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| Comment: | If the SQLITE_ENABLE_CURSOR_HINTS macro is defined, then invoke the sqlite3BtreeCursorHint() interface to provide hints to the storage engine about rows that need not be returned. Hints can be disabled using SQLITE_TESTCTRL_OPTIMIZATIONS with SQLITE_CursorHints (0x2000). Cursor hints are not used by the built-in storage engine of SQLite but might be useful to applications that provide their own storage engine. The current code is work-in-progrss and contains bugs. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | cursor-hints |
| Files: | files | file ages | folders |
| SHA1: |
3a9bec524ef2de44028b4058e67dc962 |
| User & Date: | drh 2013-12-07 20:39:19 |
Context
|
2013-12-07
| ||
| 23:35 | Do not allow cursor hints to use expressions containing subqueries. This change fixes the problem seen in the previous check-in. (check-in: bfefc575 user: drh tags: cursor-hints) | |
| 20:39 | If the SQLITE_ENABLE_CURSOR_HINTS macro is defined, then invoke the sqlite3BtreeCursorHint() interface to provide hints to the storage engine about rows that need not be returned. Hints can be disabled using SQLITE_TESTCTRL_OPTIMIZATIONS with SQLITE_CursorHints (0x2000). Cursor hints are not used by the built-in storage engine of SQLite but might be useful to applications that provide their own storage engine. The current code is work-in-progrss and contains bugs. (check-in: 3a9bec52 user: drh tags: cursor-hints) | |
| 17:01 | Increase the version number to 3.8.3. (check-in: 23d00f22 user: drh tags: trunk) | |
Changes
Changes to src/btree.c.
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*pHasMoved = 1;
}else{
*pHasMoved = 0;
}
return SQLITE_OK;
}
#ifndef SQLITE_OMIT_AUTOVACUUM
/*
** Given a page number of a regular database page, return the page
** number for the pointer-map page that contains the entry for the
** input page number.
**
** Return 0 (not a valid page) for pgno==1 since there is
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*pHasMoved = 1;
}else{
*pHasMoved = 0;
}
return SQLITE_OK;
}
#ifdef SQLITE_ENABLE_CURSOR_HINTS
/*
** Give a hint to the cursor that it only has to deliver rows for which
** the expression pExpr is true. Within this expression, rows of the
** cursor are identified by Expr.op==TK_COLUMN with Expr.iTable==iTable.
**
** This interfaces is not used by the standard storage engine of SQLite.
** It is only useful to application that replace SQLite's built-in storage
** engine with their own.
*/
void sqlite3BtreeCursorHint(BtCursor *pCur, int iTable, const Expr *pExpr){
/* Alternative storage engines might use this. */
}
#endif /* SQLITE_ENABLE_CURSOR_HINTS */
#ifndef SQLITE_OMIT_AUTOVACUUM
/*
** Given a page number of a regular database page, return the page
** number for the pointer-map page that contains the entry for the
** input page number.
**
** Return 0 (not a valid page) for pgno==1 since there is
|
Changes to src/btree.h.
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BtCursor*,
UnpackedRecord *pUnKey,
i64 intKey,
int bias,
int *pRes
);
int sqlite3BtreeCursorHasMoved(BtCursor*, int*);
int sqlite3BtreeDelete(BtCursor*);
int sqlite3BtreeInsert(BtCursor*, const void *pKey, i64 nKey,
const void *pData, int nData,
int nZero, int bias, int seekResult);
int sqlite3BtreeFirst(BtCursor*, int *pRes);
int sqlite3BtreeLast(BtCursor*, int *pRes);
int sqlite3BtreeNext(BtCursor*, int *pRes);
|
> > > |
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BtCursor*, UnpackedRecord *pUnKey, i64 intKey, int bias, int *pRes ); int sqlite3BtreeCursorHasMoved(BtCursor*, int*); #ifdef SQLITE_ENABLE_CURSOR_HINTS void sqlite3BtreeCursorHint(BtCursor*, int, const Expr*); #endif int sqlite3BtreeDelete(BtCursor*); int sqlite3BtreeInsert(BtCursor*, const void *pKey, i64 nKey, const void *pData, int nData, int nZero, int bias, int seekResult); int sqlite3BtreeFirst(BtCursor*, int *pRes); int sqlite3BtreeLast(BtCursor*, int *pRes); int sqlite3BtreeNext(BtCursor*, int *pRes); |
Changes to src/sqliteInt.h.
