text: /*-------------------------------------------------------------------------
   *
   * nodeSubplan.c
   *	  routines to support sub-selects appearing in expressions
   *
   * This module is concerned with executing SubPlan expression nodes, which
   * should not be confused with sub-SELECTs appearing in FROM.  SubPlans are
   * divided into "initplans", which are those that need only one evaluation per
   * query (among other restrictions, this requires that they don't use any
   * direct correlation variables from the parent plan level), and "regular"
   * subplans, which are re-evaluated every time their result is required.
   *
   *
   * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
   * IDENTIFICATION
   *	  src/backend/executor/nodeSubplan.c
   *
   *-------------------------------------------------------------------------
   */
  /*
   *	 INTERFACE ROUTINES
   *		ExecSubPlan  - process a subselect
   *		ExecInitSubPlan - initialize a subselect
   */
  #include "postgres.h"
  
  #include <limits.h>
  #include <math.h>
  
  #include "access/htup_details.h"
  #include "executor/executor.h"
  #include "executor/nodeSubplan.h"
  #include "nodes/makefuncs.h"
  #include "nodes/nodeFuncs.h"
  #include "miscadmin.h"
  #include "utils/array.h"
  #include "utils/lsyscache.h"
  #include "utils/memutils.h"
  
  
  static Datum ExecHashSubPlan(SubPlanState *node,
  							 ExprContext *econtext,
  							 bool *isNull);
  static Datum ExecScanSubPlan(SubPlanState *node,
  							 ExprContext *econtext,
  							 bool *isNull);
  static void buildSubPlanHash(SubPlanState *node, ExprContext *econtext);
  static bool findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot,
  							 FmgrInfo *eqfunctions);
  static bool slotAllNulls(TupleTableSlot *slot);
  static bool slotNoNulls(TupleTableSlot *slot);
  
  
  /* ----------------------------------------------------------------
   *		ExecSubPlan
   *
   * This is the main entry point for execution of a regular SubPlan.
   * ----------------------------------------------------------------
   */
  Datum
  ExecSubPlan(SubPlanState *node,
  			ExprContext *econtext,
  			bool *isNull)
  {
  	SubPlan    *subplan = node->subplan;
  	EState	   *estate = node->planstate->state;
  	ScanDirection dir = estate->es_direction;
  	Datum		retval;
  
  	CHECK_FOR_INTERRUPTS();
  
  	/* Set non-null as default */
  	*isNull = false;
  
  	/* Sanity checks */
  	if (subplan->subLinkType == CTE_SUBLINK)
  		elog(ERROR, "CTE subplans should not be executed via ExecSubPlan");
  	if (subplan->setParam != NIL && subplan->subLinkType != MULTIEXPR_SUBLINK)
  		elog(ERROR, "cannot set parent params from subquery");
  
  	/* Force forward-scan mode for evaluation */
  	estate->es_direction = ForwardScanDirection;
  
  	/* Select appropriate evaluation strategy */
  	if (subplan->useHashTable)
  		retval = ExecHashSubPlan(node, econtext, isNull);
  	else
  		retval = ExecScanSubPlan(node, econtext, isNull);
  
  	/* restore scan direction */
  	estate->es_direction = dir;
  
  	return retval;
  }
  
  /*
   * ExecHashSubPlan: store subselect result in an in-memory hash table
   */
  static Datum
  ExecHashSubPlan(SubPlanState *node,
  				ExprContext *econtext,
  				bool *isNull)
  {
  	SubPlan    *subplan = node->subplan;
  	PlanState  *planstate = node->planstate;
  	TupleTableSlot *slot;
  
  	/* Shouldn't have any direct correlation Vars */
  	if (subplan->parParam != NIL || node->args != NIL)
  		elog(ERROR, "hashed subplan with direct correlation not supported");
  
  	/*
  	 * If first time through or we need to rescan the subplan, build the hash
  	 * table.
  	 */
  	if (node->hashtable == NULL || planstate->chgParam != NULL)
  		buildSubPlanHash(node, econtext);
  
  	/*
  	 * The result for an empty subplan is always FALSE; no need to evaluate
  	 * lefthand side.
  	 */
  	*isNull = false;
  	if (!node->havehashrows && !node->havenullrows)
  		return BoolGetDatum(false);
  
  	/*
  	 * Evaluate lefthand expressions and form a projection tuple. First we
  	 * have to set the econtext to use (hack alert!).
  	 */
  	node->projLeft->pi_exprContext = econtext;
  	slot = ExecProject(node->projLeft);
  
  	/*
  	 * Note: because we are typically called in a per-tuple context, we have
  	 * to explicitly clear the projected tuple before returning. Otherwise,
  	 * we'll have a double-free situation: the per-tuple context will probably
  	 * be reset before we're called again, and then the tuple slot will think
  	 * it still needs to free the tuple.
  	 */
  
  	/*
  	 * If the LHS is all non-null, probe for an exact match in the main hash
  	 * table.  If we find one, the result is TRUE. Otherwise, scan the
  	 * partly-null table to see if there are any rows that aren't provably
  	 * unequal to the LHS; if so, the result is UNKNOWN.  (We skip that part
  	 * if we don't care about UNKNOWN.) Otherwise, the result is FALSE.
  	 *
  	 * Note: the reason we can avoid a full scan of the main hash table is
  	 * that the combining operators are assumed never to yield NULL when both
  	 * inputs are non-null.  If they were to do so, we might need to produce
  	 * UNKNOWN instead of FALSE because of an UNKNOWN result in comparing the
  	 * LHS to some main-table entry --- which is a comparison we will not even
  	 * make, unless there's a chance match of hash keys.
  	 */
  	if (slotNoNulls(slot))
  	{
  		if (node->havehashrows &&
  			FindTupleHashEntry(node->hashtable,
  							   slot,
  							   node->cur_eq_comp,
  							   node->lhs_hash_funcs) != NULL)
  		{
  			ExecClearTuple(slot);
  			return BoolGetDatum(true);
  		}
  		if (node->havenullrows &&
  			findPartialMatch(node->hashnulls, slot, node->cur_eq_funcs))
  		{
  			ExecClearTuple(slot);
  			*isNull = true;
  			return BoolGetDatum(false);
  		}
  		ExecClearTuple(slot);
  		return BoolGetDatum(false);
  	}
  
