm converted into an IN operator.
|
| - */
|
| - if( okToChngToIN ){
|
| - Expr *pDup; /* A transient duplicate expression */
|
| - ExprList *pList = 0; /* The RHS of the IN operator */
|
| - Expr *pLeft = 0; /* The LHS of the IN operator */
|
| - Expr *pNew; /* The complete IN operator */
|
| -
|
| - for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0; i--, pOrTerm++){
|
| - if( (pOrTerm->wtFlags & TERM_OR_OK)==0 ) continue;
|
| - assert( pOrTerm->eOperator==WO_EQ );
|
| - assert( pOrTerm->leftCursor==iCursor );
|
| - assert( pOrTerm->u.leftColumn==iColumn );
|
| - pDup = sqlite3ExprDup(db, pOrTerm->pExpr->pRight, 0);
|
| - pList = sqlite3ExprListAppend(pWC->pParse, pList, pDup);
|
| - pLeft = pOrTerm->pExpr->pLeft;
|
| - }
|
| - assert( pLeft!=0 );
|
| - pDup = sqlite3ExprDup(db, pLeft, 0);
|
| - pNew = sqlite3PExpr(pParse, TK_IN, pDup, 0, 0);
|
| - if( pNew ){
|
| - int idxNew;
|
| - transferJoinMarkings(pNew, pExpr);
|
| - assert( !ExprHasProperty(pNew, EP_xIsSelect) );
|
| - pNew->x.pList = pList;
|
| - idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
|
| - testcase( idxNew==0 );
|
| - exprAnalyze(pSrc, pWC, idxNew);
|
| - pTerm = &pWC->a[idxTerm];
|
| - pWC->a[idxNew].iParent = idxTerm;
|
| - pTerm->nChild = 1;
|
| - }else{
|
| - sqlite3ExprListDelete(db, pList);
|
| - }
|
| - pTerm->eOperator = 0; /* case 1 trumps case 2 */
|
| - }
|
| - }
|
| -}
|
| -#endif /* !SQLITE_OMIT_OR_OPTIMIZATION && !SQLITE_OMIT_SUBQUERY */
|
| -
|
| -
|
| -/*
|
| -** The input to this routine is an WhereTerm structure with only the
|
| -** "pExpr" field filled in. The job of this routine is to analyze the
|
| -** subexpression and populate all the other fields of the WhereTerm
|
| -** structure.
|
| -**
|
| -** If the expression is of the form "<expr> <op> X" it gets commuted
|
| -** to the standard form of "X <op> <expr>".
|
| -**
|
| -** If the expression is of the form "X <op> Y" where both X and Y are
|
| -** columns, then the original expression is unchanged and a new virtual
|
| -** term of the form "Y <op> X" is added to the WHERE clause and
|
| -** analyzed separately. The original term is marked with TERM_COPIED
|
| -** and the new term is marked with TERM_DYNAMIC (because it's pExpr
|
| -** needs to be freed with the WhereClause) and TERM_VIRTUAL (because it
|
| -** is a commuted copy of a prior term.) The original term has nChild=1
|
| -** and the copy has idxParent set to the index of the original term.
|
| -*/
|
| -static void exprAnalyze(
|
| - SrcList *pSrc, /* the FROM clause */
|
| - WhereClause *pWC, /* the WHERE clause */
|
| - int idxTerm /* Index of the term to be analyzed */
|
| -){
|
| - WhereTerm *pTerm; /* The term to be analyzed */
|
| - WhereMaskSet *pMaskSet; /* Set of table index masks */
|
| - Expr *pExpr; /* The expression to be analyzed */
|
| - Bitmask prereqLeft; /* Prerequesites of the pExpr->pLeft */
|
| - Bitmask prereqAll; /* Prerequesites of pExpr */
|
| - Bitmask extraRight = 0;
|
| - int nPattern;
|
| - int isComplete;
|
| - int noCase;
|
| - int op; /* Top-level operator. pExpr->op */
|
| - Parse *pParse = pWC->pParse; /* Parsing context */
|
| - sqlite3 *db = pParse->db; /* Database connection */
|
| -
|
| - if( db->mallocFailed ){
|
| - return;
|
| - }
|
| - pTerm = &pWC->a[idxTerm];
|
| - pMaskSet = pWC->pMaskSet;
|
| - pExpr = pTerm->pExpr;
|
| - prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
|
| - op = pExpr->op;
|
| - if( op==TK_IN ){
|
| - assert( pExpr->pRight==0 );
|
| - if( ExprHasProperty(pExpr, EP_xIsSelect) ){
|
| - pTerm->prereqRight = exprSelectTableUsage(pMaskSet, pExpr->x.pSelect);
|
| - }else{
|
| - pTerm->prereqRight = exprListTableUsage(pMaskSet, pExpr->x.pList);
|
| - }
|
| - }else if( op==TK_ISNULL ){
|
| - pTerm->prereqRight = 0;
|
| - }else{
|
| - pTerm->prereqRight = exprTableUsage(pMaskSet, pExpr->pRight);
|
| - }
|
| - prereqAll = exprTableUsage(pMaskSet, pExpr);
|
| - if( ExprHasProperty(pExpr, EP_FromJoin) ){
|
| - Bitmask x = getMask(pMaskSet, pExpr->iRightJoinTable);
|
| - prereqAll |= x;
|
| - extraRight = x-1; /* ON clause terms may not be used with an index
|
| - ** on left table of a LEFT JOIN. Ticket #3015 */
|
| - }
|
| - pTerm->prereqAll = prereqAll;
|
| - pTerm->leftCursor = -1;
|
| - pTerm->iParent = -1;
|
| - pTerm->eOperator = 0;
|
| - if( allowedOp(op) && (pTerm->prereqRight & prereqLeft)==0 ){
|
| - Expr *pLeft = pExpr->pLeft;
|
| - Expr *pRight = pExpr->pRight;
|
| - if( pLeft->op==TK_COLUMN ){
|
| - pTerm->leftCursor = pLeft->iTable;
|
| - pTerm->u.leftColumn = pLeft->iColumn;
|
| - pTerm->eOperator = operatorMask(op);
|
| - }
|
| - if( pRight && pRight->op==TK_COLUMN ){
|
| - WhereTerm *pNew;
|
| - Expr *pDup;
|
| - if( pTerm->leftCursor>=0 ){
|
| - int idxNew;
|
| - pDup = sqlite3ExprDup(db, pExpr, 0);
|
| - if( db->mallocFailed ){
|
| - sqlite3ExprDelete(db, pDup);
|
| - return;
|
| - }
|
| - idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC);
|
| - if( idxNew==0 ) return;
|
| - pNew = &pWC->a[idxNew];
|
| - pNew->iParent = idxTerm;
|
| - pTerm = &pWC->a[idxTerm];
|
| - pTerm->nChild = 1;
|
| - pTerm->wtFlags |= TERM_COPIED;
|
| - }else{
|
| - pDup = pExpr;
|
| - pNew = pTerm;
|
| - }
|
| - exprCommute(pParse, pDup);
|
| - pLeft = pDup->pLeft;
|
| - pNew->leftCursor = pLeft->iTable;
|
| - pNew->u.leftColumn = pLeft->iColumn;
|
| - pNew->prereqRight = prereqLeft;
|
| - pNew->prereqAll = prereqAll;
|
| - pNew->eOperator = operatorMask(pDup->op);
|
| - }
|
| - }
|
| -
|
| -#ifndef SQLITE_OMIT_BETWEEN_OPTIMIZATION
|
| - /* If a term is the BETWEEN operator, create two new virtual terms
|
| - ** that define the range that the BETWEEN implements. For example:
|
| - **
|
| - ** a BETWEEN b AND c
|
| - **
|
| - ** is converted into:
|
| - **
|
| - ** (a BETWEEN b AND c) AND (a>=b) AND (a<=c)
|
| - **
|
| - ** The two new terms are added onto the end of the WhereClause object.
|
| - ** The new terms are "dynamic" and are children of the original BETWEEN
|
| - ** term. That means that if the BETWEEN term is coded, the children are
|
| - ** skipped. Or, if the children are satisfied by an index, the original
|
| - ** BETWEEN term is skipped.
|
| - */
|
| - else if( pExpr->op==TK_BETWEEN && pWC->op==TK_AND ){
|
| - ExprList *pList = pExpr->x.pList;
|
| - int i;
|
| - static const u8 ops[] = {TK_GE, TK_LE};
|
| - assert( pList!=0 );
|
| - assert( pList->nExpr==2 );
|
| - for(i=0; i<2; i++){
|
| - Expr *pNewExpr;
|
| - int idxNew;
|
| - pNewExpr = sqlite3PExpr(pParse, ops[i],
|
| - sqlite3ExprDup(db, pExpr->pLeft, 0),
|
| - sqlite3ExprDup(db, pList->a[i].pExpr, 0), 0);
|
| - idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
|
| - testcase( idxNew==0 );
|
| - exprAnalyze(pSrc, pWC, idxNew);
|
| - pTerm = &pWC->a[idxTerm];
|
| - pWC->a[idxNew].iParent = idxTerm;
|
| - }
|
| - pTerm->nChild = 2;
|
| - }
|
| -#endif /* SQLITE_OMIT_BETWEEN_OPTIMIZATION */
|
| -
|
| -#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
|
| - /* Analyze a term that is composed of two or more subterms connected by
|
| - ** an OR operator.
|
| - */
|
| - else if( pExpr->op==TK_OR ){
|
| - assert( pWC->op==TK_AND );
|
| - exprAnalyzeOrTerm(pSrc, pWC, idxTerm);
|
| - pTerm = &pWC->a[idxTerm];
|
| - }
|
| -#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
|
| -
|
| -#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
|
| - /* Add constraints to reduce the search space on a LIKE or GLOB
|
| - ** operator.
|
| - **
|
| - ** A like pattern of the form "x LIKE 'abc%'" is changed into constraints
|
| - **
|
| - ** x>='abc' AND x<'abd' AND x LIKE 'abc%'
|
| - **
|
| - ** The last character of the prefix "abc" is incremented to form the
|
| - ** termination condition "abd".
|
| - */
|
| - if( isLikeOrGlob(pParse, pExpr, &nPattern, &isComplete, &noCase)
|
| - && pWC->op==TK_AND ){
|
| - Expr *pLeft, *pRight;
|
| - Expr *pStr1, *pStr2;
|
| - Expr *pNewExpr1, *pNewExpr2;
|
| - int idxNew1, idxNew2;
|
| -
|
| - pLeft = pExpr->x.pList->a[1].pExpr;
|
| - pRight = pExpr->x.pList->a[0].pExpr;
|
| - pStr1 = sqlite3Expr(db, TK_STRING, pRight->u.zToken);
|
| - if( pStr1 ) pStr1->u.zToken[nPattern] = 0;
|
| - pStr2 = sqlite3ExprDup(db, pStr1, 0);
|
| - if( !db->mallocFailed ){
|
| - u8 c, *pC; /* Last character before the first wildcard */
|
| - pC = (u8*)&pStr2->u.zToken[nPattern-1];
|
| - c = *pC;
|
| - if( noCase ){
|
| - /* The point is to increment the last character before the first
|
| - ** wildcard. But if we increment '@', that will push it into the
|
| - ** alphabetic range where case conversions will mess up the
|
| - ** inequality. To avoid this, make sure to also run the full
|
| - ** LIKE on all candidate expressions by clearing the isComplete flag
|
| - */
|
| - if( c=='A'-1 ) isComplete = 0;
|
| -
|
| - c = sqlite3UpperToLower[c];
|
| - }
|
| - *pC = c + 1;
|
| - }
|
| - pNewExpr1 = sqlite3PExpr(pParse, TK_GE, sqlite3ExprDup(db,pLeft,0),pStr1,0);
|
| - idxNew1 = whereClauseInsert(pWC, pNewExpr1, TERM_VIRTUAL|TERM_DYNAMIC);
|
| - testcase( idxNew1==0 );
|
| - exprAnalyze(pSrc, pWC, idxNew1);
|
| - pNewExpr2 = sqlite3PExpr(pParse, TK_LT, sqlite3ExprDup(db,pLeft,0),pStr2,0);
|
| - idxNew2 = whereClauseInsert(pWC, pNewExpr2, TERM_VIRTUAL|TERM_DYNAMIC);
|
| - testcase( idxNew2==0 );
|
| - exprAnalyze(pSrc, pWC, idxNew2);
|
| - pTerm = &pWC->a[idxTerm];
|
| - if( isComplete ){
|
| - pWC->a[idxNew1].iParent = idxTerm;
|
| - pWC->a[idxNew2].iParent = idxTerm;
|
| - pTerm->nChild = 2;
|
| - }
|
| - }
|
| -#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
|
| -
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| - /* Add a WO_MATCH auxiliary term to the constraint set if the
|
| - ** current expression is of the form: column MATCH expr.
|
| - ** This information is used by the xBestIndex methods of
|
| - ** virtual tables. The native query optimizer does not attempt
|
| - ** to do anything with MATCH functions.
|
| - */
|
| - if( isMatchOfColumn(pExpr) ){
|
| - int idxNew;
|
| - Expr *pRight, *pLeft;
|
| - WhereTerm *pNewTerm;
|
| - Bitmask prereqColumn, prereqExpr;
|
| -
|
| - pRight = pExpr->x.pList->a[0].pExpr;
|
| - pLeft = pExpr->x.pList->a[1].pExpr;
|
| - prereqExpr = exprTableUsage(pMaskSet, pRight);
|
| - prereqColumn = exprTableUsage(pMaskSet, pLeft);
|
| - if( (prereqExpr & prereqColumn)==0 ){
|
| - Expr *pNewExpr;
|
| - pNewExpr = sqlite3PExpr(pParse, TK_MATCH,
|
| - 0, sqlite3ExprDup(db, pRight, 0), 0);
|
| - idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
|
| - testcase( idxNew==0 );
|
| - pNewTerm = &pWC->a[idxNew];
|
| - pNewTerm->prereqRight = prereqExpr;
|
| - pNewTerm->leftCursor = pLeft->iTable;
|
| - pNewTerm->u.leftColumn = pLeft->iColumn;
|
| - pNewTerm->eOperator = WO_MATCH;
|
| - pNewTerm->iParent = idxTerm;
|
| - pTerm = &pWC->a[idxTerm];
|
| - pTerm->nChild = 1;
|
| - pTerm->wtFlags |= TERM_COPIED;
|
| - pNewTerm->prereqAll = pTerm->prereqAll;
|
| - }
|
| - }
|
| -#endif /* SQLITE_OMIT_VIRTUALTABLE */
|
| -
|
| - /* Prevent ON clause terms of a LEFT JOIN from being used to drive
|
| - ** an index for tables to the left of the join.
|
| - */
|
| - pTerm->prereqRight |= extraRight;
|
| -}
|
| -
|
| -/*
|
| -** Return TRUE if any of the expressions in pList->a[iFirst...] contain
|
| -** a reference to any table other than the iBase table.
|
| -*/
|
| -static int referencesOtherTables(
|
| - ExprList *pList, /* Search expressions in ths list */
|
| - WhereMaskSet *pMaskSet, /* Mapping from tables to bitmaps */
|
| - int iFirst, /* Be searching with the iFirst-th expression */
|
| - int iBase /* Ignore references to this table */
|
| -){
|
| - Bitmask allowed = ~getMask(pMaskSet, iBase);
|
| - while( iFirst<pList->nExpr ){
|
| - if( (exprTableUsage(pMaskSet, pList->a[iFirst++].pExpr)&allowed)!=0 ){
|
| - return 1;
|
| - }
|
| - }
|
| - return 0;
|
| -}
|
| -
|
| -
|
| -/*
|
| -** This routine decides if pIdx can be used to satisfy the ORDER BY
|
| -** clause. If it can, it returns 1. If pIdx cannot satisfy the
|
| -** ORDER BY clause, this routine returns 0.
|
| -**
|
| -** pOrderBy is an ORDER BY clause from a SELECT statement. pTab is the
|
| -** left-most table in the FROM clause of that same SELECT statement and
|
| -** the table has a cursor number of "base". pIdx is an index on pTab.
|
| -**
|
| -** nEqCol is the number of columns of pIdx that are used as equality
|
| -** constraints. Any of these columns may be missing from the ORDER BY
|
| -** clause and the match can still be a success.
