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Overview
| Comment: | Avoid storing the result register for EXISTS and SELECT in any field of the Expr object - simply return the register number as the return value of the function that codes those expressions. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
7253f8fad1efe6b88666f0f8740d247f |
| User & Date: | drh 2009-10-30 13:25:57 |
References
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2009-10-30
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| 14:05 | • Fixed ticket [6b00e0a3]: The great OP_If bug plus 3 other changes (artifact: a67b11ba user: drh) | |
Context
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2009-10-30
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| 14:27 | Increase the version number to 3.6.20. (check-in: 61295274 user: drh tags: trunk) | |
| 13:25 | Avoid storing the result register for EXISTS and SELECT in any field of the Expr object - simply return the register number as the return value of the function that codes those expressions. (check-in: 7253f8fa user: drh tags: trunk) | |
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2009-10-29
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| 13:48 | Reduce the memory required by prepared statements that use the IN operator with a list on the right and an INTEGER PRIMARY KEY on the left. (check-in: e7984ad2 user: drh tags: trunk) | |
Changes
Changes to src/expr.c.
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*/
#ifndef SQLITE_OMIT_SUBQUERY
int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
Select *p; /* SELECT to the right of IN operator */
int eType = 0; /* Type of RHS table. IN_INDEX_* */
int iTab = pParse->nTab++; /* Cursor of the RHS table */
int mustBeUnique = (prNotFound==0); /* True if RHS must be unique */
/* Check to see if an existing table or index can be used to
** satisfy the query. This is preferable to generating a new
** ephemeral table.
*/
p = (ExprHasProperty(pX, EP_xIsSelect) ? pX->x.pSelect : 0);
if( ALWAYS(pParse->nErr==0) && isCandidateForInOpt(p) ){
................................................................................
}
}
}
}
}
if( eType==0 ){
/* Could not found an existing able or index to use as the RHS b-tree.
** We will have to generate an ephemeral table to do the job.
*/
int rMayHaveNull = 0;
eType = IN_INDEX_EPH;
if( prNotFound ){
*prNotFound = rMayHaveNull = ++pParse->nMem;
}else if( pX->pLeft->iColumn<0 && !ExprHasAnyProperty(pX, EP_xIsSelect) ){
................................................................................
** all corresponding LHS elements. All this routine does is initialize
** the register given by rMayHaveNull to NULL. Calling routines will take
** care of changing this register value to non-NULL if the RHS is NULL-free.
**
** If rMayHaveNull is zero, that means that the subquery is being used
** for membership testing only. There is no need to initialize any
** registers to indicate the presense or absence of NULLs on the RHS.
*/
#ifndef SQLITE_OMIT_SUBQUERY
void sqlite3CodeSubselect(
Parse *pParse, /* Parsing context */
Expr *pExpr, /* The IN, SELECT, or EXISTS operator */
int rMayHaveNull, /* Register that records whether NULLs exist in RHS */
int isRowid /* If true, LHS of IN operator is a rowid */
){
int testAddr = 0; /* One-time test address */
Vdbe *v = sqlite3GetVdbe(pParse);
if( NEVER(v==0) ) return;
sqlite3ExprCachePush(pParse);
/* This code must be run in its entirety every time it is encountered
** if any of the following is true:
**
** * The right-hand side is a correlated subquery
** * The right-hand side is an expression list containing variables
................................................................................
ExprList *pEList;
assert( !isRowid );
sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
dest.affinity = (u8)affinity;
assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
if( sqlite3Select(pParse, pExpr->x.pSelect, &dest) ){
return;
}
pEList = pExpr->x.pSelect->pEList;
if( ALWAYS(pEList!=0 && pEList->nExpr>0) ){
keyInfo.aColl[0] = sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft,
pEList->a[0].pExpr);
}
}else if( pExpr->x.pList!=0 ){
................................................................................
dest.eDest = SRT_Exists;
sqlite3VdbeAddOp2(v, OP_Integer, 0, dest.iParm);
VdbeComment((v, "Init EXISTS result"));
}
sqlite3ExprDelete(pParse->db, pSel->pLimit);
pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &one);
if( sqlite3Select(pParse, pSel, &dest) ){
return;
}
pExpr->iColumn = (i16)dest.iParm;
ExprSetIrreducible(pExpr);
break;
}
}
if( testAddr ){
sqlite3VdbeJumpHere(v, testAddr-1);
}
sqlite3ExprCachePop(pParse, 1);
return;
}
#endif /* SQLITE_OMIT_SUBQUERY */
/*
** Duplicate an 8-byte value
*/
static char *dup8bytes(Vdbe *v, const char *in){
................................................................................
break;
}
#ifndef SQLITE_OMIT_SUBQUERY
case TK_EXISTS:
case TK_SELECT: {
testcase( op==TK_EXISTS );
testcase( op==TK_SELECT );
sqlite3CodeSubselect(pParse, pExpr, 0, 0);
inReg = pExpr->iColumn;
break;
}
case TK_IN: {
int rNotFound = 0;
int rMayHaveNull = 0;
int j2, j3, j4, j5;
char affinity;
|
> > | > > > | > | | | | | | < |
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*/
#ifndef SQLITE_OMIT_SUBQUERY
int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
Select *p; /* SELECT to the right of IN operator */
int eType = 0; /* Type of RHS table. IN_INDEX_* */
int iTab = pParse->nTab++; /* Cursor of the RHS table */
int mustBeUnique = (prNotFound==0); /* True if RHS must be unique */
assert( pX->op==TK_IN );
/* Check to see if an existing table or index can be used to
** satisfy the query. This is preferable to generating a new
** ephemeral table.
*/
p = (ExprHasProperty(pX, EP_xIsSelect) ? pX->x.pSelect : 0);
if( ALWAYS(pParse->nErr==0) && isCandidateForInOpt(p) ){
................................................................................
