database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-11 01:42:22 +03:00
Code Activity

Further refinement of the idea of multiplying run-time cost estimates by

Browse Source 
the estimated row size.

FossilOrigin-Name: 18bd6ba96d19de6047baebfa15b1f739577c9ec4
This commit is contained in:
drh
2013-10-08 18:40:37 +00:00
parent 3495d20dbe
commit 186ad8cc32
7 changed files with 51 additions and 60 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
src/where.c
View File

@@ -2450,15 +2450,15 @@ static int whereRangeScanEst(
WhereLoopBuilder *pBuilder,
WhereTerm *pLower, /* Lower bound on the range. ex: "x>123" Might be NULL */
WhereTerm *pUpper, /* Upper bound on the range. ex: "x<455" Might be NULL */
LogEst *pnOut /* IN/OUT: Number of rows visited */
WhereLoop *pLoop /* Modify the .nOut and maybe .rRun fields */
){
int rc = SQLITE_OK;
int nOut = (int)*pnOut;
int nOut = pLoop->nOut;
int nEq = pLoop->u.btree.nEq;
LogEst nNew;
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
Index *p = pBuilder->pNew->u.btree.pIndex;
int nEq = pBuilder->pNew->u.btree.nEq;
Index *p = pLoop->u.btree.pIndex;
if( p->nSample>0
&& nEq==pBuilder->nRecValid
@@ -2546,7 +2546,7 @@ static int whereRangeScanEst(
if( nNew<nOut ){
nOut = nNew;
}
*pnOut = (LogEst)nOut;
pLoop->nOut = (LogEst)nOut;
WHERETRACE(0x100, ("range scan regions: %u..%u est=%d\n",
(u32)iLower, (u32)iUpper, nOut));
return SQLITE_OK;
@@ -2570,7 +2570,7 @@ static int whereRangeScanEst(
}
if( nNew<10 ) nNew = 10;
if( nNew<nOut ) nOut = nNew;
*pnOut = (LogEst)nOut;
pLoop->nOut = (LogEst)nOut;
return rc;
}
@@ -4337,7 +4337,13 @@ static int whereLoopAddBtreeIndex(
if( pNew->wsFlags & WHERE_COLUMN_RANGE ){
/* Adjust nOut and rRun for STAT3 range values */
assert( pNew->nOut==saved_nOut );
whereRangeScanEst(pParse, pBuilder, pBtm, pTop, &pNew->nOut);
whereRangeScanEst(pParse, pBuilder, pBtm, pTop, pNew);
/* If the range constraint is the only constraint on the index and
** if the range constraint does not reduce the search space,
** then this is really just an index scan which has already
** been analyzed. */
if( pNew->nOut>=saved_nOut && pNew->u.btree.nEq==0 ) continue;
}
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
if( nInMul==0
@@ -4816,6 +4822,8 @@ static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){
pWCEnd = pWC->a + pWC->nTerm;
pNew = pBuilder->pNew;
memset(&sSum, 0, sizeof(sSum));
pItem = pWInfo->pTabList->a + pNew->iTab;
iCur = pItem->iCursor;
for(pTerm=pWC->a; pTerm<pWCEnd && rc==SQLITE_OK; pTerm++){
if( (pTerm->eOperator & WO_OR)!=0
@@ -4827,8 +4835,6 @@ static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){
int once = 1;
int i, j;
pItem = pWInfo->pTabList->a + pNew->iTab;
iCur = pItem->iCursor;
sSubBuild = *pBuilder;
sSubBuild.pOrderBy = 0;
sSubBuild.pOrSet = &sCur;
@@ -5266,8 +5272,10 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
if( pWInfo->pOrderBy==0 || nRowEst==0 ){
aFrom[0].isOrderedValid = 1;
}else{
/* TUNING: Estimated cost of sorting is N*log2(N) where N is the
** number of output rows. */
/* TUNING: Estimated cost of sorting is 48*N*log2(N) where N is the
** number of output rows. The 48 is the expected size of a row to sort.
** FIXME: compute a better estimate of the 48 multiplier based on the
** result set expressions. */
rSortCost = nRowEst + estLog(nRowEst) + 55;
WHERETRACE(0x002,("---- sort cost=%-3d\n", rSortCost));
}