  	/*
  	 * When the LHS is partly or wholly NULL, we can never return TRUE. If we
  	 * don't care about UNKNOWN, just return FALSE.  Otherwise, if the LHS is
  	 * wholly NULL, immediately return UNKNOWN.  (Since the combining
  	 * operators are strict, the result could only be FALSE if the sub-select
  	 * were empty, but we already handled that case.) Otherwise, we must scan
  	 * both the main and partly-null tables to see if there are any rows that
  	 * aren't provably unequal to the LHS; if so, the result is UNKNOWN.
  	 * Otherwise, the result is FALSE.
  	 */
  	if (node->hashnulls == NULL)
  	{
  		ExecClearTuple(slot);
  		return BoolGetDatum(false);
  	}
  	if (slotAllNulls(slot))
  	{
  		ExecClearTuple(slot);
  		*isNull = true;
  		return BoolGetDatum(false);
  	}
  	/* Scan partly-null table first, since more likely to get a match */
  	if (node->havenullrows &&
  		findPartialMatch(node->hashnulls, slot, node->cur_eq_funcs))
  	{
  		ExecClearTuple(slot);
  		*isNull = true;
  		return BoolGetDatum(false);
  	}
  	if (node->havehashrows &&
  		findPartialMatch(node->hashtable, slot, node->cur_eq_funcs))
  	{
  		ExecClearTuple(slot);
  		*isNull = true;
  		return BoolGetDatum(false);
  	}
  	ExecClearTuple(slot);
  	return BoolGetDatum(false);
  }
  
  /*
   * ExecScanSubPlan: default case where we have to rescan subplan each time
   */
  static Datum
  ExecScanSubPlan(SubPlanState *node,
  				ExprContext *econtext,
  				bool *isNull)
  {
  	SubPlan    *subplan = node->subplan;
  	PlanState  *planstate = node->planstate;
  	SubLinkType subLinkType = subplan->subLinkType;
  	MemoryContext oldcontext;
  	TupleTableSlot *slot;
  	Datum		result;
  	bool		found = false;	/* true if got at least one subplan tuple */
  	ListCell   *pvar;
  	ListCell   *l;
  	ArrayBuildStateAny *astate = NULL;
  
  	/*
  	 * MULTIEXPR subplans, when "executed", just return NULL; but first we
  	 * mark the subplan's output parameters as needing recalculation.  (This
  	 * is a bit of a hack: it relies on the subplan appearing later in its
  	 * targetlist than any of the referencing Params, so that all the Params
  	 * have been evaluated before we re-mark them for the next evaluation
  	 * cycle.  But in general resjunk tlist items appear after non-resjunk
  	 * ones, so this should be safe.)  Unlike ExecReScanSetParamPlan, we do
  	 * *not* set bits in the parent plan node's chgParam, because we don't
  	 * want to cause a rescan of the parent.
  	 */
  	if (subLinkType == MULTIEXPR_SUBLINK)
  	{
  		EState	   *estate = node->parent->state;
  
  		foreach(l, subplan->setParam)
  		{
  			int			paramid = lfirst_int(l);
  			ParamExecData *prm = &(estate->es_param_exec_vals[paramid]);
  
  			prm->execPlan = node;
  		}
  		*isNull = true;
  		return (Datum) 0;
  	}
  
  	/* Initialize ArrayBuildStateAny in caller's context, if needed */
  	if (subLinkType == ARRAY_SUBLINK)
  		astate = initArrayResultAny(subplan->firstColType,
  									CurrentMemoryContext, true);
  
  	/*
  	 * We are probably in a short-lived expression-evaluation context. Switch
  	 * to the per-query context for manipulating the child plan's chgParam,
  	 * calling ExecProcNode on it, etc.
  	 */
  	oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
  
  	/*
  	 * Set Params of this plan from parent plan correlation values. (Any
  	 * calculation we have to do is done in the parent econtext, since the
  	 * Param values don't need to have per-query lifetime.)
  	 */
  	Assert(list_length(subplan->parParam) == list_length(node->args));
  
  	forboth(l, subplan->parParam, pvar, node->args)
  	{
  		int			paramid = lfirst_int(l);
  		ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
  
  		prm->value = ExecEvalExprSwitchContext((ExprState *) lfirst(pvar),
  											   econtext,
  											   &(prm->isnull));
  		planstate->chgParam = bms_add_member(planstate->chgParam, paramid);
  	}
  
  	/*
  	 * Now that we've set up its parameters, we can reset the subplan.
  	 */
  	ExecReScan(planstate);
  
  	/*
  	 * For all sublink types except EXPR_SUBLINK and ARRAY_SUBLINK, the result
  	 * is boolean as are the results of the combining operators. We combine
  	 * results across tuples (if the subplan produces more than one) using OR
  	 * semantics for ANY_SUBLINK or AND semantics for ALL_SUBLINK.
  	 * (ROWCOMPARE_SUBLINK doesn't allow multiple tuples from the subplan.)
  	 * NULL results from the combining operators are handled according to the
  	 * usual SQL semantics for OR and AND.  The result for no input tuples is
  	 * FALSE for ANY_SUBLINK, TRUE for ALL_SUBLINK, NULL for
  	 * ROWCOMPARE_SUBLINK.
  	 *
  	 * For EXPR_SUBLINK we require the subplan to produce no more than one
  	 * tuple, else an error is raised.  If zero tuples are produced, we return
  	 * NULL.  Assuming we get a tuple, we just use its first column (there can
  	 * be only one non-junk column in this case).
  	 *
  	 * For ARRAY_SUBLINK we allow the subplan to produce any number of tuples,
  	 * and form an array of the first column's values.  Note in particular
  	 * that we produce a zero-element array if no tuples are produced (this is
  	 * a change from pre-8.3 behavior of returning NULL).
  	 */
  	result = BoolGetDatum(subLinkType == ALL_SUBLINK);
  	*isNull = false;
  
  	for (slot = ExecProcNode(planstate);
  		 !TupIsNull(slot);
  		 slot = ExecProcNode(planstate))
  	{
  		TupleDesc	tdesc = slot->tts_tupleDescriptor;
  		Datum		rowresult;
  		bool		rownull;
  		int			col;
  		ListCell   *plst;
  
  		if (subLinkType == EXISTS_SUBLINK)
  		{
  			found = true;
  			result = BoolGetDatum(true);
  			break;
  		}
  
  		if (subLinkType == EXPR_SUBLINK)
  		{
  			/* cannot allow multiple input tuples for EXPR sublink */
  			if (found)
  				ereport(ERROR,
  						(errcode(ERRCODE_CARDINALITY_VIOLATION),
  						 errmsg("more than one row returned by a subquery used as an expression")));
  			found = true;
  