|
| -**
|
| -** All terms of the ORDER BY that match against the index must be either
|
| -** ASC or DESC. (Terms of the ORDER BY clause past the end of a UNIQUE
|
| -** index do not need to satisfy this constraint.) The *pbRev value is
|
| -** set to 1 if the ORDER BY clause is all DESC and it is set to 0 if
|
| -** the ORDER BY clause is all ASC.
|
| -*/
|
| -static int isSortingIndex(
|
| - Parse *pParse, /* Parsing context */
|
| - WhereMaskSet *pMaskSet, /* Mapping from table cursor numbers to bitmaps */
|
| - Index *pIdx, /* The index we are testing */
|
| - int base, /* Cursor number for the table to be sorted */
|
| - ExprList *pOrderBy, /* The ORDER BY clause */
|
| - int nEqCol, /* Number of index columns with == constraints */
|
| - int *pbRev /* Set to 1 if ORDER BY is DESC */
|
| -){
|
| - int i, j; /* Loop counters */
|
| - int sortOrder = 0; /* XOR of index and ORDER BY sort direction */
|
| - int nTerm; /* Number of ORDER BY terms */
|
| - struct ExprList_item *pTerm; /* A term of the ORDER BY clause */
|
| - sqlite3 *db = pParse->db;
|
| -
|
| - assert( pOrderBy!=0 );
|
| - nTerm = pOrderBy->nExpr;
|
| - assert( nTerm>0 );
|
| -
|
| - /* Argument pIdx must either point to a 'real' named index structure,
|
| - ** or an index structure allocated on the stack by bestBtreeIndex() to
|
| - ** represent the rowid index that is part of every table. */
|
| - assert( pIdx->zName || (pIdx->nColumn==1 && pIdx->aiColumn[0]==-1) );
|
| -
|
| - /* Match terms of the ORDER BY clause against columns of
|
| - ** the index.
|
| - **
|
| - ** Note that indices have pIdx->nColumn regular columns plus
|
| - ** one additional column containing the rowid. The rowid column
|
| - ** of the index is also allowed to match against the ORDER BY
|
| - ** clause.
|
| - */
|
| - for(i=j=0, pTerm=pOrderBy->a; j<nTerm && i<=pIdx->nColumn; i++){
|
| - Expr *pExpr; /* The expression of the ORDER BY pTerm */
|
| - CollSeq *pColl; /* The collating sequence of pExpr */
|
| - int termSortOrder; /* Sort order for this term */
|
| - int iColumn; /* The i-th column of the index. -1 for rowid */
|
| - int iSortOrder; /* 1 for DESC, 0 for ASC on the i-th index term */
|
| - const char *zColl; /* Name of the collating sequence for i-th index term */
|
| -
|
| - pExpr = pTerm->pExpr;
|
| - if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ){
|
| - /* Can not use an index sort on anything that is not a column in the
|
| - ** left-most table of the FROM clause */
|
| - break;
|
| - }
|
| - pColl = sqlite3ExprCollSeq(pParse, pExpr);
|
| - if( !pColl ){
|
| - pColl = db->pDfltColl;
|
| - }
|
| - if( pIdx->zName && i<pIdx->nColumn ){
|
| - iColumn = pIdx->aiColumn[i];
|
| - if( iColumn==pIdx->pTable->iPKey ){
|
| - iColumn = -1;
|
| - }
|
| - iSortOrder = pIdx->aSortOrder[i];
|
| - zColl = pIdx->azColl[i];
|
| - }else{
|
| - iColumn = -1;
|
| - iSortOrder = 0;
|
| - zColl = pColl->zName;
|
| - }
|
| - if( pExpr->iColumn!=iColumn || sqlite3StrICmp(pColl->zName, zColl) ){
|
| - /* Term j of the ORDER BY clause does not match column i of the index */
|
| - if( i<nEqCol ){
|
| - /* If an index column that is constrained by == fails to match an
|
| - ** ORDER BY term, that is OK. Just ignore that column of the index
|
| - */
|
| - continue;
|
| - }else if( i==pIdx->nColumn ){
|
| - /* Index column i is the rowid. All other terms match. */
|
| - break;
|
| - }else{
|
| - /* If an index column fails to match and is not constrained by ==
|
| - ** then the index cannot satisfy the ORDER BY constraint.
|
| - */
|
| - return 0;
|
| - }
|
| - }
|
| - assert( pIdx->aSortOrder!=0 || iColumn==-1 );
|
| - assert( pTerm->sortOrder==0 || pTerm->sortOrder==1 );
|
| - assert( iSortOrder==0 || iSortOrder==1 );
|
| - termSortOrder = iSortOrder ^ pTerm->sortOrder;
|
| - if( i>nEqCol ){
|
| - if( termSortOrder!=sortOrder ){
|
| - /* Indices can only be used if all ORDER BY terms past the
|
| - ** equality constraints are all either DESC or ASC. */
|
| - return 0;
|
| - }
|
| - }else{
|
| - sortOrder = termSortOrder;
|
| - }
|
| - j++;
|
| - pTerm++;
|
| - if( iColumn<0 && !referencesOtherTables(pOrderBy, pMaskSet, j, base) ){
|
| - /* If the indexed column is the primary key and everything matches
|
| - ** so far and none of the ORDER BY terms to the right reference other
|
| - ** tables in the join, then we are assured that the index can be used
|
| - ** to sort because the primary key is unique and so none of the other
|
| - ** columns will make any difference
|
| - */
|
| - j = nTerm;
|
| - }
|
| - }
|
| -
|
| - *pbRev = sortOrder!=0;
|
| - if( j>=nTerm ){
|
| - /* All terms of the ORDER BY clause are covered by this index so
|
| - ** this index can be used for sorting. */
|
| - return 1;
|
| - }
|
| - if( pIdx->onError!=OE_None && i==pIdx->nColumn
|
| - && !referencesOtherTables(pOrderBy, pMaskSet, j, base) ){
|
| - /* All terms of this index match some prefix of the ORDER BY clause
|
| - ** and the index is UNIQUE and no terms on the tail of the ORDER BY
|
| - ** clause reference other tables in a join. If this is all true then
|
| - ** the order by clause is superfluous. */
|
| - return 1;
|
| - }
|
| - return 0;
|
| -}
|
| -
|
| -/*
|
| -** Prepare a crude estimate of the logarithm of the input value.
|
| -** The results need not be exact. This is only used for estimating
|
| -** the total cost of performing operations with O(logN) or O(NlogN)
|
| -** complexity. Because N is just a guess, it is no great tragedy if
|
| -** logN is a little off.
|
| -*/
|
| -static double estLog(double N){
|
| - double logN = 1;
|
| - double x = 10;
|
| - while( N>x ){
|
| - logN += 1;
|
| - x *= 10;
|
| - }
|
| - return logN;
|
| -}
|
| -
|
| -/*
|
| -** Two routines for printing the content of an sqlite3_index_info
|
| -** structure. Used for testing and debugging only. If neither
|
| -** SQLITE_TEST or SQLITE_DEBUG are defined, then these routines
|
| -** are no-ops.
|
| -*/
|
| -#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_DEBUG)
|
| -static void TRACE_IDX_INPUTS(sqlite3_index_info *p){
|
| - int i;
|
| - if( !sqlite3WhereTrace ) return;
|
| - for(i=0; i<p->nConstraint; i++){
|
| - sqlite3DebugPrintf(" constraint[%d]: col=%d termid=%d op=%d usabled=%d\n",
|
| - i,
|
| - p->aConstraint[i].iColumn,
|
| - p->aConstraint[i].iTermOffset,
|
| - p->aConstraint[i].op,
|
| - p->aConstraint[i].usable);
|
| - }
|
| - for(i=0; i<p->nOrderBy; i++){
|
| - sqlite3DebugPrintf(" orderby[%d]: col=%d desc=%d\n",
|
| - i,
|
| - p->aOrderBy[i].iColumn,
|
| - p->aOrderBy[i].desc);
|
| - }
|
| -}
|
| -static void TRACE_IDX_OUTPUTS(sqlite3_index_info *p){
|
| - int i;
|
| - if( !sqlite3WhereTrace ) return;
|
| - for(i=0; i<p->nConstraint; i++){
|
| - sqlite3DebugPrintf(" usage[%d]: argvIdx=%d omit=%d\n",
|
| - i,
|
| - p->aConstraintUsage[i].argvIndex,
|
| - p->aConstraintUsage[i].omit);
|
| - }
|
| - sqlite3DebugPrintf(" idxNum=%d\n", p->idxNum);
|
| - sqlite3DebugPrintf(" idxStr=%s\n", p->idxStr);
|
| - sqlite3DebugPrintf(" orderByConsumed=%d\n", p->orderByConsumed);
|
| - sqlite3DebugPrintf(" estimatedCost=%g\n", p->estimatedCost);
|
| -}
|
| -#else
|
| -#define TRACE_IDX_INPUTS(A)
|
| -#define TRACE_IDX_OUTPUTS(A)
|
| -#endif
|
| -
|
| -/*
|
| -** Required because bestIndex() is called by bestOrClauseIndex()
|
| -*/
|
| -static void bestIndex(
|
| - Parse*, WhereClause*, struct SrcList_item*, Bitmask, ExprList*, WhereCost*);
|
| -
|
| -/*
|
| -** This routine attempts to find an scanning strategy that can be used
|
| -** to optimize an 'OR' expression that is part of a WHERE clause.
|
| -**
|
| -** The table associated with FROM clause term pSrc may be either a
|
| -** regular B-Tree table or a virtual table.
|
| -*/
|
| -static void bestOrClauseIndex(
|
| - Parse *pParse, /* The parsing context */
|
| - WhereClause *pWC, /* The WHERE clause */
|
| - struct SrcList_item *pSrc, /* The FROM clause term to search */
|
| - Bitmask notReady, /* Mask of cursors that are not available */
|
| - ExprList *pOrderBy, /* The ORDER BY clause */
|
| - WhereCost *pCost /* Lowest cost query plan */
|
| -){
|
| -#ifndef SQLITE_OMIT_OR_OPTIMIZATION
|
| - const int iCur = pSrc->iCursor; /* The cursor of the table to be accessed */
|
| - const Bitmask maskSrc = getMask(pWC->pMaskSet, iCur); /* Bitmask for pSrc */
|
| - WhereTerm * const pWCEnd = &pWC->a[pWC->nTerm]; /* End of pWC->a[] */
|
| - WhereTerm *pTerm; /* A single term of the WHERE clause */
|
| -
|
| - /* Search the WHERE clause terms for a usable WO_OR term. */
|
| - for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
|
| - if( pTerm->eOperator==WO_OR
|
| - && ((pTerm->prereqAll & ~maskSrc) & notReady)==0
|
| - && (pTerm->u.pOrInfo->indexable & maskSrc)!=0
|
| - ){
|
| - WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
|
| - WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
|
| - WhereTerm *pOrTerm;
|
| - int flags = WHERE_MULTI_OR;
|
| - double rTotal = 0;
|
| - double nRow = 0;
|
| - Bitmask used = 0;
|
| -
|
| - for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){
|
| - WhereCost sTermCost;
|
| - WHERETRACE(("... Multi-index OR testing for term %d of %d....\n",
|
| - (pOrTerm - pOrWC->a), (pTerm - pWC->a)
|
| - ));
|
| - if( pOrTerm->eOperator==WO_AND ){
|
| - WhereClause *pAndWC = &pOrTerm->u.pAndInfo->wc;
|
| - bestIndex(pParse, pAndWC, pSrc, notReady, 0, &sTermCost);
|
| - }else if( pOrTerm->leftCursor==iCur ){
|
| - WhereClause tempWC;
|
| - tempWC.pParse = pWC->pParse;
|
| - tempWC.pMaskSet = pWC->pMaskSet;
|
| - tempWC.op = TK_AND;
|
| - tempWC.a = pOrTerm;
|
| - tempWC.nTerm = 1;
|
| - bestIndex(pParse, &tempWC, pSrc, notReady, 0, &sTermCost);
|
| - }else{
|
| - continue;
|
| - }
|
| - rTotal += sTermCost.rCost;
|
| - nRow += sTermCost.nRow;
|
| - used |= sTermCost.used;
|
| - if( rTotal>=pCost->rCost ) break;
|
| - }
|
| -
|
| - /* If there is an ORDER BY clause, increase the scan cost to account
|
| - ** for the cost of the sort. */
|
| - if( pOrderBy!=0 ){
|
| - rTotal += nRow*estLog(nRow);
|
| - WHERETRACE(("... sorting increases OR cost to %.9g\n", rTotal));
|
| - }
|
| -
|
| - /* If the cost of scanning using this OR term for optimization is
|
| - ** less than the current cost stored in pCost, replace the contents
|
| - ** of pCost. */
|
| - WHERETRACE(("... multi-index OR cost=%.9g nrow=%.9g\n", rTotal, nRow));
|
| - if( rTotal<pCost->rCost ){
|
| - pCost->rCost = rTotal;
|
| - pCost->nRow = nRow;
|
| - pCost->used = used;
|
| - pCost->plan.wsFlags = flags;
|
| - pCost->plan.u.pTerm = pTerm;
|
| - }
|
| - }
|
| - }
|
| -#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
|
| -}
|
| -
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| -/*
|
| -** Allocate and populate an sqlite3_index_info structure. It is the
|
| -** responsibility of the caller to eventually release the structure
|
| -** by passing the pointer returned by this function to sqlite3_free().
|
| -*/
|
| -static sqlite3_index_info *allocateIndexInfo(
|
| - Parse *pParse,
|
| - WhereClause *pWC,
|
| - struct SrcList_item *pSrc,
|
| - ExprList *pOrderBy
|
| -){
|
| - int i, j;
|
| - int nTerm;
|
| - struct sqlite3_index_constraint *pIdxCons;
|
| - struct sqlite3_index_orderby *pIdxOrderBy;
|
| - struct sqlite3_index_constraint_usage *pUsage;
|
| - WhereTerm *pTerm;
|
| - int nOrderBy;
|
| - sqlite3_index_info *pIdxInfo;
|
| -
|
| - WHERETRACE(("Recomputing index info for %s...\n", pSrc->pTab->zName));
|
| -
|
| - /* Count the number of possible WHERE clause constraints referring
|
| - ** to this virtual table */
|
| - for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
|
| - if( pTerm->leftCursor != pSrc->iCursor ) continue;
|
| - assert( (pTerm->eOperator&(pTerm->eOperator-1))==0 );
|
| - testcase( pTerm->eOperator==WO_IN );
|
| - testcase( pTerm->eOperator==WO_ISNULL );
|
| - if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
|
| - nTerm++;
|
| - }
|
| -
|
| - /* If the ORDER BY clause contains only columns in the current
|
| - ** virtual table then allocate space for the aOrderBy part of
|
| - ** the sqlite3_index_info structure.
|
| - */
|
| - nOrderBy = 0;
|
| - if( pOrderBy ){
|
| - for(i=0; i<pOrderBy->nExpr; i++){
|
| - Expr *pExpr = pOrderBy->a[i].pExpr;
|
| - if( pExpr->op!=TK_COLUMN || pExpr->iTable!=pSrc->iCursor ) break;
|
| - }
|
| - if( i==pOrderBy->nExpr ){
|
| - nOrderBy = pOrderBy->nExpr;
|
| - }
|
| - }
|
| -
|
| - /* Allocate the sqlite3_index_info structure
|
| - */
|
| - pIdxInfo = sqlite3DbMallocZero(pParse->db, sizeof(*pIdxInfo)
|
| - + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
|
| - + sizeof(*pIdxOrderBy)*nOrderBy );
|
| - if( pIdxInfo==0 ){
|
| - sqlite3ErrorMsg(pParse, "out of memory");
|
| - /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
|
| - return 0;
|
| - }
|
| -
|
| - /* Initialize the structure. The sqlite3_index_info structure contains
|
| - ** many fields that are declared "const" to prevent xBestIndex from
|
| - ** changing them. We have to do some funky casting in order to
|
| - ** initialize those fields.
