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Overview
| Comment: | Disable the OR-clause optimization if it does not result in an index being used that would not have been used otherwise. In other words, do not convert OR clauses into an IN statement if it does not help the optimizer. (CVS 2789) |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
7e7cfce0f8ed2a6e04747736a2c68484 |
| User & Date: | drh 2005-11-26 14:24:41.000 |
Context
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2005-11-28
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| 12:36 | Replace a call to sprintf() with sqlite3MPrintf() since on some embedded platforms, sprintf() is busted. Need to go through and do similar replacements elsewhere in the code. (CVS 2790) (check-in: 1b4f2d89bb user: drh tags: trunk) | |
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2005-11-26
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| 14:24 | Disable the OR-clause optimization if it does not result in an index being used that would not have been used otherwise. In other words, do not convert OR clauses into an IN statement if it does not help the optimizer. (CVS 2789) (check-in: 7e7cfce0f8 user: drh tags: trunk) | |
| 14:08 | Make sure left joins still work even when the OR clause optimization fires. Ticket #1537. (CVS 2788) (check-in: cbbeb9de00 user: drh tags: trunk) | |
Changes
Changes to src/where.c.
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12 13 14 15 16 17 18 | ** This module contains C code that generates VDBE code used to process ** the WHERE clause of SQL statements. This module is reponsible for ** generating the code that loops through a table looking for applicable ** rows. Indices are selected and used to speed the search when doing ** so is applicable. Because this module is responsible for selecting ** indices, you might also think of this module as the "query optimizer". ** | | | 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | ** This module contains C code that generates VDBE code used to process ** the WHERE clause of SQL statements. This module is reponsible for ** generating the code that loops through a table looking for applicable ** rows. Indices are selected and used to speed the search when doing ** 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 1.185 2005/11/26 14:24:41 drh Exp $ */ #include "sqliteInt.h" /* ** The number of bits in a Bitmask. "BMS" means "BitMask Size". */ #define BMS (sizeof(Bitmask)*8) |
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pDup = sqlite3Expr(TK_COLUMN, 0, 0, 0);
if( pDup ){
pDup->iTable = iCursor;
pDup->iColumn = iColumn;
}
pNew = sqlite3Expr(TK_IN, pDup, 0, 0);
if( pNew ){
transferJoinMarkings(pNew, pExpr);
pNew->pList = pList;
}else{
sqlite3ExprListDelete(pList);
}
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pDup = sqlite3Expr(TK_COLUMN, 0, 0, 0);
if( pDup ){
pDup->iTable = iCursor;
pDup->iColumn = iColumn;
}
pNew = sqlite3Expr(TK_IN, pDup, 0, 0);
if( pNew ){
int idxNew;
transferJoinMarkings(pNew, pExpr);
pNew->pList = pList;
idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
exprAnalyze(pSrc, pMaskSet, pWC, idxNew);
pTerm = &pWC->a[idxTerm];
pWC->a[idxNew].iParent = idxTerm;
pTerm->nChild = 1;
}else{
sqlite3ExprListDelete(pList);
}
}
or_not_possible:
whereClauseClear(&sOr);
}
#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
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