  			/*
  			 * We need to copy the subplan's tuple in case the result is of
  			 * pass-by-ref type --- our return value will point into this
  			 * copied tuple!  Can't use the subplan's instance of the tuple
  			 * since it won't still be valid after next ExecProcNode() call.
  			 * node->curTuple keeps track of the copied tuple for eventual
  			 * freeing.
  			 */
  			if (node->curTuple)
  				heap_freetuple(node->curTuple);
  			node->curTuple = ExecCopySlotHeapTuple(slot);
  
  			result = heap_getattr(node->curTuple, 1, tdesc, isNull);
  			/* keep scanning subplan to make sure there's only one tuple */
  			continue;
  		}
  
  		if (subLinkType == ARRAY_SUBLINK)
  		{
  			Datum		dvalue;
  			bool		disnull;
  
  			found = true;
  			/* stash away current value */
  			Assert(subplan->firstColType == TupleDescAttr(tdesc, 0)->atttypid);
  			dvalue = slot_getattr(slot, 1, &disnull);
  			astate = accumArrayResultAny(astate, dvalue, disnull,
  										 subplan->firstColType, oldcontext);
  			/* keep scanning subplan to collect all values */
  			continue;
  		}
  
  		/* cannot allow multiple input tuples for ROWCOMPARE sublink either */
  		if (subLinkType == ROWCOMPARE_SUBLINK && found)
  			ereport(ERROR,
  					(errcode(ERRCODE_CARDINALITY_VIOLATION),
  					 errmsg("more than one row returned by a subquery used as an expression")));
  
  		found = true;
  
  		/*
  		 * For ALL, ANY, and ROWCOMPARE sublinks, load up the Params
  		 * representing the columns of the sub-select, and then evaluate the
  		 * combining expression.
  		 */
  		col = 1;
  		foreach(plst, subplan->paramIds)
  		{
  			int			paramid = lfirst_int(plst);
  			ParamExecData *prmdata;
  
  			prmdata = &(econtext->ecxt_param_exec_vals[paramid]);
  			Assert(prmdata->execPlan == NULL);
  			prmdata->value = slot_getattr(slot, col, &(prmdata->isnull));
  			col++;
  		}
  
  		rowresult = ExecEvalExprSwitchContext(node->testexpr, econtext,
  											  &rownull);
  
  		if (subLinkType == ANY_SUBLINK)
  		{
  			/* combine across rows per OR semantics */
  			if (rownull)
  				*isNull = true;
  			else if (DatumGetBool(rowresult))
  			{
  				result = BoolGetDatum(true);
  				*isNull = false;
  				break;			/* needn't look at any more rows */
  			}
  		}
  		else if (subLinkType == ALL_SUBLINK)
  		{
  			/* combine across rows per AND semantics */
  			if (rownull)
  				*isNull = true;
  			else if (!DatumGetBool(rowresult))
  			{
  				result = BoolGetDatum(false);
  				*isNull = false;
  				break;			/* needn't look at any more rows */
  			}
  		}
  		else
  		{
  			/* must be ROWCOMPARE_SUBLINK */
  			result = rowresult;
  			*isNull = rownull;
  		}
  	}
  
  	MemoryContextSwitchTo(oldcontext);
  
  	if (subLinkType == ARRAY_SUBLINK)
  	{
  		/* We return the result in the caller's context */
  		result = makeArrayResultAny(astate, oldcontext, true);
  	}
  	else if (!found)
  	{
  		/*
  		 * deal with empty subplan result.  result/isNull were previously
  		 * initialized correctly for all sublink types except EXPR and
  		 * ROWCOMPARE; for those, return NULL.
  		 */
  		if (subLinkType == EXPR_SUBLINK ||
  			subLinkType == ROWCOMPARE_SUBLINK)
  		{
  			result = (Datum) 0;
  			*isNull = true;
  		}
  	}
  
  	return result;
  }
  
  /*
   * buildSubPlanHash: load hash table by scanning subplan output.
   */
  static void
  buildSubPlanHash(SubPlanState *node, ExprContext *econtext)
  {
  	SubPlan    *subplan = node->subplan;
  	PlanState  *planstate = node->planstate;
  	int			ncols = list_length(subplan->paramIds);
  	ExprContext *innerecontext = node->innerecontext;
  	MemoryContext oldcontext;
  	long		nbuckets;
  	TupleTableSlot *slot;
  
  	Assert(subplan->subLinkType == ANY_SUBLINK);
  
  	/*
  	 * If we already had any hash tables, reset 'em; otherwise create empty
  	 * hash table(s).
  	 *
  	 * If we need to distinguish accurately between FALSE and UNKNOWN (i.e.,
  	 * NULL) results of the IN operation, then we have to store subplan output
  	 * rows that are partly or wholly NULL.  We store such rows in a separate
  	 * hash table that we expect will be much smaller than the main table. (We
  	 * can use hashing to eliminate partly-null rows that are not distinct. We
  	 * keep them separate to minimize the cost of the inevitable full-table
  	 * searches; see findPartialMatch.)
  	 *
  	 * If it's not necessary to distinguish FALSE and UNKNOWN, then we don't
  	 * need to store subplan output rows that contain NULL.
  	 */
  	MemoryContextReset(node->hashtablecxt);
  	node->havehashrows = false;
  	node->havenullrows = false;
  
  	nbuckets = (long) Min(planstate->plan->plan_rows, (double) LONG_MAX);
  	if (nbuckets < 1)
  		nbuckets = 1;
  