|
| - */
|
| - pIdxCons = (struct sqlite3_index_constraint*)&pIdxInfo[1];
|
| - pIdxOrderBy = (struct sqlite3_index_orderby*)&pIdxCons[nTerm];
|
| - pUsage = (struct sqlite3_index_constraint_usage*)&pIdxOrderBy[nOrderBy];
|
| - *(int*)&pIdxInfo->nConstraint = nTerm;
|
| - *(int*)&pIdxInfo->nOrderBy = nOrderBy;
|
| - *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint = pIdxCons;
|
| - *(struct sqlite3_index_orderby**)&pIdxInfo->aOrderBy = pIdxOrderBy;
|
| - *(struct sqlite3_index_constraint_usage**)&pIdxInfo->aConstraintUsage =
|
| - pUsage;
|
| -
|
| - for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
|
| - if( pTerm->leftCursor != pSrc->iCursor ) continue;
|
| - assert( (pTerm->eOperator&(pTerm->eOperator-1))==0 );
|
| - testcase( pTerm->eOperator==WO_IN );
|
| - testcase( pTerm->eOperator==WO_ISNULL );
|
| - if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
|
| - pIdxCons[j].iColumn = pTerm->u.leftColumn;
|
| - pIdxCons[j].iTermOffset = i;
|
| - pIdxCons[j].op = (u8)pTerm->eOperator;
|
| - /* The direct assignment in the previous line is possible only because
|
| - ** the WO_ and SQLITE_INDEX_CONSTRAINT_ codes are identical. The
|
| - ** following asserts verify this fact. */
|
| - assert( WO_EQ==SQLITE_INDEX_CONSTRAINT_EQ );
|
| - assert( WO_LT==SQLITE_INDEX_CONSTRAINT_LT );
|
| - assert( WO_LE==SQLITE_INDEX_CONSTRAINT_LE );
|
| - assert( WO_GT==SQLITE_INDEX_CONSTRAINT_GT );
|
| - assert( WO_GE==SQLITE_INDEX_CONSTRAINT_GE );
|
| - assert( WO_MATCH==SQLITE_INDEX_CONSTRAINT_MATCH );
|
| - assert( pTerm->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_MATCH) );
|
| - j++;
|
| - }
|
| - for(i=0; i<nOrderBy; i++){
|
| - Expr *pExpr = pOrderBy->a[i].pExpr;
|
| - pIdxOrderBy[i].iColumn = pExpr->iColumn;
|
| - pIdxOrderBy[i].desc = pOrderBy->a[i].sortOrder;
|
| - }
|
| -
|
| - return pIdxInfo;
|
| -}
|
| -
|
| -/*
|
| -** The table object reference passed as the second argument to this function
|
| -** must represent a virtual table. This function invokes the xBestIndex()
|
| -** method of the virtual table with the sqlite3_index_info pointer passed
|
| -** as the argument.
|
| -**
|
| -** If an error occurs, pParse is populated with an error message and a
|
| -** non-zero value is returned. Otherwise, 0 is returned and the output
|
| -** part of the sqlite3_index_info structure is left populated.
|
| -**
|
| -** Whether or not an error is returned, it is the responsibility of the
|
| -** caller to eventually free p->idxStr if p->needToFreeIdxStr indicates
|
| -** that this is required.
|
| -*/
|
| -static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite3_index_info *p){
|
| - sqlite3_vtab *pVtab = sqlite3GetVTable(pParse->db, pTab)->pVtab;
|
| - int i;
|
| - int rc;
|
| -
|
| - (void)sqlite3SafetyOff(pParse->db);
|
| - WHERETRACE(("xBestIndex for %s\n", pTab->zName));
|
| - TRACE_IDX_INPUTS(p);
|
| - rc = pVtab->pModule->xBestIndex(pVtab, p);
|
| - TRACE_IDX_OUTPUTS(p);
|
| - (void)sqlite3SafetyOn(pParse->db);
|
| -
|
| - if( rc!=SQLITE_OK ){
|
| - if( rc==SQLITE_NOMEM ){
|
| - pParse->db->mallocFailed = 1;
|
| - }else if( !pVtab->zErrMsg ){
|
| - sqlite3ErrorMsg(pParse, "%s", sqlite3ErrStr(rc));
|
| - }else{
|
| - sqlite3ErrorMsg(pParse, "%s", pVtab->zErrMsg);
|
| - }
|
| - }
|
| - sqlite3DbFree(pParse->db, pVtab->zErrMsg);
|
| - pVtab->zErrMsg = 0;
|
| -
|
| - for(i=0; i<p->nConstraint; i++){
|
| - if( !p->aConstraint[i].usable && p->aConstraintUsage[i].argvIndex>0 ){
|
| - sqlite3ErrorMsg(pParse,
|
| - "table %s: xBestIndex returned an invalid plan", pTab->zName);
|
| - }
|
| - }
|
| -
|
| - return pParse->nErr;
|
| -}
|
| -
|
| -
|
| -/*
|
| -** Compute the best index for a virtual table.
|
| -**
|
| -** The best index is computed by the xBestIndex method of the virtual
|
| -** table module. This routine is really just a wrapper that sets up
|
| -** the sqlite3_index_info structure that is used to communicate with
|
| -** xBestIndex.
|
| -**
|
| -** In a join, this routine might be called multiple times for the
|
| -** same virtual table. The sqlite3_index_info structure is created
|
| -** and initialized on the first invocation and reused on all subsequent
|
| -** invocations. The sqlite3_index_info structure is also used when
|
| -** code is generated to access the virtual table. The whereInfoDelete()
|
| -** routine takes care of freeing the sqlite3_index_info structure after
|
| -** everybody has finished with it.
|
| -*/
|
| -static void bestVirtualIndex(
|
| - Parse *pParse, /* The parsing context */
|
| - WhereClause *pWC, /* The WHERE clause */
|
| - struct SrcList_item *pSrc, /* The FROM clause term to search */
|
| - Bitmask notReady, /* Mask of cursors that are not available */
|
| - ExprList *pOrderBy, /* The order by clause */
|
| - WhereCost *pCost, /* Lowest cost query plan */
|
| - sqlite3_index_info **ppIdxInfo /* Index information passed to xBestIndex */
|
| -){
|
| - Table *pTab = pSrc->pTab;
|
| - sqlite3_index_info *pIdxInfo;
|
| - struct sqlite3_index_constraint *pIdxCons;
|
| - struct sqlite3_index_constraint_usage *pUsage;
|
| - WhereTerm *pTerm;
|
| - int i, j;
|
| - int nOrderBy;
|
| -
|
| - /* Make sure wsFlags is initialized to some sane value. Otherwise, if the
|
| - ** malloc in allocateIndexInfo() fails and this function returns leaving
|
| - ** wsFlags in an uninitialized state, the caller may behave unpredictably.
|
| - */
|
| - memset(pCost, 0, sizeof(*pCost));
|
| - pCost->plan.wsFlags = WHERE_VIRTUALTABLE;
|
| -
|
| - /* If the sqlite3_index_info structure has not been previously
|
| - ** allocated and initialized, then allocate and initialize it now.
|
| - */
|
| - pIdxInfo = *ppIdxInfo;
|
| - if( pIdxInfo==0 ){
|
| - *ppIdxInfo = pIdxInfo = allocateIndexInfo(pParse, pWC, pSrc, pOrderBy);
|
| - }
|
| - if( pIdxInfo==0 ){
|
| - return;
|
| - }
|
| -
|
| - /* At this point, the sqlite3_index_info structure that pIdxInfo points
|
| - ** to will have been initialized, either during the current invocation or
|
| - ** during some prior invocation. Now we just have to customize the
|
| - ** details of pIdxInfo for the current invocation and pass it to
|
| - ** xBestIndex.
|
| - */
|
| -
|
| - /* The module name must be defined. Also, by this point there must
|
| - ** be a pointer to an sqlite3_vtab structure. Otherwise
|
| - ** sqlite3ViewGetColumnNames() would have picked up the error.
|
| - */
|
| - assert( pTab->azModuleArg && pTab->azModuleArg[0] );
|
| - assert( sqlite3GetVTable(pParse->db, pTab) );
|
| -
|
| - /* Set the aConstraint[].usable fields and initialize all
|
| - ** output variables to zero.
|
| - **
|
| - ** aConstraint[].usable is true for constraints where the right-hand
|
| - ** side contains only references to tables to the left of the current
|
| - ** table. In other words, if the constraint is of the form:
|
| - **
|
| - ** column = expr
|
| - **
|
| - ** and we are evaluating a join, then the constraint on column is
|
| - ** only valid if all tables referenced in expr occur to the left
|
| - ** of the table containing column.
|
| - **
|
| - ** The aConstraints[] array contains entries for all constraints
|
| - ** on the current table. That way we only have to compute it once
|
| - ** even though we might try to pick the best index multiple times.
|
| - ** For each attempt at picking an index, the order of tables in the
|
| - ** join might be different so we have to recompute the usable flag
|
| - ** each time.
|
| - */
|
| - pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
|
| - pUsage = pIdxInfo->aConstraintUsage;
|
| - for(i=0; i<pIdxInfo->nConstraint; i++, pIdxCons++){
|
| - j = pIdxCons->iTermOffset;
|
| - pTerm = &pWC->a[j];
|
| - pIdxCons->usable = (pTerm->prereqRight¬Ready) ? 0 : 1;
|
| - }
|
| - memset(pUsage, 0, sizeof(pUsage[0])*pIdxInfo->nConstraint);
|
| - if( pIdxInfo->needToFreeIdxStr ){
|
| - sqlite3_free(pIdxInfo->idxStr);
|
| - }
|
| - pIdxInfo->idxStr = 0;
|
| - pIdxInfo->idxNum = 0;
|
| - pIdxInfo->needToFreeIdxStr = 0;
|
| - pIdxInfo->orderByConsumed = 0;
|
| - /* ((double)2) In case of SQLITE_OMIT_FLOATING_POINT... */
|
| - pIdxInfo->estimatedCost = SQLITE_BIG_DBL / ((double)2);
|
| - nOrderBy = pIdxInfo->nOrderBy;
|
| - if( !pOrderBy ){
|
| - pIdxInfo->nOrderBy = 0;
|
| - }
|
| -
|
| - if( vtabBestIndex(pParse, pTab, pIdxInfo) ){
|
| - return;
|
| - }
|
| -
|
| - pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
|
| - for(i=0; i<pIdxInfo->nConstraint; i++){
|
| - if( pUsage[i].argvIndex>0 ){
|
| - pCost->used |= pWC->a[pIdxCons[i].iTermOffset].prereqRight;
|
| - }
|
| - }
|
| -
|
| - /* The cost is not allowed to be larger than SQLITE_BIG_DBL (the
|
| - ** inital value of lowestCost in this loop. If it is, then the
|
| - ** (cost<lowestCost) test below will never be true.
|
| - **
|
| - ** Use "(double)2" instead of "2.0" in case OMIT_FLOATING_POINT
|
| - ** is defined.
|
| - */
|
| - if( (SQLITE_BIG_DBL/((double)2))<pIdxInfo->estimatedCost ){
|
| - pCost->rCost = (SQLITE_BIG_DBL/((double)2));
|
| - }else{
|
| - pCost->rCost = pIdxInfo->estimatedCost;
|
| - }
|
| - pCost->plan.u.pVtabIdx = pIdxInfo;
|
| - if( pIdxInfo->orderByConsumed ){
|
| - pCost->plan.wsFlags |= WHERE_ORDERBY;
|
| - }
|
| - pCost->plan.nEq = 0;
|
| - pIdxInfo->nOrderBy = nOrderBy;
|
| -
|
| - /* Try to find a more efficient access pattern by using multiple indexes
|
| - ** to optimize an OR expression within the WHERE clause.
|
| - */
|
| - bestOrClauseIndex(pParse, pWC, pSrc, notReady, pOrderBy, pCost);
|
| -}
|
| -#endif /* SQLITE_OMIT_VIRTUALTABLE */
|
| -
|
| -/*
|
| -** Argument pIdx is a pointer to an index structure that has an array of
|
| -** SQLITE_INDEX_SAMPLES evenly spaced samples of the first indexed column
|
| -** stored in Index.aSample. The domain of values stored in said column
|
| -** may be thought of as divided into (SQLITE_INDEX_SAMPLES+1) regions.
|
| -** Region 0 contains all values smaller than the first sample value. Region
|
| -** 1 contains values larger than or equal to the value of the first sample,
|
| -** but smaller than the value of the second. And so on.
|
| -**
|
| -** If successful, this function determines which of the regions value
|
| -** pVal lies in, sets *piRegion to the region index (a value between 0
|
| -** and SQLITE_INDEX_SAMPLES+1, inclusive) and returns SQLITE_OK.
|
| -** Or, if an OOM occurs while converting text values between encodings,
|
| -** SQLITE_NOMEM is returned and *piRegion is undefined.
|
| -*/
|
| -#ifdef SQLITE_ENABLE_STAT2
|
| -static int whereRangeRegion(
|
| - Parse *pParse, /* Database connection */
|
| - Index *pIdx, /* Index to consider domain of */
|
| - sqlite3_value *pVal, /* Value to consider */
|
| - int *piRegion /* OUT: Region of domain in which value lies */
|
| -){
|
| - if( ALWAYS(pVal) ){
|
| - IndexSample *aSample = pIdx->aSample;
|
| - int i = 0;
|
| - int eType = sqlite3_value_type(pVal);
|
| -
|
| - if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
|
| - double r = sqlite3_value_double(pVal);
|
| - for(i=0; i<SQLITE_INDEX_SAMPLES; i++){
|
| - if( aSample[i].eType==SQLITE_NULL ) continue;
|
| - if( aSample[i].eType>=SQLITE_TEXT || aSample[i].u.r>r ) break;
|
| - }
|
| - }else{
|
| - sqlite3 *db = pParse->db;
|
| - CollSeq *pColl;
|
| - const u8 *z;
|
| - int n;
|
| -
|
| - /* pVal comes from sqlite3ValueFromExpr() so the type cannot be NULL */
|
| - assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB );
|
| -
|
| - if( eType==SQLITE_BLOB ){
|
| - z = (const u8 *)sqlite3_value_blob(pVal);
|
| - pColl = db->pDfltColl;
|
| - assert( pColl->enc==SQLITE_UTF8 );
|
| - }else{
|
| - pColl = sqlite3GetCollSeq(db, SQLITE_UTF8, 0, *pIdx->azColl);
|
| - if( pColl==0 ){
|
| - sqlite3ErrorMsg(pParse, "no such collation sequence: %s",
|
| - *pIdx->azColl);
|
| - return SQLITE_ERROR;
|
| - }
|
| - z = (const u8 *)sqlite3ValueText(pVal, pColl->enc);
|
| - if( !z ){
|
| - return SQLITE_NOMEM;
|
| - }
|
| - assert( z && pColl && pColl->xCmp );
|
| - }
|
| - n = sqlite3ValueBytes(pVal, pColl->enc);
|
| -
|
| - for(i=0; i<SQLITE_INDEX_SAMPLES; i++){
|
| - int r;
|
| - int eSampletype = aSample[i].eType;
|
| - if( eSampletype==SQLITE_NULL || eSampletype<eType ) continue;
|
| - if( (eSampletype!=eType) ) break;
|
| - if( pColl->enc==SQLITE_UTF8 ){
|
| - r = pColl->xCmp(pColl->pUser, aSample[i].nByte, aSample[i].u.z, n, z);
|
| - }else{
|
| - int nSample;
|
| - char *zSample = sqlite3Utf8to16(
|
| - db, pColl->enc, aSample[i].u.z, aSample[i].nByte, &nSample
|
| - );
|
| - if( !zSample ){
|
| - assert( db->mallocFailed );
|
| - return SQLITE_NOMEM;
|
| - }
|
| - r = pColl->xCmp(pColl->pUser, nSample, zSample, n, z);
|
| - sqlite3DbFree(db, zSample);
|
| - }
|
| - if( r>0 ) break;
|
| - }
|
| - }
|
| -
|
| - assert( i>=0 && i<=SQLITE_INDEX_SAMPLES );
|
| - *piRegion = i;
|
| - }
|
| - return SQLITE_OK;
|
| -}
|
| -#endif /* #ifdef SQLITE_ENABLE_STAT2 */
|
| -
|
| -/*
|
| -** This function is used to estimate the number of rows that will be visited
|
| -** by scanning an index for a range of values. The range may have an upper
|
| -** bound, a lower bound, or both. The WHERE clause terms that set the upper
|
| -** and lower bounds are represented by pLower and pUpper respectively. For
|
| -** example, assuming that index p is on t1(a):
|
| -**
|
| -** ... FROM t1 WHERE a > ? AND a < ? ...
