/* ----------------------------------------------------------------
* ExecReScanRecursiveUnion
*
* Rescans the relation.
* ----------------------------------------------------------------
*/
void
ExecReScanRecursiveUnion(RecursiveUnionState *node)
{
PlanState *outerPlan = outerPlanState(node);
PlanState *innerPlan = innerPlanState(node);
RecursiveUnion *plan = (RecursiveUnion *) node->ps.plan;
/*
* Set recursive term's chgParam to tell it that we'll modify the working
* table and therefore it has to rescan.
*/
innerPlan->chgParam = bms_add_member(innerPlan->chgParam, plan->wtParam);
/*
* if chgParam of subnode is not null then plan will be re-scanned by
* first ExecProcNode. Because of above, we only have to do this to the
* non-recursive term.
*/
if (outerPlan->chgParam == NULL)
ExecReScan(outerPlan);
/* Release any hashtable storage */
if (node->tableContext)
MemoryContextResetAndDeleteChildren(node->tableContext);
/* And rebuild empty hashtable if needed */
if (plan->numCols > 0)
build_hash_table(node);
/* reset processing state */
node->recursing = false;
node->intermediate_empty = true;
tuplestore_clear(node->working_table);
tuplestore_clear(node->intermediate_table);
}
/* ----------------------------------------------------------------
* ExecReScanCteScan
*
* Rescans the relation.
* ----------------------------------------------------------------
*/
void
ExecReScanCteScan(CteScanState *node)
{
Tuplestorestate *tuplestorestate = node->leader->cte_table;
ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
ExecScanReScan(&node->ss);
/*
* Clear the tuplestore if a new scan of the underlying CTE is required.
* This implicitly resets all the tuplestore's read pointers. Note that
* multiple CTE nodes might redundantly clear the tuplestore; that's OK,
* and not unduly expensive. We'll stop taking this path as soon as
* somebody has attempted to read something from the underlying CTE
* (thereby causing its chgParam to be cleared).
*/
if (node->leader->cteplanstate->chgParam != NULL)
{
tuplestore_clear(tuplestorestate);
node->leader->eof_cte = false;
}
else
{
/*
* Else, just rewind my own pointer. Either the underlying CTE
* doesn't need a rescan (and we can re-read what's in the tuplestore
* now), or somebody else already took care of it.
*/
tuplestore_select_read_pointer(tuplestorestate, node->readptr);
tuplestore_rescan(tuplestorestate);
}
}
/* ----------------------------------------------------------------
* ExecReScanCteScan
*
* Rescans the relation.
* ----------------------------------------------------------------
*/
void
ExecReScanCteScan(CteScanState *node)
{
Tuplestorestate *tuplestorestate = node->leader->cte_table;
ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
ExecScanReScan(&node->ss);
if (node->leader == node)
{
/*
* The leader is responsible for clearing the tuplestore if a new scan
* of the underlying CTE is required.
*/
if (node->cteplanstate->chgParam != NULL)
{
tuplestore_clear(tuplestorestate);
node->eof_cte = false;
}
else
{
tuplestore_select_read_pointer(tuplestorestate, node->readptr);
tuplestore_rescan(tuplestorestate);
}
}
else
{
/* Not leader, so just rewind my own pointer */
tuplestore_select_read_pointer(tuplestorestate, node->readptr);
tuplestore_rescan(tuplestorestate);
}
}