  	if (node->hashtable)
  		ResetTupleHashTable(node->hashtable);
  	else
  		node->hashtable = BuildTupleHashTableExt(node->parent,
  												 node->descRight,
  												 ncols,
  												 node->keyColIdx,
  												 node->tab_eq_funcoids,
  												 node->tab_hash_funcs,
  												 node->tab_collations,
  												 nbuckets,
  												 0,
  												 node->planstate->state->es_query_cxt,
  												 node->hashtablecxt,
  												 node->hashtempcxt,
  												 false);
  
  	if (!subplan->unknownEqFalse)
  	{
  		if (ncols == 1)
  			nbuckets = 1;		/* there can only be one entry */
  		else
  		{
  			nbuckets /= 16;
  			if (nbuckets < 1)
  				nbuckets = 1;
  		}
  
  		if (node->hashnulls)
  			ResetTupleHashTable(node->hashnulls);
  		else
  			node->hashnulls = BuildTupleHashTableExt(node->parent,
  													 node->descRight,
  													 ncols,
  													 node->keyColIdx,
  													 node->tab_eq_funcoids,
  													 node->tab_hash_funcs,
  													 node->tab_collations,
  													 nbuckets,
  													 0,
  													 node->planstate->state->es_query_cxt,
  													 node->hashtablecxt,
  													 node->hashtempcxt,
  													 false);
  	}
  	else
  		node->hashnulls = NULL;
  
  	/*
  	 * We are probably in a short-lived expression-evaluation context. Switch
  	 * to the per-query context for manipulating the child plan.
  	 */
  	oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
  
  	/*
  	 * Reset subplan to start.
  	 */
  	ExecReScan(planstate);
  
  	/*
  	 * Scan the subplan and load the hash table(s).  Note that when there are
  	 * duplicate rows coming out of the sub-select, only one copy is stored.
  	 */
  	for (slot = ExecProcNode(planstate);
  		 !TupIsNull(slot);
  		 slot = ExecProcNode(planstate))
  	{
  		int			col = 1;
  		ListCell   *plst;
  		bool		isnew;
  
  		/*
  		 * Load up the Params representing the raw sub-select outputs, then
  		 * form the projection tuple to store in the hashtable.
  		 */
  		foreach(plst, subplan->paramIds)
  		{
  			int			paramid = lfirst_int(plst);
  			ParamExecData *prmdata;
  
  			prmdata = &(innerecontext->ecxt_param_exec_vals[paramid]);
  			Assert(prmdata->execPlan == NULL);
  			prmdata->value = slot_getattr(slot, col,
  										  &(prmdata->isnull));
  			col++;
  		}
  		slot = ExecProject(node->projRight);
  
  		/*
  		 * If result contains any nulls, store separately or not at all.
  		 */
  		if (slotNoNulls(slot))
  		{
  			(void) LookupTupleHashEntry(node->hashtable, slot, &isnew);
  			node->havehashrows = true;
  		}
  		else if (node->hashnulls)
  		{
  			(void) LookupTupleHashEntry(node->hashnulls, slot, &isnew);
  			node->havenullrows = true;
  		}
  
  		/*
  		 * Reset innerecontext after each inner tuple to free any memory used
  		 * during ExecProject.
  		 */
  		ResetExprContext(innerecontext);
  	}
  
  	/*
  	 * Since the projected tuples are in the sub-query's context and not the
  	 * main context, we'd better clear the tuple slot before there's any
  	 * chance of a reset of the sub-query's context.  Else we will have the
  	 * potential for a double free attempt.  (XXX possibly no longer needed,
  	 * but can't hurt.)
  	 */
  	ExecClearTuple(node->projRight->pi_state.resultslot);
  
  	MemoryContextSwitchTo(oldcontext);
  }
  
  /*
   * execTuplesUnequal
   *		Return true if two tuples are definitely unequal in the indicated
   *		fields.
   *
   * Nulls are neither equal nor unequal to anything else.  A true result
   * is obtained only if there are non-null fields that compare not-equal.
   *
   * slot1, slot2: the tuples to compare (must have same columns!)
   * numCols: the number of attributes to be examined
   * matchColIdx: array of attribute column numbers
   * eqFunctions: array of fmgr lookup info for the equality functions to use
   * evalContext: short-term memory context for executing the functions
   */
  static bool
  execTuplesUnequal(TupleTableSlot *slot1,
  				  TupleTableSlot *slot2,
  				  int numCols,
  				  AttrNumber *matchColIdx,
  				  FmgrInfo *eqfunctions,
  				  const Oid *collations,
  				  MemoryContext evalContext)
  {
  	MemoryContext oldContext;
  	bool		result;
  	int			i;
  
  	/* Reset and switch into the temp context. */
  	MemoryContextReset(evalContext);
  	oldContext = MemoryContextSwitchTo(evalContext);
  
  	/*
  	 * We cannot report a match without checking all the fields, but we can
  	 * report a non-match as soon as we find unequal fields.  So, start
  	 * comparing at the last field (least significant sort key). That's the
  	 * most likely to be different if we are dealing with sorted input.
  	 */
  	result = false;
  
  	for (i = numCols; --i >= 0;)
  	{
  		AttrNumber	att = matchColIdx[i];
  		Datum		attr1,
  					attr2;
  		bool		isNull1,
  					isNull2;
  
  		attr1 = slot_getattr(slot1, att, &isNull1);
  
  		if (isNull1)
  			continue;			/* can't prove anything here */
  
  		attr2 = slot_getattr(slot2, att, &isNull2);
  
  		if (isNull2)
  			continue;			/* can't prove anything here */
  
  		/* Apply the type-specific equality function */
  		if (!DatumGetBool(FunctionCall2Coll(&eqfunctions[i],
  											collations[i],
  											attr1, attr2)))
  		{
  			result = true;		/* they are unequal */
  			break;
  		}
  	}
  
  	MemoryContextSwitchTo(oldContext);
  
  	return result;
  }
  
  /*
   * findPartialMatch: does the hashtable contain an entry that is not
   * provably distinct from the tuple?
   *
   * We have to scan the whole hashtable; we can't usefully use hashkeys
   * to guide probing, since we might get partial matches on tuples with
   * hashkeys quite unrelated to what we'd get from the given tuple.
   *
   * Caller must provide the equality functions to use, since in cross-type
   * cases these are different from the hashtable's internal functions.
   */
  static bool
  findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot,
  				 FmgrInfo *eqfunctions)
  {
  	int			numCols = hashtable->numCols;
  	AttrNumber *keyColIdx = hashtable->keyColIdx;
  	TupleHashIterator hashiter;
  	TupleHashEntry entry;
  
