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Do not use a co-routine on a subquery that is participating in a self-join.

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FossilOrigin-Name: ea4306a03cd8dd706100dac3f11653068a25c50c5d06c34ad08534aec0a580bc
This commit is contained in:
drh
2022-12-08 13:56:06 +00:00
parent 619ff3f505
commit 05cb9d881e
3 changed files with 22 additions and 13 deletions
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21
src/select.c
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@@ -6697,18 +6697,23 @@ static void havingToWhere(Parse *pParse, Select *p){
}
/*
** Check to see if the pThis entry of pTabList is a self-join of a prior view.
** If it is, then return the SrcItem for the prior view. If it is not,
** then return 0.
** Check to see if the pThis entry of pTabList is a self-join of another view.
** Search FROM-clause entries in the range of iFirst..iEnd, including iFirst
** but stopping before iEnd.
**
** If pThis is a self-join, then return the SrcItem for the first other
** instance of that view found. If pThis is not a self-join then return 0.
*/
static SrcItem *isSelfJoinView(
SrcList *pTabList, /* Search for self-joins in this FROM clause */
SrcItem *pThis /* Search for prior reference to this subquery */
SrcItem *pThis, /* Search for prior reference to this subquery */
int iFirst, int iEnd /* Range of FROM-clause entries to search. */
){
SrcItem *pItem;
assert( pThis->pSelect!=0 );
if( pThis->pSelect->selFlags & SF_PushDown ) return 0;
for(pItem = pTabList->a; pItem<pThis; pItem++){
while( iFirst<iEnd ){
pItem = &pTabList->a[iFirst++];
Select *pS1;
if( pItem->pSelect==0 ) continue;
if( pItem->fg.viaCoroutine ) continue;
@@ -6873,6 +6878,7 @@ static int sameSrcAlias(SrcItem *p0, SrcList *pSrc){
** (2) The subquery is not a CTE that should be materialized
** (3) The subquery is not part of a left operand for a RIGHT JOIN
** (4) The SQLITE_Coroutine optimization disable flag is not set
** (5) The subquery is not self-joined
*/
static int fromClauseTermCanBeCoroutine(
Parse *pParse, /* Parsing context */
@@ -6883,6 +6889,9 @@ static int fromClauseTermCanBeCoroutine(
if( pItem->fg.isCte && pItem->u2.pCteUse->eM10d==M10d_Yes ) return 0;/* (2) */
if( pTabList->a[0].fg.jointype & JT_LTORJ ) return 0; /* (3) */
if( OptimizationDisabled(pParse->db, SQLITE_Coroutines) ) return 0; /* (4) */
if( isSelfJoinView(pTabList, pItem, i+1, pTabList->nSrc)!=0 ){
return 0; /* (5) */
}
if( i==0 ){
if( pTabList->nSrc==1 ) return 1; /* (1a-i) */
if( pTabList->a[1].fg.jointype & JT_CROSS ) return 1; /* (1a-ii) */
@@ -7319,7 +7328,7 @@ int sqlite3Select(
VdbeComment((v, "%!S", pItem));
}
pSub->nSelectRow = pCteUse->nRowEst;
}else if( (pPrior = isSelfJoinView(pTabList, pItem))!=0 ){
}else if( (pPrior = isSelfJoinView(pTabList, pItem, 0, i))!=0 ){
/* This view has already been materialized by a prior entry in
** this same FROM clause. Reuse it. */
if( pPrior->addrFillSub ){