/* ----------------------------------------------------------------
 *		ExecInitSeqScan
 * ----------------------------------------------------------------
 */
SeqScanState *
ExecInitSeqScan(SeqScan *node, EState *estate, int eflags)
{
	SeqScanState *scanstate;
	AttrNumber ctid_attrno;

	/*
	 * Once upon a time it was possible to have an outerPlan of a SeqScan, but
	 * not any more.
	 */
	Assert(outerPlan(node) == NULL);
	Assert(innerPlan(node) == NULL);

	/*
	 * create state structure
	 */
	scanstate = makeNode(SeqScanState);
	scanstate->ps.plan = (Plan *) node;
	scanstate->ps.state = estate;

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &scanstate->ps);

	/*
	 * initialize child expressions
	 */
	scanstate->ps.targetlist = (List *)
		ExecInitExpr((Expr *) node->plan.targetlist,
					 (PlanState *) scanstate);
	scanstate->ps.qual = (List *)
		ExecInitExpr((Expr *) node->plan.qual,
					 (PlanState *) scanstate);

#define SEQSCAN_NSLOTS 2

	/*
	 * tuple table initialization
	 */
	ExecInitResultTupleSlot(estate, &scanstate->ps);
	ExecInitScanTupleSlot(estate, scanstate);

	/*
	 * initialize scan relation
	 */
	InitScanRelation(scanstate, estate);

	scanstate->ps.ps_TupFromTlist = false;

	/*
	 * Initialize result tuple type and projection info.
	 */
	ExecAssignResultTypeFromTL(&scanstate->ps);
	ExecAssignScanProjectionInfo(scanstate);

	return scanstate;
}

/* ----------------------------------------------------------------
 *		ExecInitUnique
 *
 *		This initializes the unique node state structures and
 *		the node's subplan.
 * ----------------------------------------------------------------
 */
UniqueState *
ExecInitUnique(Unique *node, EState *estate, int eflags)
{
	UniqueState *uniquestate;

	/* check for unsupported flags */
	Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));

	/*
	 * create state structure
	 */
	uniquestate = makeNode(UniqueState);
	uniquestate->ps.plan = (Plan *) node;
	uniquestate->ps.state = estate;

	/*
	 * Miscellaneous initialization
	 *
	 * Unique nodes have no ExprContext initialization because they never call
	 * ExecQual or ExecProject.  But they do need a per-tuple memory context
	 * anyway for calling execTuplesMatch.
	 */
	uniquestate->tempContext =
		AllocSetContextCreate(CurrentMemoryContext,
							  "Unique",
							  ALLOCSET_DEFAULT_MINSIZE,
							  ALLOCSET_DEFAULT_INITSIZE,
							  ALLOCSET_DEFAULT_MAXSIZE);

#define UNIQUE_NSLOTS 1

	/*
	 * Tuple table initialization
	 */
	ExecInitResultTupleSlot(estate, &uniquestate->ps);

	/*
	 * then initialize outer plan
	 */
	outerPlanState(uniquestate) = ExecInitNode(outerPlan(node), estate, eflags);

	/*
	 * unique nodes do no projections, so initialize projection info for this
	 * node appropriately
	 */
	ExecAssignResultTypeFromTL(&uniquestate->ps);
	uniquestate->ps.ps_ProjInfo = NULL;

	/*
	 * Precompute fmgr lookup data for inner loop
	 */
	uniquestate->eqfunctions =
		execTuplesMatchPrepare(ExecGetResultType(&uniquestate->ps),
							   node->numCols,
							   node->uniqColIdx);

	initGpmonPktForUnique((Plan *)node, &uniquestate->ps.gpmon_pkt, estate);
	
	return uniquestate;
}

/* ----------------------------------------------------------------
 *		ExecInitWorkTableScan
 * ----------------------------------------------------------------
 */
WorkTableScanState *
ExecInitWorkTableScan(WorkTableScan *node, EState *estate, int eflags)
{
	WorkTableScanState *scanstate;

	/* check for unsupported flags */
	/*
	 * GPDB_84_MERGE_FIXME: Make sure we don't require EXEC_FLAG_BACKWARD
	 * in GPDB.
	 */
	Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));

