/*-------------------------------------------------------------------------
 *
 * execMain.c
 *	  top level executor interface routines
 *
 * INTERFACE ROUTINES
 *	ExecutorStart()
 *	ExecutorRun()
 *	ExecutorFinish()
 *	ExecutorEnd()
 *
 *	These four procedures are the external interface to the executor.
 *	In each case, the query descriptor is required as an argument.
 *
 *	ExecutorStart must be called at the beginning of execution of any
 *	query plan and ExecutorEnd must always be called at the end of
 *	execution of a plan (unless it is aborted due to error).
 *
 *	ExecutorRun accepts direction and count arguments that specify whether
 *	the plan is to be executed forwards, backwards, and for how many tuples.
 *	In some cases ExecutorRun may be called multiple times to process all
 *	the tuples for a plan.  It is also acceptable to stop short of executing
 *	the whole plan (but only if it is a SELECT).
 *
 *	ExecutorFinish must be called after the final ExecutorRun call and
 *	before ExecutorEnd.  This can be omitted only in case of EXPLAIN,
 *	which should also omit ExecutorRun.
 *
 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  src/backend/executor/execMain.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/heapam.h"
#include "access/htup_details.h"
#include "access/sysattr.h"
#include "access/tableam.h"
#include "access/transam.h"
#include "access/xact.h"
#include "catalog/namespace.h"
#include "catalog/pg_publication.h"
#include "commands/matview.h"
#include "commands/trigger.h"
#include "executor/execdebug.h"
#include "executor/nodeSubplan.h"
#include "foreign/fdwapi.h"
#include "jit/jit.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "parser/parsetree.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "tcop/utility.h"
#include "utils/acl.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/partcache.h"
#include "utils/rls.h"
#include "utils/ruleutils.h"
#include "utils/snapmgr.h"


/* Hooks for plugins to get control in ExecutorStart/Run/Finish/End */
ExecutorStart_hook_type ExecutorStart_hook = NULL;
ExecutorRun_hook_type ExecutorRun_hook = NULL;
ExecutorFinish_hook_type ExecutorFinish_hook = NULL;
ExecutorEnd_hook_type ExecutorEnd_hook = NULL;

/* Hook for plugin to get control in ExecCheckRTPerms() */
ExecutorCheckPerms_hook_type ExecutorCheckPerms_hook = NULL;

/* decls for local routines only used within this module */
static void InitPlan(QueryDesc *queryDesc, int eflags);
static void CheckValidRowMarkRel(Relation rel, RowMarkType markType);
static void ExecPostprocessPlan(EState *estate);
static void ExecEndPlan(PlanState *planstate, EState *estate);
static void ExecutePlan(EState *estate, PlanState *planstate,
						bool use_parallel_mode,
						CmdType operation,
						bool sendTuples,
						uint64 numberTuples,
						ScanDirection direction,
						DestReceiver *dest,
						bool execute_once);
static bool ExecCheckRTEPerms(RangeTblEntry *rte);
static bool ExecCheckRTEPermsModified(Oid relOid, Oid userid,
									  Bitmapset *modifiedCols,
									  AclMode requiredPerms);
static void ExecCheckXactReadOnly(PlannedStmt *plannedstmt);
static char *ExecBuildSlotValueDescription(Oid reloid,
										   TupleTableSlot *slot,
										   TupleDesc tupdesc,
										   Bitmapset *modifiedCols,
										   int maxfieldlen);
static void EvalPlanQualStart(EPQState *epqstate, Plan *planTree);

/*
 * Note that GetAllUpdatedColumns() also exists in commands/trigger.c.  There does
 * not appear to be any good header to put it into, given the structures that
 * it uses, so we let them be duplicated.  Be sure to update both if one needs
 * to be changed, however.
 */
#define GetInsertedColumns(relinfo, estate) \
	(exec_rt_fetch((relinfo)->ri_RangeTableIndex, estate)->insertedCols)
#define GetUpdatedColumns(relinfo, estate) \
	(exec_rt_fetch((relinfo)->ri_RangeTableIndex, estate)->updatedCols)
#define GetAllUpdatedColumns(relinfo, estate) \
	(bms_union(exec_rt_fetch((relinfo)->ri_RangeTableIndex, estate)->updatedCols, \
			   exec_rt_fetch((relinfo)->ri_RangeTableIndex, estate)->extraUpdatedCols))

/* end of local decls */


/* ----------------------------------------------------------------
 *		ExecutorStart
 *
 *		This routine must be called at the beginning of any execution of any
 *		query plan
 *
 * Takes a QueryDesc previously created by CreateQueryDesc (which is separate
 * only because some places use QueryDescs for utility commands).  The tupDesc
 * field of the QueryDesc is filled in to describe the tuples that will be
 * returned, and the internal fields (estate and planstate) are set up.
 *
 * eflags contains flag bits as described in executor.h.
 *
 * NB: the CurrentMemoryContext when this is called will become the parent
 * of the per-query context used for this Executor invocation.
 *
 * We provide a function hook variable that lets loadable plugins
 * get control when ExecutorStart is called.  Such a plugin would
 * normally call standard_ExecutorStart().
 *
 * ----------------------------------------------------------------
 */
void
ExecutorStart(QueryDesc *queryDesc, int eflags)
{
	if (ExecutorStart_hook)
		(*ExecutorStart_hook) (queryDesc, eflags);
	else
		standard_ExecutorStart(queryDesc, eflags);
}

void
standard_ExecutorStart(QueryDesc *queryDesc, int eflags)
{
	EState	   *estate;
	MemoryContext oldcontext;

	/* sanity checks: queryDesc must not be started already */
	Assert(queryDesc != NULL);
	Assert(queryDesc->estate == NULL);

	/*
	 * If the transaction is read-only, we need to check if any writes are
	 * planned to non-temporary tables.  EXPLAIN is considered read-only.
	 *
	 * Don't allow writes in parallel mode.  Supporting UPDATE and DELETE
	 * would require (a) storing the combocid hash in shared memory, rather
	 * than synchronizing it just once at the start of parallelism, and (b) an
	 * alternative to heap_update()'s reliance on xmax for mutual exclusion.
	 * INSERT may have no such troubles, but we forbid it to simplify the
	 * checks.
	 *
	 * We have lower-level defenses in CommandCounterIncrement and elsewhere
	 * against performing unsafe operations in parallel mode, but this gives a
	 * more user-friendly error message.
	 */
	if ((XactReadOnly || IsInParallelMode()) &&
		!(eflags & EXEC_FLAG_EXPLAIN_ONLY))
		ExecCheckXactReadOnly(queryDesc->plannedstmt);

	/*
	 * Build EState, switch into per-query memory context for startup.
	 */
	estate = CreateExecutorState();
	queryDesc->estate = estate;

	oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);

	/*
	 * Fill in external parameters, if any, from queryDesc; and allocate
	 * workspace for internal parameters
	 */
	estate->es_param_list_info = queryDesc->params;

	if (queryDesc->plannedstmt->paramExecTypes != NIL)
	{
		int			nParamExec;

		nParamExec = list_length(queryDesc->plannedstmt->paramExecTypes);
		estate->es_param_exec_vals = (ParamExecData *)
			palloc0(nParamExec * sizeof(ParamExecData));
	}

	estate->es_sourceText = queryDesc->sourceText;

	/*
	 * Fill in the query environment, if any, from queryDesc.
	 */
	estate->es_queryEnv = queryDesc->queryEnv;

	/*
	 * If non-read-only query, set the command ID to mark output tuples with
	 */
	switch (queryDesc->operation)
	{
		case CMD_SELECT:

			/*
			 * SELECT FOR [KEY] UPDATE/SHARE and modifying CTEs need to mark
			 * tuples
			 */
			if (queryDesc->plannedstmt->rowMarks != NIL ||
				queryDesc->plannedstmt->hasModifyingCTE)
				estate->es_output_cid = GetCurrentCommandId(true);

