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Disable the flattening optimization if the parent query is the recursive part of a recursive CTE and the sub-query is a compound query.

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FossilOrigin-Name: 6bfa387e82de47ca1f40225fe28d873e29d6f481
This commit is contained in:
dan
2014-01-16 10:58:39 +00:00
parent 7b19f25247
commit 8290c2ad5a
4 changed files with 22 additions and 14 deletions
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15
src/select.c
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@@ -1849,9 +1849,11 @@ static int multiSelect(
** references to the current CTE. */
p->pPrior = 0;
p->pRecurse->tnum = tmp1;
assert( (p->pRecurse->tabFlags & TF_Recursive)==0 );
p->pRecurse->tabFlags |= TF_Recursive;
rc = sqlite3Select(pParse, p, &tmp2dest);
p->pRecurse->tabFlags &= ~TF_Recursive;
assert( p->pPrior==0 );
p->pPrior = pPrior;
if( rc ) goto multi_select_end;
@@ -2845,8 +2847,6 @@ static void substSelect(
**
** Flattening is only attempted if all of the following are true:
**
** (0) The subquery is not a recursive CTE.
**
** (1) The subquery and the outer query do not both use aggregates.
**
** (2) The subquery is not an aggregate or the outer query is not a join.
@@ -2930,6 +2930,14 @@ static void substSelect(
** (21) The subquery does not use LIMIT or the outer query is not
** DISTINCT. (See ticket [752e1646fc]).
**
** (22) The subquery is not a recursive CTE.
**
** (23) The parent is not a recursive CTE, or the sub-query is not a
** compound query. This restriction is because transforming the
** parent to a compound query confuses the code that handles
** recursive queries in multiSelect().
**
**
** In this routine, the "p" parameter is a pointer to the outer query.
** The subquery is p->pSrc->a[iFrom]. isAgg is true if the outer query
** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
@@ -2971,7 +2979,6 @@ static int flattenSubquery(
iParent = pSubitem->iCursor;
pSub = pSubitem->pSelect;
assert( pSub!=0 );
if( pSub->pRecurse ) return 0; /* Restriction (0) */
if( isAgg && subqueryIsAgg ) return 0; /* Restriction (1) */
if( subqueryIsAgg && pSrc->nSrc>1 ) return 0; /* Restriction (2) */
pSubSrc = pSub->pSrc;
@@ -3002,6 +3009,8 @@ static int flattenSubquery(
if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){
return 0; /* Restriction (21) */
}
if( pSub->pRecurse ) return 0; /* Restriction (22) */
if( p->pRecurse && pSub->pPrior ) return 0; /* Restriction (23) */
/* OBSOLETE COMMENT 1:
** Restriction 3: If the subquery is a join, make sure the subquery is