	/*
	 * WorkTableScan should not have any children.
	 */
	Assert(outerPlan(node) == NULL);
	Assert(innerPlan(node) == NULL);

	/*
	 * create new WorkTableScanState for node
	 */
	scanstate = makeNode(WorkTableScanState);
	scanstate->ss.ps.plan = (Plan *) node;
	scanstate->ss.ps.state = estate;
	scanstate->rustate = NULL;	/* we'll set this later */

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &scanstate->ss.ps);

	/*
	 * initialize child expressions
	 */
	scanstate->ss.ps.targetlist = (List *)
		ExecInitExpr((Expr *) node->scan.plan.targetlist,
					 (PlanState *) scanstate);
	scanstate->ss.ps.qual = (List *)
		ExecInitExpr((Expr *) node->scan.plan.qual,
					 (PlanState *) scanstate);

#define WORKTABLESCAN_NSLOTS 2

	/*
	 * tuple table initialization
	 */
	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
	ExecInitScanTupleSlot(estate, &scanstate->ss);

	/*
	 * Initialize result tuple type, but not yet projection info.
	 */
	ExecAssignResultTypeFromTL(&scanstate->ss.ps);

	/* scanstate->ss.ps.ps_TupFromTlist = false; */

	return scanstate;
}

/* ----------------------------------------------------------------
 *		ExecInitAppendOnlyScan
 * ----------------------------------------------------------------
 */
AppendOnlyScanState *
ExecInitAppendOnlyScan(AppendOnlyScan *node, EState *estate, int eflags)
{
	AppendOnlyScanState	*appendonlystate;
	Relation			currentRelation;
	
	Assert(outerPlan(node) == NULL);
	Assert(innerPlan(node) == NULL);

	/*
	 * create state structure
	 */
	appendonlystate = makeNode(AppendOnlyScanState);
	appendonlystate->ss.ps.plan = (Plan *) node;
	appendonlystate->ss.ps.state = estate;

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &appendonlystate->ss.ps);

	/*
	 * initialize child expressions
	 */
	appendonlystate->ss.ps.targetlist = (List *)
		ExecInitExpr((Expr *) node->scan.plan.targetlist,
					 (PlanState *) appendonlystate);
	appendonlystate->ss.ps.qual = (List *)
		ExecInitExpr((Expr *) node->scan.plan.qual,
					 (PlanState *) appendonlystate);

#define AOSCAN_NSLOTS 2

	/*
	 * tuple table initialization
	 */
	ExecInitResultTupleSlot(estate, &appendonlystate->ss.ps);
	ExecInitScanTupleSlot(estate, &appendonlystate->ss);

	/*
	 * get the relation object id from the relid'th entry in the range table
	 * and open that relation.
	 */
	currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid);	
	appendonlystate->ss.ss_currentRelation = currentRelation;
	ExecAssignScanType(&appendonlystate->ss, RelationGetDescr(currentRelation));
	
	/*
	 * Initialize result tuple type and projection info.
	 */
	ExecAssignResultTypeFromTL(&appendonlystate->ss.ps);
	ExecAssignScanProjectionInfo(&appendonlystate->ss);

	initGpmonPktForAppendOnlyScan((Plan *)node, &appendonlystate->ss.ps.gpmon_pkt, estate);

	return appendonlystate;
}

/* ----------------------------------------------------------------
 *		ExecInitResult
 *
 *		Creates the run-time state information for the result node
 *		produced by the planner and initailizes outer relations
 *		(child nodes).
 * ----------------------------------------------------------------
 */
ResultState *
ExecInitResult(Result *node, EState *estate)
{
	ResultState *resstate;

	/*
	 * create state structure
	 */
	resstate = makeNode(ResultState);
	resstate->ps.plan = (Plan *) node;
	resstate->ps.state = estate;

	resstate->rs_done = false;
	resstate->rs_checkqual = (node->resconstantqual == NULL) ? false : true;

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &resstate->ps);

#define RESULT_NSLOTS 1

	/*
	 * tuple table initialization
	 */
	ExecInitResultTupleSlot(estate, &resstate->ps);