|
| -** |_____| |_____|
|
| -** | |
|
| -** pLower pUpper
|
| -**
|
| -** If either of the upper or lower bound is not present, then NULL is passed in
|
| -** place of the corresponding WhereTerm.
|
| -**
|
| -** The nEq parameter is passed the index of the index column subject to the
|
| -** range constraint. Or, equivalently, the number of equality constraints
|
| -** optimized by the proposed index scan. For example, assuming index p is
|
| -** on t1(a, b), and the SQL query is:
|
| -**
|
| -** ... FROM t1 WHERE a = ? AND b > ? AND b < ? ...
|
| -**
|
| -** then nEq should be passed the value 1 (as the range restricted column,
|
| -** b, is the second left-most column of the index). Or, if the query is:
|
| -**
|
| -** ... FROM t1 WHERE a > ? AND a < ? ...
|
| -**
|
| -** then nEq should be passed 0.
|
| -**
|
| -** The returned value is an integer between 1 and 100, inclusive. A return
|
| -** value of 1 indicates that the proposed range scan is expected to visit
|
| -** approximately 1/100th (1%) of the rows selected by the nEq equality
|
| -** constraints (if any). A return value of 100 indicates that it is expected
|
| -** that the range scan will visit every row (100%) selected by the equality
|
| -** constraints.
|
| -**
|
| -** In the absence of sqlite_stat2 ANALYZE data, each range inequality
|
| -** reduces the search space by 2/3rds. Hence a single constraint (x>?)
|
| -** results in a return of 33 and a range constraint (x>? AND x<?) results
|
| -** in a return of 11.
|
| -*/
|
| -static int whereRangeScanEst(
|
| - Parse *pParse, /* Parsing & code generating context */
|
| - Index *p, /* The index containing the range-compared column; "x" */
|
| - int nEq, /* index into p->aCol[] of the range-compared column */
|
| - WhereTerm *pLower, /* Lower bound on the range. ex: "x>123" Might be NULL */
|
| - WhereTerm *pUpper, /* Upper bound on the range. ex: "x<455" Might be NULL */
|
| - int *piEst /* OUT: Return value */
|
| -){
|
| - int rc = SQLITE_OK;
|
| -
|
| -#ifdef SQLITE_ENABLE_STAT2
|
| - sqlite3 *db = pParse->db;
|
| - sqlite3_value *pLowerVal = 0;
|
| - sqlite3_value *pUpperVal = 0;
|
| -
|
| - if( nEq==0 && p->aSample ){
|
| - int iEst;
|
| - int iLower = 0;
|
| - int iUpper = SQLITE_INDEX_SAMPLES;
|
| - u8 aff = p->pTable->aCol[0].affinity;
|
| -
|
| - if( pLower ){
|
| - Expr *pExpr = pLower->pExpr->pRight;
|
| - rc = sqlite3ValueFromExpr(db, pExpr, SQLITE_UTF8, aff, &pLowerVal);
|
| - }
|
| - if( rc==SQLITE_OK && pUpper ){
|
| - Expr *pExpr = pUpper->pExpr->pRight;
|
| - rc = sqlite3ValueFromExpr(db, pExpr, SQLITE_UTF8, aff, &pUpperVal);
|
| - }
|
| -
|
| - if( rc!=SQLITE_OK || (pLowerVal==0 && pUpperVal==0) ){
|
| - sqlite3ValueFree(pLowerVal);
|
| - sqlite3ValueFree(pUpperVal);
|
| - goto range_est_fallback;
|
| - }else if( pLowerVal==0 ){
|
| - rc = whereRangeRegion(pParse, p, pUpperVal, &iUpper);
|
| - if( pLower ) iLower = iUpper/2;
|
| - }else if( pUpperVal==0 ){
|
| - rc = whereRangeRegion(pParse, p, pLowerVal, &iLower);
|
| - if( pUpper ) iUpper = (iLower + SQLITE_INDEX_SAMPLES + 1)/2;
|
| - }else{
|
| - rc = whereRangeRegion(pParse, p, pUpperVal, &iUpper);
|
| - if( rc==SQLITE_OK ){
|
| - rc = whereRangeRegion(pParse, p, pLowerVal, &iLower);
|
| - }
|
| - }
|
| -
|
| - iEst = iUpper - iLower;
|
| - testcase( iEst==SQLITE_INDEX_SAMPLES );
|
| - assert( iEst<=SQLITE_INDEX_SAMPLES );
|
| - if( iEst<1 ){
|
| - iEst = 1;
|
| - }
|
| -
|
| - sqlite3ValueFree(pLowerVal);
|
| - sqlite3ValueFree(pUpperVal);
|
| - *piEst = (iEst * 100)/SQLITE_INDEX_SAMPLES;
|
| - return rc;
|
| - }
|
| -range_est_fallback:
|
| -#else
|
| - UNUSED_PARAMETER(pParse);
|
| - UNUSED_PARAMETER(p);
|
| - UNUSED_PARAMETER(nEq);
|
| -#endif
|
| - assert( pLower || pUpper );
|
| - if( pLower && pUpper ){
|
| - *piEst = 11;
|
| - }else{
|
| - *piEst = 33;
|
| - }
|
| - return rc;
|
| -}
|
| -
|
| -
|
| -/*
|
| -** Find the query plan for accessing a particular table. Write the
|
| -** best query plan and its cost into the WhereCost object supplied as the
|
| -** last parameter.
|
| -**
|
| -** The lowest cost plan wins. The cost is an estimate of the amount of
|
| -** CPU and disk I/O need to process the request using the selected plan.
|
| -** Factors that influence cost include:
|
| -**
|
| -** * The estimated number of rows that will be retrieved. (The
|
| -** fewer the better.)
|
| -**
|
| -** * Whether or not sorting must occur.
|
| -**
|
| -** * Whether or not there must be separate lookups in the
|
| -** index and in the main table.
|
| -**
|
| -** If there was an INDEXED BY clause (pSrc->pIndex) attached to the table in
|
| -** the SQL statement, then this function only considers plans using the
|
| -** named index. If no such plan is found, then the returned cost is
|
| -** SQLITE_BIG_DBL. If a plan is found that uses the named index,
|
| -** then the cost is calculated in the usual way.
|
| -**
|
| -** If a NOT INDEXED clause (pSrc->notIndexed!=0) was attached to the table
|
| -** in the SELECT statement, then no indexes are considered. However, the
|
| -** selected plan may still take advantage of the tables built-in rowid
|
| -** index.
|
| -*/
|
| -static void bestBtreeIndex(
|
| - Parse *pParse, /* The parsing context */
|
| - WhereClause *pWC, /* The WHERE clause */
|
| - struct SrcList_item *pSrc, /* The FROM clause term to search */
|
| - Bitmask notReady, /* Mask of cursors that are not available */
|
| - ExprList *pOrderBy, /* The ORDER BY clause */
|
| - WhereCost *pCost /* Lowest cost query plan */
|
| -){
|
| - int iCur = pSrc->iCursor; /* The cursor of the table to be accessed */
|
| - Index *pProbe; /* An index we are evaluating */
|
| - Index *pIdx; /* Copy of pProbe, or zero for IPK index */
|
| - int eqTermMask; /* Current mask of valid equality operators */
|
| - int idxEqTermMask; /* Index mask of valid equality operators */
|
| - Index sPk; /* A fake index object for the primary key */
|
| - unsigned int aiRowEstPk[2]; /* The aiRowEst[] value for the sPk index */
|
| - int aiColumnPk = -1; /* The aColumn[] value for the sPk index */
|
| - int wsFlagMask; /* Allowed flags in pCost->plan.wsFlag */
|
| -
|
| - /* Initialize the cost to a worst-case value */
|
| - memset(pCost, 0, sizeof(*pCost));
|
| - pCost->rCost = SQLITE_BIG_DBL;
|
| -
|
| - /* If the pSrc table is the right table of a LEFT JOIN then we may not
|
| - ** use an index to satisfy IS NULL constraints on that table. This is
|
| - ** because columns might end up being NULL if the table does not match -
|
| - ** a circumstance which the index cannot help us discover. Ticket #2177.
|
| - */
|
| - if( pSrc->jointype & JT_LEFT ){
|
| - idxEqTermMask = WO_EQ|WO_IN;
|
| - }else{
|
| - idxEqTermMask = WO_EQ|WO_IN|WO_ISNULL;
|
| - }
|
| -
|
| - if( pSrc->pIndex ){
|
| - /* An INDEXED BY clause specifies a particular index to use */
|
| - pIdx = pProbe = pSrc->pIndex;
|
| - wsFlagMask = ~(WHERE_ROWID_EQ|WHERE_ROWID_RANGE);
|
| - eqTermMask = idxEqTermMask;
|
| - }else{
|
| - /* There is no INDEXED BY clause. Create a fake Index object to
|
| - ** represent the primary key */
|
| - Index *pFirst; /* Any other index on the table */
|
| - memset(&sPk, 0, sizeof(Index));
|
| - sPk.nColumn = 1;
|
| - sPk.aiColumn = &aiColumnPk;
|
| - sPk.aiRowEst = aiRowEstPk;
|
| - aiRowEstPk[1] = 1;
|
| - sPk.onError = OE_Replace;
|
| - sPk.pTable = pSrc->pTab;
|
| - pFirst = pSrc->pTab->pIndex;
|
| - if( pSrc->notIndexed==0 ){
|
| - sPk.pNext = pFirst;
|
| - }
|
| - /* The aiRowEstPk[0] is an estimate of the total number of rows in the
|
| - ** table. Get this information from the ANALYZE information if it is
|
| - ** available. If not available, assume the table 1 million rows in size.
|
| - */
|
| - if( pFirst ){
|
| - assert( pFirst->aiRowEst!=0 ); /* Allocated together with pFirst */
|
| - aiRowEstPk[0] = pFirst->aiRowEst[0];
|
| - }else{
|
| - aiRowEstPk[0] = 1000000;
|
| - }
|
| - pProbe = &sPk;
|
| - wsFlagMask = ~(
|
| - WHERE_COLUMN_IN|WHERE_COLUMN_EQ|WHERE_COLUMN_NULL|WHERE_COLUMN_RANGE
|
| - );
|
| - eqTermMask = WO_EQ|WO_IN;
|
| - pIdx = 0;
|
| - }
|
| -
|
| - /* Loop over all indices looking for the best one to use
|
| - */
|
| - for(; pProbe; pIdx=pProbe=pProbe->pNext){
|
| - const unsigned int * const aiRowEst = pProbe->aiRowEst;
|
| - double cost; /* Cost of using pProbe */
|
| - double nRow; /* Estimated number of rows in result set */
|
| - int rev; /* True to scan in reverse order */
|
| - int wsFlags = 0;
|
| - Bitmask used = 0;
|
| -
|
| - /* The following variables are populated based on the properties of
|
| - ** scan being evaluated. They are then used to determine the expected
|
| - ** cost and number of rows returned.
|
| - **
|
| - ** nEq:
|
| - ** Number of equality terms that can be implemented using the index.
|
| - **
|
| - ** nInMul:
|
| - ** The "in-multiplier". This is an estimate of how many seek operations
|
| - ** SQLite must perform on the index in question. For example, if the
|
| - ** WHERE clause is:
|
| - **
|
| - ** WHERE a IN (1, 2, 3) AND b IN (4, 5, 6)
|
| - **
|
| - ** SQLite must perform 9 lookups on an index on (a, b), so nInMul is
|
| - ** set to 9. Given the same schema and either of the following WHERE
|
| - ** clauses:
|
| - **
|
| - ** WHERE a = 1
|
| - ** WHERE a >= 2
|
| - **
|
| - ** nInMul is set to 1.
|
| - **
|
| - ** If there exists a WHERE term of the form "x IN (SELECT ...)", then
|
| - ** the sub-select is assumed to return 25 rows for the purposes of
|
| - ** determining nInMul.
|
| - **
|
| - ** bInEst:
|
| - ** Set to true if there was at least one "x IN (SELECT ...)" term used
|
| - ** in determining the value of nInMul.
|
| - **
|
| - ** nBound:
|
| - ** An estimate on the amount of the table that must be searched. A
|
| - ** value of 100 means the entire table is searched. Range constraints
|
| - ** might reduce this to a value less than 100 to indicate that only
|
| - ** a fraction of the table needs searching. In the absence of
|
| - ** sqlite_stat2 ANALYZE data, a single inequality reduces the search
|
| - ** space to 1/3rd its original size. So an x>? constraint reduces
|
| - ** nBound to 33. Two constraints (x>? AND x<?) reduce nBound to 11.
|
| - **
|
| - ** bSort:
|
| - ** Boolean. True if there is an ORDER BY clause that will require an
|
| - ** external sort (i.e. scanning the index being evaluated will not
|
| - ** correctly order records).
|
| - **
|
| - ** bLookup:
|
| - ** Boolean. True if for each index entry visited a lookup on the
|
| - ** corresponding table b-tree is required. This is always false
|
| - ** for the rowid index. For other indexes, it is true unless all the
|
| - ** columns of the table used by the SELECT statement are present in
|
| - ** the index (such an index is sometimes described as a covering index).
|
| - ** For example, given the index on (a, b), the second of the following
|
| - ** two queries requires table b-tree lookups, but the first does not.
|
| - **
|
| - ** SELECT a, b FROM tbl WHERE a = 1;
|
| - ** SELECT a, b, c FROM tbl WHERE a = 1;
|
| - */
|
| - int nEq;
|
| - int bInEst = 0;
|
| - int nInMul = 1;
|
| - int nBound = 100;
|
| - int bSort = 0;
|
| - int bLookup = 0;
|
| -
|
| - /* Determine the values of nEq and nInMul */
|
| - for(nEq=0; nEq<pProbe->nColumn; nEq++){
|
| - WhereTerm *pTerm; /* A single term of the WHERE clause */
|
| - int j = pProbe->aiColumn[nEq];
|
| - pTerm = findTerm(pWC, iCur, j, notReady, eqTermMask, pIdx);
|
| - if( pTerm==0 ) break;
|
| - wsFlags |= (WHERE_COLUMN_EQ|WHERE_ROWID_EQ);
|
| - if( pTerm->eOperator & WO_IN ){
|
| - Expr *pExpr = pTerm->pExpr;
|
| - wsFlags |= WHERE_COLUMN_IN;
|
| - if( ExprHasProperty(pExpr, EP_xIsSelect) ){
|
| - nInMul *= 25;
|
| - bInEst = 1;
|
| - }else if( pExpr->x.pList ){
|
| - nInMul *= pExpr->x.pList->nExpr + 1;
|
| - }
|
| - }else if( pTerm->eOperator & WO_ISNULL ){
|
| - wsFlags |= WHERE_COLUMN_NULL;
|
| - }
|
| - used |= pTerm->prereqRight;
|
| - }
|
| -
|
| - /* Determine the value of nBound. */
|
| - if( nEq<pProbe->nColumn ){
|
| - int j = pProbe->aiColumn[nEq];
|
| - if( findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE|WO_GT|WO_GE, pIdx) ){
|
| - WhereTerm *pTop = findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE, pIdx);
|
| - WhereTerm *pBtm = findTerm(pWC, iCur, j, notReady, WO_GT|WO_GE, pIdx);
|
| - whereRangeScanEst(pParse, pProbe, nEq, pBtm, pTop, &nBound);
|
| - if( pTop ){
|
| - wsFlags |= WHERE_TOP_LIMIT;
|
| - used |= pTop->prereqRight;
|
| - }
|
| - if( pBtm ){
|
| - wsFlags |= WHERE_BTM_LIMIT;
|
| - used |= pBtm->prereqRight;
|
| - }
|
| - wsFlags |= (WHERE_COLUMN_RANGE|WHERE_ROWID_RANGE);
|
| - }
|
| - }else if( pProbe->onError!=OE_None ){
|
| - testcase( wsFlags & WHERE_COLUMN_IN );
|
| - testcase( wsFlags & WHERE_COLUMN_NULL );
|
| - if( (wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_NULL))==0 ){
|
| - wsFlags |= WHERE_UNIQUE;
|
| - }
|
| - }
|
| -
|
| - /* If there is an ORDER BY clause and the index being considered will
|
| - ** naturally scan rows in the required order, set the appropriate flags
|
| - ** in wsFlags. Otherwise, if there is an ORDER BY clause but the index
|
| - ** will scan rows in a different order, set the bSort variable. */
|
| - if( pOrderBy ){
|
| - if( (wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_NULL))==0
|
| - && isSortingIndex(pParse,pWC->pMaskSet,pProbe,iCur,pOrderBy,nEq,&rev)
|
| - ){
|
| - wsFlags |= WHERE_ROWID_RANGE|WHERE_COLUMN_RANGE|WHERE_ORDERBY;
|
| - wsFlags |= (rev ? WHERE_REVERSE : 0);
|
| - }else{
|
| - bSort = 1;
|
| - }
|
| - }
|
| -
|
| - /* If currently calculating the cost of using an index (not the IPK
|
| - ** index), determine if all required column data may be obtained without
|
| - ** seeking to entries in the main table (i.e. if the index is a covering
|
| - ** index for this query). If it is, set the WHERE_IDX_ONLY flag in
|
| - ** wsFlags. Otherwise, set the bLookup variable to true. */
|
| - if( pIdx && wsFlags ){
|
| - Bitmask m = pSrc->colUsed;
|
| - int j;
|
| - for(j=0; j<pIdx->nColumn; j++){
|
| - int x = pIdx->aiColumn[j];
|
| - if( x<BMS-1 ){
|
| - m &= ~(((Bitmask)1)<<x);
|
| - }
|
| - }
|
| - if( m==0 ){
|
| - wsFlags |= WHERE_IDX_ONLY;
|
| - }else{
|
| - bLookup = 1;
|
| - }
|
| - }
|
| -
|
| - /**** Begin adding up the cost of using this index (Needs improvements)
|
| - **
|
| - ** Estimate the number of rows of output. For an IN operator,
|
| - ** do not let the estimate exceed half the rows in the table.