  	InitTupleHashIterator(hashtable, &hashiter);
  	while ((entry = ScanTupleHashTable(hashtable, &hashiter)) != NULL)
  	{
  		CHECK_FOR_INTERRUPTS();
  
  		ExecStoreMinimalTuple(entry->firstTuple, hashtable->tableslot, false);
  		if (!execTuplesUnequal(slot, hashtable->tableslot,
  							   numCols, keyColIdx,
  							   eqfunctions,
  							   hashtable->tab_collations,
  							   hashtable->tempcxt))
  		{
  			TermTupleHashIterator(&hashiter);
  			return true;
  		}
  	}
  	/* No TermTupleHashIterator call needed here */
  	return false;
  }
  
  /*
   * slotAllNulls: is the slot completely NULL?
   *
   * This does not test for dropped columns, which is OK because we only
   * use it on projected tuples.
   */
  static bool
  slotAllNulls(TupleTableSlot *slot)
  {
  	int			ncols = slot->tts_tupleDescriptor->natts;
  	int			i;
  
  	for (i = 1; i <= ncols; i++)
  	{
  		if (!slot_attisnull(slot, i))
  			return false;
  	}
  	return true;
  }
  
  /*
   * slotNoNulls: is the slot entirely not NULL?
   *
   * This does not test for dropped columns, which is OK because we only
   * use it on projected tuples.
   */
  static bool
  slotNoNulls(TupleTableSlot *slot)
  {
  	int			ncols = slot->tts_tupleDescriptor->natts;
  	int			i;
  
  	for (i = 1; i <= ncols; i++)
  	{
  		if (slot_attisnull(slot, i))
  			return false;
  	}
  	return true;
  }
  
  /* ----------------------------------------------------------------
   *		ExecInitSubPlan
   *
   * Create a SubPlanState for a SubPlan; this is the SubPlan-specific part
   * of ExecInitExpr().  We split it out so that it can be used for InitPlans
   * as well as regular SubPlans.  Note that we don't link the SubPlan into
   * the parent's subPlan list, because that shouldn't happen for InitPlans.
   * Instead, ExecInitExpr() does that one part.
   * ----------------------------------------------------------------
   */
  SubPlanState *
  ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
  {
  	SubPlanState *sstate = makeNode(SubPlanState);
  	EState	   *estate = parent->state;
  
  	sstate->subplan = subplan;
  
  	/* Link the SubPlanState to already-initialized subplan */
  	sstate->planstate = (PlanState *) list_nth(estate->es_subplanstates,
  											   subplan->plan_id - 1);
  
  	/* ... and to its parent's state */
  	sstate->parent = parent;
  
  	/* Initialize subexpressions */
  	sstate->testexpr = ExecInitExpr((Expr *) subplan->testexpr, parent);
  	sstate->args = ExecInitExprList(subplan->args, parent);
  
  	/*
  	 * initialize my state
  	 */
  	sstate->curTuple = NULL;
  	sstate->curArray = PointerGetDatum(NULL);
  	sstate->projLeft = NULL;
  	sstate->projRight = NULL;
  	sstate->hashtable = NULL;
  	sstate->hashnulls = NULL;
  	sstate->hashtablecxt = NULL;
  	sstate->hashtempcxt = NULL;
  	sstate->innerecontext = NULL;
  	sstate->keyColIdx = NULL;
  	sstate->tab_eq_funcoids = NULL;
  	sstate->tab_hash_funcs = NULL;
  	sstate->tab_eq_funcs = NULL;
  	sstate->tab_collations = NULL;
  	sstate->lhs_hash_funcs = NULL;
  	sstate->cur_eq_funcs = NULL;
  
  	/*
  	 * If this is an initplan or MULTIEXPR subplan, it has output parameters
  	 * that the parent plan will use, so mark those parameters as needing
  	 * evaluation.  We don't actually run the subplan until we first need one
  	 * of its outputs.
  	 *
  	 * A CTE subplan's output parameter is never to be evaluated in the normal
  	 * way, so skip this in that case.
  	 *
  	 * Note that we don't set parent->chgParam here: the parent plan hasn't
  	 * been run yet, so no need to force it to re-run.
  	 */
  	if (subplan->setParam != NIL && subplan->subLinkType != CTE_SUBLINK)
  	{
  		ListCell   *lst;
  
  		foreach(lst, subplan->setParam)
  		{
  			int			paramid = lfirst_int(lst);
  			ParamExecData *prm = &(estate->es_param_exec_vals[paramid]);
  
  			prm->execPlan = sstate;
  		}
  	}
  
  	/*
  	 * If we are going to hash the subquery output, initialize relevant stuff.
  	 * (We don't create the hashtable until needed, though.)
  	 */
  	if (subplan->useHashTable)
  	{
  		int			ncols,
  					i;
  		TupleDesc	tupDescLeft;
  		TupleDesc	tupDescRight;
  		Oid		   *cross_eq_funcoids;
  		TupleTableSlot *slot;
  		List	   *oplist,
  				   *lefttlist,
  				   *righttlist;
  		ListCell   *l;
  
  		/* We need a memory context to hold the hash table(s) */
  		sstate->hashtablecxt =
  			AllocSetContextCreate(CurrentMemoryContext,
  								  "Subplan HashTable Context",
  								  ALLOCSET_DEFAULT_SIZES);
  		/* and a small one for the hash tables to use as temp storage */
  		sstate->hashtempcxt =
  			AllocSetContextCreate(CurrentMemoryContext,
  								  "Subplan HashTable Temp Context",
  								  ALLOCSET_SMALL_SIZES);
  		/* and a short-lived exprcontext for function evaluation */
  		sstate->innerecontext = CreateExprContext(estate);
  		/* Silly little array of column numbers 1..n */
  		ncols = list_length(subplan->paramIds);
  		sstate->keyColIdx = (AttrNumber *) palloc(ncols * sizeof(AttrNumber));
  		for (i = 0; i < ncols; i++)
  			sstate->keyColIdx[i] = i + 1;
  