	/*
	 * initialize child expressions
	 */
	resstate->ps.targetlist = (List *)
		ExecInitExpr((Expr *) node->plan.targetlist,
					 (PlanState *) resstate);
	resstate->ps.qual = (List *)
		ExecInitExpr((Expr *) node->plan.qual,
					 (PlanState *) resstate);
	resstate->resconstantqual = ExecInitExpr((Expr *) node->resconstantqual,
											 (PlanState *) resstate);

	/*
	 * initialize child nodes
	 */
	outerPlanState(resstate) = ExecInitNode(outerPlan(node), estate);

	/*
	 * we don't use inner plan
	 */
	Assert(innerPlan(node) == NULL);

	/*
	 * initialize tuple type and projection info
	 */
	ExecAssignResultTypeFromTL(&resstate->ps);
	ExecAssignProjectionInfo(&resstate->ps);

	return resstate;
}

/* -----------------
 * ExecInitGroup
 *
 *	Creates the run-time information for the group node produced by the
 *	planner and initializes its outer subtree
 * -----------------
 */
GroupState *
ExecInitGroup(Group *node, EState *estate, int eflags)
{
	GroupState *grpstate;

	/* check for unsupported flags */
	Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));

	/*
	 * create state structure
	 */
	grpstate = makeNode(GroupState);
	grpstate->ss.ps.plan = (Plan *) node;
	grpstate->ss.ps.state = estate;
	grpstate->ss.ps.ExecProcNode = ExecGroup;
	grpstate->grp_done = false;

	/*
	 * create expression context
	 */
	ExecAssignExprContext(estate, &grpstate->ss.ps);

	/*
	 * tuple table initialization
	 */
	ExecInitScanTupleSlot(estate, &grpstate->ss);
	ExecInitResultTupleSlot(estate, &grpstate->ss.ps);

	/*
	 * initialize child expressions
	 */
	grpstate->ss.ps.qual =
		ExecInitQual(node->plan.qual, (PlanState *) grpstate);

	/*
	 * initialize child nodes
	 */
	outerPlanState(grpstate) = ExecInitNode(outerPlan(node), estate, eflags);

	/*
	 * initialize tuple type.
	 */
	ExecAssignScanTypeFromOuterPlan(&grpstate->ss);

	/*
	 * Initialize result tuple type and projection info.
	 */
	ExecAssignResultTypeFromTL(&grpstate->ss.ps);
	ExecAssignProjectionInfo(&grpstate->ss.ps, NULL);

	/*
	 * Precompute fmgr lookup data for inner loop
	 */
	grpstate->eqfunctions =
		execTuplesMatchPrepare(node->numCols,
							   node->grpOperators);

	return grpstate;
}

/**
 * Init nodeDML, which initializes the insert TupleTableSlot.
 * */
DMLState*
ExecInitDML(DML *node, EState *estate, int eflags)
{
	
	/* check for unsupported flags */
	Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK | EXEC_FLAG_REWIND)));
	
	DMLState *dmlstate = makeNode(DMLState);
	dmlstate->ps.plan = (Plan *)node;
	dmlstate->ps.state = estate;

	ExecInitResultTupleSlot(estate, &dmlstate->ps);

	dmlstate->ps.targetlist = (List *)
						ExecInitExpr((Expr *) node->plan.targetlist,
						(PlanState *) dmlstate);

	Plan *outerPlan  = outerPlan(node);
	outerPlanState(dmlstate) = ExecInitNode(outerPlan, estate, eflags);

	ExecAssignResultTypeFromTL(&dmlstate->ps);

	/* Create expression evaluation context. This will be used for projections */
	ExecAssignExprContext(estate, &dmlstate->ps);

	/*
	 * Create projection info from the child tuple descriptor and our target list
	 * Projection will be placed in the ResultSlot
	 */
	TupleTableSlot *childResultSlot = outerPlanState(dmlstate)->ps_ResultTupleSlot;
	ExecAssignProjectionInfo(&dmlstate->ps, childResultSlot->tts_tupleDescriptor);
	
	/*
	 * Initialize slot to insert/delete using output relation descriptor.
	 */
	dmlstate->cleanedUpSlot = ExecInitExtraTupleSlot(estate);