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#define SQLITE_CoverIdxScan 0x0040 /* Covering index scans */ #define SQLITE_OrderByIdxJoin 0x0080 /* ORDER BY of joins via index */ #define SQLITE_SubqCoroutine 0x0100 /* Evaluate subqueries as coroutines */ #define SQLITE_Transitive 0x0200 /* Transitive constraints */ #define SQLITE_OmitNoopJoin 0x0400 /* Omit unused tables in joins */ #define SQLITE_Stat3 0x0800 /* Use the SQLITE_STAT3 table */ #define SQLITE_AdjustOutEst 0x1000 /* Adjust output estimates using WHERE */ #define SQLITE_AllOpts 0xffff /* All optimizations */ /* ** Macros for testing whether or not optimizations are enabled or disabled. */ #ifndef SQLITE_OMIT_BUILTIN_TEST #define OptimizationDisabled(db, mask) (((db)->dbOptFlags&(mask))!=0) |
> |
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#define SQLITE_CoverIdxScan 0x0040 /* Covering index scans */
#define SQLITE_OrderByIdxJoin 0x0080 /* ORDER BY of joins via index */
#define SQLITE_SubqCoroutine 0x0100 /* Evaluate subqueries as coroutines */
#define SQLITE_Transitive 0x0200 /* Transitive constraints */
#define SQLITE_OmitNoopJoin 0x0400 /* Omit unused tables in joins */
#define SQLITE_Stat3 0x0800 /* Use the SQLITE_STAT3 table */
#define SQLITE_AdjustOutEst 0x1000 /* Adjust output estimates using WHERE */
#define SQLITE_CursorHints 0x2000 /* Add OP_CursorHint opcodes */
#define SQLITE_AllOpts 0xffff /* All optimizations */
/*
** Macros for testing whether or not optimizations are enabled or disabled.
*/
#ifndef SQLITE_OMIT_BUILTIN_TEST
#define OptimizationDisabled(db, mask) (((db)->dbOptFlags&(mask))!=0)
|
Changes to src/vdbe.c.
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sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);
}
#endif /* SQLITE_DEBUG */
break;
}
#endif
/* Opcode: Noop * * * * *
**
** Do nothing. This instruction is often useful as a jump
** destination.
*/
/*
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sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);
}
#endif /* SQLITE_DEBUG */
break;
}
#endif
#ifdef SQLITE_ENABLE_CURSOR_HINTS
/* Opcode: CursorHint P1 P2 * P4 *
**
** Provide a hint to cursor P1 that it only needs to return rows that
** satisfy the Expr tree given in P4. P2 is the table number of cursor P1
** such that references to cursor P1 in the Expr tree are given by
** Expr.iTable==P2.
*/
case OP_CursorHint: {
VdbeCursor *pC;
assert( pOp->p1>=0 && pOp->p1<p->nCursor );
assert( pOp->p4type==P4_EXPR );
pC = p->apCsr[pOp->p1];
if( pC ) sqlite3BtreeCursorHint(pC->pCursor, pOp->p2, pOp->p4.pExpr);
break;
}
#endif /* SQLITE_ENABLE_CURSOR_HINTS */
/* Opcode: Noop * * * * *
**
** Do nothing. This instruction is often useful as a jump
** destination.
*/
/*
|
Changes to src/vdbe.h.
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FuncDef *pFunc; /* Used when p4type is P4_FUNCDEF */
CollSeq *pColl; /* Used when p4type is P4_COLLSEQ */
Mem *pMem; /* Used when p4type is P4_MEM */
VTable *pVtab; /* Used when p4type is P4_VTAB */
KeyInfo *pKeyInfo; /* Used when p4type is P4_KEYINFO */
int *ai; /* Used when p4type is P4_INTARRAY */
SubProgram *pProgram; /* Used when p4type is P4_SUBPROGRAM */
int (*xAdvance)(BtCursor *, int *);
} p4;
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
char *zComment; /* Comment to improve readability */
#endif
#ifdef VDBE_PROFILE
int cnt; /* Number of times this instruction was executed */
................................................................................
