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Overview
| Comment: | Avoid redundant constraint checking due to transitive constraints. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
329478cbed06f93652de50abdb31a6b4 |
| User & Date: | drh 2013-05-01 17:22:38 |
Context
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2013-05-01
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| 17:58 | Do not use a transitive constraint to an IN operator where the RHS is a constant if there exists a direct == operator to another table in an outer loop. check-in: faedaeac user: drh tags: trunk | |
| 17:22 | Avoid redundant constraint checking due to transitive constraints. check-in: 329478cb user: drh tags: trunk | |
|
2013-04-30
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| 14:25 | Update the documentation to explain that when the 3rd parameter to sqlite3_bind_text() and friends is NULL the result is to bind a NULL SQL value. Ticket [19b44e35753ba] check-in: bd92de0e user: drh tags: trunk | |
Changes
Changes to src/where.c.
4879 4880 4881 4882 4883 4884 4885 4886 4887 4888 4889 4890 4891 4892 |
if( pTerm->eOperator!=(WO_EQUIV|WO_EQ) ) continue;
if( pTerm->leftCursor!=iCur ) continue;
pE = pTerm->pExpr;
assert( !ExprHasProperty(pE, EP_FromJoin) );
assert( (pTerm->prereqRight & newNotReady)!=0 );
pAlt = findTerm(pWC, iCur, pTerm->u.leftColumn, notReady, WO_EQ|WO_IN, 0);
if( pAlt==0 ) continue;
VdbeNoopComment((v, "begin transitive constraint"));
sEq = *pAlt->pExpr;
sEq.pLeft = pE->pLeft;
sqlite3ExprIfFalse(pParse, &sEq, addrCont, SQLITE_JUMPIFNULL);
}
/* For a LEFT OUTER JOIN, generate code that will record the fact that
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> |
4879 4880 4881 4882 4883 4884 4885 4886 4887 4888 4889 4890 4891 4892 4893 |
if( pTerm->eOperator!=(WO_EQUIV|WO_EQ) ) continue;
if( pTerm->leftCursor!=iCur ) continue;
pE = pTerm->pExpr;
assert( !ExprHasProperty(pE, EP_FromJoin) );
assert( (pTerm->prereqRight & newNotReady)!=0 );
pAlt = findTerm(pWC, iCur, pTerm->u.leftColumn, notReady, WO_EQ|WO_IN, 0);
if( pAlt==0 ) continue;
if( pAlt->wtFlags & (TERM_CODED) ) continue;
VdbeNoopComment((v, "begin transitive constraint"));
sEq = *pAlt->pExpr;
sEq.pLeft = pE->pLeft;
sqlite3ExprIfFalse(pParse, &sEq, addrCont, SQLITE_JUMPIFNULL);
}
/* For a LEFT OUTER JOIN, generate code that will record the fact that
|