			/*
			 * A SELECT without modifying CTEs can't possibly queue triggers,
			 * so force skip-triggers mode. This is just a marginal efficiency
			 * hack, since AfterTriggerBeginQuery/AfterTriggerEndQuery aren't
			 * all that expensive, but we might as well do it.
			 */
			if (!queryDesc->plannedstmt->hasModifyingCTE)
				eflags |= EXEC_FLAG_SKIP_TRIGGERS;
			break;

		case CMD_INSERT:
		case CMD_DELETE:
		case CMD_UPDATE:
			estate->es_output_cid = GetCurrentCommandId(true);
			break;

		default:
			elog(ERROR, "unrecognized operation code: %d",
				 (int) queryDesc->operation);
			break;
	}

	/*
	 * Copy other important information into the EState
	 */
	estate->es_snapshot = RegisterSnapshot(queryDesc->snapshot);
	estate->es_crosscheck_snapshot = RegisterSnapshot(queryDesc->crosscheck_snapshot);
	estate->es_top_eflags = eflags;
	estate->es_instrument = queryDesc->instrument_options;
	estate->es_jit_flags = queryDesc->plannedstmt->jitFlags;

	/*
	 * Set up an AFTER-trigger statement context, unless told not to, or
	 * unless it's EXPLAIN-only mode (when ExecutorFinish won't be called).
	 */
	if (!(eflags & (EXEC_FLAG_SKIP_TRIGGERS | EXEC_FLAG_EXPLAIN_ONLY)))
		AfterTriggerBeginQuery();

	/*
	 * Initialize the plan state tree
	 */
	InitPlan(queryDesc, eflags);

	MemoryContextSwitchTo(oldcontext);
}

/* ----------------------------------------------------------------
 *		ExecutorRun
 *
 *		This is the main routine of the executor module. It accepts
 *		the query descriptor from the traffic cop and executes the
 *		query plan.
 *
 *		ExecutorStart must have been called already.
 *
 *		If direction is NoMovementScanDirection then nothing is done
 *		except to start up/shut down the destination.  Otherwise,
 *		we retrieve up to 'count' tuples in the specified direction.
 *
 *		Note: count = 0 is interpreted as no portal limit, i.e., run to
 *		completion.  Also note that the count limit is only applied to
 *		retrieved tuples, not for instance to those inserted/updated/deleted
 *		by a ModifyTable plan node.
 *
 *		There is no return value, but output tuples (if any) are sent to
 *		the destination receiver specified in the QueryDesc; and the number
 *		of tuples processed at the top level can be found in
 *		estate->es_processed.
 *
 *		We provide a function hook variable that lets loadable plugins
 *		get control when ExecutorRun is called.  Such a plugin would
 *		normally call standard_ExecutorRun().
 *
 * ----------------------------------------------------------------
 */
void
ExecutorRun(QueryDesc *queryDesc,
			ScanDirection direction, uint64 count,
			bool execute_once)
{
	if (ExecutorRun_hook)
		(*ExecutorRun_hook) (queryDesc, direction, count, execute_once);
	else
		standard_ExecutorRun(queryDesc, direction, count, execute_once);
}

void
standard_ExecutorRun(QueryDesc *queryDesc,
					 ScanDirection direction, uint64 count, bool execute_once)
{
	EState	   *estate;
	CmdType		operation;
	DestReceiver *dest;
	bool		sendTuples;
	MemoryContext oldcontext;

	/* sanity checks */
	Assert(queryDesc != NULL);

	estate = queryDesc->estate;

	Assert(estate != NULL);
	Assert(!(estate->es_top_eflags & EXEC_FLAG_EXPLAIN_ONLY));

	/*
	 * Switch into per-query memory context
	 */
	oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);

	/* Allow instrumentation of Executor overall runtime */
	if (queryDesc->totaltime)
		InstrStartNode(queryDesc->totaltime);

	/*
	 * extract information from the query descriptor and the query feature.
	 */
	operation = queryDesc->operation;
	dest = queryDesc->dest;

	/*
	 * startup tuple receiver, if we will be emitting tuples
	 */
	estate->es_processed = 0;

	sendTuples = (operation == CMD_SELECT ||
				  queryDesc->plannedstmt->hasReturning);

	if (sendTuples)
		dest->rStartup(dest, operation, queryDesc->tupDesc);

	/*
	 * run plan
	 */
	if (!ScanDirectionIsNoMovement(direction))
	{
		if (execute_once && queryDesc->already_executed)
			elog(ERROR, "can't re-execute query flagged for single execution");
		queryDesc->already_executed = true;

		ExecutePlan(estate,
					queryDesc->planstate,
					queryDesc->plannedstmt->parallelModeNeeded,
					operation,
					sendTuples,
					count,
					direction,
					dest,
					execute_once);
	}

	/*
	 * shutdown tuple receiver, if we started it
	 */
	if (sendTuples)
		dest->rShutdown(dest);

	if (queryDesc->totaltime)
		InstrStopNode(queryDesc->totaltime, estate->es_processed);

	MemoryContextSwitchTo(oldcontext);
}

/* ----------------------------------------------------------------
 *		ExecutorFinish
 *
 *		This routine must be called after the last ExecutorRun call.
 *		It performs cleanup such as firing AFTER triggers.  It is
 *		separate from ExecutorEnd because EXPLAIN ANALYZE needs to
 *		include these actions in the total runtime.
 *
 *		We provide a function hook variable that lets loadable plugins
 *		get control when ExecutorFinish is called.  Such a plugin would
 *		normally call standard_ExecutorFinish().
 *
 * ----------------------------------------------------------------
 */
void
ExecutorFinish(QueryDesc *queryDesc)
{
	if (ExecutorFinish_hook)
		(*ExecutorFinish_hook) (queryDesc);
	else
		standard_ExecutorFinish(queryDesc);
}

void
standard_ExecutorFinish(QueryDesc *queryDesc)
{
	EState	   *estate;
	MemoryContext oldcontext;

	/* sanity checks */
	Assert(queryDesc != NULL);

	estate = queryDesc->estate;

	Assert(estate != NULL);
	Assert(!(estate->es_top_eflags & EXEC_FLAG_EXPLAIN_ONLY));

	/* This should be run once and only once per Executor instance */
	Assert(!estate->es_finished);

	/* Switch into per-query memory context */
	oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);

	/* Allow instrumentation of Executor overall runtime */
	if (queryDesc->totaltime)
		InstrStartNode(queryDesc->totaltime);

	/* Run ModifyTable nodes to completion */
	ExecPostprocessPlan(estate);

	/* Execute queued AFTER triggers, unless told not to */
	if (!(estate->es_top_eflags & EXEC_FLAG_SKIP_TRIGGERS))
		AfterTriggerEndQuery(estate);

	if (queryDesc->totaltime)
		InstrStopNode(queryDesc->totaltime, 0);

	MemoryContextSwitchTo(oldcontext);

	estate->es_finished = true;
}

/* ----------------------------------------------------------------
 *		ExecutorEnd
 *
 *		This routine must be called at the end of execution of any
 *		query plan
 *
 *		We provide a function hook variable that lets loadable plugins
 *		get control when ExecutorEnd is called.  Such a plugin would
 *		normally call standard_ExecutorEnd().
 *
 * ----------------------------------------------------------------
 */
void
ExecutorEnd(QueryDesc *queryDesc)
{
	if (ExecutorEnd_hook)
		(*ExecutorEnd_hook) (queryDesc);
	else
		standard_ExecutorEnd(queryDesc);
}

void
standard_ExecutorEnd(QueryDesc *queryDesc)
{
	EState	   *estate;
	MemoryContext oldcontext;

	/* sanity checks */
	Assert(queryDesc != NULL);

	estate = queryDesc->estate;

	Assert(estate != NULL);

	/*
	 * Check that ExecutorFinish was called, unless in EXPLAIN-only mode. This
	 * Assert is needed because ExecutorFinish is new as of 9.1, and callers
	 * might forget to call it.
	 */
	Assert(estate->es_finished ||
		   (estate->es_top_eflags & EXEC_FLAG_EXPLAIN_ONLY));

	/*
	 * Switch into per-query memory context to run ExecEndPlan
	 */
	oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);

	ExecEndPlan(queryDesc->planstate, estate);

	/* do away with our snapshots */
	UnregisterSnapshot(estate->es_snapshot);
	UnregisterSnapshot(estate->es_crosscheck_snapshot);

	/*
	 * Must switch out of context before destroying it
	 */
	MemoryContextSwitchTo(oldcontext);

