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Do not reduce the number of rows scanned at all for "IS NOT NULL" constraints. Fix a bug in calculating the number of rows visited by scans of partial indicies.

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FossilOrigin-Name: a8ae93f0cffa116df0ba34d46a53f49d42dace41
This commit is contained in:
dan
2014-04-28 20:11:20 +00:00
parent 42685f211e
commit 7de2a1faf6
5 changed files with 112 additions and 14 deletions
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8
src/where.c
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@@ -1992,9 +1992,7 @@ static LogEst whereRangeAdjust(WhereTerm *pTerm, LogEst nNew){
if( pTerm ){
if( pTerm->truthProb<=0 ){
nRet += pTerm->truthProb;
}else if( pTerm->wtFlags & TERM_VNULL ){
nRet -= 10; assert( 10==sqlite3LogEst(2) );
}else{
}else if( (pTerm->wtFlags & TERM_VNULL)==0 ){
nRet -= 20; assert( 20==sqlite3LogEst(4) );
}
}
@@ -2153,14 +2151,17 @@ static int whereRangeScanEst(
UNUSED_PARAMETER(pBuilder);
#endif
assert( pLower || pUpper );
assert( pUpper==0 || (pUpper->wtFlags & TERM_VNULL)==0 );
nNew = whereRangeAdjust(pLower, nOut);
nNew = whereRangeAdjust(pUpper, nNew);
/* TUNING: If there is both an upper and lower limit, assume the range is
** reduced by an additional 75%. This means that, by default, an open-ended
** range query (e.g. col > ?) is assumed to match 1/4 of the rows in the
** index. While a closed range (e.g. col BETWEEN ? AND ?) is estimated to
** match 1/64 of the index. */
if( pLower && pUpper ) nNew -= 20;
nOut -= (pLower!=0) + (pUpper!=0);
if( nNew<10 ) nNew = 10;
if( nNew<nOut ) nOut = nNew;
@@ -4446,6 +4447,7 @@ static int whereLoopAddBtree(
&& !whereUsablePartialIndex(pNew->iTab, pWC, pProbe->pPartIdxWhere) ){
continue; /* Partial index inappropriate for this query */
}
rSize = pProbe->aiRowLogEst[0];
pNew->u.btree.nEq = 0;
pNew->u.btree.nSkip = 0;
pNew->nLTerm = 0;