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Constant propagation is now restricted to just the WHERE clause. The

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mechanism is changed to take affinity and collation into account.  This
seems to give correct answers.  But the search for constant propagation
costs 4 million cycles in the speed test.

FossilOrigin-Name: 82c67efb723dba387964f690cd459b420e59e3367d9589016597a76531596391
This commit is contained in:
drh
2018-07-27 16:57:11 +00:00
parent 7de7602eb7
commit efad2e2366
8 changed files with 94 additions and 41 deletions
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23
src/expr.c
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@@ -328,6 +328,15 @@ CollSeq *sqlite3BinaryCompareCollSeq(
return pColl;
}
/*
** Return true if CollSeq is the default built-in BINARY.
*/
int sqlite3IsBinary(const CollSeq *p){
if( p==0 ) return 1;
if( sqlite3_stricmp(p->zName,"BINARY")==0 ) return 1;
return 0;
}
/*
** Generate code for a comparison operator.
*/
@@ -1839,6 +1848,9 @@ static int exprNodeIsConstant(Walker *pWalker, Expr *pExpr){
testcase( pExpr->op==TK_COLUMN );
testcase( pExpr->op==TK_AGG_FUNCTION );
testcase( pExpr->op==TK_AGG_COLUMN );
if( ExprHasProperty(pExpr, EP_FixedCol) ){
return WRC_Continue;
}
if( pWalker->eCode==3 && pExpr->iTable==pWalker->u.iCur ){
return WRC_Continue;
}
@@ -1927,7 +1939,7 @@ static int exprNodeIsConstantOrGroupBy(Walker *pWalker, Expr *pExpr){
Expr *p = pGroupBy->a[i].pExpr;
if( sqlite3ExprCompare(0, pExpr, p, -1)<2 ){
CollSeq *pColl = sqlite3ExprNNCollSeq(pWalker->pParse, p);
if( sqlite3_stricmp("BINARY", pColl->zName)==0 ){
if( sqlite3IsBinary(pColl) ){
return WRC_Prune;
}
}
@@ -3581,6 +3593,10 @@ expr_code_doover:
}
case TK_COLUMN: {
int iTab = pExpr->iTable;
if( ExprHasProperty(pExpr, EP_FixedCol) ){
pExpr = pExpr->pLeft;
goto expr_code_doover;
}
if( iTab<0 ){
if( pParse->iSelfTab<0 ){
/* Generating CHECK constraints or inserting into partial index */
@@ -4935,14 +4951,15 @@ int sqlite3ExprCompare(Parse *pParse, Expr *pA, Expr *pB, int iTab){
if( sqlite3StrICmp(pA->u.zToken,pB->u.zToken)!=0 ) return 2;
}else if( pA->op==TK_COLLATE ){
if( sqlite3_stricmp(pA->u.zToken,pB->u.zToken)!=0 ) return 2;
}else if( pA->op!=TK_UPLUS && strcmp(pA->u.zToken,pB->u.zToken)!=0 ){
}else if( strcmp(pA->u.zToken,pB->u.zToken)!=0 ){
return 2;
}
}
if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 2;
if( ALWAYS((combinedFlags & EP_TokenOnly)==0) ){
if( combinedFlags & EP_xIsSelect ) return 2;
if( sqlite3ExprCompare(pParse, pA->pLeft, pB->pLeft, iTab) ) return 2;
if( (combinedFlags & EP_FixedCol)==0
&& sqlite3ExprCompare(pParse, pA->pLeft, pB->pLeft, iTab) ) return 2;
if( sqlite3ExprCompare(pParse, pA->pRight, pB->pRight, iTab) ) return 2;
if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList, iTab) ) return 2;
assert( (combinedFlags & EP_Reduced)==0 );