	/*
	 * Both input and output of the junk filter include dropped attributes, so
	 * the junk filter doesn't need to do anything special there about them
	 */
	TupleDesc cleanTupType = CreateTupleDescCopy(dmlstate->ps.state->es_result_relation_info->ri_RelationDesc->rd_att); 
	dmlstate->junkfilter = ExecInitJunkFilter(node->plan.targetlist,
			cleanTupType,
			dmlstate->cleanedUpSlot);

	if (estate->es_instrument)
	{
	        dmlstate->ps.cdbexplainbuf = makeStringInfo();

	        /* Request a callback at end of query. */
	        dmlstate->ps.cdbexplainfun = ExecDMLExplainEnd;
	}

	initGpmonPktForDML((Plan *)node, &dmlstate->ps.gpmon_pkt, estate);
	
	return dmlstate;
}

/* ----------------------------------------------------------------
 *		ExecInitHash
 *
 *		Init routine for Hash node
 * ----------------------------------------------------------------
 */
HashState *
ExecInitHash(Hash *node, EState *estate, int eflags)
{
	HashState  *hashstate;

	/* check for unsupported flags */
	Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));

	/*
	 * create state structure
	 */
	hashstate = makeNode(HashState);
	hashstate->ps.plan = (Plan *) node;
	hashstate->ps.state = estate;
	hashstate->hashtable = NULL;
	hashstate->hashkeys = NIL;	/* will be set by parent HashJoin */

	/*CHANGED BY YASIN*/
	if (eflags & EXEC_FLAG_INAROUND) hashstate->ps.ps_InAround = true;

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &hashstate->ps);

#define HASH_NSLOTS 1

	/*
	 * initialize our result slot
	 */
	ExecInitResultTupleSlot(estate, &hashstate->ps);

	/*
	 * initialize child expressions
	 */
	hashstate->ps.targetlist = (List *)
		ExecInitExpr((Expr *) node->plan.targetlist,
					 (PlanState *) hashstate);
	hashstate->ps.qual = (List *)
		ExecInitExpr((Expr *) node->plan.qual,
					 (PlanState *) hashstate);

	/*
	 * initialize child nodes
	 */
	outerPlanState(hashstate) = ExecInitNode(outerPlan(node), estate, eflags);

	/*
	 * initialize tuple type. no need to initialize projection info because
	 * this node doesn't do projections
	 */
	ExecAssignResultTypeFromTL(&hashstate->ps);
	hashstate->ps.ps_ProjInfo = NULL;

	return hashstate;
}

/* ----------------------------------------------------------------
 *   	ExecInitHash
 *
 *   	Init routine for Hash node
 * ----------------------------------------------------------------
 */
bool
ExecInitHash(Hash *node, EState *estate, Plan *parent)
{
    HashState		*hashstate;
    Plan		*outerPlan;
    
    SO1_printf("ExecInitHash: %s\n",
	       "initializing hash node");
    
    /* ----------------
     *  assign the node's execution state
     * ----------------
     */
    node->plan.state = estate;
    
    /* ----------------
     * create state structure
     * ----------------
     */
    hashstate = makeNode(HashState);
    node->hashstate = hashstate;
    hashstate->hashBatches = NULL;
    
    /* ----------------
     *  Miscellanious initialization
     *
     *	     +	assign node's base_id
     *       +	assign debugging hooks and
     *       +	create expression context for node
     * ----------------
     */
    ExecAssignNodeBaseInfo(estate, &hashstate->cstate, parent);
    ExecAssignExprContext(estate, &hashstate->cstate);
    
#define HASH_NSLOTS 1
    /* ----------------
     * initialize our result slot
     * ----------------
     */
    ExecInitResultTupleSlot(estate, &hashstate->cstate);
    
    /* ----------------
     * initializes child nodes
     * ----------------
     */
    outerPlan = outerPlan(node);
    ExecInitNode(outerPlan, estate, (Plan *)node);
    
    /* ----------------
     * 	initialize tuple type. no need to initialize projection
     *  info because this node doesn't do projections
     * ----------------
     */
    ExecAssignResultTypeFromOuterPlan((Plan *) node, &hashstate->cstate);
    hashstate->cstate.cs_ProjInfo = NULL;
    
    return TRUE;
}

/* ----------------------------------------------------------------
 *		ExecInitLimit
 *
 *		This initializes the limit node state structures and
 *		the node's subplan.
 * ----------------------------------------------------------------
 */
LimitState *
ExecInitLimit(Limit *node, EState *estate, int eflags)
{
	LimitState *limitstate;
	Plan	   *outerPlan;

