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Add CteNameExists function and improve CTE unification logic in PrepareInsertSelectForCitusPlanner

mehmet/issue_7784
Mehmet Yilmaz 2025-04-18 11:48:38 +00:00
parent b1a38e0bca
commit 7dd4c18935
1 changed files with 43 additions and 35 deletions
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78
src/backend/distributed/planner/insert_select_planner.c
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@ -128,6 +128,9 @@ DecrementInsertLevelReferences(Query *subquery,
int offset, /* typically -1 */
List *topLevelCteList);
static bool
CteNameExists(List *cteList, const char *ctename);
/* depth of current insert/select planner. */
static int insertSelectPlannerLevel = 0;
@ -554,27 +557,47 @@ PrepareInsertSelectForCitusPlanner(Query *insertSelectQuery)
if (list_length(insertSelectQuery->cteList) > 0)
{
/* we physically unify ctes from top-level into subquery,
* then want references in the subquery from ctelevelsup=1 => 0
*/
elog(DEBUG1, "Unifying top-level cteList with subquery cteList");
List *topCopy = copyObject(insertSelectQuery->cteList);
ListCell *lc;
elog(DEBUG1, "Unifying top‑level CTEs into subquery");
/* append only the *new* ones */
foreach(lc, topCopy)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
if (!CteNameExists(selectRte->subquery->cteList, cte->ctename))
selectRte->subquery->cteList =
lappend(selectRte->subquery->cteList, cte);
}
List *topLevelCteListCopy = copyObject(insertSelectQuery->cteList);
selectRte->subquery->cteList =
list_concat(selectRte->subquery->cteList,
copyObject(insertSelectQuery->cteList));
insertSelectQuery->cteList = NIL;
/* Suppose we physically appended the top-level cteList into the subquery,
so references are at ctelevelsup=1, 2, etc. We want them all to shift by -1. */
DecrementInsertLevelReferences(selectRte->subquery, -1, topLevelCteListCopy /* for ctename check */);
DecrementInsertLevelReferences(selectRte->subquery, -1, topCopy /* for ctename check */);
elog(DEBUG1, "Done shifting ctelevelsup X->X-1 for subquery references");
}
}
static bool
CteNameExists(List *cteList, const char *ctename)
{
ListCell *lc;
foreach(lc, cteList)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
if (strcmp(cte->ctename, ctename) == 0)
return true;
}
return false;
}
/*
* inline_cte_walker
*
@ -630,32 +653,13 @@ inline_cte_walker(Node *node, ShiftReferencesWalkerContext *context)
*/
if (rte->ctelevelsup == (context->levelsup + 1))
{
/* optionally verify ctename is in topLevelCteList */
bool foundName = false;
if (context->topLevelCteList != NULL)
if (context->topLevelCteList == NULL ||
CteNameExists(context->topLevelCteList, rte->ctename))
{
ListCell *lc = NULL;
foreach(lc, context->topLevelCteList)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
if (strcmp(cte->ctename, rte->ctename) == 0)
{
foundName = true;
break;
}
}
}
else
{
foundName = true; /* if we don't need a name check */
}
if (foundName)
{
int oldSup = rte->ctelevelsup;
rte->ctelevelsup += context->offset; /* e.g. -1 => (k+1) → k */
elog(DEBUG2, "Shifting ctelevelsup for ctename=%s from %d to %d",
rte->ctename, oldSup, rte->ctelevelsup);
int old = rte->ctelevelsup;
rte->ctelevelsup += context->offset; /* usually ‑1 */
elog(DEBUG2, "Shifted ctelevelsup for %s from %d to %d",
rte->ctename, old, rte->ctelevelsup);
}
else
{
@ -665,6 +669,10 @@ inline_cte_walker(Node *node, ShiftReferencesWalkerContext *context)
}
}
/* look into sub‑queries held inside an RTE */
if (rte->rtekind == RTE_SUBQUERY && rte->subquery)
inline_cte_walker((Node *) rte->subquery, context);
return false;
}