*/
#define P4_NOTUSED 0 /* The P4 parameter is not used */
#define P4_DYNAMIC (-1) /* Pointer to a string obtained from sqliteMalloc() */
#define P4_STATIC (-2) /* Pointer to a static string */
#define P4_COLLSEQ (-4) /* P4 is a pointer to a CollSeq structure */
#define P4_FUNCDEF (-5) /* P4 is a pointer to a FuncDef structure */
#define P4_KEYINFO (-6) /* P4 is a pointer to a KeyInfo structure */
#define P4_MEM (-8) /* P4 is a pointer to a Mem* structure */
#define P4_TRANSIENT 0 /* P4 is a pointer to a transient string */
#define P4_VTAB (-10) /* P4 is a pointer to an sqlite3_vtab structure */
#define P4_MPRINTF (-11) /* P4 is a string obtained from sqlite3_mprintf() */
#define P4_REAL (-12) /* P4 is a 64-bit floating point value */
#define P4_INT64 (-13) /* P4 is a 64-bit signed integer */
#define P4_INT32 (-14) /* P4 is a 32-bit signed integer */
|
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FuncDef *pFunc; /* Used when p4type is P4_FUNCDEF */
CollSeq *pColl; /* Used when p4type is P4_COLLSEQ */
Mem *pMem; /* Used when p4type is P4_MEM */
VTable *pVtab; /* Used when p4type is P4_VTAB */
KeyInfo *pKeyInfo; /* Used when p4type is P4_KEYINFO */
int *ai; /* Used when p4type is P4_INTARRAY */
SubProgram *pProgram; /* Used when p4type is P4_SUBPROGRAM */
#ifdef SQLITE_ENABLE_CURSOR_HINTS
Expr *pExpr; /* Used when p4type is P4_EXPR */
#endif
int (*xAdvance)(BtCursor *, int *);
} p4;
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
char *zComment; /* Comment to improve readability */
#endif
#ifdef VDBE_PROFILE
int cnt; /* Number of times this instruction was executed */
................................................................................
*/
#define P4_NOTUSED 0 /* The P4 parameter is not used */
#define P4_DYNAMIC (-1) /* Pointer to a string obtained from sqliteMalloc() */
#define P4_STATIC (-2) /* Pointer to a static string */
#define P4_COLLSEQ (-4) /* P4 is a pointer to a CollSeq structure */
#define P4_FUNCDEF (-5) /* P4 is a pointer to a FuncDef structure */
#define P4_KEYINFO (-6) /* P4 is a pointer to a KeyInfo structure */
#define P4_EXPR (-7) /* P4 is a pointer to an Expr tree */
#define P4_MEM (-8) /* P4 is a pointer to a Mem* structure */
#define P4_TRANSIENT 0 /* P4 is a pointer to a transient string */
#define P4_VTAB (-10) /* P4 is a pointer to an sqlite3_vtab structure */
#define P4_MPRINTF (-11) /* P4 is a string obtained from sqlite3_mprintf() */
#define P4_REAL (-12) /* P4 is a 64-bit floating point value */
#define P4_INT64 (-13) /* P4 is a 64-bit signed integer */
#define P4_INT32 (-14) /* P4 is a 32-bit signed integer */
|
Changes to src/vdbeaux.c.
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sqlite3DbFree(db, p4);
break;
}
case P4_KEYINFO: {
if( db->pnBytesFreed==0 ) sqlite3KeyInfoUnref((KeyInfo*)p4);
break;
}
case P4_MPRINTF: {
if( db->pnBytesFreed==0 ) sqlite3_free(p4);
break;
}
case P4_FUNCDEF: {
freeEphemeralFunction(db, (FuncDef*)p4);
break;
................................................................................
pOp->p4type = P4_INT32;
}else if( zP4==0 ){
pOp->p4.p = 0;
pOp->p4type = P4_NOTUSED;
}else if( n==P4_KEYINFO ){
pOp->p4.p = (void*)zP4;
pOp->p4type = P4_KEYINFO;
}else if( n==P4_VTAB ){
pOp->p4.p = (void*)zP4;
pOp->p4type = P4_VTAB;
sqlite3VtabLock((VTable *)zP4);
assert( ((VTable *)zP4)->db==p->db );
}else if( n<0 ){
pOp->p4.p = (void*)zP4;
................................................................................