|
| - */
|
| - nRow = (double)(aiRowEst[nEq] * nInMul);
|
| - if( bInEst && nRow*2>aiRowEst[0] ){
|
| - nRow = aiRowEst[0]/2;
|
| - nInMul = (int)(nRow / aiRowEst[nEq]);
|
| - }
|
| -
|
| - /* Assume constant cost to access a row and logarithmic cost to
|
| - ** do a binary search. Hence, the initial cost is the number of output
|
| - ** rows plus log2(table-size) times the number of binary searches.
|
| - */
|
| - cost = nRow + nInMul*estLog(aiRowEst[0]);
|
| -
|
| - /* Adjust the number of rows and the cost downward to reflect rows
|
| - ** that are excluded by range constraints.
|
| - */
|
| - nRow = (nRow * (double)nBound) / (double)100;
|
| - cost = (cost * (double)nBound) / (double)100;
|
| -
|
| - /* Add in the estimated cost of sorting the result
|
| - */
|
| - if( bSort ){
|
| - cost += cost*estLog(cost);
|
| - }
|
| -
|
| - /* If all information can be taken directly from the index, we avoid
|
| - ** doing table lookups. This reduces the cost by half. (Not really -
|
| - ** this needs to be fixed.)
|
| - */
|
| - if( pIdx && bLookup==0 ){
|
| - cost /= (double)2;
|
| - }
|
| - /**** Cost of using this index has now been computed ****/
|
| -
|
| - WHERETRACE((
|
| - "tbl=%s idx=%s nEq=%d nInMul=%d nBound=%d bSort=%d bLookup=%d"
|
| - " wsFlags=%d (nRow=%.2f cost=%.2f)\n",
|
| - pSrc->pTab->zName, (pIdx ? pIdx->zName : "ipk"),
|
| - nEq, nInMul, nBound, bSort, bLookup, wsFlags, nRow, cost
|
| - ));
|
| -
|
| - /* If this index is the best we have seen so far, then record this
|
| - ** index and its cost in the pCost structure.
|
| - */
|
| - if( (!pIdx || wsFlags) && cost<pCost->rCost ){
|
| - pCost->rCost = cost;
|
| - pCost->nRow = nRow;
|
| - pCost->used = used;
|
| - pCost->plan.wsFlags = (wsFlags&wsFlagMask);
|
| - pCost->plan.nEq = nEq;
|
| - pCost->plan.u.pIdx = pIdx;
|
| - }
|
| -
|
| - /* If there was an INDEXED BY clause, then only that one index is
|
| - ** considered. */
|
| - if( pSrc->pIndex ) break;
|
| -
|
| - /* Reset masks for the next index in the loop */
|
| - wsFlagMask = ~(WHERE_ROWID_EQ|WHERE_ROWID_RANGE);
|
| - eqTermMask = idxEqTermMask;
|
| - }
|
| -
|
| - /* If there is no ORDER BY clause and the SQLITE_ReverseOrder flag
|
| - ** is set, then reverse the order that the index will be scanned
|
| - ** in. This is used for application testing, to help find cases
|
| - ** where application behaviour depends on the (undefined) order that
|
| - ** SQLite outputs rows in in the absence of an ORDER BY clause. */
|
| - if( !pOrderBy && pParse->db->flags & SQLITE_ReverseOrder ){
|
| - pCost->plan.wsFlags |= WHERE_REVERSE;
|
| - }
|
| -
|
| - assert( pOrderBy || (pCost->plan.wsFlags&WHERE_ORDERBY)==0 );
|
| - assert( pCost->plan.u.pIdx==0 || (pCost->plan.wsFlags&WHERE_ROWID_EQ)==0 );
|
| - assert( pSrc->pIndex==0
|
| - || pCost->plan.u.pIdx==0
|
| - || pCost->plan.u.pIdx==pSrc->pIndex
|
| - );
|
| -
|
| - WHERETRACE(("best index is: %s\n",
|
| - (pCost->plan.u.pIdx ? pCost->plan.u.pIdx->zName : "ipk")
|
| - ));
|
| -
|
| - bestOrClauseIndex(pParse, pWC, pSrc, notReady, pOrderBy, pCost);
|
| - pCost->plan.wsFlags |= eqTermMask;
|
| -}
|
| -
|
| -/*
|
| -** Find the query plan for accessing table pSrc->pTab. Write the
|
| -** best query plan and its cost into the WhereCost object supplied
|
| -** as the last parameter. This function may calculate the cost of
|
| -** both real and virtual table scans.
|
| -*/
|
| -static void bestIndex(
|
| - Parse *pParse, /* The parsing context */
|
| - WhereClause *pWC, /* The WHERE clause */
|
| - struct SrcList_item *pSrc, /* The FROM clause term to search */
|
| - Bitmask notReady, /* Mask of cursors that are not available */
|
| - ExprList *pOrderBy, /* The ORDER BY clause */
|
| - WhereCost *pCost /* Lowest cost query plan */
|
| -){
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| - if( IsVirtual(pSrc->pTab) ){
|
| - sqlite3_index_info *p = 0;
|
| - bestVirtualIndex(pParse, pWC, pSrc, notReady, pOrderBy, pCost, &p);
|
| - if( p->needToFreeIdxStr ){
|
| - sqlite3_free(p->idxStr);
|
| - }
|
| - sqlite3DbFree(pParse->db, p);
|
| - }else
|
| -#endif
|
| - {
|
| - bestBtreeIndex(pParse, pWC, pSrc, notReady, pOrderBy, pCost);
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** 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.
|
| -*/
|
| -static void disableTerm(WhereLevel *pLevel, WhereTerm *pTerm){
|
| - if( pTerm
|
| - && ALWAYS((pTerm->wtFlags & TERM_CODED)==0)
|
| - && (pLevel->iLeftJoin==0 || ExprHasProperty(pTerm->pExpr, EP_FromJoin))
|
| - ){
|
| - pTerm->wtFlags |= TERM_CODED;
|
| - if( pTerm->iParent>=0 ){
|
| - WhereTerm *pOther = &pTerm->pWC->a[pTerm->iParent];
|
| - if( (--pOther->nChild)==0 ){
|
| - disableTerm(pLevel, pOther);
|
| - }
|
| - }
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** Code an OP_Affinity opcode to apply the column affinity string zAff
|
| -** to the n registers starting at base.
|
| -**
|
| -** Buffer zAff was allocated using sqlite3DbMalloc(). It is the
|
| -** responsibility of this function to arrange for it to be eventually
|
| -** freed using sqlite3DbFree().
|
| -*/
|
| -static void codeApplyAffinity(Parse *pParse, int base, int n, char *zAff){
|
| - Vdbe *v = pParse->pVdbe;
|
| - assert( v!=0 );
|
| - sqlite3VdbeAddOp2(v, OP_Affinity, base, n);
|
| - sqlite3VdbeChangeP4(v, -1, zAff, P4_DYNAMIC);
|
| - 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, /* When level of the FROM clause we are working on */
|
| - 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 ){
|
| - 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;
|
| -
|
| - assert( pX->op==TK_IN );
|
| - iReg = iTarget;
|
| - eType = sqlite3FindInIndex(pParse, pX, 0);
|
| - iTab = pX->iTable;
|
| - sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0);
|
| - assert( pLevel->plan.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);
|
| - }
|
| - sqlite3VdbeAddOp1(v, OP_IsNull, iReg);
|
| - }else{
|
| - pLevel->u.in.nIn = 0;
|
| - }
|
| -#endif
|
| - }
|
| - disableTerm(pLevel, pTerm);
|
| - return iReg;
|
| -}
|
| -
|
| -/*
|
| -** Generate code that will evaluate all == and IN constraints for an
|
| -** index. The values for all constraints are left on the stack.
|
| -**
|
| -** 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.
|
| -**
|
| -** This routine always allocates at least one memory cell and returns
|
| -** the index of that memory cell. The code that
|
| -** calls this routine will use that memory cell to store the termination
|
| -** 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 NONE affinity are set to
|
| -** SQLITE_AFF_NONE. 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 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_NONE.
|
| -*/
|
| -static int codeAllEqualityTerms(
|
| - Parse *pParse, /* Parsing context */
|
| - WhereLevel *pLevel, /* Which nested loop of the FROM we are coding */
|
| - WhereClause *pWC, /* The WHERE clause */
|
| - Bitmask notReady, /* Which parts of FROM have not yet been coded */
|
| - int nExtraReg, /* Number of extra registers to allocate */
|
| - char **pzAff /* OUT: Set to point to affinity string */
|
| -){
|
| - int nEq = pLevel->plan.nEq; /* The number of == or IN constraints to code */
|
| - Vdbe *v = pParse->pVdbe; /* The vm under construction */
|
| - Index *pIdx; /* The index being used for this loop */
|
| - int iCur = pLevel->iTabCur; /* The cursor of the table */
|
| - WhereTerm *pTerm; /* A single constraint term */
|
| - 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. */
|
| - assert( pLevel->plan.wsFlags & WHERE_INDEXED );
|
| - pIdx = pLevel->plan.u.pIdx;
|
| -
|
| - /* Figure out how many memory cells we will need then allocate them.
|
| - */
|
| - regBase = pParse->nMem + 1;
|
| - nReg = pLevel->plan.nEq + nExtraReg;
|
| - pParse->nMem += nReg;
|
| -
|
| - zAff = sqlite3DbStrDup(pParse->db, sqlite3IndexAffinityStr(v, pIdx));
|
| - if( !zAff ){
|
| - pParse->db->mallocFailed = 1;
|
| - }
|
| -
|
| - /* Evaluate the equality constraints
|
| - */
|
| - assert( pIdx->nColumn>=nEq );
|
| - for(j=0; j<nEq; j++){
|
| - int r1;
|
| - int k = pIdx->aiColumn[j];
|
| - pTerm = findTerm(pWC, iCur, k, notReady, pLevel->plan.wsFlags, pIdx);
|
| - if( NEVER(pTerm==0) ) break;
|
| - assert( (pTerm->wtFlags & TERM_CODED)==0 );
|
| - r1 = codeEqualityTerm(pParse, pTerm, pLevel, 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 ){
|
| - sqlite3VdbeAddOp2(v, OP_IsNull, regBase+j, pLevel->addrBrk);
|
| - if( zAff
|
| - && sqlite3CompareAffinity(pTerm->pExpr->pRight, zAff[j])==SQLITE_AFF_NONE
|
| - ){
|
| - zAff[j] = SQLITE_AFF_NONE;
|
| - }
|
| - }
|
| - }
|
| - *pzAff = zAff;
|
| - return regBase;
|
| -}
|
| -
|
| -/*
|
| -** Generate code for the start of the iLevel-th loop in the WHERE clause
|
| -** implementation described by pWInfo.
|
| -*/
|
| -static Bitmask codeOneLoopStart(
|
| - WhereInfo *pWInfo, /* Complete information about the WHERE clause */
|
| - int iLevel, /* Which level of pWInfo->a[] should be coded */
|
| - u16 wctrlFlags, /* One of the WHERE_* flags defined in sqliteInt.h */
|
| - 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 */
|
| - WhereClause *pWC; /* Decomposition of the entire WHERE clause */
|
| - WhereTerm *pTerm; /* A WHERE clause term */
|
| - Parse *pParse; /* Parsing context */
|
| - 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->pWC;
|
| - pLevel = &pWInfo->a[iLevel];
|
| - pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
|
| - iCur = pTabItem->iCursor;
|
| - bRev = (pLevel->plan.wsFlags & WHERE_REVERSE)!=0;
|
| - omitTable = (pLevel->plan.wsFlags & WHERE_IDX_ONLY)!=0
|
| - && (wctrlFlags & WHERE_FORCE_TABLE)==0;
|
| -
|
| - /* 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].jointype & JT_LEFT)!=0 ){
|
| - pLevel->iLeftJoin = ++pParse->nMem;
|
| - sqlite3VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
|
| - VdbeComment((v, "init LEFT JOIN no-match flag"));
|
| - }
|
| -
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| - if( (pLevel->plan.wsFlags & WHERE_VIRTUALTABLE)!=0 ){
|
| - /* Case 0: The table is a virtual-table. Use the VFilter and VNext
|
| - ** to access the data.
|
| - */
|
| - int iReg; /* P3 Value for OP_VFilter */
|
| - sqlite3_index_info *pVtabIdx = pLevel->plan.u.pVtabIdx;
|
| - int nConstraint = pVtabIdx->nConstraint;
|
| - struct sqlite3_index_constraint_usage *aUsage =
|
| - pVtabIdx->aConstraintUsage;
|
| - const struct sqlite3_index_constraint *aConstraint =
|
| - pVtabIdx->aConstraint;
|
| -
|
| - iReg = sqlite3GetTempRange(pParse, nConstraint+2);
|
| - for(j=1; j<=nConstraint; j++){
|
| - for(k=0; k<nConstraint; k++){
|
| - if( aUsage[k].argvIndex==j ){
|
| - int iTerm = aConstraint[k].iTermOffset;
|
| - sqlite3ExprCode(pParse, pWC->a[iTerm].pExpr->pRight, iReg+j+1);
|
| - break;
|
| - }
|
| - }
|
| - if( k==nConstraint ) break;
|
| - }
|
| - sqlite3VdbeAddOp2(v, OP_Integer, pVtabIdx->idxNum, iReg);
|
| - sqlite3VdbeAddOp2(v, OP_Integer, j-1, iReg+1);
|
| - sqlite3VdbeAddOp4(v, OP_VFilter, iCur, addrBrk, iReg, pVtabIdx->idxStr,
|
| - pVtabIdx->needToFreeIdxStr ? P4_MPRINTF : P4_STATIC);
|
| - pVtabIdx->needToFreeIdxStr = 0;
|
| - for(j=0; j<nConstraint; j++){
|
| - if( aUsage[j].omit ){
|
| - int iTerm = aConstraint[j].iTermOffset;
|
| - disableTerm(pLevel, &pWC->a[iTerm]);
|
| - }
|
| - }
|
| - pLevel->op = OP_VNext;
|
| - pLevel->p1 = iCur;
|
| - pLevel->p2 = sqlite3VdbeCurrentAddr(v);
|
| - sqlite3ReleaseTempRange(pParse, iReg, nConstraint+2);
|
| - }else
|
| -#endif /* SQLITE_OMIT_VIRTUALTABLE */
|
| -
|
| - if( pLevel->plan.wsFlags & WHERE_ROWID_EQ ){
|
| - /* Case 1: We can directly reference a single row using an
|
| - ** equality comparison against the ROWID field. Or
|
| - ** we reference multiple rows using a "rowid IN (...)"
