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If the user provides likelihood() data for a WHERE clause term used as part of an index key, have the planner use it when calculating the expected number of rows visited by the loop.

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FossilOrigin-Name: c51efaa5d29ee0a91b9e6a83a8dd82530670811a
This commit is contained in:
dan
2014-04-25 20:22:45 +00:00
parent cfc9df76e1
commit 8ad1d8ba38
6 changed files with 111 additions and 77 deletions
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146
src/where.c
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@@ -4040,7 +4040,6 @@ static int whereLoopAddBtreeIndex(
LogEst saved_nOut; /* Original value of pNew->nOut */
int iCol; /* Index of the column in the table */
int rc = SQLITE_OK; /* Return code */
LogEst nRowEst; /* Estimated index selectivity */
LogEst rLogSize; /* Logarithm of table size */
WhereTerm *pTop = 0, *pBtm = 0; /* Top and bottom range constraints */
@@ -4061,10 +4060,8 @@ static int whereLoopAddBtreeIndex(
assert( pNew->u.btree.nEq<=pProbe->nKeyCol );
if( pNew->u.btree.nEq < pProbe->nKeyCol ){
iCol = pProbe->aiColumn[pNew->u.btree.nEq];
nRowEst = pProbe->aiRowLogEst[pNew->u.btree.nEq+1];
}else{
iCol = -1;
nRowEst = 0;
}
pTerm = whereScanInit(&scan, pBuilder->pWC, pSrc->iCursor, iCol,
opMask, pProbe);
@@ -4095,35 +4092,40 @@ static int whereLoopAddBtreeIndex(
pNew->u.btree.nSkip++;
pNew->aLTerm[pNew->nLTerm++] = 0;
pNew->wsFlags |= WHERE_SKIPSCAN;
nIter = pProbe->aiRowLogEst[0] - pProbe->aiRowLogEst[saved_nEq+1];
pNew->rRun = rLogSize + nIter;
pNew->nOut += nIter;
whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nIter);
nIter = pProbe->aiRowLogEst[saved_nEq] - pProbe->aiRowLogEst[saved_nEq+1];
pNew->nOut -= nIter;
whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nIter + nInMul);
pNew->nOut = saved_nOut;
}
for(; rc==SQLITE_OK && pTerm!=0; pTerm = whereScanNext(&scan)){
u16 eOp = pTerm->eOperator; /* Shorthand for pTerm->eOperator */
LogEst rCostIdx;
LogEst nOutUnadjusted; /* nOut before IN() and WHERE adjustments */
int nIn = 0;
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
int nRecValid = pBuilder->nRecValid;
#endif
if( (pTerm->eOperator==WO_ISNULL || (pTerm->wtFlags&TERM_VNULL)!=0)
if( (eOp==WO_ISNULL || (pTerm->wtFlags&TERM_VNULL)!=0)
&& (iCol<0 || pSrc->pTab->aCol[iCol].notNull)
){
continue; /* ignore IS [NOT] NULL constraints on NOT NULL columns */