	/* check for unsupported flags */
	Assert(!(eflags & EXEC_FLAG_MARK));

	/*
	 * create state structure
	 */
	limitstate = makeNode(LimitState);
	limitstate->ps.plan = (Plan *) node;
	limitstate->ps.state = estate;

	limitstate->lstate = LIMIT_INITIAL;

	/*
	 * Miscellaneous initialization
	 *
	 * Limit nodes never call ExecQual or ExecProject, but they need an
	 * exprcontext anyway to evaluate the limit/offset parameters in.
	 */
	ExecAssignExprContext(estate, &limitstate->ps);

	/*
	 * initialize child expressions
	 */
	limitstate->limitOffset = ExecInitExpr((Expr *) node->limitOffset,
										   (PlanState *) limitstate);
	limitstate->limitCount = ExecInitExpr((Expr *) node->limitCount,
										  (PlanState *) limitstate);

#define LIMIT_NSLOTS 1

	/*
	 * Tuple table initialization (XXX not actually used...)
	 */
	ExecInitResultTupleSlot(estate, &limitstate->ps);

	/*
	 * then initialize outer plan
	 */
	outerPlan = outerPlan(node);
	outerPlanState(limitstate) = ExecInitNode(outerPlan, estate, eflags);

	/*
	 * limit nodes do no projections, so initialize projection info for this
	 * node appropriately
	 */
	ExecAssignResultTypeFromTL(&limitstate->ps);
	limitstate->ps.ps_ProjInfo = NULL;

	initGpmonPktForLimit((Plan *)node, &limitstate->ps.gpmon_pkt, estate);
	
	return limitstate;
}

/* ----------------------------------------------------------------
 *		ExecInitHash
 *
 *		Init routine for Hash node
 * ----------------------------------------------------------------
 */
HashState *
ExecInitHash(Hash *node, EState *estate)
{
	HashState  *hashstate;

	SO_printf("ExecInitHash: initializing hash node\n");

	/*
	 * create state structure
	 */
	hashstate = makeNode(HashState);
	hashstate->ps.plan = (Plan *) node;
	hashstate->ps.state = estate;
	hashstate->hashtable = NULL;
	hashstate->hashkeys = NIL;	/* will be set by parent HashJoin */

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &hashstate->ps);

#define HASH_NSLOTS 1

	/*
	 * initialize our result slot
	 */
	ExecInitResultTupleSlot(estate, &hashstate->ps);

	/*
	 * initialize child expressions
	 */
	hashstate->ps.targetlist = (List *)
		ExecInitExpr((Expr *) node->plan.targetlist,
					 (PlanState *) hashstate);
	hashstate->ps.qual = (List *)
		ExecInitExpr((Expr *) node->plan.qual,
					 (PlanState *) hashstate);

	/*
	 * initialize child nodes
	 */
	outerPlanState(hashstate) = ExecInitNode(outerPlan(node), estate);

	/*
	 * initialize tuple type. no need to initialize projection info
	 * because this node doesn't do projections
	 */
	ExecAssignResultTypeFromOuterPlan(&hashstate->ps);
	hashstate->ps.ps_ProjInfo = NULL;

	return hashstate;
}

/* ----------------------------------------------------------------
 *		ExecInitLimit
 *
 *		This initializes the limit node state structures and
 *		the node's subplan.
 * ----------------------------------------------------------------
 */
LimitState *
ExecInitLimit(Limit *node, EState *estate)
{
	LimitState *limitstate;
	Plan	   *outerPlan;

	/*
	 * create state structure
	 */
	limitstate = makeNode(LimitState);
	limitstate->ps.plan = (Plan *) node;
	limitstate->ps.state = estate;

	limitstate->lstate = LIMIT_INITIAL;

	/*
	 * Miscellaneous initialization
	 *
	 * Limit nodes never call ExecQual or ExecProject, but they need an
	 * exprcontext anyway to evaluate the limit/offset parameters in.
	 */
	ExecAssignExprContext(estate, &limitstate->ps);