|
| - ** construct.
|
| - */
|
| - iReleaseReg = sqlite3GetTempReg(pParse);
|
| - pTerm = findTerm(pWC, iCur, -1, notReady, WO_EQ|WO_IN, 0);
|
| - assert( pTerm!=0 );
|
| - assert( pTerm->pExpr!=0 );
|
| - assert( pTerm->leftCursor==iCur );
|
| - assert( omitTable==0 );
|
| - iRowidReg = codeEqualityTerm(pParse, pTerm, pLevel, iReleaseReg);
|
| - addrNxt = pLevel->addrNxt;
|
| - sqlite3VdbeAddOp2(v, OP_MustBeInt, iRowidReg, addrNxt);
|
| - sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addrNxt, iRowidReg);
|
| - sqlite3ExprCacheStore(pParse, iCur, -1, iRowidReg);
|
| - VdbeComment((v, "pk"));
|
| - pLevel->op = OP_Noop;
|
| - }else if( pLevel->plan.wsFlags & WHERE_ROWID_RANGE ){
|
| - /* Case 2: We have an inequality comparison against the ROWID field.
|
| - */
|
| - int testOp = OP_Noop;
|
| - int start;
|
| - int memEndValue = 0;
|
| - WhereTerm *pStart, *pEnd;
|
| -
|
| - assert( omitTable==0 );
|
| - pStart = findTerm(pWC, iCur, -1, notReady, WO_GT|WO_GE, 0);
|
| - pEnd = findTerm(pWC, iCur, -1, notReady, WO_LT|WO_LE, 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. */
|
| -
|
| - pX = pStart->pExpr;
|
| - assert( pX!=0 );
|
| - assert( pStart->leftCursor==iCur );
|
| - r1 = sqlite3ExprCodeTemp(pParse, pX->pRight, &rTemp);
|
| - sqlite3VdbeAddOp3(v, aMoveOp[pX->op-TK_GT], iCur, addrBrk, r1);
|
| - VdbeComment((v, "pk"));
|
| - sqlite3ExprCacheAffinityChange(pParse, r1, 1);
|
| - sqlite3ReleaseTempReg(pParse, rTemp);
|
| - disableTerm(pLevel, pStart);
|
| - }else{
|
| - sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, addrBrk);
|
| - }
|
| - if( pEnd ){
|
| - Expr *pX;
|
| - pX = pEnd->pExpr;
|
| - assert( pX!=0 );
|
| - assert( pEnd->leftCursor==iCur );
|
| - 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;
|
| - pLevel->p5 = (pStart==0 && pEnd==0) ?1:0;
|
| - if( testOp!=OP_Noop ){
|
| - iRowidReg = iReleaseReg = sqlite3GetTempReg(pParse);
|
| - sqlite3VdbeAddOp2(v, OP_Rowid, iCur, iRowidReg);
|
| - sqlite3ExprCacheStore(pParse, iCur, -1, iRowidReg);
|
| - sqlite3VdbeAddOp3(v, testOp, memEndValue, addrBrk, iRowidReg);
|
| - sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC | SQLITE_JUMPIFNULL);
|
| - }
|
| - }else if( pLevel->plan.wsFlags & (WHERE_COLUMN_RANGE|WHERE_COLUMN_EQ) ){
|
| - /* Case 3: 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.
|
| - */
|
| - int 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) */
|
| - };
|
| - int aEndOp[] = {
|
| - OP_Noop, /* 0: (!end_constraints) */
|
| - OP_IdxGE, /* 1: (end_constraints && !bRev) */
|
| - OP_IdxLT /* 2: (end_constraints && bRev) */
|
| - };
|
| - int nEq = pLevel->plan.nEq;
|
| - int isMinQuery = 0; /* If this is an optimized SELECT min(x).. */
|
| - int regBase; /* Base register holding constraint values */
|
| - int r1; /* Temp register */
|
| - 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 *zAff;
|
| -
|
| - pIdx = pLevel->plan.u.pIdx;
|
| - iIdxCur = pLevel->iIdxCur;
|
| - k = pIdx->aiColumn[nEq]; /* Column for inequality constraints */
|
| -
|
| - /* 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.
|
| - */
|
| - if( (wctrlFlags&WHERE_ORDERBY_MIN)!=0
|
| - && (pLevel->plan.wsFlags&WHERE_ORDERBY)
|
| - && (pIdx->nColumn>nEq)
|
| - ){
|
| - /* assert( pOrderBy->nExpr==1 ); */
|
| - /* assert( pOrderBy->a[0].pExpr->iColumn==pIdx->aiColumn[nEq] ); */
|
| - isMinQuery = 1;
|
| - nExtraReg = 1;
|
| - }
|
| -
|
| - /* Find any inequality constraint terms for the start and end
|
| - ** of the range.
|
| - */
|
| - if( pLevel->plan.wsFlags & WHERE_TOP_LIMIT ){
|
| - pRangeEnd = findTerm(pWC, iCur, k, notReady, (WO_LT|WO_LE), pIdx);
|
| - nExtraReg = 1;
|
| - }
|
| - if( pLevel->plan.wsFlags & WHERE_BTM_LIMIT ){
|
| - pRangeStart = findTerm(pWC, iCur, k, notReady, (WO_GT|WO_GE), pIdx);
|
| - nExtraReg = 1;
|
| - }
|
| -
|
| - /* 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, pWC, notReady, nExtraReg, &zAff
|
| - );
|
| - 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( bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC) ){
|
| - SWAP(WhereTerm *, pRangeEnd, pRangeStart);
|
| - }
|
| -
|
| - testcase( pRangeStart && pRangeStart->eOperator & WO_LE );
|
| - testcase( pRangeStart && pRangeStart->eOperator & WO_GE );
|
| - testcase( pRangeEnd && pRangeEnd->eOperator & WO_LE );
|
| - testcase( pRangeEnd && pRangeEnd->eOperator & WO_GE );
|
| - 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);
|
| - sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
|
| - if( zAff
|
| - && sqlite3CompareAffinity(pRight, zAff[nConstraint])==SQLITE_AFF_NONE
|
| - ){
|
| - /* Since the comparison is to be performed with no conversions applied
|
| - ** to the operands, set the affinity to apply to pRight to
|
| - ** SQLITE_AFF_NONE. */
|
| - zAff[nConstraint] = SQLITE_AFF_NONE;
|
| - }
|
| - nConstraint++;
|
| - }else if( isMinQuery ){
|
| - sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
|
| - nConstraint++;
|
| - startEq = 0;
|
| - start_constraints = 1;
|
| - }
|
| - codeApplyAffinity(pParse, regBase, nConstraint, zAff);
|
| - op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev];
|
| - assert( op!=0 );
|
| - testcase( op==OP_Rewind );
|
| - testcase( op==OP_Last );
|
| - testcase( op==OP_SeekGt );
|
| - testcase( op==OP_SeekGe );
|
| - testcase( op==OP_SeekLe );
|
| - testcase( op==OP_SeekLt );
|
| - sqlite3VdbeAddOp4(v, op, iIdxCur, addrNxt, regBase,
|
| - SQLITE_INT_TO_PTR(nConstraint), P4_INT32);
|
| -
|
| - /* 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);
|
| - sqlite3ExprCode(pParse, pRight, regBase+nEq);
|
| - sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
|
| - zAff = sqlite3DbStrDup(pParse->db, zAff);
|
| - if( zAff
|
| - && sqlite3CompareAffinity(pRight, zAff[nConstraint])==SQLITE_AFF_NONE
|
| - ){
|
| - /* Since the comparison is to be performed with no conversions applied
|
| - ** to the operands, set the affinity to apply to pRight to
|
| - ** SQLITE_AFF_NONE. */
|
| - zAff[nConstraint] = SQLITE_AFF_NONE;
|
| - }
|
| - codeApplyAffinity(pParse, regBase, nEq+1, zAff);
|
| - nConstraint++;
|
| - }
|
| -
|
| - /* Top of the loop body */
|
| - pLevel->p2 = sqlite3VdbeCurrentAddr(v);
|
| -
|
| - /* Check if the index cursor is past the end of the range. */
|
| - op = aEndOp[(pRangeEnd || nEq) * (1 + bRev)];
|
| - testcase( op==OP_Noop );
|
| - testcase( op==OP_IdxGE );
|
| - testcase( op==OP_IdxLT );
|
| - if( op!=OP_Noop ){
|
| - sqlite3VdbeAddOp4(v, op, iIdxCur, addrNxt, regBase,
|
| - SQLITE_INT_TO_PTR(nConstraint), P4_INT32);
|
| - sqlite3VdbeChangeP5(v, endEq!=bRev ?1:0);
|
| - }
|
| -
|
| - /* If there are inequality constraints, check that the value
|
| - ** of the table column that the inequality contrains is not NULL.
|
| - ** If it is, jump to the next iteration of the loop.
|
| - */
|
| - r1 = sqlite3GetTempReg(pParse);
|
| - testcase( pLevel->plan.wsFlags & WHERE_BTM_LIMIT );
|
| - testcase( pLevel->plan.wsFlags & WHERE_TOP_LIMIT );
|
| - if( pLevel->plan.wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT) ){
|
| - sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, nEq, r1);
|
| - sqlite3VdbeAddOp2(v, OP_IsNull, r1, addrCont);
|
| - }
|
| - sqlite3ReleaseTempReg(pParse, r1);
|
| -
|
| - /* Seek the table cursor, if required */
|
| - disableTerm(pLevel, pRangeStart);
|
| - disableTerm(pLevel, pRangeEnd);
|
| - if( !omitTable ){
|
| - iRowidReg = iReleaseReg = sqlite3GetTempReg(pParse);
|
| - sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, iRowidReg);
|
| - sqlite3ExprCacheStore(pParse, iCur, -1, iRowidReg);
|
| - sqlite3VdbeAddOp2(v, OP_Seek, iCur, iRowidReg); /* Deferred seek */
|
| - }
|
| -
|
| - /* Record the instruction used to terminate the loop. Disable
|
| - ** WHERE clause terms made redundant by the index range scan.
|
| - */
|
| - pLevel->op = bRev ? OP_Prev : OP_Next;
|
| - pLevel->p1 = iIdxCur;
|
| - }else
|
| -
|
| -#ifndef SQLITE_OMIT_OR_OPTIMIZATION
|
| - if( pLevel->plan.wsFlags & WHERE_MULTI_OR ){
|
| - /* Case 4: 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>
|
| - **
|
| - */
|
| - WhereClause *pOrWc; /* The OR-clause broken out into subterms */
|
| - WhereTerm *pFinal; /* Final subterm within the OR-clause. */
|
| - SrcList oneTab; /* Shortened table list */
|
| -
|
| - 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 ii;
|
| -
|
| - pTerm = pLevel->plan.u.pTerm;
|
| - assert( pTerm!=0 );
|
| - assert( pTerm->eOperator==WO_OR );
|
| - assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
|
| - pOrWc = &pTerm->u.pOrInfo->wc;
|
| - pFinal = &pOrWc->a[pOrWc->nTerm-1];
|
| -
|
| - /* Set up a SrcList containing just the table being scanned by this loop. */
|
| - oneTab.nSrc = 1;
|
| - oneTab.nAlloc = 1;
|
| - oneTab.a[0] = *pTabItem;
|
| -
|
| - /* Initialize the rowset register to contain NULL. An SQL NULL is
|
| - ** equivalent to an empty rowset.
|
| - **
|
| - ** 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( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
|
| - regRowset = ++pParse->nMem;
|
| - regRowid = ++pParse->nMem;
|
| - sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset);
|
| - }
|
| - iRetInit = sqlite3VdbeAddOp2(v, OP_Integer, 0, regReturn);
|
| -
|
| - for(ii=0; ii<pOrWc->nTerm; ii++){
|
| - WhereTerm *pOrTerm = &pOrWc->a[ii];
|
| - if( pOrTerm->leftCursor==iCur || pOrTerm->eOperator==WO_AND ){
|
| - WhereInfo *pSubWInfo; /* Info for single OR-term scan */
|
| - /* Loop through table entries that match term pOrTerm. */
|
| - pSubWInfo = sqlite3WhereBegin(pParse, &oneTab, pOrTerm->pExpr, 0,
|
| - WHERE_OMIT_OPEN | WHERE_OMIT_CLOSE | WHERE_FORCE_TABLE);
|
| - if( pSubWInfo ){
|
| - if( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
|
| - int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
|
| - int r;
|
| - r = sqlite3ExprCodeGetColumn(pParse, pTabItem->pTab, -1, iCur,
|
| - regRowid, 0);
|
| - sqlite3VdbeAddOp4(v, OP_RowSetTest, regRowset,
|
| - sqlite3VdbeCurrentAddr(v)+2,
|
| - r, SQLITE_INT_TO_PTR(iSet), P4_INT32);
|
| - }
|
| - sqlite3VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);
|
| -
|
| - /* Finish the loop through table entries that match term pOrTerm. */
|
| - sqlite3WhereEnd(pSubWInfo);
|
| - }
|
| - }
|
| - }
|
| - sqlite3VdbeChangeP1(v, iRetInit, sqlite3VdbeCurrentAddr(v));
|
| - /* sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset); */
|
| - sqlite3VdbeAddOp2(v, OP_Goto, 0, pLevel->addrBrk);
|
| - sqlite3VdbeResolveLabel(v, iLoopBody);
|
| -
|
| - pLevel->op = OP_Return;
|
| - pLevel->p1 = regReturn;
|
| - disableTerm(pLevel, pTerm);
|
| - }else
|
| -#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
|
| -
|
| - {
|
| - /* Case 5: 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 );
|
| - assert( omitTable==0 );
|
| - pLevel->op = aStep[bRev];
|
| - pLevel->p1 = iCur;
|
| - pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
|
| - pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
|
| - }
|
| - notReady &= ~getMask(pWC->pMaskSet, iCur);
|
| -
|
| - /* Insert code to test every subexpression that can be completely
|
| - ** computed using the current set of tables.
|
| - */
|
| - k = 0;
|
| - for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
|
| - Expr *pE;
|
| - testcase( pTerm->wtFlags & TERM_VIRTUAL );
|
| - testcase( pTerm->wtFlags & TERM_CODED );
|
| - if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
|
| - if( (pTerm->prereqAll & notReady)!=0 ) continue;
|
| - pE = pTerm->pExpr;
|
| - assert( pE!=0 );
|
| - if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){
|
| - continue;
|
| - }
|
| - sqlite3ExprIfFalse(pParse, pE, addrCont, SQLITE_JUMPIFNULL);
|
| - k = 1;
|
| - pTerm->wtFlags |= TERM_CODED;
|
| - }
|
| -
|
| - /* 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 & notReady)!=0 ) continue;
|
| - assert( pTerm->pExpr );
|
| - sqlite3ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE_JUMPIFNULL);
|
| - pTerm->wtFlags |= TERM_CODED;
|
| - }
|
| - }
|
| - sqlite3ReleaseTempReg(pParse, iReleaseReg);
|
| -
|
| - return notReady;
|
| -}
|
| -
|
| -#if defined(SQLITE_TEST)
|
| -/*
|
| -** The following variable holds a text description of query plan generated
|
| -** by the most recent call to sqlite3WhereBegin(). Each call to WhereBegin
|
| -** overwrites the previous. This information is used for testing and
|
| -** analysis only.