i += n;
}
zTemp[i++] = ')';
zTemp[i] = 0;
assert( i<nTemp );
break;
}
case P4_COLLSEQ: {
CollSeq *pColl = pOp->p4.pColl;
sqlite3_snprintf(nTemp, zTemp, "(%.20s)", pColl->zName);
break;
}
case P4_FUNCDEF: {
FuncDef *pDef = pOp->p4.pFunc;
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sqlite3DbFree(db, p4);
break;
}
case P4_KEYINFO: {
if( db->pnBytesFreed==0 ) sqlite3KeyInfoUnref((KeyInfo*)p4);
break;
}
#ifdef SQLITE_ENABLE_CURSOR_HINTS
case P4_EXPR: {
sqlite3ExprDelete(db, (Expr*)p4);
break;
}
#endif
case P4_MPRINTF: {
if( db->pnBytesFreed==0 ) sqlite3_free(p4);
break;
}
case P4_FUNCDEF: {
freeEphemeralFunction(db, (FuncDef*)p4);
break;
................................................................................
pOp->p4type = P4_INT32;
}else if( zP4==0 ){
pOp->p4.p = 0;
pOp->p4type = P4_NOTUSED;
}else if( n==P4_KEYINFO ){
pOp->p4.p = (void*)zP4;
pOp->p4type = P4_KEYINFO;
#ifdef SQLITE_ENABLE_CURSOR_HINTS
}else if( n==P4_EXPR ){
/* Responsibility for deleting the Expr tree is handed over to the
** VDBE by this operation. The caller should have already invoked
** sqlite3ExprDup() or whatever other routine is needed to make a
** private copy of the tree. */
pOp->p4.pExpr = (Expr*)zP4;
pOp->p4type = P4_EXPR;
#endif
}else if( n==P4_VTAB ){
pOp->p4.p = (void*)zP4;
pOp->p4type = P4_VTAB;
sqlite3VtabLock((VTable *)zP4);
assert( ((VTable *)zP4)->db==p->db );
}else if( n<0 ){
pOp->p4.p = (void*)zP4;
................................................................................
i += n;
}
zTemp[i++] = ')';
zTemp[i] = 0;
assert( i<nTemp );
break;
}
#ifdef SQLITE_ENABLE_CURSOR_HINTS
case P4_EXPR: {
sqlite3_snprintf(nTemp, zTemp, "(expr)");
break;
}
#endif
case P4_COLLSEQ: {
CollSeq *pColl = pOp->p4.pColl;
sqlite3_snprintf(nTemp, zTemp, "(%.20s)", pColl->zName);
break;
}
case P4_FUNCDEF: {
FuncDef *pDef = pOp->p4.pFunc;
|
Changes to src/where.c.
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sqlite3VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC);
}
}
#else
# define explainOneScan(u,v,w,x,y,z)
#endif /* SQLITE_OMIT_EXPLAIN */
/*
** 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 */
................................................................................
if( pLoop->wsFlags & WHERE_TOP_LIMIT ) pEnd = pLoop->aLTerm[j++];
assert( pStart!=0 || pEnd!=0 );
if( bRev ){
pTerm = pStart;
pStart = pEnd;
pEnd = pTerm;
}
if( pStart ){
Expr *pX; /* The expression that defines the start bound */
int r1, rTemp; /* Registers for holding the start boundary */
/* The following constant maps TK_xx codes into corresponding
** seek opcodes. It depends on a particular ordering of TK_xx
*/
................................................................................
testcase( pRangeEnd && (pRangeEnd->eOperator & WO_LE)!=0 );
testcase( pRangeEnd && (pRangeEnd->eOperator & WO_GE)!=0 );
startEq = !pRangeStart || pRangeStart->eOperator & (WO_LE|WO_GE);
endEq = !pRangeEnd || pRangeEnd->eOperator & (WO_LE|WO_GE);
start_constraints = pRangeStart || nEq>0;
/* Seek the index cursor to the start of the range. */
nConstraint = nEq;
if( pRangeStart ){
Expr *pRight = pRangeStart->pExpr->pRight;
sqlite3ExprCode(pParse, pRight, regBase+nEq);
if( (pRangeStart->wtFlags & TERM_VNULL)==0 ){
sqlite3ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
}
................................................................................