}
if( pTerm->prereqRight & pNew->maskSelf ) continue;
assert( pNew->nOut==saved_nOut );
pNew->wsFlags = saved_wsFlags;
pNew->u.btree.nEq = saved_nEq;
pNew->nLTerm = saved_nLTerm;
if( whereLoopResize(db, pNew, pNew->nLTerm+1) ) break; /* OOM */
pNew->aLTerm[pNew->nLTerm++] = pTerm;
pNew->prereq = (saved_prereq | pTerm->prereqRight) & ~pNew->maskSelf;
pNew->rRun = rLogSize; /* Baseline cost is log2(N). Adjustments below */
if( pTerm->eOperator & WO_IN ){
assert( nInMul==0
|| (pNew->wsFlags & WHERE_COLUMN_NULL)!=0
|| (pNew->wsFlags & WHERE_COLUMN_IN)!=0
|| (pNew->wsFlags & WHERE_SKIPSCAN)!=0
);
if( eOp & WO_IN ){
Expr *pExpr = pTerm->pExpr;
pNew->wsFlags |= WHERE_COLUMN_IN;
if( ExprHasProperty(pExpr, EP_xIsSelect) ){
@@ -4135,87 +4137,111 @@ static int whereLoopAddBtreeIndex(
}
assert( nIn>0 ); /* RHS always has 2 or more terms... The parser
** changes "x IN (?)" into "x=?". */
pNew->rRun += nIn;
pNew->u.btree.nEq++;
pNew->nOut = nRowEst + nInMul + nIn;
}else if( pTerm->eOperator & (WO_EQ) ){
assert(
(pNew->wsFlags & (WHERE_COLUMN_NULL|WHERE_COLUMN_IN|WHERE_SKIPSCAN))!=0
|| nInMul==0
);
}else if( eOp & (WO_EQ) ){
pNew->wsFlags |= WHERE_COLUMN_EQ;
if( iCol<0 || (nInMul==0 && pNew->u.btree.nEq==pProbe->nKeyCol-1)){
assert( (pNew->wsFlags & WHERE_COLUMN_IN)==0 || iCol<0 );
if( iCol<0 || (nInMul==0 && pNew->u.btree.nEq==pProbe->nKeyCol-1) ){
if( iCol>=0 && pProbe->onError==OE_None ){
pNew->wsFlags |= WHERE_UNQ_WANTED;
}else{
pNew->wsFlags |= WHERE_ONEROW;
}
}
pNew->u.btree.nEq++;
pNew->nOut = nRowEst + nInMul;
}else if( pTerm->eOperator & (WO_ISNULL) ){
pNew->wsFlags |= WHERE_COLUMN_NULL;
pNew->u.btree.nEq++;
/* TUNING: IS NULL selects 2 rows */
nIn = 10; assert( 10==sqlite3LogEst(2) );
pNew->nOut = nRowEst + nInMul + nIn;
}else if( pTerm->eOperator & (WO_GT|WO_GE) ){
testcase( pTerm->eOperator & WO_GT );
testcase( pTerm->eOperator & WO_GE );
}else if( eOp & (WO_GT|WO_GE) ){
testcase( eOp & WO_GT );
testcase( eOp & WO_GE );
pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_BTM_LIMIT;
pBtm = pTerm;
pTop = 0;
}else{
assert( pTerm->eOperator & (WO_LT|WO_LE) );
testcase( pTerm->eOperator & WO_LT );
testcase( pTerm->eOperator & WO_LE );
}else if( (eOp & WO_ISNULL)==0 ){
assert( eOp & (WO_LT|WO_LE) );
testcase( eOp & WO_LT );
testcase( eOp & WO_LE );
pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_TOP_LIMIT;
pTop = pTerm;
pBtm = (pNew->wsFlags & WHERE_BTM_LIMIT)!=0 ?