}
}
}
}
}
if( eType==0 ){
/* Could not found an existing table or index to use as the RHS b-tree.
** We will have to generate an ephemeral table to do the job.
*/
int rMayHaveNull = 0;
eType = IN_INDEX_EPH;
if( prNotFound ){
*prNotFound = rMayHaveNull = ++pParse->nMem;
}else if( pX->pLeft->iColumn<0 && !ExprHasAnyProperty(pX, EP_xIsSelect) ){
................................................................................
** all corresponding LHS elements. All this routine does is initialize
** the register given by rMayHaveNull to NULL. Calling routines will take
** care of changing this register value to non-NULL if the RHS is NULL-free.
**
** If rMayHaveNull is zero, that means that the subquery is being used
** for membership testing only. There is no need to initialize any
** registers to indicate the presense or absence of NULLs on the RHS.
**
** For a SELECT or EXISTS operator, return the register that holds the
** result. For IN operators or if an error occurs, the return value is 0.
*/
#ifndef SQLITE_OMIT_SUBQUERY
int sqlite3CodeSubselect(
Parse *pParse, /* Parsing context */
Expr *pExpr, /* The IN, SELECT, or EXISTS operator */
int rMayHaveNull, /* Register that records whether NULLs exist in RHS */
int isRowid /* If true, LHS of IN operator is a rowid */
){
int testAddr = 0; /* One-time test address */
int rReg = 0; /* Register storing resulting */
Vdbe *v = sqlite3GetVdbe(pParse);
if( NEVER(v==0) ) return 0;
sqlite3ExprCachePush(pParse);
/* This code must be run in its entirety every time it is encountered
** if any of the following is true:
**
** * The right-hand side is a correlated subquery
** * The right-hand side is an expression list containing variables
................................................................................
ExprList *pEList;
assert( !isRowid );
sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
dest.affinity = (u8)affinity;
assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
if( sqlite3Select(pParse, pExpr->x.pSelect, &dest) ){
return 0;
}
pEList = pExpr->x.pSelect->pEList;
if( ALWAYS(pEList!=0 && pEList->nExpr>0) ){
keyInfo.aColl[0] = sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft,
pEList->a[0].pExpr);
}
}else if( pExpr->x.pList!=0 ){
................................................................................
dest.eDest = SRT_Exists;
sqlite3VdbeAddOp2(v, OP_Integer, 0, dest.iParm);
VdbeComment((v, "Init EXISTS result"));
}
sqlite3ExprDelete(pParse->db, pSel->pLimit);
pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &one);
if( sqlite3Select(pParse, pSel, &dest) ){
return 0;
}
rReg = dest.iParm;
ExprSetIrreducible(pExpr);
break;
}
}
if( testAddr ){
sqlite3VdbeJumpHere(v, testAddr-1);
}
sqlite3ExprCachePop(pParse, 1);
return rReg;
}
#endif /* SQLITE_OMIT_SUBQUERY */
/*
** Duplicate an 8-byte value
*/
static char *dup8bytes(Vdbe *v, const char *in){
................................................................................
break;
}
#ifndef SQLITE_OMIT_SUBQUERY
case TK_EXISTS:
case TK_SELECT: {
testcase( op==TK_EXISTS );
testcase( op==TK_SELECT );
inReg = sqlite3CodeSubselect(pParse, pExpr, 0, 0);
break;
}
case TK_IN: {
int rNotFound = 0;
int rMayHaveNull = 0;
int j2, j3, j4, j5;
char affinity;
|
Changes to src/sqliteInt.h.
2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 |
void sqlite3RootPageMoved(Db*, int, int);
void sqlite3Reindex(Parse*, Token*, Token*);
void sqlite3AlterFunctions(sqlite3*);
void sqlite3AlterRenameTable(Parse*, SrcList*, Token*);
int sqlite3GetToken(const unsigned char *, int *);
void sqlite3NestedParse(Parse*, const char*, ...);
void sqlite3ExpirePreparedStatements(sqlite3*);
void sqlite3CodeSubselect(Parse *, Expr *, int, int);
void sqlite3SelectPrep(Parse*, Select*, NameContext*);
int sqlite3ResolveExprNames(NameContext*, Expr*);
void sqlite3ResolveSelectNames(Parse*, Select*, NameContext*);
int sqlite3ResolveOrderGroupBy(Parse*, Select*, ExprList*, const char*);
void sqlite3ColumnDefault(Vdbe *, Table *, int, int);
void sqlite3AlterFinishAddColumn(Parse *, Token *);
void sqlite3AlterBeginAddColumn(Parse *, SrcList *);
|
| |
2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 |
void sqlite3RootPageMoved(Db*, int, int);
void sqlite3Reindex(Parse*, Token*, Token*);
void sqlite3AlterFunctions(sqlite3*);
void sqlite3AlterRenameTable(Parse*, SrcList*, Token*);
int sqlite3GetToken(const unsigned char *, int *);
void sqlite3NestedParse(Parse*, const char*, ...);
void sqlite3ExpirePreparedStatements(sqlite3*);
int sqlite3CodeSubselect(Parse *, Expr *, int, int);
void sqlite3SelectPrep(Parse*, Select*, NameContext*);
int sqlite3ResolveExprNames(NameContext*, Expr*);
void sqlite3ResolveSelectNames(Parse*, Select*, NameContext*);
int sqlite3ResolveOrderGroupBy(Parse*, Select*, ExprList*, const char*);
void sqlite3ColumnDefault(Vdbe *, Table *, int, int);
void sqlite3AlterFinishAddColumn(Parse *, Token *);
void sqlite3AlterBeginAddColumn(Parse *, SrcList *);
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