	/*
	 * Release EState and per-query memory context.  This should release
	 * everything the executor has allocated.
	 */
	FreeExecutorState(estate);

	/* Reset queryDesc fields that no longer point to anything */
	queryDesc->tupDesc = NULL;
	queryDesc->estate = NULL;
	queryDesc->planstate = NULL;
	queryDesc->totaltime = NULL;
}

/* ----------------------------------------------------------------
 *		ExecutorRewind
 *
 *		This routine may be called on an open queryDesc to rewind it
 *		to the start.
 * ----------------------------------------------------------------
 */
void
ExecutorRewind(QueryDesc *queryDesc)
{
	EState	   *estate;
	MemoryContext oldcontext;

	/* sanity checks */
	Assert(queryDesc != NULL);

	estate = queryDesc->estate;

	Assert(estate != NULL);

	/* It's probably not sensible to rescan updating queries */
	Assert(queryDesc->operation == CMD_SELECT);

	/*
	 * Switch into per-query memory context
	 */
	oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);

	/*
	 * rescan plan
	 */
	ExecReScan(queryDesc->planstate);

	MemoryContextSwitchTo(oldcontext);
}


/*
 * ExecCheckRTPerms
 *		Check access permissions for all relations listed in a range table.
 *
 * Returns true if permissions are adequate.  Otherwise, throws an appropriate
 * error if ereport_on_violation is true, or simply returns false otherwise.
 *
 * Note that this does NOT address row level security policies (aka: RLS).  If
 * rows will be returned to the user as a result of this permission check
 * passing, then RLS also needs to be consulted (and check_enable_rls()).
 *
 * See rewrite/rowsecurity.c.
 */
bool
ExecCheckRTPerms(List *rangeTable, bool ereport_on_violation)
{
	ListCell   *l;
	bool		result = true;

	foreach(l, rangeTable)
	{
		RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);

		result = ExecCheckRTEPerms(rte);
		if (!result)
		{
			Assert(rte->rtekind == RTE_RELATION);
			if (ereport_on_violation)
				aclcheck_error(ACLCHECK_NO_PRIV, get_relkind_objtype(get_rel_relkind(rte->relid)),
							   get_rel_name(rte->relid));
			return false;
		}
	}

	if (ExecutorCheckPerms_hook)
		result = (*ExecutorCheckPerms_hook) (rangeTable,
											 ereport_on_violation);
	return result;
}

/*
 * ExecCheckRTEPerms
 *		Check access permissions for a single RTE.
 */
static bool
ExecCheckRTEPerms(RangeTblEntry *rte)
{
	AclMode		requiredPerms;
	AclMode		relPerms;
	AclMode		remainingPerms;
	Oid			relOid;
	Oid			userid;

	/*
	 * Only plain-relation RTEs need to be checked here.  Function RTEs are
	 * checked when the function is prepared for execution.  Join, subquery,
	 * and special RTEs need no checks.
	 */
	if (rte->rtekind != RTE_RELATION)
		return true;

	/*
	 * No work if requiredPerms is empty.
	 */
	requiredPerms = rte->requiredPerms;
	if (requiredPerms == 0)
		return true;

	relOid = rte->relid;

	/*
	 * userid to check as: current user unless we have a setuid indication.
	 *
	 * Note: GetUserId() is presently fast enough that there's no harm in
	 * calling it separately for each RTE.  If that stops being true, we could
	 * call it once in ExecCheckRTPerms and pass the userid down from there.
	 * But for now, no need for the extra clutter.
	 */
	userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();

	/*
	 * We must have *all* the requiredPerms bits, but some of the bits can be
	 * satisfied from column-level rather than relation-level permissions.
	 * First, remove any bits that are satisfied by relation permissions.
	 */
	relPerms = pg_class_aclmask(relOid, userid, requiredPerms, ACLMASK_ALL);
	remainingPerms = requiredPerms & ~relPerms;
	if (remainingPerms != 0)
	{
		int			col = -1;

		/*
		 * If we lack any permissions that exist only as relation permissions,
		 * we can fail straight away.
		 */
		if (remainingPerms & ~(ACL_SELECT | ACL_INSERT | ACL_UPDATE))
			return false;

		/*
		 * Check to see if we have the needed privileges at column level.
		 *
		 * Note: failures just report a table-level error; it would be nicer
		 * to report a column-level error if we have some but not all of the
		 * column privileges.
		 */
		if (remainingPerms & ACL_SELECT)
		{
			/*
			 * When the query doesn't explicitly reference any columns (for
			 * example, SELECT COUNT(*) FROM table), allow the query if we
			 * have SELECT on any column of the rel, as per SQL spec.
			 */
			if (bms_is_empty(rte->selectedCols))
			{
				if (pg_attribute_aclcheck_all(relOid, userid, ACL_SELECT,
											  ACLMASK_ANY) != ACLCHECK_OK)
					return false;
			}

			while ((col = bms_next_member(rte->selectedCols, col)) >= 0)
			{
				/* bit #s are offset by FirstLowInvalidHeapAttributeNumber */
				AttrNumber	attno = col + FirstLowInvalidHeapAttributeNumber;

				if (attno == InvalidAttrNumber)
				{
					/* Whole-row reference, must have priv on all cols */
					if (pg_attribute_aclcheck_all(relOid, userid, ACL_SELECT,
												  ACLMASK_ALL) != ACLCHECK_OK)
						return false;
				}
				else
				{
					if (pg_attribute_aclcheck(relOid, attno, userid,
											  ACL_SELECT) != ACLCHECK_OK)
						return false;
				}
			}
		}

		/*
		 * Basically the same for the mod columns, for both INSERT and UPDATE
		 * privilege as specified by remainingPerms.
		 */
		if (remainingPerms & ACL_INSERT && !ExecCheckRTEPermsModified(relOid,
																	  userid,
																	  rte->insertedCols,
																	  ACL_INSERT))
			return false;

		if (remainingPerms & ACL_UPDATE && !ExecCheckRTEPermsModified(relOid,
																	  userid,
																	  rte->updatedCols,
																	  ACL_UPDATE))
			return false;
	}
	return true;
}

/*
 * ExecCheckRTEPermsModified
 *		Check INSERT or UPDATE access permissions for a single RTE (these
 *		are processed uniformly).
 */
static bool
ExecCheckRTEPermsModified(Oid relOid, Oid userid, Bitmapset *modifiedCols,
						  AclMode requiredPerms)
{
	int			col = -1;

	/*
	 * When the query doesn't explicitly update any columns, allow the query
	 * if we have permission on any column of the rel.  This is to handle
	 * SELECT FOR UPDATE as well as possible corner cases in UPDATE.
	 */
	if (bms_is_empty(modifiedCols))
	{
		if (pg_attribute_aclcheck_all(relOid, userid, requiredPerms,
									  ACLMASK_ANY) != ACLCHECK_OK)
			return false;
	}

	while ((col = bms_next_member(modifiedCols, col)) >= 0)
	{
		/* bit #s are offset by FirstLowInvalidHeapAttributeNumber */
		AttrNumber	attno = col + FirstLowInvalidHeapAttributeNumber;

		if (attno == InvalidAttrNumber)
		{
			/* whole-row reference can't happen here */
			elog(ERROR, "whole-row update is not implemented");
		}
		else
		{
			if (pg_attribute_aclcheck(relOid, attno, userid,
									  requiredPerms) != ACLCHECK_OK)
				return false;
		}
	}
	return true;
}

/*
 * Check that the query does not imply any writes to non-temp tables;
 * unless we're in parallel mode, in which case don't even allow writes
 * to temp tables.
 *
 * Note: in a Hot Standby this would need to reject writes to temp
 * tables just as we do in parallel mode; but an HS standby can't have created
 * any temp tables in the first place, so no need to check that.
 */
static void
ExecCheckXactReadOnly(PlannedStmt *plannedstmt)
{
	ListCell   *l;

	/*
	 * Fail if write permissions are requested in parallel mode for table
	 * (temp or non-temp), otherwise fail for any non-temp table.
	 */
	foreach(l, plannedstmt->rtable)
	{
		RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);

		if (rte->rtekind != RTE_RELATION)
			continue;

		if ((rte->requiredPerms & (~ACL_SELECT)) == 0)
			continue;

		if (isTempNamespace(get_rel_namespace(rte->relid)))
			continue;