	/*
	 * initialize child expressions
	 */
	limitstate->limitOffset = ExecInitExpr((Expr *) node->limitOffset,
										   (PlanState *) limitstate);
	limitstate->limitCount = ExecInitExpr((Expr *) node->limitCount,
										  (PlanState *) limitstate);

#define LIMIT_NSLOTS 1

	/*
	 * Tuple table initialization
	 */
	ExecInitResultTupleSlot(estate, &limitstate->ps);

	/*
	 * then initialize outer plan
	 */
	outerPlan = outerPlan(node);
	outerPlanState(limitstate) = ExecInitNode(outerPlan, estate);

	/*
	 * limit nodes do no projections, so initialize projection info for
	 * this node appropriately
	 */
	ExecAssignResultTypeFromOuterPlan(&limitstate->ps);
	limitstate->ps.ps_ProjInfo = NULL;

	return limitstate;
}

/* ----------------------------------------------------------------
 *		ExecInitSeqScan
 * ----------------------------------------------------------------
 */
SeqScanState *
ExecInitSeqScan(SeqScan *node, EState *estate, int eflags)
{
	SeqScanState *scanstate;

	/*
	 * Once upon a time it was possible to have an outerPlan of a SeqScan, but
	 * not any more.
	 */
	Assert(outerPlan(node) == NULL);
	Assert(innerPlan(node) == NULL);

	/*
	 * create state structure
	 */
	scanstate = makeNode(SeqScanState);
	scanstate->ss.ps.plan = (Plan *) node;
	scanstate->ss.ps.state = estate;
	scanstate->ss.ps.ExecProcNode = ExecSeqScan;

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &scanstate->ss.ps);

	/*
	 * initialize child expressions
	 */
	scanstate->ss.ps.qual =
		ExecInitQual(node->plan.qual, (PlanState *) scanstate);

	/*
	 * tuple table initialization
	 */
	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
	ExecInitScanTupleSlot(estate, &scanstate->ss);

	/*
	 * initialize scan relation
	 */
	InitScanRelation(scanstate, estate, eflags);

	/*
	 * Initialize result tuple type and projection info.
	 */
	ExecAssignResultTypeFromTL(&scanstate->ss.ps);
	ExecAssignScanProjectionInfo(&scanstate->ss);

	return scanstate;
}

/* ----------------------------------------------------------------
 *		ExecInitHash
 *
 *		Init routine for Hash node
 * ----------------------------------------------------------------
 */
HashState *
ExecInitHash(Hash *node, EState *estate, int eflags)
{
	HashState  *hashstate;

	/* check for unsupported flags */
	Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));

	/*
	 * create state structure
	 */
	hashstate = makeNode(HashState);
	hashstate->ps.plan = (Plan *) node;
	hashstate->ps.state = estate;
	hashstate->ps.ExecProcNode = ExecHash;
	hashstate->hashtable = NULL;
	hashstate->hashkeys = NIL;	/* will be set by parent HashJoin */

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &hashstate->ps);

	/*
	 * initialize our result slot
	 */
	ExecInitResultTupleSlot(estate, &hashstate->ps);

	/*
	 * initialize child expressions
	 */
	hashstate->ps.qual =
		ExecInitQual(node->plan.qual, (PlanState *) hashstate);

	/*
	 * initialize child nodes
	 */
	outerPlanState(hashstate) = ExecInitNode(outerPlan(node), estate, eflags);

	/*
	 * initialize tuple type. no need to initialize projection info because
	 * this node doesn't do projections
	 */
	ExecAssignResultTypeFromTL(&hashstate->ps);
	hashstate->ps.ps_ProjInfo = NULL;

	return hashstate;
}

/* ----------------------------------------------------------------
 *		ExecInitMaterial
 * ----------------------------------------------------------------
 */
MaterialState *
ExecInitMaterial(Material *node, EState *estate)
{
	MaterialState *matstate;
	Plan	   *outerPlan;

	/*
	 * create state structure
	 */
	matstate = makeNode(MaterialState);
	matstate->ss.ps.plan = (Plan *) node;
	matstate->ss.ps.state = estate;

	matstate->tuplestorestate = NULL;
	matstate->eof_underlying = false;

