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-rw-r--r--src/where.c36
1 files changed, 32 insertions, 4 deletions
diff --git a/src/where.c b/src/where.c
index a0dc86842..24b059e2d 100644
--- a/src/where.c
+++ b/src/where.c
@@ -4161,6 +4161,7 @@ static Bitmask codeOneLoopStart(
int addrCont; /* Jump here to continue with next cycle */
int iRowidReg = 0; /* Rowid is stored in this register, if not zero */
int iReleaseReg = 0; /* Temp register to free before returning */
+ Bitmask newNotReady; /* Return value */
pParse = pWInfo->pParse;
v = pParse->pVdbe;
@@ -4171,6 +4172,7 @@ static Bitmask codeOneLoopStart(
bRev = (pLevel->plan.wsFlags & WHERE_REVERSE)!=0;
omitTable = (pLevel->plan.wsFlags & WHERE_IDX_ONLY)!=0
&& (wctrlFlags & WHERE_FORCE_TABLE)==0;
+ VdbeNoopComment((v, "Begin Join Loop %d", iLevel));
/* Create labels for the "break" and "continue" instructions
** for the current loop. Jump to addrBrk to break out of a loop.
@@ -4821,7 +4823,7 @@ static Bitmask codeOneLoopStart(
pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
}
- notReady &= ~getMask(pWC->pMaskSet, iCur);
+ newNotReady = notReady & ~getMask(pWC->pMaskSet, iCur);
/* Insert code to test every subexpression that can be completely
** computed using the current set of tables.
@@ -4835,7 +4837,7 @@ static Bitmask codeOneLoopStart(
testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* IMP: R-30575-11662 */
testcase( pTerm->wtFlags & TERM_CODED );
if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
- if( (pTerm->prereqAll & notReady)!=0 ){
+ if( (pTerm->prereqAll & newNotReady)!=0 ){
testcase( pWInfo->untestedTerms==0
&& (pWInfo->wctrlFlags & WHERE_ONETABLE_ONLY)!=0 );
pWInfo->untestedTerms = 1;
@@ -4850,6 +4852,32 @@ static Bitmask codeOneLoopStart(
pTerm->wtFlags |= TERM_CODED;
}
+ /* Insert code to test for implied constraints based on transitivity
+ ** of the "==" operator.
+ **
+ ** Example: If the WHERE clause contains "t1.a=t2.b" and "t2.b=123"
+ ** and we are coding the t1 loop and the t2 loop has not yet coded,
+ ** then we cannot use the "t1.a=t2.b" constraint, but we can code
+ ** the implied "t1.a=123" constraint.
+ */
+ for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
+ Expr *pE;
+ WhereTerm *pAlt;
+ Expr sEq;
+ if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
+ 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
** at least one row of the right table has matched the left table.
*/
@@ -4862,7 +4890,7 @@ static Bitmask codeOneLoopStart(
testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* IMP: R-30575-11662 */
testcase( pTerm->wtFlags & TERM_CODED );
if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
- if( (pTerm->prereqAll & notReady)!=0 ){
+ if( (pTerm->prereqAll & newNotReady)!=0 ){
assert( pWInfo->untestedTerms );
continue;
}
@@ -4873,7 +4901,7 @@ static Bitmask codeOneLoopStart(
}
sqlite3ReleaseTempReg(pParse, iReleaseReg);
- return notReady;
+ return newNotReady;
}
#if defined(SQLITE_TEST)