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Improvements to the query optimizer. This is a work in progress. (CVS 2169)

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FossilOrigin-Name: 9b86993ff721b577b920c7c67fb41d3d4355fe88
This commit is contained in:
drh
2004-12-18 18:40:26 +00:00
parent 9ee3cdcba7
commit 51669863a8
6 changed files with 310 additions and 92 deletions
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26
src/expr.c
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@@ -12,7 +12,7 @@
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.175 2004/12/07 15:41:49 drh Exp $
** $Id: expr.c,v 1.176 2004/12/18 18:40:27 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
@@ -690,7 +690,9 @@ static int lookupName(
int i, j; /* Loop counters */
int cnt = 0; /* Number of matching column names */
int cntTab = 0; /* Number of matching table names */
sqlite3 *db = pParse->db; /* The database */
sqlite3 *db = pParse->db; /* The database */
struct SrcList_item *pItem; /* Use for looping over pSrcList items */
struct SrcList_item *pMatch = 0; /* The matching pSrcList item */
assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */
zDb = sqlite3NameFromToken(pDbToken);
@@ -702,8 +704,7 @@ static int lookupName(
assert( zTab==0 || pEList==0 );
pExpr->iTable = -1;
for(i=0; i<pSrcList->nSrc; i++){
struct SrcList_item *pItem = &pSrcList->a[i];
for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
Table *pTab = pItem->pTab;
Column *pCol;
@@ -724,11 +725,13 @@ static int lookupName(
if( 0==(cntTab++) ){
pExpr->iTable = pItem->iCursor;
pExpr->iDb = pTab->iDb;
pMatch = pItem;
}
for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
cnt++;
pExpr->iTable = pItem->iCursor;
pMatch = pItem;
pExpr->iDb = pTab->iDb;
/* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
pExpr->iColumn = j==pTab->iPKey ? -1 : j;
@@ -842,6 +845,21 @@ static int lookupName(
sqliteFree(z);
}
/* If a column from a table in pSrcList is referenced, then record
** this fact in the pSrcList.a[].colUsed bitmask. Column 0 causes
** bit 0 to be set. Column 1 sets bit 1. And so forth. If the
** column number is greater than the number of bits in the bitmask
** then set the high-order bit of the bitmask.
*/
if( pExpr->iColumn>=0 && pMatch!=0 ){
int n = pExpr->iColumn;
if( n>=sizeof(Bitmask)*8 ){
n = sizeof(Bitmask)*8-1;
}
assert( pMatch->iCursor==pExpr->iTable );
pMatch->colUsed |= 1<<n;
}
/* Clean up and return
*/
sqliteFree(zDb);