	/*
	 * Miscellaneous initialization
	 *
	 * Materialization nodes don't need ExprContexts because they never call
	 * ExecQual or ExecProject.
	 */

#define MATERIAL_NSLOTS 2

	/*
	 * tuple table initialization
	 *
	 * material nodes only return tuples from their materialized relation.
	 */
	ExecInitResultTupleSlot(estate, &matstate->ss.ps);
	ExecInitScanTupleSlot(estate, &matstate->ss);

	/*
	 * initializes child nodes
	 */
	outerPlan = outerPlan(node);
	outerPlanState(matstate) = ExecInitNode(outerPlan, estate);

	/*
	 * initialize tuple type.  no need to initialize projection info because
	 * this node doesn't do projections.
	 */
	ExecAssignResultTypeFromTL(&matstate->ss.ps);
	ExecAssignScanTypeFromOuterPlan(&matstate->ss);
	matstate->ss.ps.ps_ProjInfo = NULL;

	return matstate;
}

/*
 * InitScanStateInternal
 *   Initialize ScanState common variables for various Scan node.
 */
void
InitScanStateInternal(ScanState *scanState, Plan *plan, EState *estate,
		int eflags, bool initCurrentRelation)
{
	Assert(IsA(plan, SeqScan) ||
		   IsA(plan, AppendOnlyScan) ||
		   IsA(plan, ParquetScan) ||
		   IsA(plan, TableScan) ||
		   IsA(plan, DynamicTableScan) ||
		   IsA(plan, BitmapTableScan));

	PlanState *planState = &scanState->ps;

	planState->plan = plan;
	planState->state = estate;

	/* Create expression evaluation context */
	ExecAssignExprContext(estate, planState);
	
	/* Initialize tuple table slot */
	ExecInitResultTupleSlot(estate, planState);
	ExecInitScanTupleSlot(estate, scanState);
	
	/*
	 * For dynamic table scan, We do not initialize expression states; instead
	 * we wait until the first partition, and initialize the expression state
	 * at that time. Also, for dynamic table scan, we do not need to open the
	 * parent partition relation.
	 */
	if (initCurrentRelation)
	{
		InitScanStateRelationDetails(scanState, plan, estate);
	}

	/* Initialize result tuple type. */
	ExecAssignResultTypeFromTL(planState);

	/*
	 * If eflag contains EXEC_FLAG_REWIND or EXEC_FLAG_BACKWARD or EXEC_FLAG_MARK,
	 * then this node is not eager free safe.
	 */
	scanState->ps.delayEagerFree =
		((eflags & (EXEC_FLAG_REWIND | EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)) != 0);

	/* Currently, only SeqScan supports Mark/Restore. */
	AssertImply((eflags & EXEC_FLAG_MARK) != 0, IsA(plan, SeqScan));

}

RepeatState *
ExecInitRepeat(Repeat *node, EState *estate, int eflags)
{
	RepeatState *repeatstate;

	/* Check for unsupported flag */
	Assert(!(eflags & (EXEC_FLAG_MARK | EXEC_FLAG_BACKWARD)) ||
		   outerPlan(node) != NULL);

	/*
	 * Create state structure.
	 */
	repeatstate = makeNode(RepeatState);
	repeatstate->ps.plan = (Plan *)node;
	repeatstate->ps.state = estate;

	/* Create expression context for the node. */
	ExecAssignExprContext(estate, &repeatstate->ps);
	
	ExecInitResultTupleSlot(estate, &repeatstate->ps);
	
	/* Initialize child expressions */
	repeatstate->ps.targetlist = (List *)
		ExecInitExpr((Expr *)node->plan.targetlist,
					 (PlanState *)repeatstate);
	repeatstate->ps.qual = (List *)
		ExecInitExpr((Expr *)node->plan.qual,
					 (PlanState *)repeatstate);
	repeatstate->expr_state =
		ExecInitExpr(node->repeatCountExpr,
					 (PlanState *)repeatstate);

	/* Initialize child nodes */
	outerPlanState(repeatstate) = ExecInitNode(outerPlan(node), estate, eflags);

	/* Inner plan is not used. */
	Assert(innerPlan(node) == NULL);
	
