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 IS NULL optimization introduced by check-in (3494) correctly

Browse Source 
handles a LEFT JOIN where the a term from the right table of the join uses
an IS NULL constraint.  Ticket #2177.  This check-in also adds the new test
cases that were suppose to have been added with (3494) but which were
mistakenly omitted. (CVS 3595)

FossilOrigin-Name: 335863e4d16113fb9ecebce35d2db043771d98b1
This commit is contained in:
drh
2007-01-19 01:06:01 +00:00
parent cb6c565eab
commit c49de5d98c
5 changed files with 176 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
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 1.234 2006/12/20 03:24:19 drh Exp $
** $Id: where.c,v 1.235 2007/01/19 01:06:03 drh Exp $
*/
#include "sqliteInt.h"
@@ -1275,6 +1275,7 @@ static double bestIndex(
int rev; /* True to scan in reverse order */
int flags; /* Flags associated with pProbe */
int nEq; /* Number of == or IN constraints */
int eqTermMask; /* Mask of valid equality operators */
double cost; /* Cost of using pProbe */
TRACE(("bestIndex: tbl=%s notReady=%x\n", pSrc->pTab->zName, notReady));
@@ -1366,6 +1367,17 @@ static double bestIndex(
bestFlags = flags;
}
/* If the pSrc table is the right table of a LEFT JOIN then we may not
** use an index to satisfy IS NULL constraints on that table. This is
** because columns might end up being NULL if the table does not match -
** a circumstance which the index cannot help us discover. Ticket #2177.
*/
if( (pSrc->jointype & JT_LEFT)!=0 ){
eqTermMask = WO_EQ|WO_IN;
}else{
eqTermMask = WO_EQ|WO_IN|WO_ISNULL;
}
/* Look at each index.
*/
for(; pProbe; pProbe=pProbe->pNext){
@@ -1380,7 +1392,7 @@ static double bestIndex(
flags = 0;
for(i=0; i<pProbe->nColumn; i++){
int j = pProbe->aiColumn[i];
pTerm = findTerm(pWC, iCur, j, notReady, WO_EQ|WO_IN|WO_ISNULL, pProbe);
pTerm = findTerm(pWC, iCur, j, notReady, eqTermMask, pProbe);
if( pTerm==0 ) break;
flags |= WHERE_COLUMN_EQ;
if( pTerm->eOperator & WO_IN ){
@@ -1636,7 +1648,8 @@ static void codeAllEqualityTerms(
/* Evaluate the equality constraints
*/
for(j=0; j<pIdx->nColumn; j++){
assert( pIdx->nColumn>=nEq );
for(j=0; j<nEq; j++){
int k = pIdx->aiColumn[j];
pTerm = findTerm(pWC, iCur, k, notReady, WO_EQ|WO_IN|WO_ISNULL, pIdx);
if( pTerm==0 ) break;
@@ -1649,7 +1662,6 @@ static void codeAllEqualityTerms(
sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem+j+1, 1);
}
}
assert( j==nEq );
/* Make sure all the constraint values are on the top of the stack
*/