  		/*
  		 * We use ExecProject to evaluate the lefthand and righthand
  		 * expression lists and form tuples.  (You might think that we could
  		 * use the sub-select's output tuples directly, but that is not the
  		 * case if we had to insert any run-time coercions of the sub-select's
  		 * output datatypes; anyway this avoids storing any resjunk columns
  		 * that might be in the sub-select's output.)  Run through the
  		 * combining expressions to build tlists for the lefthand and
  		 * righthand sides.
  		 *
  		 * We also extract the combining operators themselves to initialize
  		 * the equality and hashing functions for the hash tables.
  		 */
  		if (IsA(subplan->testexpr, OpExpr))
  		{
  			/* single combining operator */
  			oplist = list_make1(subplan->testexpr);
  		}
  		else if (is_andclause(subplan->testexpr))
  		{
  			/* multiple combining operators */
  			oplist = castNode(BoolExpr, subplan->testexpr)->args;
  		}
  		else
  		{
  			/* shouldn't see anything else in a hashable subplan */
  			elog(ERROR, "unrecognized testexpr type: %d",
  				 (int) nodeTag(subplan->testexpr));
  			oplist = NIL;		/* keep compiler quiet */
  		}
  		Assert(list_length(oplist) == ncols);
  
  		lefttlist = righttlist = NIL;
  		sstate->tab_eq_funcoids = (Oid *) palloc(ncols * sizeof(Oid));
  		sstate->tab_hash_funcs = (FmgrInfo *) palloc(ncols * sizeof(FmgrInfo));
  		sstate->tab_eq_funcs = (FmgrInfo *) palloc(ncols * sizeof(FmgrInfo));
  		sstate->tab_collations = (Oid *) palloc(ncols * sizeof(Oid));
  		sstate->lhs_hash_funcs = (FmgrInfo *) palloc(ncols * sizeof(FmgrInfo));
  		sstate->cur_eq_funcs = (FmgrInfo *) palloc(ncols * sizeof(FmgrInfo));
  		/* we'll need the cross-type equality fns below, but not in sstate */
  		cross_eq_funcoids = (Oid *) palloc(ncols * sizeof(Oid));
  
  		i = 1;
  		foreach(l, oplist)
  		{
  			OpExpr	   *opexpr = lfirst_node(OpExpr, l);
  			Expr	   *expr;
  			TargetEntry *tle;
  			Oid			rhs_eq_oper;
  			Oid			left_hashfn;
  			Oid			right_hashfn;
  
  			Assert(list_length(opexpr->args) == 2);
  
  			/* Process lefthand argument */
  			expr = (Expr *) linitial(opexpr->args);
  			tle = makeTargetEntry(expr,
  								  i,
  								  NULL,
  								  false);
  			lefttlist = lappend(lefttlist, tle);
  
  			/* Process righthand argument */
  			expr = (Expr *) lsecond(opexpr->args);
  			tle = makeTargetEntry(expr,
  								  i,
  								  NULL,
  								  false);
  			righttlist = lappend(righttlist, tle);
  
  			/* Lookup the equality function (potentially cross-type) */
  			cross_eq_funcoids[i - 1] = opexpr->opfuncid;
  			fmgr_info(opexpr->opfuncid, &sstate->cur_eq_funcs[i - 1]);
  			fmgr_info_set_expr((Node *) opexpr, &sstate->cur_eq_funcs[i - 1]);
  
  			/* Look up the equality function for the RHS type */
  			if (!get_compatible_hash_operators(opexpr->opno,
  											   NULL, &rhs_eq_oper))
  				elog(ERROR, "could not find compatible hash operator for operator %u",
  					 opexpr->opno);
  			sstate->tab_eq_funcoids[i - 1] = get_opcode(rhs_eq_oper);
  			fmgr_info(sstate->tab_eq_funcoids[i - 1],
  					  &sstate->tab_eq_funcs[i - 1]);
  
  			/* Lookup the associated hash functions */
  			if (!get_op_hash_functions(opexpr->opno,
  									   &left_hashfn, &right_hashfn))
  				elog(ERROR, "could not find hash function for hash operator %u",
  					 opexpr->opno);
  			fmgr_info(left_hashfn, &sstate->lhs_hash_funcs[i - 1]);
  			fmgr_info(right_hashfn, &sstate->tab_hash_funcs[i - 1]);
  
  			/* Set collation */
  			sstate->tab_collations[i - 1] = opexpr->inputcollid;
  
  			i++;
  		}
  
  		/*
  		 * Construct tupdescs, slots and projection nodes for left and right
  		 * sides.  The lefthand expressions will be evaluated in the parent
  		 * plan node's exprcontext, which we don't have access to here.
  		 * Fortunately we can just pass NULL for now and fill it in later
  		 * (hack alert!).  The righthand expressions will be evaluated in our
  		 * own innerecontext.
  		 */
  		tupDescLeft = ExecTypeFromTL(lefttlist);
  		slot = ExecInitExtraTupleSlot(estate, tupDescLeft, &TTSOpsVirtual);
  		sstate->projLeft = ExecBuildProjectionInfo(lefttlist,
  												   NULL,
  												   slot,
  												   parent,
  												   NULL);
  
  		sstate->descRight = tupDescRight = ExecTypeFromTL(righttlist);
  		slot = ExecInitExtraTupleSlot(estate, tupDescRight, &TTSOpsVirtual);
  		sstate->projRight = ExecBuildProjectionInfo(righttlist,
  													sstate->innerecontext,
  													slot,
  													sstate->planstate,
  													NULL);
  
