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Overview
| Comment: | Backport the "x IS NULL" query planner enhancement of [2353176811f] to the 3.7.2 branch. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | branch-3.7.2 |
| Files: | files | file ages | folders |
| SHA1: |
68daf20d019a0a84764d635a91eaa9fa |
| User & Date: | drh 2011-03-17 01:53:00 |
Context
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2011-03-31
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| 18:36 | Provide hints to the btree layer Next and Previous primitives to let them know if they can be no-ops if the underlying index is unique. check-in: a5aae174 user: drh tags: branch-3.7.2 | |
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2011-03-17
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| 01:53 | Backport the "x IS NULL" query planner enhancement of [2353176811f] to the 3.7.2 branch. check-in: 68daf20d user: drh tags: branch-3.7.2 | |
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2011-03-12
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| 05:55 | Backport the SQLITE_OMIT_UNIQUE_ENFORCEMENT change from check-in [b86999436e] on the trunk. check-in: 668b91db user: shaneh tags: branch-3.7.2 | |
Changes
Changes to src/where.c.
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int iLower, iUpper; /* Range of histogram regions containing pRhs */
u8 aff; /* Column affinity */
int rc; /* Subfunction return code */
double nRowEst; /* New estimate of the number of rows */
assert( p->aSample!=0 );
aff = p->pTable->aCol[p->aiColumn[0]].affinity;
rc = valueFromExpr(pParse, pExpr, aff, &pRhs);
if( rc ) goto whereEqualScanEst_cancel;
if( pRhs==0 ) return SQLITE_NOTFOUND;
rc = whereRangeRegion(pParse, p, pRhs, 0, &iLower);
if( rc ) goto whereEqualScanEst_cancel;
rc = whereRangeRegion(pParse, p, pRhs, 1, &iUpper);
if( rc ) goto whereEqualScanEst_cancel;
WHERETRACE(("equality scan regions: %d..%d\n", iLower, iUpper));
if( iLower>=iUpper ){
................................................................................
#ifdef SQLITE_ENABLE_STAT2
/* If the constraint is of the form x=VALUE and histogram
** data is available for column x, then it might be possible
** to get a better estimate on the number of rows based on
** VALUE and how common that value is according to the histogram.
*/
if( nRow>(double)1 && nEq==1 && pFirstTerm!=0 ){
if( pFirstTerm->eOperator==WO_EQ ){
whereEqualScanEst(pParse, pProbe, pFirstTerm->pExpr->pRight, &nRow);
}else if( pFirstTerm->eOperator==WO_IN && bInEst==0 ){
whereInScanEst(pParse, pProbe, pFirstTerm->pExpr->x.pList, &nRow);
}
}
#endif /* SQLITE_ENABLE_STAT2 */
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int iLower, iUpper; /* Range of histogram regions containing pRhs */ u8 aff; /* Column affinity */ int rc; /* Subfunction return code */ double nRowEst; /* New estimate of the number of rows */ assert( p->aSample!=0 ); aff = p->pTable->aCol[p->aiColumn[0]].affinity; if( pExpr ){ rc = valueFromExpr(pParse, pExpr, aff, &pRhs); if( rc ) goto whereEqualScanEst_cancel; }else{ pRhs = sqlite3ValueNew(pParse->db); } if( pRhs==0 ) return SQLITE_NOTFOUND; rc = whereRangeRegion(pParse, p, pRhs, 0, &iLower); if( rc ) goto whereEqualScanEst_cancel; rc = whereRangeRegion(pParse, p, pRhs, 1, &iUpper); if( rc ) goto whereEqualScanEst_cancel; WHERETRACE(("equality scan regions: %d..%d\n", iLower, iUpper)); if( iLower>=iUpper ){ ................................................................................ #ifdef SQLITE_ENABLE_STAT2 /* If the constraint is of the form x=VALUE and histogram ** data is available for column x, then it might be possible ** to get a better estimate on the number of rows based on ** VALUE and how common that value is according to the histogram. */ if( nRow>(double)1 && nEq==1 && pFirstTerm!=0 ){ if( pFirstTerm->eOperator & (WO_EQ|WO_ISNULL) ){ testcase( pFirstTerm->eOperator==WO_EQ ); testcase( pFirstTerm->pOperator==WO_ISNULL ); whereEqualScanEst(pParse, pProbe, pFirstTerm->pExpr->pRight, &nRow); }else if( pFirstTerm->eOperator==WO_IN && bInEst==0 ){ whereInScanEst(pParse, pProbe, pFirstTerm->pExpr->x.pList, &nRow); } } #endif /* SQLITE_ENABLE_STAT2 */ |