database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-16 23:02:26 +03:00
Code Activity

Make sure the OR-clause optimizer takes the cost of sorting into account.

Browse Source 
Reset the rowid cache on the OP_Rewind and OP_Last opcodes.  Bump the
version number so that we can do an emergency release.  Ticket #3581. (CVS 6173)

FossilOrigin-Name: d28b58209bf5eb575d0cad8dc71ac043395c6471
This commit is contained in:
drh
2009-01-14 00:55:09 +00:00
parent a9e364f00f
commit a7e770612b
6 changed files with 33 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
src/where.c
View File

@@ -16,7 +16,7 @@
** so is applicable. Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.363 2009/01/10 15:34:12 drh Exp $
** $Id: where.c,v 1.364 2009/01/14 00:55:10 drh Exp $
*/
#include "sqliteInt.h"
@@ -1846,6 +1846,7 @@ static void bestIndex(
WhereClause *pOrWC = &pTerm->u.pOrInfo->wc;
WhereTerm *pOrTerm;
int j;
int sortable = 0;
double rTotal = 0;
nRow = 0;
for(j=0, pOrTerm=pOrWC->a; j<pOrWC->nTerm; j++, pOrTerm++){
@@ -1865,6 +1866,14 @@ static void bestIndex(
nRow += sTermCost.nRow;
if( rTotal>=pCost->rCost ) break;
}
if( pOrderBy!=0 ){
if( sortableByRowid(iCur, pOrderBy, pWC->pMaskSet, &rev) && !rev ){
sortable = 1;
}else{
rTotal += nRow*estLog(nRow);
WHERETRACE(("... sorting increases OR cost to %.9g\n", rTotal));
}
}
WHERETRACE(("... multi-index OR cost=%.9g nrow=%.9g\n",
rTotal, nRow));
if( rTotal<pCost->rCost ){
@@ -1872,10 +1881,7 @@ static void bestIndex(
pCost->nRow = nRow;
pCost->plan.wsFlags = WHERE_MULTI_OR;
pCost->plan.u.pTerm = pTerm;
if( pOrderBy!=0
&& sortableByRowid(iCur, pOrderBy, pWC->pMaskSet, &rev)
&& !rev
){
if( sortable ){
pCost->plan.wsFlags = WHERE_ORDERBY|WHERE_MULTI_OR;
}
}