		PreventCommandIfReadOnly(CreateCommandName((Node *) plannedstmt));
	}

	if (plannedstmt->commandType != CMD_SELECT || plannedstmt->hasModifyingCTE)
		PreventCommandIfParallelMode(CreateCommandName((Node *) plannedstmt));
}


/* ----------------------------------------------------------------
 *		InitPlan
 *
 *		Initializes the query plan: open files, allocate storage
 *		and start up the rule manager
 * ----------------------------------------------------------------
 */
static void
InitPlan(QueryDesc *queryDesc, int eflags)
{
	CmdType		operation = queryDesc->operation;
	PlannedStmt *plannedstmt = queryDesc->plannedstmt;
	Plan	   *plan = plannedstmt->planTree;
	List	   *rangeTable = plannedstmt->rtable;
	EState	   *estate = queryDesc->estate;
	PlanState  *planstate;
	TupleDesc	tupType;
	ListCell   *l;
	int			i;

	/*
	 * Do permissions checks
	 */
	ExecCheckRTPerms(rangeTable, true);

	/*
	 * initialize the node's execution state
	 */
	ExecInitRangeTable(estate, rangeTable);

	estate->es_plannedstmt = plannedstmt;

	/*
	 * Next, build the ExecRowMark array from the PlanRowMark(s), if any.
	 */
	if (plannedstmt->rowMarks)
	{
		estate->es_rowmarks = (ExecRowMark **)
			palloc0(estate->es_range_table_size * sizeof(ExecRowMark *));
		foreach(l, plannedstmt->rowMarks)
		{
			PlanRowMark *rc = (PlanRowMark *) lfirst(l);
			Oid			relid;
			Relation	relation;
			ExecRowMark *erm;

			/* ignore "parent" rowmarks; they are irrelevant at runtime */
			if (rc->isParent)
				continue;

			/* get relation's OID (will produce InvalidOid if subquery) */
			relid = exec_rt_fetch(rc->rti, estate)->relid;

			/* open relation, if we need to access it for this mark type */
			switch (rc->markType)
			{
				case ROW_MARK_EXCLUSIVE:
				case ROW_MARK_NOKEYEXCLUSIVE:
				case ROW_MARK_SHARE:
				case ROW_MARK_KEYSHARE:
				case ROW_MARK_REFERENCE:
					relation = ExecGetRangeTableRelation(estate, rc->rti);
					break;
				case ROW_MARK_COPY:
					/* no physical table access is required */
					relation = NULL;
					break;
				default:
					elog(ERROR, "unrecognized markType: %d", rc->markType);
					relation = NULL;	/* keep compiler quiet */
					break;
			}

			/* Check that relation is a legal target for marking */
			if (relation)
				CheckValidRowMarkRel(relation, rc->markType);

			erm = (ExecRowMark *) palloc(sizeof(ExecRowMark));
			erm->relation = relation;
			erm->relid = relid;
			erm->rti = rc->rti;
			erm->prti = rc->prti;
			erm->rowmarkId = rc->rowmarkId;
			erm->markType = rc->markType;
			erm->strength = rc->strength;
			erm->waitPolicy = rc->waitPolicy;
			erm->ermActive = false;
			ItemPointerSetInvalid(&(erm->curCtid));
			erm->ermExtra = NULL;

			Assert(erm->rti > 0 && erm->rti <= estate->es_range_table_size &&
				   estate->es_rowmarks[erm->rti - 1] == NULL);

			estate->es_rowmarks[erm->rti - 1] = erm;
		}
	}

	/*
	 * Initialize the executor's tuple table to empty.
	 */
	estate->es_tupleTable = NIL;

	/* signal that this EState is not used for EPQ */
	estate->es_epq_active = NULL;

	/*
	 * Initialize private state information for each SubPlan.  We must do this
	 * before running ExecInitNode on the main query tree, since
	 * ExecInitSubPlan expects to be able to find these entries.
	 */
	Assert(estate->es_subplanstates == NIL);
	i = 1;						/* subplan indices count from 1 */
	foreach(l, plannedstmt->subplans)
	{
		Plan	   *subplan = (Plan *) lfirst(l);
		PlanState  *subplanstate;
		int			sp_eflags;

		/*
		 * A subplan will never need to do BACKWARD scan nor MARK/RESTORE. If
		 * it is a parameterless subplan (not initplan), we suggest that it be
		 * prepared to handle REWIND efficiently; otherwise there is no need.
		 */
		sp_eflags = eflags
			& (EXEC_FLAG_EXPLAIN_ONLY | EXEC_FLAG_WITH_NO_DATA);
		if (bms_is_member(i, plannedstmt->rewindPlanIDs))
			sp_eflags |= EXEC_FLAG_REWIND;

		subplanstate = ExecInitNode(subplan, estate, sp_eflags);

		estate->es_subplanstates = lappend(estate->es_subplanstates,
										   subplanstate);

		i++;
	}

	/*
	 * Initialize the private state information for all the nodes in the query
	 * tree.  This opens files, allocates storage and leaves us ready to start
	 * processing tuples.
	 */
	planstate = ExecInitNode(plan, estate, eflags);

	/*
	 * Get the tuple descriptor describing the type of tuples to return.
	 */
	tupType = ExecGetResultType(planstate);

	/*
	 * Initialize the junk filter if needed.  SELECT queries need a filter if
	 * there are any junk attrs in the top-level tlist.
	 */
	if (operation == CMD_SELECT)
	{
		bool		junk_filter_needed = false;
		ListCell   *tlist;

		foreach(tlist, plan->targetlist)
		{
			TargetEntry *tle = (TargetEntry *) lfirst(tlist);

			if (tle->resjunk)
			{
				junk_filter_needed = true;
				break;
			}
		}

		if (junk_filter_needed)
		{
			JunkFilter *j;
			TupleTableSlot *slot;

			slot = ExecInitExtraTupleSlot(estate, NULL, &TTSOpsVirtual);
			j = ExecInitJunkFilter(planstate->plan->targetlist,
								   slot);
			estate->es_junkFilter = j;

			/* Want to return the cleaned tuple type */
			tupType = j->jf_cleanTupType;
		}
	}

	queryDesc->tupDesc = tupType;
	queryDesc->planstate = planstate;
}

/*
 * Check that a proposed result relation is a legal target for the operation
 *
 * Generally the parser and/or planner should have noticed any such mistake
 * already, but let's make sure.
 *
 * Note: when changing this function, you probably also need to look at
 * CheckValidRowMarkRel.
 */
void
CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation)
{
	Relation	resultRel = resultRelInfo->ri_RelationDesc;
	TriggerDesc *trigDesc = resultRel->trigdesc;
	FdwRoutine *fdwroutine;

	switch (resultRel->rd_rel->relkind)
	{
		case RELKIND_RELATION:
		case RELKIND_PARTITIONED_TABLE:
			CheckCmdReplicaIdentity(resultRel, operation);
			break;
		case RELKIND_SEQUENCE:
			ereport(ERROR,
					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
					 errmsg("cannot change sequence \"%s\"",
							RelationGetRelationName(resultRel))));
			break;
		case RELKIND_TOASTVALUE:
			ereport(ERROR,
					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
					 errmsg("cannot change TOAST relation \"%s\"",
							RelationGetRelationName(resultRel))));
			break;
		case RELKIND_VIEW:

