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In the WHERE-constraint propagation optimization, if there are duplicate

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constraint, make sure only one of them propagates.  Proposed fix for
ticket [cf5ed20fc8621b165].

FossilOrigin-Name: 5d5b596f152bb2781011a05f75f9e200774d4f69d648ef68de577b4ace973e07
This commit is contained in:
drh
2018-10-25 14:15:37 +00:00
parent e23d05e807
commit 8e5bfedd22
4 changed files with 39 additions and 13 deletions
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25
src/select.c
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@@ -4074,7 +4074,7 @@ static int flattenSubquery(
#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
/*
** A structure to keep track of all of the column values that fixed to
** A structure to keep track of all of the column values that are fixed to
** a known value due to WHERE clause constraints of the form COLUMN=VALUE.
*/
typedef struct WhereConst WhereConst;
@@ -4086,13 +4086,28 @@ struct WhereConst {
};
/*
** Add a new entry to the pConst object
** Add a new entry to the pConst object. Except, do not add duplicate
** pColumn entires.
*/
static void constInsert(
WhereConst *pConst,
Expr *pColumn,
Expr *pValue
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 */
){
int i;
assert( pColumn->op==TK_COLUMN );
/* 2018-10-25 ticket [cf5ed20f]
** Make sure the same pColumn is not inserted more than once */
for(i=0; i<pConst->nConst; i++){
const Expr *pExpr = pConst->apExpr[i*2];
assert( pExpr->op==TK_COLUMN );
if( pExpr->iTable==pColumn->iTable
&& pExpr->iColumn==pColumn->iColumn
){
return; /* Already present. Return without doing anything. */
}
}
pConst->nConst++;
pConst->apExpr = sqlite3DbReallocOrFree(pConst->pParse->db, pConst->apExpr,