	/* Initialize tuple type and projection info */
	ExecAssignResultTypeFromTL(&repeatstate->ps);
	ExecAssignProjectionInfo(&repeatstate->ps, NULL);

	init_RepeatState(repeatstate);
	
	initGpmonPktForRepeat((Plan *)node, &repeatstate->ps.gpmon_pkt, estate);
	
	return repeatstate;
}

/* ----------------------------------------------------------------
 *		ExecInitPartitionSelector
 *
 *		Create the run-time state information for PartitionSelector node
 *		produced by Orca and initializes outer child if exists.
 *
 * ----------------------------------------------------------------
 */
PartitionSelectorState *
ExecInitPartitionSelector(PartitionSelector *node, EState *estate, int eflags)
{
	/* check for unsupported flags */
	Assert (!(eflags & (EXEC_FLAG_MARK | EXEC_FLAG_BACKWARD)));

	PartitionSelectorState *psstate = initPartitionSelection(node, estate);

	/* tuple table initialization */
	ExecInitResultTupleSlot(estate, &psstate->ps);
	ExecAssignResultTypeFromTL(&psstate->ps);
	ExecAssignProjectionInfo(&psstate->ps, NULL);

	/* initialize child nodes */
	/* No inner plan for PartitionSelector */
	Assert(NULL == innerPlan(node));
	if (NULL != outerPlan(node))
	{
		outerPlanState(psstate) = ExecInitNode(outerPlan(node), estate, eflags);
	}

	/*
	 * Initialize projection, to produce a tuple that has the partitioning key
	 * columns at the same positions as in the partitioned table.
	 */
	if (node->partTabTargetlist)
	{
		List	   *exprStates;

		exprStates = (List *) ExecInitExpr((Expr *) node->partTabTargetlist,
										   (PlanState *) psstate);

		psstate->partTabDesc = ExecTypeFromTL(node->partTabTargetlist, false);
		psstate->partTabSlot = MakeSingleTupleTableSlot(psstate->partTabDesc);
		psstate->partTabProj = ExecBuildProjectionInfo(exprStates,
													   psstate->ps.ps_ExprContext,
													   psstate->partTabSlot,
													   ExecGetResultType(&psstate->ps));
	}

	initGpmonPktForPartitionSelector((Plan *)node, &psstate->ps.gpmon_pkt, estate);

	return psstate;
}

extern TuplestoreScanState *
ExecInitTuplestoreScan(TuplestoreScan *node, EState *estate, int eflags)
{
	TuplestoreScanState *tss = makeNode(TuplestoreScanState);
	tss->ss.ps.plan = (Plan *) node;
	tss->ss.ps.state = estate;
	tss->ss.ps.ps_ExprContext = CreateExprContext(estate);

	ExecInitResultTupleSlot(estate, &tss->ss.ps);
	ExecInitScanTupleSlot(estate, &tss->ss);

	ExecSetSlotDescriptor(tss->ss.ss_ScanTupleSlot, node->desc);
	ExecSetSlotDescriptor(tss->ss.ps.ps_ResultTupleSlot, node->desc);

	tss->ss.ps.targetlist = node->scan.plan.targetlist;

	tuplestore_rescan(node->store);

	return tss;
}

TwiceState *
ExecInitTwice(Twice *node, EState *estate, int eflags)
{
	TwiceState *twicestate;

	/*
	 * create state structure
	 */
	twicestate = makeNode(TwiceState);
	twicestate->ps.plan = (Plan *) node;
	twicestate->ps.state = estate;

	/*
	 * Tuple table initialization
	 */
	ExecInitResultTupleSlot(estate, &twicestate->ps);

	/*
	 * then initialize outer plan
	 */
	outerPlanState(twicestate) = ExecInitNode(outerPlan(node),
											  estate,
											  eflags);

	/*
	 * twice nodes do no projections, so initialize projection info for this
	 * node appropriately, i.e. keep all attributes as they are.
	 */
	ExecAssignResultTypeFromTL(&twicestate->ps);
	twicestate->ps.ps_ProjInfo = NULL;

	/*
	 * Set output counter for each tuple to zero, s.t. we know that it is the
	 * first output overall.
	 */
	twicestate->isFirst = true;

	return twicestate;
}