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Overview
| Comment: | Performance improvements for whereScan methods. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | nextgen-query-plan-exp |
| Files: | files | file ages | folders |
| SHA1: |
aae14350a37ad50e4607953ab496cba0 |
| User & Date: | drh 2013-06-10 12:34:45 |
Context
|
2013-06-10
| ||
| 14:56 | Simplification and performance tweak to the high-speed NGQP bypass. (check-in: 0f8a38ee user: drh tags: nextgen-query-plan-exp) | |
| 12:34 | Performance improvements for whereScan methods. (check-in: aae14350 user: drh tags: nextgen-query-plan-exp) | |
| 12:17 | Add a high-speed bypass for the NGQP for the common case of a simply query with quality constraints that outputs a single row. (check-in: 8d1ba309 user: drh tags: nextgen-query-plan-exp) | |
Changes
Changes to src/where.c.
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#endif
/*
** An instance of the WhereScan object is used as an iterator for locating
** terms in the WHERE clause that are useful to the query planner.
*/
struct WhereScan {
WhereTerm *pCurrent; /* Most recent match */
WhereClause *pOrigWC; /* Original, innermost WhereClause */
WhereClause *pWC; /* WhereClause currently being scanned */
char *zCollName; /* Required collating sequence, if not NULL */
char idxaff; /* Must match this affinity, if zCollName!=NULL */
unsigned char nEquiv; /* Number of entries in aEquiv[] */
unsigned char iEquiv; /* Next unused slot in aEquiv[] */
u32 opMask; /* Acceptable operators */
................................................................................
*/
WhereTerm *whereScanNext(WhereScan *pScan){
int iCur; /* The cursor on the LHS of the term */
int iColumn; /* The column on the LHS of the term. -1 for IPK */
Expr *pX; /* An expression being tested */
WhereClause *pWC; /* Shorthand for pScan->pWC */
WhereTerm *pTerm; /* The term being tested */
while( pScan->iEquiv<=pScan->nEquiv ){
iCur = pScan->aEquiv[pScan->iEquiv-2];
iColumn = pScan->aEquiv[pScan->iEquiv-1];
while( (pWC = pScan->pWC)!=0 ){
for(pTerm=pWC->a+pScan->k; pScan->k<pWC->nTerm; pScan->k++, pTerm++){
if( pTerm->leftCursor==iCur && pTerm->u.leftColumn==iColumn ){
if( (pTerm->eOperator & WO_EQUIV)!=0
&& pScan->nEquiv<ArraySize(pScan->aEquiv)
){
int j;
pX = sqlite3ExprSkipCollate(pTerm->pExpr->pRight);
assert( pX->op==TK_COLUMN );
................................................................................
if( (pTerm->eOperator & WO_EQ)!=0
&& (pX = pTerm->pExpr->pRight)->op==TK_COLUMN
&& pX->iTable==pScan->aEquiv[0]
&& pX->iColumn==pScan->aEquiv[1]
){
continue;
}
pScan->pCurrent = pTerm;
pScan->k++;
return pTerm;
}
}
}
pWC = pScan->pWC = pScan->pWC->pOuter;
pScan->k = 0;
}
pScan->pWC = pScan->pOrigWC;
pScan->k = 0;
pScan->iEquiv += 2;
}
pScan->pCurrent = 0;
return 0;
}
/*
** Initialize a WHERE clause scanner object. Return a pointer to the
** first match. Return NULL if there are no matches.
**
................................................................................
int iColumn, /* Column to scan for */
u32 opMask, /* Operator(s) to scan for */
Index *pIdx /* Must be compatible with this index */
){
int j;
/* memset(pScan, 0, sizeof(*pScan)); */
pScan->pCurrent = 0;
pScan->pOrigWC = pWC;
pScan->pWC = pWC;
if( pIdx && iColumn>=0 ){
pScan->idxaff = pIdx->pTable->aCol[iColumn].affinity;
for(j=0; pIdx->aiColumn[j]!=iColumn; j++){
if( NEVER(j>=pIdx->nColumn) ) return 0;
}
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#endif
/*
** An instance of the WhereScan object is used as an iterator for locating
** terms in the WHERE clause that are useful to the query planner.
*/
struct WhereScan {
WhereClause *pOrigWC; /* Original, innermost WhereClause */
WhereClause *pWC; /* WhereClause currently being scanned */
char *zCollName; /* Required collating sequence, if not NULL */
char idxaff; /* Must match this affinity, if zCollName!=NULL */
unsigned char nEquiv; /* Number of entries in aEquiv[] */
unsigned char iEquiv; /* Next unused slot in aEquiv[] */
u32 opMask; /* Acceptable operators */
................................................................................
*/
WhereTerm *whereScanNext(WhereScan *pScan){
int iCur; /* The cursor on the LHS of the term */
int iColumn; /* The column on the LHS of the term. -1 for IPK */
Expr *pX; /* An expression being tested */
WhereClause *pWC; /* Shorthand for pScan->pWC */
WhereTerm *pTerm; /* The term being tested */
int k = pScan->k; /* Where to start scanning */
while( pScan->iEquiv<=pScan->nEquiv ){
iCur = pScan->aEquiv[pScan->iEquiv-2];
iColumn = pScan->aEquiv[pScan->iEquiv-1];
while( (pWC = pScan->pWC)!=0 ){
for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){
if( pTerm->leftCursor==iCur && pTerm->u.leftColumn==iColumn ){
if( (pTerm->eOperator & WO_EQUIV)!=0
&& pScan->nEquiv<ArraySize(pScan->aEquiv)
){
int j;
pX = sqlite3ExprSkipCollate(pTerm->pExpr->pRight);
assert( pX->op==TK_COLUMN );
................................................................................
if( (pTerm->eOperator & WO_EQ)!=0
&& (pX = pTerm->pExpr->pRight)->op==TK_COLUMN
&& pX->iTable==pScan->aEquiv[0]
&& pX->iColumn==pScan->aEquiv[1]
){
continue;
}
pScan->k = k+1;
return pTerm;
}
}
}
pWC = pScan->pWC = pScan->pWC->pOuter;
k = 0;
}
pScan->pWC = pScan->pOrigWC;
k = 0;
pScan->iEquiv += 2;
}
return 0;
}
/*
** Initialize a WHERE clause scanner object. Return a pointer to the
** first match. Return NULL if there are no matches.
**
................................................................................
int iColumn, /* Column to scan for */
u32 opMask, /* Operator(s) to scan for */
Index *pIdx /* Must be compatible with this index */
){
int j;
/* memset(pScan, 0, sizeof(*pScan)); */
pScan->pOrigWC = pWC;
pScan->pWC = pWC;
if( pIdx && iColumn>=0 ){
pScan->idxaff = pIdx->pTable->aCol[iColumn].affinity;
for(j=0; pIdx->aiColumn[j]!=iColumn; j++){
if( NEVER(j>=pIdx->nColumn) ) return 0;
}
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