pNew->aLTerm[pNew->nLTerm-2] : 0;
}
/* At this point pNew->nOut is set to the number of rows expected to
** be visited by the index scan before considering term pTerm, or the
** values of nIn and nInMul. In other words, assuming that all
** "x IN(...)" terms are replaced with "x = ?". This block updates
** the value of pNew->nOut to account for pTerm (but not nIn/nInMul). */
assert( pNew->nOut==saved_nOut );
if( pNew->wsFlags & WHERE_COLUMN_RANGE ){
/* Adjust nOut using stat3/stat4 data. Or, if there is no stat3/stat4
** data, using some other estimate. */
assert( pNew->nOut==saved_nOut );
whereRangeScanEst(pParse, pBuilder, pBtm, pTop, pNew);
}
}else{
int nEq = ++pNew->u.btree.nEq;
assert( eOp & (WO_ISNULL|WO_EQ|WO_IN) );
assert( pNew->nOut==saved_nOut );
if( pTerm->truthProb<=0 ){
assert( (eOp & WO_IN) || nIn==0 );
pNew->nOut += pTerm->truthProb;
pNew->nOut -= nIn;
pNew->wsFlags |= WHERE_LIKELIHOOD;
}else{
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
if( nInMul==0
&& pProbe->nSample
&& pNew->u.btree.nEq<=pProbe->nSampleCol
&& OptimizationEnabled(db, SQLITE_Stat3)
){
Expr *pExpr = pTerm->pExpr;
tRowcnt nOut = 0;
if( (pTerm->eOperator & (WO_EQ|WO_ISNULL))!=0 ){
testcase( pTerm->eOperator & WO_EQ );
testcase( pTerm->eOperator & WO_ISNULL );
rc = whereEqualScanEst(pParse, pBuilder, pExpr->pRight, &nOut);
}else if( (pTerm->eOperator & WO_IN)
&& !ExprHasProperty(pExpr, EP_xIsSelect) ){
rc = whereInScanEst(pParse, pBuilder, pExpr->x.pList, &nOut);
}
assert( nOut==0 || rc==SQLITE_OK );
if( nOut ){
pNew->nOut = sqlite3LogEst(nOut);
if( pNew->nOut>saved_nOut ) pNew->nOut = saved_nOut;
tRowcnt nOut = 0;
if( nInMul==0
&& pProbe->nSample
&& pNew->u.btree.nEq<=pProbe->nSampleCol
&& OptimizationEnabled(db, SQLITE_Stat3)
&& ((eOp & WO_IN)==0 || !ExprHasProperty(pTerm->pExpr, EP_xIsSelect))
&& (pNew->wsFlags & WHERE_LIKELIHOOD)==0
){
Expr *pExpr = pTerm->pExpr;
if( (eOp & (WO_EQ|WO_ISNULL))!=0 ){
testcase( eOp & WO_EQ );
testcase( eOp & WO_ISNULL );
rc = whereEqualScanEst(pParse, pBuilder, pExpr->pRight, &nOut);
}else{
rc = whereInScanEst(pParse, pBuilder, pExpr->x.pList, &nOut);
}
assert( rc!=SQLITE_OK || nOut>0 );
if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
if( rc!=SQLITE_OK ) break; /* Jump out of the pTerm loop */
if( nOut ){
pNew->nOut = sqlite3LogEst(nOut);
if( pNew->nOut>saved_nOut ) pNew->nOut = saved_nOut;
pNew->nOut -= nIn;
}
}
if( nOut==0 )
#endif
{
pNew->nOut += (pProbe->aiRowLogEst[nEq] - pProbe->aiRowLogEst[nEq-1]);
if( eOp & WO_ISNULL ){
/* TUNING: If there is no likelihood() value, assume that a
** "col IS NULL" expression matches twice as many rows
** as (col=?). */
pNew->nOut += 10;
}
}
}
}
#endif
/* Set rCostIdx to the cost of visiting selected rows in index. Add
** it to pNew->rRun, which is currently set to the cost of the index
** seek only. Then, if this is a non-covering index, add the cost of
** visiting the rows in the main table. */
rCostIdx = pNew->nOut + 1 + (15*pProbe->szIdxRow)/pSrc->pTab->szTabRow;
pNew->rRun = sqlite3LogEstAdd(pNew->rRun, rCostIdx);
pNew->rRun = sqlite3LogEstAdd(rLogSize, rCostIdx);
if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK))==0 ){
pNew->rRun = sqlite3LogEstAdd(pNew->rRun, pNew->nOut + 16);
}
nOutUnadjusted = pNew->nOut;
pNew->rRun += nInMul + nIn;
pNew->nOut += nInMul + nIn;
whereLoopOutputAdjust(pBuilder->pWC, pNew);
rc = whereLoopInsert(pBuilder, pNew);
pNew->nOut = nOutUnadjusted;
if( (pNew->wsFlags & WHERE_TOP_LIMIT)==0
&& pNew->u.btree.nEq<(pProbe->nKeyCol + (pProbe->zName!=0))
){