{
/* Case 6: There is no usable index. We must do a complete
** scan of the entire table.
*/
static const u8 aStep[] = { OP_Next, OP_Prev };
static const u8 aStart[] = { OP_Rewind, OP_Last };
assert( bRev==0 || bRev==1 );
pLevel->op = aStep[bRev];
pLevel->p1 = iCur;
pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
}
/* Insert code to test every subexpression that can be completely
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sqlite3VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC);
}
}
#else
# define explainOneScan(u,v,w,x,y,z)
#endif /* SQLITE_OMIT_EXPLAIN */
#ifdef SQLITE_ENABLE_CURSOR_HINTS
/*
** Insert an OP_CursorHint instruction if it is appropriate to do so.
*/
static void codeCursorHint(
WhereInfo *pWInfo,
int iLevel
){
Parse *pParse = pWInfo->pParse;
sqlite3 *db = pParse->db;
Vdbe *v = pParse->pVdbe;
WhereLevel *pLevel;
Expr *pExpr = 0;
int iCur;
Bitmask msk;
WhereClause *pWC;
WhereTerm *pTerm;
WhereLoop *pWLoop;
int i, j;
if( OptimizationDisabled(db, SQLITE_CursorHints) ) return;
pLevel = &pWInfo->a[iLevel];
pWLoop = pLevel->pWLoop;
iCur = pWInfo->pTabList->a[pLevel->iFrom].iCursor;
msk = ~getMask(&pWInfo->sMaskSet, iCur);
pWC = &pWInfo->sWC;
for(i=0; i<pWC->nTerm; i++){
pTerm = &pWC->a[i];
if( pTerm->prereqAll & msk ) continue;
if( ExprHasProperty(pTerm->pExpr, EP_FromJoin) ) continue;
for(j=0; j<pWLoop->nLTerm && pWLoop->aLTerm[j]!=pTerm; j++){}
if( j<pWLoop->nLTerm ) continue;
pExpr = sqlite3ExprAnd(db, pExpr, sqlite3ExprDup(db, pTerm->pExpr, 0));
}
if( pExpr!=0 ){
sqlite3VdbeAddOp4(v, OP_CursorHint, pLevel->iTabCur, iCur, 0,
(const char*)pExpr, P4_EXPR);
}
}
#else
# define codeCursorHint(A,B) /* No-op */
#endif /* SQLITE_ENABLE_CURSOR_HINTS */
/*
** Generate code for the start of the iLevel-th loop in the WHERE clause
** implementation described by pWInfo.
*/
static Bitmask codeOneLoopStart(
WhereInfo *pWInfo, /* Complete information about the WHERE clause */
................................................................................
if( pLoop->wsFlags & WHERE_TOP_LIMIT ) pEnd = pLoop->aLTerm[j++];
assert( pStart!=0 || pEnd!=0 );
if( bRev ){
pTerm = pStart;
pStart = pEnd;
pEnd = pTerm;
}
codeCursorHint(pWInfo, iLevel);
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
*/
................................................................................
testcase( pRangeEnd && (pRangeEnd->eOperator & WO_LE)!=0 );
testcase( pRangeEnd && (pRangeEnd->eOperator & WO_GE)!=0 );
startEq = !pRangeStart || pRangeStart->eOperator & (WO_LE|WO_GE);
endEq = !pRangeEnd || pRangeEnd->eOperator & (WO_LE|WO_GE);
start_constraints = pRangeStart || nEq>0;
/* Seek the index cursor to the start of the range. */
codeCursorHint(pWInfo, iLevel);
nConstraint = nEq;
if( pRangeStart ){
Expr *pRight = pRangeStart->pExpr->pRight;
sqlite3ExprCode(pParse, pRight, regBase+nEq);
if( (pRangeStart->wtFlags & TERM_VNULL)==0 ){
sqlite3ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
}
................................................................................
{
/* Case 6: There is no usable index. We must do a complete
** scan of the entire table.
*/
static const u8 aStep[] = { OP_Next, OP_Prev };
static const u8 aStart[] = { OP_Rewind, OP_Last };
assert( bRev==0 || bRev==1 );
codeCursorHint(pWInfo, iLevel);
pLevel->op = aStep[bRev];
pLevel->p1 = iCur;
pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
}
/* Insert code to test every subexpression that can be completely
|