			/*
			 * Okay only if there's a suitable INSTEAD OF trigger.  Messages
			 * here should match rewriteHandler.c's rewriteTargetView and
			 * RewriteQuery, except that we omit errdetail because we haven't
			 * got the information handy (and given that we really shouldn't
			 * get here anyway, it's not worth great exertion to get).
			 */
			switch (operation)
			{
				case CMD_INSERT:
					if (!trigDesc || !trigDesc->trig_insert_instead_row)
						ereport(ERROR,
								(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
								 errmsg("cannot insert into view \"%s\"",
										RelationGetRelationName(resultRel)),
								 errhint("To enable inserting into the view, provide an INSTEAD OF INSERT trigger or an unconditional ON INSERT DO INSTEAD rule.")));
					break;
				case CMD_UPDATE:
					if (!trigDesc || !trigDesc->trig_update_instead_row)
						ereport(ERROR,
								(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
								 errmsg("cannot update view \"%s\"",
										RelationGetRelationName(resultRel)),
								 errhint("To enable updating the view, provide an INSTEAD OF UPDATE trigger or an unconditional ON UPDATE DO INSTEAD rule.")));
					break;
				case CMD_DELETE:
					if (!trigDesc || !trigDesc->trig_delete_instead_row)
						ereport(ERROR,
								(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
								 errmsg("cannot delete from view \"%s\"",
										RelationGetRelationName(resultRel)),
								 errhint("To enable deleting from the view, provide an INSTEAD OF DELETE trigger or an unconditional ON DELETE DO INSTEAD rule.")));
					break;
				default:
					elog(ERROR, "unrecognized CmdType: %d", (int) operation);
					break;
			}
			break;
		case RELKIND_MATVIEW:
			if (!MatViewIncrementalMaintenanceIsEnabled())
				ereport(ERROR,
						(errcode(ERRCODE_WRONG_OBJECT_TYPE),
						 errmsg("cannot change materialized view \"%s\"",
								RelationGetRelationName(resultRel))));
			break;
		case RELKIND_FOREIGN_TABLE:
			/* Okay only if the FDW supports it */
			fdwroutine = resultRelInfo->ri_FdwRoutine;
			switch (operation)
			{
				case CMD_INSERT:
					if (fdwroutine->ExecForeignInsert == NULL)
						ereport(ERROR,
								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
								 errmsg("cannot insert into foreign table \"%s\"",
										RelationGetRelationName(resultRel))));
					if (fdwroutine->IsForeignRelUpdatable != NULL &&
						(fdwroutine->IsForeignRelUpdatable(resultRel) & (1 << CMD_INSERT)) == 0)
						ereport(ERROR,
								(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
								 errmsg("foreign table \"%s\" does not allow inserts",
										RelationGetRelationName(resultRel))));
					break;
				case CMD_UPDATE:
					if (fdwroutine->ExecForeignUpdate == NULL)
						ereport(ERROR,
								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
								 errmsg("cannot update foreign table \"%s\"",
										RelationGetRelationName(resultRel))));
					if (fdwroutine->IsForeignRelUpdatable != NULL &&
						(fdwroutine->IsForeignRelUpdatable(resultRel) & (1 << CMD_UPDATE)) == 0)
						ereport(ERROR,
								(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
								 errmsg("foreign table \"%s\" does not allow updates",
										RelationGetRelationName(resultRel))));
					break;
				case CMD_DELETE:
					if (fdwroutine->ExecForeignDelete == NULL)
						ereport(ERROR,
								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
								 errmsg("cannot delete from foreign table \"%s\"",
										RelationGetRelationName(resultRel))));
					if (fdwroutine->IsForeignRelUpdatable != NULL &&
						(fdwroutine->IsForeignRelUpdatable(resultRel) & (1 << CMD_DELETE)) == 0)
						ereport(ERROR,
								(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
								 errmsg("foreign table \"%s\" does not allow deletes",
										RelationGetRelationName(resultRel))));
					break;
				default:
					elog(ERROR, "unrecognized CmdType: %d", (int) operation);
					break;
			}
			break;
		default:
			ereport(ERROR,
					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
					 errmsg("cannot change relation \"%s\"",
							RelationGetRelationName(resultRel))));
			break;
	}
}

/*
 * Check that a proposed rowmark target relation is a legal target
 *
 * In most cases parser and/or planner should have noticed this already, but
 * they don't cover all cases.
 */
static void
CheckValidRowMarkRel(Relation rel, RowMarkType markType)
{
	FdwRoutine *fdwroutine;

	switch (rel->rd_rel->relkind)
	{
		case RELKIND_RELATION:
		case RELKIND_PARTITIONED_TABLE:
			/* OK */
			break;
		case RELKIND_SEQUENCE:
			/* Must disallow this because we don't vacuum sequences */
			ereport(ERROR,
					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
					 errmsg("cannot lock rows in sequence \"%s\"",
							RelationGetRelationName(rel))));
			break;
		case RELKIND_TOASTVALUE:
			/* We could allow this, but there seems no good reason to */
			ereport(ERROR,
					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
					 errmsg("cannot lock rows in TOAST relation \"%s\"",
							RelationGetRelationName(rel))));
			break;
		case RELKIND_VIEW:
			/* Should not get here; planner should have expanded the view */
			ereport(ERROR,
					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
					 errmsg("cannot lock rows in view \"%s\"",
							RelationGetRelationName(rel))));
			break;
		case RELKIND_MATVIEW:
			/* Allow referencing a matview, but not actual locking clauses */
			if (markType != ROW_MARK_REFERENCE)
				ereport(ERROR,
						(errcode(ERRCODE_WRONG_OBJECT_TYPE),
						 errmsg("cannot lock rows in materialized view \"%s\"",
								RelationGetRelationName(rel))));
			break;
		case RELKIND_FOREIGN_TABLE:
			/* Okay only if the FDW supports it */
			fdwroutine = GetFdwRoutineForRelation(rel, false);
			if (fdwroutine->RefetchForeignRow == NULL)
				ereport(ERROR,
						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
						 errmsg("cannot lock rows in foreign table \"%s\"",
								RelationGetRelationName(rel))));
			break;
		default:
			ereport(ERROR,
					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
					 errmsg("cannot lock rows in relation \"%s\"",
							RelationGetRelationName(rel))));
			break;
	}
}

/*
 * Initialize ResultRelInfo data for one result relation
 *
 * Caution: before Postgres 9.1, this function included the relkind checking
 * that's now in CheckValidResultRel, and it also did ExecOpenIndices if
 * appropriate.  Be sure callers cover those needs.
 */
void
InitResultRelInfo(ResultRelInfo *resultRelInfo,
				  Relation resultRelationDesc,
				  Index resultRelationIndex,
				  Relation partition_root,
				  int instrument_options)
{
	MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
	resultRelInfo->type = T_ResultRelInfo;
	resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
	resultRelInfo->ri_RelationDesc = resultRelationDesc;
	resultRelInfo->ri_NumIndices = 0;
	resultRelInfo->ri_IndexRelationDescs = NULL;
	resultRelInfo->ri_IndexRelationInfo = NULL;
	/* make a copy so as not to depend on relcache info not changing... */
	resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
	if (resultRelInfo->ri_TrigDesc)
	{
		int			n = resultRelInfo->ri_TrigDesc->numtriggers;

		resultRelInfo->ri_TrigFunctions = (FmgrInfo *)
			palloc0(n * sizeof(FmgrInfo));
		resultRelInfo->ri_TrigWhenExprs = (ExprState **)
			palloc0(n * sizeof(ExprState *));
		if (instrument_options)
			resultRelInfo->ri_TrigInstrument = InstrAlloc(n, instrument_options);
	}
	else
	{
		resultRelInfo->ri_TrigFunctions = NULL;
		resultRelInfo->ri_TrigWhenExprs = NULL;
		resultRelInfo->ri_TrigInstrument = NULL;
	}
	if (resultRelationDesc->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
		resultRelInfo->ri_FdwRoutine = GetFdwRoutineForRelation(resultRelationDesc, true);
	else
		resultRelInfo->ri_FdwRoutine = NULL;

	/* The following fields are set later if needed */
	resultRelInfo->ri_FdwState = NULL;
	resultRelInfo->ri_usesFdwDirectModify = false;
	resultRelInfo->ri_ConstraintExprs = NULL;
	resultRelInfo->ri_GeneratedExprs = NULL;
	resultRelInfo->ri_junkFilter = NULL;
	resultRelInfo->ri_projectReturning = NULL;
	resultRelInfo->ri_onConflictArbiterIndexes = NIL;
	resultRelInfo->ri_onConflict = NULL;
	resultRelInfo->ri_ReturningSlot = NULL;
	resultRelInfo->ri_TrigOldSlot = NULL;
	resultRelInfo->ri_TrigNewSlot = NULL;
	resultRelInfo->ri_PartitionRoot = partition_root;
	resultRelInfo->ri_RootToPartitionMap = NULL;	/* set by
													 * ExecInitRoutingInfo */
	resultRelInfo->ri_PartitionTupleSlot = NULL;	/* ditto */
	resultRelInfo->ri_ChildToRootMap = NULL;
	resultRelInfo->ri_CopyMultiInsertBuffer = NULL;
}