  		/*
  		 * Create comparator for lookups of rows in the table (potentially
  		 * cross-type comparisons).
  		 */
  		sstate->cur_eq_comp = ExecBuildGroupingEqual(tupDescLeft, tupDescRight,
  													 &TTSOpsVirtual, &TTSOpsMinimalTuple,
  													 ncols,
  													 sstate->keyColIdx,
  													 cross_eq_funcoids,
  													 sstate->tab_collations,
  													 parent);
  	}
  
  	return sstate;
  }
  
  /* ----------------------------------------------------------------
   *		ExecSetParamPlan
   *
   *		Executes a subplan and sets its output parameters.
   *
   * This is called from ExecEvalParamExec() when the value of a PARAM_EXEC
   * parameter is requested and the param's execPlan field is set (indicating
   * that the param has not yet been evaluated).  This allows lazy evaluation
   * of initplans: we don't run the subplan until/unless we need its output.
   * Note that this routine MUST clear the execPlan fields of the plan's
   * output parameters after evaluating them!
   *
   * The results of this function are stored in the EState associated with the
   * ExprContext (particularly, its ecxt_param_exec_vals); any pass-by-ref
   * result Datums are allocated in the EState's per-query memory.  The passed
   * econtext can be any ExprContext belonging to that EState; which one is
   * important only to the extent that the ExprContext's per-tuple memory
   * context is used to evaluate any parameters passed down to the subplan.
   * (Thus in principle, the shorter-lived the ExprContext the better, since
   * that data isn't needed after we return.  In practice, because initplan
   * parameters are never more complex than Vars, Aggrefs, etc, evaluating them
   * currently never leaks any memory anyway.)
   * ----------------------------------------------------------------
   */
  void
  ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
  {
  	SubPlan    *subplan = node->subplan;
  	PlanState  *planstate = node->planstate;
  	SubLinkType subLinkType = subplan->subLinkType;
  	EState	   *estate = planstate->state;
  	ScanDirection dir = estate->es_direction;
  	MemoryContext oldcontext;
  	TupleTableSlot *slot;
  	ListCell   *pvar;
  	ListCell   *l;
  	bool		found = false;
  	ArrayBuildStateAny *astate = NULL;
  
  	if (subLinkType == ANY_SUBLINK ||
  		subLinkType == ALL_SUBLINK)
  		elog(ERROR, "ANY/ALL subselect unsupported as initplan");
  	if (subLinkType == CTE_SUBLINK)
  		elog(ERROR, "CTE subplans should not be executed via ExecSetParamPlan");
  
  	/*
  	 * Enforce forward scan direction regardless of caller. It's hard but not
  	 * impossible to get here in backward scan, so make it work anyway.
  	 */
  	estate->es_direction = ForwardScanDirection;
  
  	/* Initialize ArrayBuildStateAny in caller's context, if needed */
  	if (subLinkType == ARRAY_SUBLINK)
  		astate = initArrayResultAny(subplan->firstColType,
  									CurrentMemoryContext, true);
  
  	/*
  	 * Must switch to per-query memory context.
  	 */
  	oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
  
  	/*
  	 * Set Params of this plan from parent plan correlation values. (Any
  	 * calculation we have to do is done in the parent econtext, since the
  	 * Param values don't need to have per-query lifetime.)  Currently, we
  	 * expect only MULTIEXPR_SUBLINK plans to have any correlation values.
  	 */
  	Assert(subplan->parParam == NIL || subLinkType == MULTIEXPR_SUBLINK);
  	Assert(list_length(subplan->parParam) == list_length(node->args));
  
  	forboth(l, subplan->parParam, pvar, node->args)
  	{
  		int			paramid = lfirst_int(l);
  		ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
  
  		prm->value = ExecEvalExprSwitchContext((ExprState *) lfirst(pvar),
  											   econtext,
  											   &(prm->isnull));
  		planstate->chgParam = bms_add_member(planstate->chgParam, paramid);
  	}
  
  	/*
  	 * Run the plan.  (If it needs to be rescanned, the first ExecProcNode
  	 * call will take care of that.)
  	 */
  	for (slot = ExecProcNode(planstate);
  		 !TupIsNull(slot);
  		 slot = ExecProcNode(planstate))
  	{
  		TupleDesc	tdesc = slot->tts_tupleDescriptor;
  		int			i = 1;
  
  		if (subLinkType == EXISTS_SUBLINK)
  		{
  			/* There can be only one setParam... */
  			int			paramid = linitial_int(subplan->setParam);
  			ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
  
  			prm->execPlan = NULL;
  			prm->value = BoolGetDatum(true);
  			prm->isnull = false;
  			found = true;
  			break;
  		}
  
  		if (subLinkType == ARRAY_SUBLINK)
  		{
  			Datum		dvalue;
  			bool		disnull;
  
  			found = true;
  			/* stash away current value */
  			Assert(subplan->firstColType == TupleDescAttr(tdesc, 0)->atttypid);
  			dvalue = slot_getattr(slot, 1, &disnull);
  			astate = accumArrayResultAny(astate, dvalue, disnull,
  										 subplan->firstColType, oldcontext);
  			/* keep scanning subplan to collect all values */
  			continue;
  		}
  
  		if (found &&
  			(subLinkType == EXPR_SUBLINK ||
  			 subLinkType == MULTIEXPR_SUBLINK ||
  			 subLinkType == ROWCOMPARE_SUBLINK))
  			ereport(ERROR,
  					(errcode(ERRCODE_CARDINALITY_VIOLATION),
  					 errmsg("more than one row returned by a subquery used as an expression")));
  
  		found = true;
  
  		/*
  		 * We need to copy the subplan's tuple into our own context, in case
  		 * any of the params are pass-by-ref type --- the pointers stored in
  		 * the param structs will point at this copied tuple! node->curTuple
  		 * keeps track of the copied tuple for eventual freeing.
  		 */
  		if (node->curTuple)
  			heap_freetuple(node->curTuple);
  		node->curTuple = ExecCopySlotHeapTuple(slot);
  
  		/*
  		 * Now set all the setParam params from the columns of the tuple
  		 */
  		foreach(l, subplan->setParam)
  		{
  			int			paramid = lfirst_int(l);
  			ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
  
  			prm->execPlan = NULL;
  			prm->value = heap_getattr(node->curTuple, i, tdesc,
  									  &(prm->isnull));
  			i++;
  		}
  	}
  
  	if (subLinkType == ARRAY_SUBLINK)
  	{
  		/* There can be only one setParam... */
  		int			paramid = linitial_int(subplan->setParam);
  		ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
  
