/*
* Read the next tuple. We might fetch a tuple from one of the tuple queues
* using gather_readnext, or if no tuple queue contains a tuple and the
* single_copy flag is not set, we might generate one locally instead.
*/
static TupleTableSlot *
gather_getnext(GatherState *gatherstate)
{
PlanState *outerPlan = outerPlanState(gatherstate);
TupleTableSlot *outerTupleSlot;
TupleTableSlot *fslot = gatherstate->funnel_slot;
HeapTuple tup;
while (gatherstate->nreaders > 0 || gatherstate->need_to_scan_locally)
{
CHECK_FOR_INTERRUPTS();
if (gatherstate->nreaders > 0)
{
tup = gather_readnext(gatherstate);
if (HeapTupleIsValid(tup))
{
ExecStoreTuple(tup, /* tuple to store */
fslot, /* slot in which to store the tuple */
InvalidBuffer, /* buffer associated with this
* tuple */
true); /* pfree tuple when done with it */
return fslot;
}
}
if (gatherstate->need_to_scan_locally)
{
EState *estate = gatherstate->ps.state;
/* Install our DSA area while executing the plan. */
estate->es_query_dsa =
gatherstate->pei ? gatherstate->pei->area : NULL;
outerTupleSlot = ExecProcNode(outerPlan);
estate->es_query_dsa = NULL;
if (!TupIsNull(outerTupleSlot))
return outerTupleSlot;
gatherstate->need_to_scan_locally = false;
}
}
return ExecClearTuple(fslot);
}
/*
* Read the next tuple. We might fetch a tuple from one of the tuple queues
* using gather_readnext, or if no tuple queue contains a tuple and the
* single_copy flag is not set, we might generate one locally instead.
*/
static TupleTableSlot *
gather_getnext(GatherState *gatherstate)
{
PlanState *outerPlan = outerPlanState(gatherstate);
TupleTableSlot *outerTupleSlot;
TupleTableSlot *fslot = gatherstate->funnel_slot;
HeapTuple tup;
while (gatherstate->reader != NULL || gatherstate->need_to_scan_locally)
{
if (gatherstate->reader != NULL)
{
tup = gather_readnext(gatherstate);
if (HeapTupleIsValid(tup))
{
ExecStoreTuple(tup, /* tuple to store */
fslot, /* slot in which to store the tuple */
InvalidBuffer, /* buffer associated with this
* tuple */
true); /* pfree this pointer if not from heap */
return fslot;
}
}
if (gatherstate->need_to_scan_locally)
{
outerTupleSlot = ExecProcNode(outerPlan);
if (!TupIsNull(outerTupleSlot))
return outerTupleSlot;
gatherstate->need_to_scan_locally = false;
}
}
return ExecClearTuple(fslot);
}