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Overview
| Comment: | Cherrypicked from trunk: Do not try to use STAT2 for row estimates if the index is unique or nearly so. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | branch-3.7.2 |
| Files: | files | file ages | folders |
| SHA1: |
d55b64ef7e04e10a31360dea55751a33 |
| User & Date: | drh 2011-07-13 18:53:13 |
Context
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2011-08-26
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| 17:17 | Cherrypick the recursion fix to test_vfs.c from [065e5a5ea4f82]. Also fix the nan.test module to handle upper/lower case changes in TCL. (check-in: 41b5f869 user: drh tags: branch-3.7.2) | |
| 13:52 | Merge branches branch-3.7.2 and stat3-enhancement into a new branch for testing purposes. (check-in: 0df04f92 user: drh tags: stat3-3.7.2) | |
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2011-07-13
| ||
| 18:53 | Cherrypicked from trunk: Do not try to use STAT2 for row estimates if the index is unique or nearly so. (check-in: d55b64ef user: drh tags: branch-3.7.2) | |
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2011-07-12
| ||
| 14:48 | Cherrypick change [9f14fa56ba] (the fix for [54844eea3f]) from the trunk. (check-in: 7afb2354 user: dan tags: branch-3.7.2) | |
Changes
Changes to src/where.c.
3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 |
nRow = (double)(aiRowEst[nEq] * nInMul);
if( bInEst && nRow*2>aiRowEst[0] ){
nRow = aiRowEst[0]/2;
nInMul = (int)(nRow / aiRowEst[nEq]);
}
#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);
}
|
| > | |
3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 |
nRow = (double)(aiRowEst[nEq] * nInMul);
if( bInEst && nRow*2>aiRowEst[0] ){
nRow = aiRowEst[0]/2;
nInMul = (int)(nRow / aiRowEst[nEq]);
}
#ifdef SQLITE_ENABLE_STAT2
/* If the constraint is of the form x=VALUE or x IN (E1,E2,...)
** and we do not think that values of x are unique and if 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 && aiRowEst[1]>1 ){
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);
}
|