/*
 * ExecGetTriggerResultRel
 *		Get a ResultRelInfo for a trigger target relation.
 *
 * Most of the time, triggers are fired on one of the result relations of the
 * query, and so we can just return a member of the es_result_relations array,
 * or the es_tuple_routing_result_relations list (if any). (Note: in self-join
 * situations there might be multiple members with the same OID; if so it
 * doesn't matter which one we pick.)
 *
 * However, it is sometimes necessary to fire triggers on other relations;
 * this happens mainly when an RI update trigger queues additional triggers
 * on other relations, which will be processed in the context of the outer
 * query.  For efficiency's sake, we want to have a ResultRelInfo for those
 * triggers too; that can avoid repeated re-opening of the relation.  (It
 * also provides a way for EXPLAIN ANALYZE to report the runtimes of such
 * triggers.)  So we make additional ResultRelInfo's as needed, and save them
 * in es_trig_target_relations.
 */
ResultRelInfo *
ExecGetTriggerResultRel(EState *estate, Oid relid)
{
	ResultRelInfo *rInfo;
	ListCell   *l;
	Relation	rel;
	MemoryContext oldcontext;

	/* First, search through the query result relations */
	foreach(l, estate->es_opened_result_relations)
	{
		rInfo = lfirst(l);
		if (RelationGetRelid(rInfo->ri_RelationDesc) == relid)
			return rInfo;
	}

	/*
	 * Third, search through the result relations that were created during
	 * tuple routing, if any.
	 */
	foreach(l, estate->es_tuple_routing_result_relations)
	{
		rInfo = (ResultRelInfo *) lfirst(l);
		if (RelationGetRelid(rInfo->ri_RelationDesc) == relid)
			return rInfo;
	}

	/* Nope, but maybe we already made an extra ResultRelInfo for it */
	foreach(l, estate->es_trig_target_relations)
	{
		rInfo = (ResultRelInfo *) lfirst(l);
		if (RelationGetRelid(rInfo->ri_RelationDesc) == relid)
			return rInfo;
	}
	/* Nope, so we need a new one */

	/*
	 * Open the target relation's relcache entry.  We assume that an
	 * appropriate lock is still held by the backend from whenever the trigger
	 * event got queued, so we need take no new lock here.  Also, we need not
	 * recheck the relkind, so no need for CheckValidResultRel.
	 */
	rel = table_open(relid, NoLock);

	/*
	 * Make the new entry in the right context.
	 */
	oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
	rInfo = makeNode(ResultRelInfo);
	InitResultRelInfo(rInfo,
					  rel,
					  0,		/* dummy rangetable index */
					  NULL,
					  estate->es_instrument);
	estate->es_trig_target_relations =
		lappend(estate->es_trig_target_relations, rInfo);
	MemoryContextSwitchTo(oldcontext);

	/*
	 * Currently, we don't need any index information in ResultRelInfos used
	 * only for triggers, so no need to call ExecOpenIndices.
	 */

	return rInfo;
}

/* ----------------------------------------------------------------
 *		ExecPostprocessPlan
 *
 *		Give plan nodes a final chance to execute before shutdown
 * ----------------------------------------------------------------
 */
static void
ExecPostprocessPlan(EState *estate)
{
	ListCell   *lc;

	/*
	 * Make sure nodes run forward.
	 */
	estate->es_direction = ForwardScanDirection;

	/*
	 * Run any secondary ModifyTable nodes to completion, in case the main
	 * query did not fetch all rows from them.  (We do this to ensure that
	 * such nodes have predictable results.)
	 */
	foreach(lc, estate->es_auxmodifytables)
	{
		PlanState  *ps = (PlanState *) lfirst(lc);

		for (;;)
		{
			TupleTableSlot *slot;

			/* Reset the per-output-tuple exprcontext each time */
			ResetPerTupleExprContext(estate);

			slot = ExecProcNode(ps);

			if (TupIsNull(slot))
				break;
		}
	}
}

/* ----------------------------------------------------------------
 *		ExecEndPlan
 *
 *		Cleans up the query plan -- closes files and frees up storage
 *
 * NOTE: we are no longer very worried about freeing storage per se
 * in this code; FreeExecutorState should be guaranteed to release all
 * memory that needs to be released.  What we are worried about doing
 * is closing relations and dropping buffer pins.  Thus, for example,
 * tuple tables must be cleared or dropped to ensure pins are released.
 * ----------------------------------------------------------------
 */
static void
ExecEndPlan(PlanState *planstate, EState *estate)
{
	ListCell   *l;

	/*
	 * shut down the node-type-specific query processing
	 */
	ExecEndNode(planstate);

	/*
	 * for subplans too
	 */
	foreach(l, estate->es_subplanstates)
	{
		PlanState  *subplanstate = (PlanState *) lfirst(l);

		ExecEndNode(subplanstate);
	}

	/*
	 * destroy the executor's tuple table.  Actually we only care about
	 * releasing buffer pins and tupdesc refcounts; there's no need to pfree
	 * the TupleTableSlots, since the containing memory context is about to go
	 * away anyway.
	 */
	ExecResetTupleTable(estate->es_tupleTable, false);

	/*
	 * Close any Relations that have been opened for range table entries or
	 * result relations.
	 */
	ExecCloseResultRelations(estate);
	ExecCloseRangeTableRelations(estate);
}

/*
 * Close any relations that have been opened for ResultRelInfos.
 */
void
ExecCloseResultRelations(EState *estate)
{
	ListCell   *l;

	/*
	 * close indexes of result relation(s) if any.  (Rels themselves are
	 * closed in ExecCloseRangeTableRelations())
	 */
	foreach(l, estate->es_opened_result_relations)
	{
		ResultRelInfo *resultRelInfo = lfirst(l);

		ExecCloseIndices(resultRelInfo);
	}

	/* Close any relations that have been opened by ExecGetTriggerResultRel(). */
	foreach(l, estate->es_trig_target_relations)
	{
		ResultRelInfo *resultRelInfo = (ResultRelInfo *) lfirst(l);

		/*
		 * Assert this is a "dummy" ResultRelInfo, see above.  Otherwise we
		 * might be issuing a duplicate close against a Relation opened by
		 * ExecGetRangeTableRelation.
		 */
		Assert(resultRelInfo->ri_RangeTableIndex == 0);

		/*
		 * Since ExecGetTriggerResultRel doesn't call ExecOpenIndices for
		 * these rels, we needn't call ExecCloseIndices either.
		 */
		Assert(resultRelInfo->ri_NumIndices == 0);

		table_close(resultRelInfo->ri_RelationDesc, NoLock);
	}
}

/*
 * Close all relations opened by ExecGetRangeTableRelation().
 *
 * We do not release any locks we might hold on those rels.
 */
void
ExecCloseRangeTableRelations(EState *estate)
{
	int			i;

	for (i = 0; i < estate->es_range_table_size; i++)
	{
		if (estate->es_relations[i])
			table_close(estate->es_relations[i], NoLock);
	}
}

/* ----------------------------------------------------------------
 *		ExecutePlan
 *
 *		Processes the query plan until we have retrieved 'numberTuples' tuples,
 *		moving in the specified direction.
 *
 *		Runs to completion if numberTuples is 0
 *
 * Note: the ctid attribute is a 'junk' attribute that is removed before the
 * user can see it
 * ----------------------------------------------------------------
 */
static void
ExecutePlan(EState *estate,
			PlanState *planstate,
			bool use_parallel_mode,
			CmdType operation,
			bool sendTuples,
			uint64 numberTuples,
			ScanDirection direction,
			DestReceiver *dest,
			bool execute_once)
{
	TupleTableSlot *slot;
	uint64		current_tuple_count;

	/*
	 * initialize local variables
	 */
	current_tuple_count = 0;

	/*
	 * Set the direction.
	 */
	estate->es_direction = direction;

