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Avoid evaluating PARTITION BY or ORDER BY expressions multiple times for window function queries that use multiple window functions with the same window-definition.

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FossilOrigin-Name: 57070c68bbe15fc1d19a765182432e844c082909bdbc63b58fd86b96e2c521dd
This commit is contained in:
dan
2019-11-23 15:10:28 +00:00
parent 0f31327eee
commit 62be2dc753
4 changed files with 40 additions and 13 deletions
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18
src/window.c
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@@ -787,8 +787,20 @@ static int selectWindowRewriteExprCb(Walker *pWalker, Expr *pExpr){
case TK_AGG_FUNCTION:
case TK_COLUMN: {
Expr *pDup = sqlite3ExprDup(pParse->db, pExpr, 0);
p->pSub = sqlite3ExprListAppend(pParse, p->pSub, pDup);
int iCol = -1;
if( p->pSub ){
int i;
for(i=0; i<p->pSub->nExpr; i++){
if( 0==sqlite3ExprCompare(0, p->pSub->a[i].pExpr, pExpr, -1) ){
iCol = i;
break;
}
}
}
if( iCol<0 ){
Expr *pDup = sqlite3ExprDup(pParse->db, pExpr, 0);
p->pSub = sqlite3ExprListAppend(pParse, p->pSub, pDup);
}
if( p->pSub ){
assert( ExprHasProperty(pExpr, EP_Static)==0 );
ExprSetProperty(pExpr, EP_Static);
@@ -797,7 +809,7 @@ static int selectWindowRewriteExprCb(Walker *pWalker, Expr *pExpr){
memset(pExpr, 0, sizeof(Expr));
pExpr->op = TK_COLUMN;
pExpr->iColumn = p->pSub->nExpr-1;
pExpr->iColumn = (iCol<0 ? p->pSub->nExpr-1: iCol);
pExpr->iTable = p->pWin->iEphCsr;
pExpr->y.pTab = p->pTab;
}