/*
* ExecSetOp for hashed case: phase 2, retrieving groups from hash table
*/
static TupleTableSlot *
setop_retrieve_hash_table(SetOpState *setopstate)
{
TupleHashEntryData *entry;
TupleTableSlot *resultTupleSlot;
/*
* get state info from node
*/
resultTupleSlot = setopstate->ps.ps_ResultTupleSlot;
/*
* We loop retrieving groups until we find one we should return
*/
while (!setopstate->setop_done)
{
CHECK_FOR_INTERRUPTS();
/*
* Find the next entry in the hash table
*/
entry = ScanTupleHashTable(setopstate->hashtable, &setopstate->hashiter);
if (entry == NULL)
{
/* No more entries in hashtable, so done */
setopstate->setop_done = true;
return NULL;
}
/*
* See if we should emit any copies of this tuple, and if so return
* the first copy.
*/
set_output_count(setopstate, (SetOpStatePerGroup) entry->additional);
if (setopstate->numOutput > 0)
{
setopstate->numOutput--;
return ExecStoreMinimalTuple(entry->firstTuple,
resultTupleSlot,
false);
}
}
/* No more groups */
ExecClearTuple(resultTupleSlot);
return NULL;
}
/*
* ExecSetOp for non-hashed case
*/
static TupleTableSlot *
setop_retrieve_direct(SetOpState *setopstate)
{
SetOp *node = (SetOp *) setopstate->ps.plan;
PlanState *outerPlan;
SetOpStatePerGroup pergroup;
TupleTableSlot *outerslot;
TupleTableSlot *resultTupleSlot;
/*
* get state info from node
*/
outerPlan = outerPlanState(setopstate);
pergroup = setopstate->pergroup;
resultTupleSlot = setopstate->ps.ps_ResultTupleSlot;
/*
* We loop retrieving groups until we find one we should return
*/
while (!setopstate->setop_done)
{
/*
* If we don't already have the first tuple of the new group, fetch it
* from the outer plan.
*/
if (setopstate->grp_firstTuple == NULL)
{
outerslot = ExecProcNode(outerPlan);
if (!TupIsNull(outerslot))
{
/* Make a copy of the first input tuple */
setopstate->grp_firstTuple = ExecCopySlotTuple(outerslot);
}
else
{
/* outer plan produced no tuples at all */
setopstate->setop_done = true;
return NULL;
}
}
/*
* Store the copied first input tuple in the tuple table slot reserved
* for it. The tuple will be deleted when it is cleared from the
* slot.
*/
ExecStoreTuple(setopstate->grp_firstTuple,
resultTupleSlot,
InvalidBuffer,
true);
setopstate->grp_firstTuple = NULL; /* don't keep two pointers */
/* Initialize working state for a new input tuple group */
initialize_counts(pergroup);
/* Count the first input tuple */
advance_counts(pergroup,
fetch_tuple_flag(setopstate, resultTupleSlot));
/*
* Scan the outer plan until we exhaust it or cross a group boundary.
*/
for (;;)
{
outerslot = ExecProcNode(outerPlan);
if (TupIsNull(outerslot))
{
/* no more outer-plan tuples available */
setopstate->setop_done = true;
break;
}
/*
* Check whether we've crossed a group boundary.
*/
if (!execTuplesMatch(resultTupleSlot,
outerslot,
node->numCols, node->dupColIdx,
setopstate->eqfunctions,
setopstate->tempContext))
{
/*
* Save the first input tuple of the next group.
*/
setopstate->grp_firstTuple = ExecCopySlotTuple(outerslot);
break;
}
/* Still in same group, so count this tuple */
advance_counts(pergroup,
fetch_tuple_flag(setopstate, outerslot));
}
/*
* Done scanning input tuple group. See if we should emit any copies
* of result tuple, and if so return the first copy.
*/
set_output_count(setopstate, pergroup);
if (setopstate->numOutput > 0)
{
setopstate->numOutput--;
return resultTupleSlot;
}
}
/* No more groups */
ExecClearTuple(resultTupleSlot);
return NULL;
}