	/*
	 * If the plan might potentially be executed multiple times, we must force
	 * it to run without parallelism, because we might exit early.
	 */
	if (!execute_once)
		use_parallel_mode = false;

	estate->es_use_parallel_mode = use_parallel_mode;
	if (use_parallel_mode)
		EnterParallelMode();

	/*
	 * Loop until we've processed the proper number of tuples from the plan.
	 */
	for (;;)
	{
		/* Reset the per-output-tuple exprcontext */
		ResetPerTupleExprContext(estate);

		/*
		 * Execute the plan and obtain a tuple
		 */
		slot = ExecProcNode(planstate);

		/*
		 * if the tuple is null, then we assume there is nothing more to
		 * process so we just end the loop...
		 */
		if (TupIsNull(slot))
			break;

		/*
		 * If we have a junk filter, then project a new tuple with the junk
		 * removed.
		 *
		 * Store this new "clean" tuple in the junkfilter's resultSlot.
		 * (Formerly, we stored it back over the "dirty" tuple, which is WRONG
		 * because that tuple slot has the wrong descriptor.)
		 */
		if (estate->es_junkFilter != NULL)
			slot = ExecFilterJunk(estate->es_junkFilter, slot);

		/*
		 * If we are supposed to send the tuple somewhere, do so. (In
		 * practice, this is probably always the case at this point.)
		 */
		if (sendTuples)
		{
			/*
			 * If we are not able to send the tuple, we assume the destination
			 * has closed and no more tuples can be sent. If that's the case,
			 * end the loop.
			 */
			if (!dest->receiveSlot(slot, dest))
				break;
		}

		/*
		 * Count tuples processed, if this is a SELECT.  (For other operation
		 * types, the ModifyTable plan node must count the appropriate
		 * events.)
		 */
		if (operation == CMD_SELECT)
			(estate->es_processed)++;

		/*
		 * check our tuple count.. if we've processed the proper number then
		 * quit, else loop again and process more tuples.  Zero numberTuples
		 * means no limit.
		 */
		current_tuple_count++;
		if (numberTuples && numberTuples == current_tuple_count)
			break;
	}

	/*
	 * If we know we won't need to back up, we can release resources at this
	 * point.
	 */
	if (!(estate->es_top_eflags & EXEC_FLAG_BACKWARD))
		(void) ExecShutdownNode(planstate);

	if (use_parallel_mode)
		ExitParallelMode();
}


/*
 * ExecRelCheck --- check that tuple meets constraints for result relation
 *
 * Returns NULL if OK, else name of failed check constraint
 */
static const char *
ExecRelCheck(ResultRelInfo *resultRelInfo,
			 TupleTableSlot *slot, EState *estate)
{
	Relation	rel = resultRelInfo->ri_RelationDesc;
	int			ncheck = rel->rd_att->constr->num_check;
	ConstrCheck *check = rel->rd_att->constr->check;
	ExprContext *econtext;
	MemoryContext oldContext;
	int			i;

	/*
	 * If first time through for this result relation, build expression
	 * nodetrees for rel's constraint expressions.  Keep them in the per-query
	 * memory context so they'll survive throughout the query.
	 */
	if (resultRelInfo->ri_ConstraintExprs == NULL)
	{
		oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
		resultRelInfo->ri_ConstraintExprs =
			(ExprState **) palloc(ncheck * sizeof(ExprState *));
		for (i = 0; i < ncheck; i++)
		{
			Expr	   *checkconstr;

			checkconstr = stringToNode(check[i].ccbin);
			resultRelInfo->ri_ConstraintExprs[i] =
				ExecPrepareExpr(checkconstr, estate);
		}
		MemoryContextSwitchTo(oldContext);
	}

	/*
	 * We will use the EState's per-tuple context for evaluating constraint
	 * expressions (creating it if it's not already there).
	 */
	econtext = GetPerTupleExprContext(estate);

	/* Arrange for econtext's scan tuple to be the tuple under test */
	econtext->ecxt_scantuple = slot;

	/* And evaluate the constraints */
	for (i = 0; i < ncheck; i++)
	{
		ExprState  *checkconstr = resultRelInfo->ri_ConstraintExprs[i];

		/*
		 * NOTE: SQL specifies that a NULL result from a constraint expression
		 * is not to be treated as a failure.  Therefore, use ExecCheck not
		 * ExecQual.
		 */
		if (!ExecCheck(checkconstr, econtext))
			return check[i].ccname;
	}

	/* NULL result means no error */
	return NULL;
}

/*
 * ExecPartitionCheck --- check that tuple meets the partition constraint.
 *
 * Returns true if it meets the partition constraint.  If the constraint
 * fails and we're asked to emit an error, do so and don't return; otherwise
 * return false.
 */
bool
ExecPartitionCheck(ResultRelInfo *resultRelInfo, TupleTableSlot *slot,
				   EState *estate, bool emitError)
{
	ExprContext *econtext;
	bool		success;

	/*
	 * If first time through, build expression state tree for the partition
	 * check expression.  (In the corner case where the partition check
	 * expression is empty, ie there's a default partition and nothing else,
	 * we'll be fooled into executing this code each time through.  But it's
	 * pretty darn cheap in that case, so we don't worry about it.)
	 */
	if (resultRelInfo->ri_PartitionCheckExpr == NULL)
	{
		/*
		 * Ensure that the qual tree and prepared expression are in the
		 * query-lifespan context.
		 */
		MemoryContext oldcxt = MemoryContextSwitchTo(estate->es_query_cxt);
		List	   *qual = RelationGetPartitionQual(resultRelInfo->ri_RelationDesc);

		resultRelInfo->ri_PartitionCheckExpr = ExecPrepareCheck(qual, estate);
		MemoryContextSwitchTo(oldcxt);
	}

	/*
	 * We will use the EState's per-tuple context for evaluating constraint
	 * expressions (creating it if it's not already there).
	 */
	econtext = GetPerTupleExprContext(estate);

	/* Arrange for econtext's scan tuple to be the tuple under test */
	econtext->ecxt_scantuple = slot;

	/*
	 * As in case of the catalogued constraints, we treat a NULL result as
	 * success here, not a failure.
	 */
	success = ExecCheck(resultRelInfo->ri_PartitionCheckExpr, econtext);

	/* if asked to emit error, don't actually return on failure */
	if (!success && emitError)
		ExecPartitionCheckEmitError(resultRelInfo, slot, estate);

	return success;
}

/*
 * ExecPartitionCheckEmitError - Form and emit an error message after a failed
 * partition constraint check.
 */
void
ExecPartitionCheckEmitError(ResultRelInfo *resultRelInfo,
							TupleTableSlot *slot,
							EState *estate)
{
	Oid			root_relid;
	TupleDesc	tupdesc;
	char	   *val_desc;
	Bitmapset  *modifiedCols;

	/*
	 * If the tuple has been routed, it's been converted to the partition's
	 * rowtype, which might differ from the root table's.  We must convert it
	 * back to the root table's rowtype so that val_desc in the error message
	 * matches the input tuple.
	 */
	if (resultRelInfo->ri_PartitionRoot)
	{
		TupleDesc	old_tupdesc;
		AttrMap    *map;

		root_relid = RelationGetRelid(resultRelInfo->ri_PartitionRoot);
		tupdesc = RelationGetDescr(resultRelInfo->ri_PartitionRoot);

		old_tupdesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
		/* a reverse map */
		map = build_attrmap_by_name_if_req(old_tupdesc, tupdesc);

		/*
		 * Partition-specific slot's tupdesc can't be changed, so allocate a
		 * new one.
		 */
		if (map != NULL)
			slot = execute_attr_map_slot(map, slot,
										 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
	}
	else
	{
		root_relid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
		tupdesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
	}

	modifiedCols = bms_union(GetInsertedColumns(resultRelInfo, estate),
							 GetUpdatedColumns(resultRelInfo, estate));

	val_desc = ExecBuildSlotValueDescription(root_relid,
											 slot,
											 tupdesc,
											 modifiedCols,
											 64);
	ereport(ERROR,
			(errcode(ERRCODE_CHECK_VIOLATION),
			 errmsg("new row for relation \"%s\" violates partition constraint",
					RelationGetRelationName(resultRelInfo->ri_RelationDesc)),
			 val_desc ? errdetail("Failing row contains %s.", val_desc) : 0,
			 errtable(resultRelInfo->ri_RelationDesc)));
}

