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Simplification of the logic in the constant-propagation optimization.

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FossilOrigin-Name: 1c3e5c20a9e6f501befa2bf6241a1b5190872bd83b765dac67065d252d04ea4f
This commit is contained in:
drh
2020-01-08 04:36:01 +00:00
parent c9301e6e7c
commit f8f76d672b
3 changed files with 32 additions and 27 deletions
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45
src/select.c
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@@ -4146,15 +4146,28 @@ struct WhereConst {
/*
** Add a new entry to the pConst object. Except, do not add duplicate
** pColumn entires.
** pColumn entires. Also, do not add if doing so would not be appropriate.
**
** The caller guarantees the pColumn is a column and pValue is a constant.
** This routine has to do some additional checks before completing the
** insert.
*/
static void constInsert(
WhereConst *pConst, /* The WhereConst into which we are inserting */
Expr *pColumn, /* The COLUMN part of the constraint */
Expr *pValue /* The VALUE part of the constraint */
WhereConst *pConst, /* The WhereConst into which we are inserting */
Expr *pColumn, /* The COLUMN part of the constraint */
Expr *pValue, /* The VALUE part of the constraint */
Expr *pExpr /* Overall expression: COLUMN=VALUE or VALUE=COLUMN */
){
int i;
assert( pColumn->op==TK_COLUMN );
assert( sqlite3ExprIsConstant(pValue) );
if( !ExprHasProperty(pValue, EP_FixedCol) && sqlite3ExprAffinity(pValue)!=0 ){
return;
}
if( !sqlite3IsBinary(sqlite3ExprCompareCollSeq(pConst->pParse,pExpr)) ){
return;
}
/* 2018-10-25 ticket [cf5ed20f]
** Make sure the same pColumn is not inserted more than once */
@@ -4174,7 +4187,9 @@ static void constInsert(
if( pConst->apExpr==0 ){
pConst->nConst = 0;
}else{
if( ExprHasProperty(pValue, EP_FixedCol) ) pValue = pValue->pLeft;
if( ExprHasProperty(pValue, EP_FixedCol) ){
pValue = pValue->pLeft;
}
pConst->apExpr[pConst->nConst*2-2] = pColumn;
pConst->apExpr[pConst->nConst*2-1] = pValue;
}
@@ -4200,21 +4215,11 @@ static void findConstInWhere(WhereConst *pConst, Expr *pExpr){
pLeft = pExpr->pLeft;
assert( pRight!=0 );
assert( pLeft!=0 );
if( pRight->op==TK_COLUMN
&& !ExprHasProperty(pRight, EP_FixedCol)
&& sqlite3ExprIsConstant(pLeft)
&& sqlite3ExprAffinity(pLeft)==0
&& sqlite3IsBinary(sqlite3ExprCompareCollSeq(pConst->pParse,pExpr))
){
constInsert(pConst, pRight, pLeft);
}else
if( pLeft->op==TK_COLUMN
&& !ExprHasProperty(pLeft, EP_FixedCol)
&& sqlite3ExprIsConstant(pRight)
&& sqlite3ExprAffinity(pRight)==0
&& sqlite3IsBinary(sqlite3ExprCompareCollSeq(pConst->pParse,pExpr))
){
constInsert(pConst, pLeft, pRight);
if( pRight->op==TK_COLUMN && sqlite3ExprIsConstant(pLeft) ){
constInsert(pConst,pRight,pLeft,pExpr);
}
if( pLeft->op==TK_COLUMN && sqlite3ExprIsConstant(pRight) ){
constInsert(pConst,pLeft,pRight,pExpr);
}
}