|
| -*/
|
| -char sqlite3_query_plan[BMS*2*40]; /* Text of the join */
|
| -static int nQPlan = 0; /* Next free slow in _query_plan[] */
|
| -
|
| -#endif /* SQLITE_TEST */
|
| -
|
| -
|
| -/*
|
| -** Free a WhereInfo structure
|
| -*/
|
| -static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){
|
| - if( pWInfo ){
|
| - int i;
|
| - for(i=0; i<pWInfo->nLevel; i++){
|
| - sqlite3_index_info *pInfo = pWInfo->a[i].pIdxInfo;
|
| - if( pInfo ){
|
| - /* assert( pInfo->needToFreeIdxStr==0 || db->mallocFailed ); */
|
| - if( pInfo->needToFreeIdxStr ){
|
| - sqlite3_free(pInfo->idxStr);
|
| - }
|
| - sqlite3DbFree(db, pInfo);
|
| - }
|
| - }
|
| - whereClauseClear(pWInfo->pWC);
|
| - sqlite3DbFree(db, pWInfo);
|
| - }
|
| -}
|
| -
|
| -
|
| -/*
|
| -** Generate the beginning of the loop used for WHERE clause processing.
|
| -** The return value is a pointer to an opaque structure that contains
|
| -** information needed to terminate the loop. Later, the calling routine
|
| -** should invoke sqlite3WhereEnd() with the return value of this function
|
| -** in order to complete the WHERE clause processing.
|
| -**
|
| -** If an error occurs, this routine returns NULL.
|
| -**
|
| -** The basic idea is to do a nested loop, one loop for each table in
|
| -** the FROM clause of a select. (INSERT and UPDATE statements are the
|
| -** same as a SELECT with only a single table in the FROM clause.) For
|
| -** example, if the SQL is this:
|
| -**
|
| -** SELECT * FROM t1, t2, t3 WHERE ...;
|
| -**
|
| -** Then the code generated is conceptually like the following:
|
| -**
|
| -** foreach row1 in t1 do \ Code generated
|
| -** foreach row2 in t2 do |-- by sqlite3WhereBegin()
|
| -** foreach row3 in t3 do /
|
| -** ...
|
| -** end \ Code generated
|
| -** end |-- by sqlite3WhereEnd()
|
| -** end /
|
| -**
|
| -** Note that the loops might not be nested in the order in which they
|
| -** appear in the FROM clause if a different order is better able to make
|
| -** use of indices. Note also that when the IN operator appears in
|
| -** the WHERE clause, it might result in additional nested loops for
|
| -** scanning through all values on the right-hand side of the IN.
|
| -**
|
| -** There are Btree cursors associated with each table. t1 uses cursor
|
| -** number pTabList->a[0].iCursor. t2 uses the cursor pTabList->a[1].iCursor.
|
| -** And so forth. This routine generates code to open those VDBE cursors
|
| -** and sqlite3WhereEnd() generates the code to close them.
|
| -**
|
| -** The code that sqlite3WhereBegin() generates leaves the cursors named
|
| -** in pTabList pointing at their appropriate entries. The [...] code
|
| -** can use OP_Column and OP_Rowid opcodes on these cursors to extract
|
| -** data from the various tables of the loop.
|
| -**
|
| -** If the WHERE clause is empty, the foreach loops must each scan their
|
| -** entire tables. Thus a three-way join is an O(N^3) operation. But if
|
| -** the tables have indices and there are terms in the WHERE clause that
|
| -** refer to those indices, a complete table scan can be avoided and the
|
| -** code will run much faster. Most of the work of this routine is checking
|
| -** to see if there are indices that can be used to speed up the loop.
|
| -**
|
| -** Terms of the WHERE clause are also used to limit which rows actually
|
| -** make it to the "..." in the middle of the loop. After each "foreach",
|
| -** terms of the WHERE clause that use only terms in that loop and outer
|
| -** loops are evaluated and if false a jump is made around all subsequent
|
| -** inner loops (or around the "..." if the test occurs within the inner-
|
| -** most loop)
|
| -**
|
| -** OUTER JOINS
|
| -**
|
| -** An outer join of tables t1 and t2 is conceptally coded as follows:
|
| -**
|
| -** foreach row1 in t1 do
|
| -** flag = 0
|
| -** foreach row2 in t2 do
|
| -** start:
|
| -** ...
|
| -** flag = 1
|
| -** end
|
| -** if flag==0 then
|
| -** move the row2 cursor to a null row
|
| -** goto start
|
| -** fi
|
| -** end
|
| -**
|
| -** ORDER BY CLAUSE PROCESSING
|
| -**
|
| -** *ppOrderBy is a pointer to the ORDER BY clause of a SELECT statement,
|
| -** if there is one. If there is no ORDER BY clause or if this routine
|
| -** is called from an UPDATE or DELETE statement, then ppOrderBy is NULL.
|
| -**
|
| -** If an index can be used so that the natural output order of the table
|
| -** scan is correct for the ORDER BY clause, then that index is used and
|
| -** *ppOrderBy is set to NULL. This is an optimization that prevents an
|
| -** unnecessary sort of the result set if an index appropriate for the
|
| -** ORDER BY clause already exists.
|
| -**
|
| -** If the where clause loops cannot be arranged to provide the correct
|
| -** output order, then the *ppOrderBy is unchanged.
|
| -*/
|
| -WhereInfo *sqlite3WhereBegin(
|
| - Parse *pParse, /* The parser context */
|
| - SrcList *pTabList, /* A list of all tables to be scanned */
|
| - Expr *pWhere, /* The WHERE clause */
|
| - ExprList **ppOrderBy, /* An ORDER BY clause, or NULL */
|
| - u16 wctrlFlags /* One of the WHERE_* flags defined in sqliteInt.h */
|
| -){
|
| - int i; /* Loop counter */
|
| - int nByteWInfo; /* Num. bytes allocated for WhereInfo struct */
|
| - WhereInfo *pWInfo; /* Will become the return value of this function */
|
| - Vdbe *v = pParse->pVdbe; /* The virtual database engine */
|
| - Bitmask notReady; /* Cursors that are not yet positioned */
|
| - WhereMaskSet *pMaskSet; /* The expression mask set */
|
| - WhereClause *pWC; /* Decomposition of the WHERE clause */
|
| - struct SrcList_item *pTabItem; /* A single entry from pTabList */
|
| - WhereLevel *pLevel; /* A single level in the pWInfo list */
|
| - int iFrom; /* First unused FROM clause element */
|
| - int andFlags; /* AND-ed combination of all pWC->a[].wtFlags */
|
| - sqlite3 *db; /* Database connection */
|
| -
|
| - /* The number of tables in the FROM clause is limited by the number of
|
| - ** bits in a Bitmask
|
| - */
|
| - if( pTabList->nSrc>BMS ){
|
| - sqlite3ErrorMsg(pParse, "at most %d tables in a join", BMS);
|
| - return 0;
|
| - }
|
| -
|
| - /* Allocate and initialize the WhereInfo structure that will become the
|
| - ** return value. A single allocation is used to store the WhereInfo
|
| - ** struct, the contents of WhereInfo.a[], the WhereClause structure
|
| - ** and the WhereMaskSet structure. Since WhereClause contains an 8-byte
|
| - ** field (type Bitmask) it must be aligned on an 8-byte boundary on
|
| - ** some architectures. Hence the ROUND8() below.
|
| - */
|
| - db = pParse->db;
|
| - nByteWInfo = ROUND8(sizeof(WhereInfo)+(pTabList->nSrc-1)*sizeof(WhereLevel));
|
| - pWInfo = sqlite3DbMallocZero(db,
|
| - nByteWInfo +
|
| - sizeof(WhereClause) +
|
| - sizeof(WhereMaskSet)
|
| - );
|
| - if( db->mallocFailed ){
|
| - goto whereBeginError;
|
| - }
|
| - pWInfo->nLevel = pTabList->nSrc;
|
| - pWInfo->pParse = pParse;
|
| - pWInfo->pTabList = pTabList;
|
| - pWInfo->iBreak = sqlite3VdbeMakeLabel(v);
|
| - pWInfo->pWC = pWC = (WhereClause *)&((u8 *)pWInfo)[nByteWInfo];
|
| - pWInfo->wctrlFlags = wctrlFlags;
|
| - pMaskSet = (WhereMaskSet*)&pWC[1];
|
| -
|
| - /* Split the WHERE clause into separate subexpressions where each
|
| - ** subexpression is separated by an AND operator.
|
| - */
|
| - initMaskSet(pMaskSet);
|
| - whereClauseInit(pWC, pParse, pMaskSet);
|
| - sqlite3ExprCodeConstants(pParse, pWhere);
|
| - whereSplit(pWC, pWhere, TK_AND);
|
| -
|
| - /* Special case: a WHERE clause that is constant. Evaluate the
|
| - ** expression and either jump over all of the code or fall thru.
|
| - */
|
| - if( pWhere && (pTabList->nSrc==0 || sqlite3ExprIsConstantNotJoin(pWhere)) ){
|
| - sqlite3ExprIfFalse(pParse, pWhere, pWInfo->iBreak, SQLITE_JUMPIFNULL);
|
| - pWhere = 0;
|
| - }
|
| -
|
| - /* Assign a bit from the bitmask to every term in the FROM clause.
|
| - **
|
| - ** When assigning bitmask values to FROM clause cursors, it must be
|
| - ** the case that if X is the bitmask for the N-th FROM clause term then
|
| - ** the bitmask for all FROM clause terms to the left of the N-th term
|
| - ** is (X-1). An expression from the ON clause of a LEFT JOIN can use
|
| - ** its Expr.iRightJoinTable value to find the bitmask of the right table
|
| - ** of the join. Subtracting one from the right table bitmask gives a
|
| - ** bitmask for all tables to the left of the join. Knowing the bitmask
|
| - ** for all tables to the left of a left join is important. Ticket #3015.
|
| - **
|
| - ** Configure the WhereClause.vmask variable so that bits that correspond
|
| - ** to virtual table cursors are set. This is used to selectively disable
|
| - ** the OR-to-IN transformation in exprAnalyzeOrTerm(). It is not helpful
|
| - ** with virtual tables.
|
| - */
|
| - assert( pWC->vmask==0 && pMaskSet->n==0 );
|
| - for(i=0; i<pTabList->nSrc; i++){
|
| - createMask(pMaskSet, pTabList->a[i].iCursor);
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| - if( ALWAYS(pTabList->a[i].pTab) && IsVirtual(pTabList->a[i].pTab) ){
|
| - pWC->vmask |= ((Bitmask)1 << i);
|
| - }
|
| -#endif
|
| - }
|
| -#ifndef NDEBUG
|
| - {
|
| - Bitmask toTheLeft = 0;
|
| - for(i=0; i<pTabList->nSrc; i++){
|
| - Bitmask m = getMask(pMaskSet, pTabList->a[i].iCursor);
|
| - assert( (m-1)==toTheLeft );
|
| - toTheLeft |= m;
|
| - }
|
| - }
|
| -#endif
|
| -
|
| - /* Analyze all of the subexpressions. Note that exprAnalyze() might
|
| - ** add new virtual terms onto the end of the WHERE clause. We do not
|
| - ** want to analyze these virtual terms, so start analyzing at the end
|
| - ** and work forward so that the added virtual terms are never processed.
|
| - */
|
| - exprAnalyzeAll(pTabList, pWC);
|
| - if( db->mallocFailed ){
|
| - goto whereBeginError;
|
| - }
|
| -
|
| - /* Chose the best index to use for each table in the FROM clause.
|
| - **
|
| - ** This loop fills in the following fields:
|
| - **
|
| - ** pWInfo->a[].pIdx The index to use for this level of the loop.
|
| - ** pWInfo->a[].wsFlags WHERE_xxx flags associated with pIdx
|
| - ** pWInfo->a[].nEq The number of == and IN constraints
|
| - ** pWInfo->a[].iFrom Which term of the FROM clause is being coded
|
| - ** pWInfo->a[].iTabCur The VDBE cursor for the database table
|
| - ** pWInfo->a[].iIdxCur The VDBE cursor for the index
|
| - ** pWInfo->a[].pTerm When wsFlags==WO_OR, the OR-clause term
|
| - **
|
| - ** This loop also figures out the nesting order of tables in the FROM
|
| - ** clause.
|
| - */
|
| - notReady = ~(Bitmask)0;
|
| - pTabItem = pTabList->a;
|
| - pLevel = pWInfo->a;
|
| - andFlags = ~0;
|
| - WHERETRACE(("*** Optimizer Start ***\n"));
|
| - for(i=iFrom=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
|
| - WhereCost bestPlan; /* Most efficient plan seen so far */
|
| - Index *pIdx; /* Index for FROM table at pTabItem */
|
| - int j; /* For looping over FROM tables */
|
| - int bestJ = -1; /* The value of j */
|
| - Bitmask m; /* Bitmask value for j or bestJ */
|
| - int isOptimal; /* Iterator for optimal/non-optimal search */
|
| -
|
| - memset(&bestPlan, 0, sizeof(bestPlan));
|
| - bestPlan.rCost = SQLITE_BIG_DBL;
|
| -
|
| - /* Loop through the remaining entries in the FROM clause to find the
|
| - ** next nested loop. The FROM clause entries may be iterated through
|
| - ** either once or twice.
|
| - **
|
| - ** The first iteration, which is always performed, searches for the
|
| - ** FROM clause entry that permits the lowest-cost, "optimal" scan. In
|
| - ** this context an optimal scan is one that uses the same strategy
|
| - ** for the given FROM clause entry as would be selected if the entry
|
| - ** were used as the innermost nested loop. In other words, a table
|
| - ** is chosen such that the cost of running that table cannot be reduced
|
| - ** by waiting for other tables to run first.
|
| - **
|
| - ** The second iteration is only performed if no optimal scan strategies
|
| - ** were found by the first. This iteration is used to search for the
|
| - ** lowest cost scan overall.
|
| - **
|
| - ** Previous versions of SQLite performed only the second iteration -
|
| - ** the next outermost loop was always that with the lowest overall
|
| - ** cost. However, this meant that SQLite could select the wrong plan
|
| - ** for scripts such as the following:
|
| - **
|
| - ** CREATE TABLE t1(a, b);
|
| - ** CREATE TABLE t2(c, d);
|
| - ** SELECT * FROM t2, t1 WHERE t2.rowid = t1.a;
|
| - **
|
| - ** The best strategy is to iterate through table t1 first. However it
|
| - ** is not possible to determine this with a simple greedy algorithm.
|
| - ** However, since the cost of a linear scan through table t2 is the same
|
| - ** as the cost of a linear scan through table t1, a simple greedy
|
| - ** algorithm may choose to use t2 for the outer loop, which is a much
|
| - ** costlier approach.
|
| - */
|
| - for(isOptimal=1; isOptimal>=0 && bestJ<0; isOptimal--){
|
| - Bitmask mask = (isOptimal ? 0 : notReady);
|
| - assert( (pTabList->nSrc-iFrom)>1 || isOptimal );
|
| - for(j=iFrom, pTabItem=&pTabList->a[j]; j<pTabList->nSrc; j++, pTabItem++){
|
| - int doNotReorder; /* True if this table should not be reordered */
|
| - WhereCost sCost; /* Cost information from best[Virtual]Index() */
|
| - ExprList *pOrderBy; /* ORDER BY clause for index to optimize */
|
| -
|
| - doNotReorder = (pTabItem->jointype & (JT_LEFT|JT_CROSS))!=0;
|
| - if( j!=iFrom && doNotReorder ) break;
|
| - m = getMask(pMaskSet, pTabItem->iCursor);
|
| - if( (m & notReady)==0 ){
|
| - if( j==iFrom ) iFrom++;
|
| - continue;
|
| - }
|
| - pOrderBy = ((i==0 && ppOrderBy )?*ppOrderBy:0);
|
| -
|
| - assert( pTabItem->pTab );
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| - if( IsVirtual(pTabItem->pTab) ){
|
| - sqlite3_index_info **pp = &pWInfo->a[j].pIdxInfo;
|
| - bestVirtualIndex(pParse, pWC, pTabItem, mask, pOrderBy, &sCost, pp);
|
| - }else
|
| -#endif
|
| - {
|
| - bestBtreeIndex(pParse, pWC, pTabItem, mask, pOrderBy, &sCost);
|
| - }
|
| - assert( isOptimal || (sCost.used¬Ready)==0 );
|
| -
|
| - if( (sCost.used¬Ready)==0
|
| - && (j==iFrom || sCost.rCost<bestPlan.rCost)
|
| - ){
|
| - bestPlan = sCost;
|
| - bestJ = j;
|
| - }
|
| - if( doNotReorder ) break;
|
| - }
|
| - }
|
| - assert( bestJ>=0 );
|
| - assert( notReady & getMask(pMaskSet, pTabList->a[bestJ].iCursor) );
|
| - WHERETRACE(("*** Optimizer selects table %d for loop %d\n", bestJ,
|
| - pLevel-pWInfo->a));
|
| - if( (bestPlan.plan.wsFlags & WHERE_ORDERBY)!=0 ){
|
| - *ppOrderBy = 0;
|
| - }
|
| - andFlags &= bestPlan.plan.wsFlags;
|
| - pLevel->plan = bestPlan.plan;
|
| - if( bestPlan.plan.wsFlags & WHERE_INDEXED ){
|
| - pLevel->iIdxCur = pParse->nTab++;
|
| - }else{
|
| - pLevel->iIdxCur = -1;
|
| - }
|
| - notReady &= ~getMask(pMaskSet, pTabList->a[bestJ].iCursor);
|
| - pLevel->iFrom = (u8)bestJ;
|
| -
|
| - /* Check that if the table scanned by this loop iteration had an
|
| - ** INDEXED BY clause attached to it, that the named index is being
|
| - ** used for the scan. If not, then query compilation has failed.