  		/*
  		 * We build the result array in query context so it won't disappear;
  		 * to avoid leaking memory across repeated calls, we have to remember
  		 * the latest value, much as for curTuple above.
  		 */
  		if (node->curArray != PointerGetDatum(NULL))
  			pfree(DatumGetPointer(node->curArray));
  		node->curArray = makeArrayResultAny(astate,
  											econtext->ecxt_per_query_memory,
  											true);
  		prm->execPlan = NULL;
  		prm->value = node->curArray;
  		prm->isnull = false;
  	}
  	else if (!found)
  	{
  		if (subLinkType == EXISTS_SUBLINK)
  		{
  			/* There can be only one setParam... */
  			int			paramid = linitial_int(subplan->setParam);
  			ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
  
  			prm->execPlan = NULL;
  			prm->value = BoolGetDatum(false);
  			prm->isnull = false;
  		}
  		else
  		{
  			/* For other sublink types, set all the output params to NULL */
  			foreach(l, subplan->setParam)
  			{
  				int			paramid = lfirst_int(l);
  				ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
  
  				prm->execPlan = NULL;
  				prm->value = (Datum) 0;
  				prm->isnull = true;
  			}
  		}
  	}
  
  	MemoryContextSwitchTo(oldcontext);
  
  	/* restore scan direction */
  	estate->es_direction = dir;
  }
  
  /*
   * ExecSetParamPlanMulti
   *
   * Apply ExecSetParamPlan to evaluate any not-yet-evaluated initplan output
   * parameters whose ParamIDs are listed in "params".  Any listed params that
   * are not initplan outputs are ignored.
   *
   * As with ExecSetParamPlan, any ExprContext belonging to the current EState
   * can be used, but in principle a shorter-lived ExprContext is better than a
   * longer-lived one.
   */
  void
  ExecSetParamPlanMulti(const Bitmapset *params, ExprContext *econtext)
  {
  	int			paramid;
  
  	paramid = -1;
  	while ((paramid = bms_next_member(params, paramid)) >= 0)
  	{
  		ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
  
  		if (prm->execPlan != NULL)
  		{
  			/* Parameter not evaluated yet, so go do it */
  			ExecSetParamPlan(prm->execPlan, econtext);
  			/* ExecSetParamPlan should have processed this param... */
  			Assert(prm->execPlan == NULL);
  		}
  	}
  }
  
  /*
   * Mark an initplan as needing recalculation
   */
  void
  ExecReScanSetParamPlan(SubPlanState *node, PlanState *parent)
  {
  	PlanState  *planstate = node->planstate;
  	SubPlan    *subplan = node->subplan;
  	EState	   *estate = parent->state;
  	ListCell   *l;
  
  	/* sanity checks */
  	if (subplan->parParam != NIL)
  		elog(ERROR, "direct correlated subquery unsupported as initplan");
  	if (subplan->setParam == NIL)
  		elog(ERROR, "setParam list of initplan is empty");
  	if (bms_is_empty(planstate->plan->extParam))
  		elog(ERROR, "extParam set of initplan is empty");
  
  	/*
  	 * Don't actually re-scan: it'll happen inside ExecSetParamPlan if needed.
  	 */
  
  	/*
  	 * Mark this subplan's output parameters as needing recalculation.
  	 *
  	 * CTE subplans are never executed via parameter recalculation; instead
  	 * they get run when called by nodeCtescan.c.  So don't mark the output
  	 * parameter of a CTE subplan as dirty, but do set the chgParam bit for it
  	 * so that dependent plan nodes will get told to rescan.
  	 */
  	foreach(l, subplan->setParam)
  	{
  		int			paramid = lfirst_int(l);
  		ParamExecData *prm = &(estate->es_param_exec_vals[paramid]);
  
  		if (subplan->subLinkType != CTE_SUBLINK)
  			prm->execPlan = node;
  
  		parent->chgParam = bms_add_member(parent->chgParam, paramid);
  	}
  }
  
  
  /*
   * ExecInitAlternativeSubPlan
   *
   * Initialize for execution of one of a set of alternative subplans.
   */
  AlternativeSubPlanState *
  ExecInitAlternativeSubPlan(AlternativeSubPlan *asplan, PlanState *parent)
  {
  	AlternativeSubPlanState *asstate = makeNode(AlternativeSubPlanState);
  	double		num_calls;
  	SubPlan    *subplan1;
  	SubPlan    *subplan2;
  	Cost		cost1;
  	Cost		cost2;
  	ListCell   *lc;
  
  	asstate->subplan = asplan;
  
  	/*
  	 * Initialize subplans.  (Can we get away with only initializing the one
  	 * we're going to use?)
  	 */
  	foreach(lc, asplan->subplans)
  	{
  		SubPlan    *sp = lfirst_node(SubPlan, lc);
  		SubPlanState *sps = ExecInitSubPlan(sp, parent);
  
  		asstate->subplans = lappend(asstate->subplans, sps);
  		parent->subPlan = lappend(parent->subPlan, sps);
  	}
  
  	/*
  	 * Select the one to be used.  For this, we need an estimate of the number
  	 * of executions of the subplan.  We use the number of output rows
  	 * expected from the parent plan node.  This is a good estimate if we are
  	 * in the parent's targetlist, and an underestimate (but probably not by
  	 * more than a factor of 2) if we are in the qual.
  	 */
  	num_calls = parent->plan->plan_rows;
  
  	/*
  	 * The planner saved enough info so that we don't have to work very hard
  	 * to estimate the total cost, given the number-of-calls estimate.
  	 */
  	Assert(list_length(asplan->subplans) == 2);
  	subplan1 = (SubPlan *) linitial(asplan->subplans);
  	subplan2 = (SubPlan *) lsecond(asplan->subplans);
  
  	cost1 = subplan1->startup_cost + num_calls * subplan1->per_call_cost;
  	cost2 = subplan2->startup_cost + num_calls * subplan2->per_call_cost;
  
  	if (cost1 < cost2)
  		asstate->active = 0;
  	else
  		asstate->active = 1;
  
  	return asstate;
  }
  
  /*
   * ExecAlternativeSubPlan
   *
   * Execute one of a set of alternative subplans.
   *
   * Note: in future we might consider changing to different subplans on the
   * fly, in case the original rowcount estimate turns out to be way off.
   */
  Datum
  ExecAlternativeSubPlan(AlternativeSubPlanState *node,
  					   ExprContext *econtext,
  					   bool *isNull)
  {
  	/* Just pass control to the active subplan */
  	SubPlanState *activesp = list_nth_node(SubPlanState,
  										   node->subplans, node->active);
  
  	return ExecSubPlan(activesp, econtext, isNull);
  }
  