|
| - ** Return an error.
|
| - */
|
| - pIdx = pTabList->a[bestJ].pIndex;
|
| - if( pIdx ){
|
| - if( (bestPlan.plan.wsFlags & WHERE_INDEXED)==0 ){
|
| - sqlite3ErrorMsg(pParse, "cannot use index: %s", pIdx->zName);
|
| - goto whereBeginError;
|
| - }else{
|
| - /* If an INDEXED BY clause is used, the bestIndex() function is
|
| - ** guaranteed to find the index specified in the INDEXED BY clause
|
| - ** if it find an index at all. */
|
| - assert( bestPlan.plan.u.pIdx==pIdx );
|
| - }
|
| - }
|
| - }
|
| - WHERETRACE(("*** Optimizer Finished ***\n"));
|
| - if( pParse->nErr || db->mallocFailed ){
|
| - goto whereBeginError;
|
| - }
|
| -
|
| - /* If the total query only selects a single row, then the ORDER BY
|
| - ** clause is irrelevant.
|
| - */
|
| - if( (andFlags & WHERE_UNIQUE)!=0 && ppOrderBy ){
|
| - *ppOrderBy = 0;
|
| - }
|
| -
|
| - /* If the caller is an UPDATE or DELETE statement that is requesting
|
| - ** to use a one-pass algorithm, determine if this is appropriate.
|
| - ** The one-pass algorithm only works if the WHERE clause constraints
|
| - ** the statement to update a single row.
|
| - */
|
| - assert( (wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 );
|
| - if( (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 && (andFlags & WHERE_UNIQUE)!=0 ){
|
| - pWInfo->okOnePass = 1;
|
| - pWInfo->a[0].plan.wsFlags &= ~WHERE_IDX_ONLY;
|
| - }
|
| -
|
| - /* Open all tables in the pTabList and any indices selected for
|
| - ** searching those tables.
|
| - */
|
| - sqlite3CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
|
| - for(i=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
|
| - Table *pTab; /* Table to open */
|
| - int iDb; /* Index of database containing table/index */
|
| -
|
| -#ifndef SQLITE_OMIT_EXPLAIN
|
| - if( pParse->explain==2 ){
|
| - char *zMsg;
|
| - struct SrcList_item *pItem = &pTabList->a[pLevel->iFrom];
|
| - zMsg = sqlite3MPrintf(db, "TABLE %s", pItem->zName);
|
| - if( pItem->zAlias ){
|
| - zMsg = sqlite3MAppendf(db, zMsg, "%s AS %s", zMsg, pItem->zAlias);
|
| - }
|
| - if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
|
| - zMsg = sqlite3MAppendf(db, zMsg, "%s WITH INDEX %s",
|
| - zMsg, pLevel->plan.u.pIdx->zName);
|
| - }else if( pLevel->plan.wsFlags & WHERE_MULTI_OR ){
|
| - zMsg = sqlite3MAppendf(db, zMsg, "%s VIA MULTI-INDEX UNION", zMsg);
|
| - }else if( pLevel->plan.wsFlags & (WHERE_ROWID_EQ|WHERE_ROWID_RANGE) ){
|
| - zMsg = sqlite3MAppendf(db, zMsg, "%s USING PRIMARY KEY", zMsg);
|
| - }
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| - else if( (pLevel->plan.wsFlags & WHERE_VIRTUALTABLE)!=0 ){
|
| - sqlite3_index_info *pVtabIdx = pLevel->plan.u.pVtabIdx;
|
| - zMsg = sqlite3MAppendf(db, zMsg, "%s VIRTUAL TABLE INDEX %d:%s", zMsg,
|
| - pVtabIdx->idxNum, pVtabIdx->idxStr);
|
| - }
|
| -#endif
|
| - if( pLevel->plan.wsFlags & WHERE_ORDERBY ){
|
| - zMsg = sqlite3MAppendf(db, zMsg, "%s ORDER BY", zMsg);
|
| - }
|
| - sqlite3VdbeAddOp4(v, OP_Explain, i, pLevel->iFrom, 0, zMsg, P4_DYNAMIC);
|
| - }
|
| -#endif /* SQLITE_OMIT_EXPLAIN */
|
| - pTabItem = &pTabList->a[pLevel->iFrom];
|
| - pTab = pTabItem->pTab;
|
| - iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
|
| - if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ) continue;
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| - if( (pLevel->plan.wsFlags & WHERE_VIRTUALTABLE)!=0 ){
|
| - const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
|
| - int iCur = pTabItem->iCursor;
|
| - sqlite3VdbeAddOp4(v, OP_VOpen, iCur, 0, 0, pVTab, P4_VTAB);
|
| - }else
|
| -#endif
|
| - if( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0
|
| - && (wctrlFlags & WHERE_OMIT_OPEN)==0 ){
|
| - int op = pWInfo->okOnePass ? OP_OpenWrite : OP_OpenRead;
|
| - sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, op);
|
| - if( !pWInfo->okOnePass && pTab->nCol<BMS ){
|
| - Bitmask b = pTabItem->colUsed;
|
| - int n = 0;
|
| - for(; b; b=b>>1, n++){}
|
| - sqlite3VdbeChangeP4(v, sqlite3VdbeCurrentAddr(v)-1, SQLITE_INT_TO_PTR(n), P4_INT32);
|
| - assert( n<=pTab->nCol );
|
| - }
|
| - }else{
|
| - sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
|
| - }
|
| - pLevel->iTabCur = pTabItem->iCursor;
|
| - if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
|
| - Index *pIx = pLevel->plan.u.pIdx;
|
| - KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIx);
|
| - int iIdxCur = pLevel->iIdxCur;
|
| - assert( pIx->pSchema==pTab->pSchema );
|
| - assert( iIdxCur>=0 );
|
| - sqlite3VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIx->tnum, iDb,
|
| - (char*)pKey, P4_KEYINFO_HANDOFF);
|
| - VdbeComment((v, "%s", pIx->zName));
|
| - }
|
| - sqlite3CodeVerifySchema(pParse, iDb);
|
| - }
|
| - pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
|
| -
|
| - /* Generate the code to do the search. Each iteration of the for
|
| - ** loop below generates code for a single nested loop of the VM
|
| - ** program.
|
| - */
|
| - notReady = ~(Bitmask)0;
|
| - for(i=0; i<pTabList->nSrc; i++){
|
| - notReady = codeOneLoopStart(pWInfo, i, wctrlFlags, notReady);
|
| - pWInfo->iContinue = pWInfo->a[i].addrCont;
|
| - }
|
| -
|
| -#ifdef SQLITE_TEST /* For testing and debugging use only */
|
| - /* Record in the query plan information about the current table
|
| - ** and the index used to access it (if any). If the table itself
|
| - ** is not used, its name is just '{}'. If no index is used
|
| - ** the index is listed as "{}". If the primary key is used the
|
| - ** index name is '*'.
|
| - */
|
| - for(i=0; i<pTabList->nSrc; i++){
|
| - char *z;
|
| - int n;
|
| - pLevel = &pWInfo->a[i];
|
| - pTabItem = &pTabList->a[pLevel->iFrom];
|
| - z = pTabItem->zAlias;
|
| - if( z==0 ) z = pTabItem->pTab->zName;
|
| - n = sqlite3Strlen30(z);
|
| - if( n+nQPlan < sizeof(sqlite3_query_plan)-10 ){
|
| - if( pLevel->plan.wsFlags & WHERE_IDX_ONLY ){
|
| - memcpy(&sqlite3_query_plan[nQPlan], "{}", 2);
|
| - nQPlan += 2;
|
| - }else{
|
| - memcpy(&sqlite3_query_plan[nQPlan], z, n);
|
| - nQPlan += n;
|
| - }
|
| - sqlite3_query_plan[nQPlan++] = ' ';
|
| - }
|
| - testcase( pLevel->plan.wsFlags & WHERE_ROWID_EQ );
|
| - testcase( pLevel->plan.wsFlags & WHERE_ROWID_RANGE );
|
| - if( pLevel->plan.wsFlags & (WHERE_ROWID_EQ|WHERE_ROWID_RANGE) ){
|
| - memcpy(&sqlite3_query_plan[nQPlan], "* ", 2);
|
| - nQPlan += 2;
|
| - }else if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
|
| - n = sqlite3Strlen30(pLevel->plan.u.pIdx->zName);
|
| - if( n+nQPlan < sizeof(sqlite3_query_plan)-2 ){
|
| - memcpy(&sqlite3_query_plan[nQPlan], pLevel->plan.u.pIdx->zName, n);
|
| - nQPlan += n;
|
| - sqlite3_query_plan[nQPlan++] = ' ';
|
| - }
|
| - }else{
|
| - memcpy(&sqlite3_query_plan[nQPlan], "{} ", 3);
|
| - nQPlan += 3;
|
| - }
|
| - }
|
| - while( nQPlan>0 && sqlite3_query_plan[nQPlan-1]==' ' ){
|
| - sqlite3_query_plan[--nQPlan] = 0;
|
| - }
|
| - sqlite3_query_plan[nQPlan] = 0;
|
| - nQPlan = 0;
|
| -#endif /* SQLITE_TEST // Testing and debugging use only */
|
| -
|
| - /* Record the continuation address in the WhereInfo structure. Then
|
| - ** clean up and return.
|
| - */
|
| - return pWInfo;
|
| -
|
| - /* Jump here if malloc fails */
|
| -whereBeginError:
|
| - whereInfoFree(db, pWInfo);
|
| - return 0;
|
| -}
|
| -
|
| -/*
|
| -** Generate the end of the WHERE loop. See comments on
|
| -** sqlite3WhereBegin() for additional information.
|
| -*/
|
| -void sqlite3WhereEnd(WhereInfo *pWInfo){
|
| - Parse *pParse = pWInfo->pParse;
|
| - Vdbe *v = pParse->pVdbe;
|
| - int i;
|
| - WhereLevel *pLevel;
|
| - SrcList *pTabList = pWInfo->pTabList;
|
| - sqlite3 *db = pParse->db;
|
| -
|
| - /* Generate loop termination code.
|
| - */
|
| - sqlite3ExprCacheClear(pParse);
|
| - for(i=pTabList->nSrc-1; i>=0; i--){
|
| - pLevel = &pWInfo->a[i];
|
| - sqlite3VdbeResolveLabel(v, pLevel->addrCont);
|
| - if( pLevel->op!=OP_Noop ){
|
| - sqlite3VdbeAddOp2(v, pLevel->op, pLevel->p1, pLevel->p2);
|
| - sqlite3VdbeChangeP5(v, pLevel->p5);
|
| - }
|
| - if( pLevel->plan.wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){
|
| - struct InLoop *pIn;
|
| - int j;
|
| - sqlite3VdbeResolveLabel(v, pLevel->addrNxt);
|
| - for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
|
| - sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
|
| - sqlite3VdbeAddOp2(v, OP_Next, pIn->iCur, pIn->addrInTop);
|
| - sqlite3VdbeJumpHere(v, pIn->addrInTop-1);
|
| - }
|
| - sqlite3DbFree(db, pLevel->u.in.aInLoop);
|
| - }
|
| - sqlite3VdbeResolveLabel(v, pLevel->addrBrk);
|
| - if( pLevel->iLeftJoin ){
|
| - int addr;
|
| - addr = sqlite3VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin);
|
| - sqlite3VdbeAddOp1(v, OP_NullRow, pTabList->a[i].iCursor);
|
| - if( pLevel->iIdxCur>=0 ){
|
| - sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
|
| - }
|
| - if( pLevel->op==OP_Return ){
|
| - sqlite3VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst);
|
| - }else{
|
| - sqlite3VdbeAddOp2(v, OP_Goto, 0, pLevel->addrFirst);
|
| - }
|
| - sqlite3VdbeJumpHere(v, addr);
|
| - }
|
| - }
|
| -
|
| - /* The "break" point is here, just past the end of the outer loop.
|
| - ** Set it.
|
| - */
|
| - sqlite3VdbeResolveLabel(v, pWInfo->iBreak);
|
| -
|
| - /* Close all of the cursors that were opened by sqlite3WhereBegin.
|
| - */
|
| - for(i=0, pLevel=pWInfo->a; i<pTabList->nSrc; i++, pLevel++){
|
| - struct SrcList_item *pTabItem = &pTabList->a[pLevel->iFrom];
|
| - Table *pTab = pTabItem->pTab;
|
| - assert( pTab!=0 );
|
| - if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ) continue;
|
| - if( (pWInfo->wctrlFlags & WHERE_OMIT_CLOSE)==0 ){
|
| - if( !pWInfo->okOnePass && (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0 ){
|
| - sqlite3VdbeAddOp1(v, OP_Close, pTabItem->iCursor);
|
| - }
|
| - if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
|
| - sqlite3VdbeAddOp1(v, OP_Close, pLevel->iIdxCur);
|
| - }
|
| - }
|
| -
|
| - /* If this scan uses an index, make code substitutions to read data
|
| - ** from the index in preference to the table. Sometimes, this means
|
| - ** the table need never be read from. This is a performance boost,
|
| - ** as the vdbe level waits until the table is read before actually
|
| - ** seeking the table cursor to the record corresponding to the current
|
| - ** position in the index.
|
| - **
|
| - ** Calls to the code generator in between sqlite3WhereBegin and
|
| - ** sqlite3WhereEnd will have created code that references the table
|
| - ** directly. This loop scans all that code looking for opcodes
|
| - ** that reference the table and converts them into opcodes that
|
| - ** reference the index.
|
| - */
|
| - if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 && !db->mallocFailed){
|
| - int k, j, last;
|
| - VdbeOp *pOp;
|
| - Index *pIdx = pLevel->plan.u.pIdx;
|
| - int useIndexOnly = pLevel->plan.wsFlags & WHERE_IDX_ONLY;
|
| -
|
| - assert( pIdx!=0 );
|
| - pOp = sqlite3VdbeGetOp(v, pWInfo->iTop);
|
| - last = sqlite3VdbeCurrentAddr(v);
|
| - for(k=pWInfo->iTop; k<last; k++, pOp++){
|
| - if( pOp->p1!=pLevel->iTabCur ) continue;
|
| - if( pOp->opcode==OP_Column ){
|
| - for(j=0; j<pIdx->nColumn; j++){
|
| - if( pOp->p2==pIdx->aiColumn[j] ){
|
| - pOp->p2 = j;
|
| - pOp->p1 = pLevel->iIdxCur;
|
| - break;
|
| - }
|
| - }
|
| - assert(!useIndexOnly || j<pIdx->nColumn);
|
| - }else if( pOp->opcode==OP_Rowid ){
|
| - pOp->p1 = pLevel->iIdxCur;
|
| - pOp->opcode = OP_IdxRowid;
|
| - }else if( pOp->opcode==OP_NullRow && useIndexOnly ){
|
| - pOp->opcode = OP_Noop;
|
| - }
|
| - }
|
| - }
|
| - }
|
| -
|
| - /* Final cleanup
|
| - */
|
| - whereInfoFree(db, pWInfo);
|
| - return;
|
| -}
|
|
|
Chromium Code Reviews
Issue 3108030:
Move bundled copy of sqlite one level deeper to better separate it... (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src/