/*
 * ExecConstraints - check constraints of the tuple in 'slot'
 *
 * This checks the traditional NOT NULL and check constraints.
 *
 * The partition constraint is *NOT* checked.
 *
 * Note: 'slot' contains the tuple to check the constraints of, which may
 * have been converted from the original input tuple after tuple routing.
 * 'resultRelInfo' is the final result relation, after tuple routing.
 */
void
ExecConstraints(ResultRelInfo *resultRelInfo,
				TupleTableSlot *slot, EState *estate)
{
	Relation	rel = resultRelInfo->ri_RelationDesc;
	TupleDesc	tupdesc = RelationGetDescr(rel);
	TupleConstr *constr = tupdesc->constr;
	Bitmapset  *modifiedCols;
	Bitmapset  *insertedCols;
	Bitmapset  *updatedCols;

	Assert(constr);				/* we should not be called otherwise */

	if (constr->has_not_null)
	{
		int			natts = tupdesc->natts;
		int			attrChk;

		for (attrChk = 1; attrChk <= natts; attrChk++)
		{
			Form_pg_attribute att = TupleDescAttr(tupdesc, attrChk - 1);

			if (att->attnotnull && slot_attisnull(slot, attrChk))
			{
				char	   *val_desc;
				Relation	orig_rel = rel;
				TupleDesc	orig_tupdesc = RelationGetDescr(rel);

				/*
				 * If the tuple has been routed, it's been converted to the
				 * partition's rowtype, which might differ from the root
				 * table's.  We must convert it back to the root table's
				 * rowtype so that val_desc shown error message matches the
				 * input tuple.
				 */
				if (resultRelInfo->ri_PartitionRoot)
				{
					AttrMap    *map;

					rel = resultRelInfo->ri_PartitionRoot;
					tupdesc = RelationGetDescr(rel);
					/* a reverse map */
					map = build_attrmap_by_name_if_req(orig_tupdesc,
													   tupdesc);

					/*
					 * Partition-specific slot's tupdesc can't be changed, so
					 * allocate a new one.
					 */
					if (map != NULL)
						slot = execute_attr_map_slot(map, slot,
													 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
				}

				insertedCols = GetInsertedColumns(resultRelInfo, estate);
				updatedCols = GetUpdatedColumns(resultRelInfo, estate);
				modifiedCols = bms_union(insertedCols, updatedCols);
				val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
														 slot,
														 tupdesc,
														 modifiedCols,
														 64);

				ereport(ERROR,
						(errcode(ERRCODE_NOT_NULL_VIOLATION),
						 errmsg("null value in column \"%s\" of relation \"%s\" violates not-null constraint",
								NameStr(att->attname),
								RelationGetRelationName(orig_rel)),
						 val_desc ? errdetail("Failing row contains %s.", val_desc) : 0,
						 errtablecol(orig_rel, attrChk)));
			}
		}
	}

	if (constr->num_check > 0)
	{
		const char *failed;

		if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
		{
			char	   *val_desc;
			Relation	orig_rel = rel;

			/* See the comment above. */
			if (resultRelInfo->ri_PartitionRoot)
			{
				TupleDesc	old_tupdesc = RelationGetDescr(rel);
				AttrMap    *map;

				rel = resultRelInfo->ri_PartitionRoot;
				tupdesc = RelationGetDescr(rel);
				/* a reverse map */
				map = build_attrmap_by_name_if_req(old_tupdesc,
												   tupdesc);

				/*
				 * Partition-specific slot's tupdesc can't be changed, so
				 * allocate a new one.
				 */
				if (map != NULL)
					slot = execute_attr_map_slot(map, slot,
												 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
			}

			insertedCols = GetInsertedColumns(resultRelInfo, estate);
			updatedCols = GetUpdatedColumns(resultRelInfo, estate);
			modifiedCols = bms_union(insertedCols, updatedCols);
			val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
													 slot,
													 tupdesc,
													 modifiedCols,
													 64);
			ereport(ERROR,
					(errcode(ERRCODE_CHECK_VIOLATION),
					 errmsg("new row for relation \"%s\" violates check constraint \"%s\"",
							RelationGetRelationName(orig_rel), failed),
					 val_desc ? errdetail("Failing row contains %s.", val_desc) : 0,
					 errtableconstraint(orig_rel, failed)));
		}
	}
}

/*
 * ExecWithCheckOptions -- check that tuple satisfies any WITH CHECK OPTIONs
 * of the specified kind.
 *
 * Note that this needs to be called multiple times to ensure that all kinds of
 * WITH CHECK OPTIONs are handled (both those from views which have the WITH
 * CHECK OPTION set and from row level security policies).  See ExecInsert()
 * and ExecUpdate().
 */
void
ExecWithCheckOptions(WCOKind kind, ResultRelInfo *resultRelInfo,
					 TupleTableSlot *slot, EState *estate)
{
	Relation	rel = resultRelInfo->ri_RelationDesc;
	TupleDesc	tupdesc = RelationGetDescr(rel);
	ExprContext *econtext;
	ListCell   *l1,
			   *l2;

	/*
	 * We will use the EState's per-tuple context for evaluating constraint
	 * expressions (creating it if it's not already there).
	 */
	econtext = GetPerTupleExprContext(estate);

	/* Arrange for econtext's scan tuple to be the tuple under test */
	econtext->ecxt_scantuple = slot;

	/* Check each of the constraints */
	forboth(l1, resultRelInfo->ri_WithCheckOptions,
			l2, resultRelInfo->ri_WithCheckOptionExprs)
	{
		WithCheckOption *wco = (WithCheckOption *) lfirst(l1);
		ExprState  *wcoExpr = (ExprState *) lfirst(l2);

		/*
		 * Skip any WCOs which are not the kind we are looking for at this
		 * time.
		 */
		if (wco->kind != kind)
			continue;

		/*
		 * WITH CHECK OPTION checks are intended to ensure that the new tuple
		 * is visible (in the case of a view) or that it passes the
		 * 'with-check' policy (in the case of row security). If the qual
		 * evaluates to NULL or FALSE, then the new tuple won't be included in
		 * the view or doesn't pass the 'with-check' policy for the table.
		 */
		if (!ExecQual(wcoExpr, econtext))
		{
			char	   *val_desc;
			Bitmapset  *modifiedCols;
			Bitmapset  *insertedCols;
			Bitmapset  *updatedCols;

			switch (wco->kind)
			{
					/*
					 * For WITH CHECK OPTIONs coming from views, we might be
					 * able to provide the details on the row, depending on
					 * the permissions on the relation (that is, if the user
					 * could view it directly anyway).  For RLS violations, we
					 * don't include the data since we don't know if the user
					 * should be able to view the tuple as that depends on the
					 * USING policy.
					 */
				case WCO_VIEW_CHECK:
					/* See the comment in ExecConstraints(). */
					if (resultRelInfo->ri_PartitionRoot)
					{
						TupleDesc	old_tupdesc = RelationGetDescr(rel);
						AttrMap    *map;

						rel = resultRelInfo->ri_PartitionRoot;
						tupdesc = RelationGetDescr(rel);
						/* a reverse map */
						map = build_attrmap_by_name_if_req(old_tupdesc,
														   tupdesc);

						/*
						 * Partition-specific slot's tupdesc can't be changed,
						 * so allocate a new one.
						 */
						if (map != NULL)
							slot = execute_attr_map_slot(map, slot,
														 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
					}

					insertedCols = GetInsertedColumns(resultRelInfo, estate);
					updatedCols = GetUpdatedColumns(resultRelInfo, estate);
					modifiedCols = bms_union(insertedCols, updatedCols);
					val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
															 slot,
															 tupdesc,
															 modifiedCols,
															 64);

					ereport(ERROR,
							(errcode(ERRCODE_WITH_CHECK_OPTION_VIOLATION),
							 errmsg("new row violates check option for view \"%s\"",
									wco->relname),
							 val_desc ? errdetail("Failing row contains %s.",
												  val_desc) : 0));
					break;
				case WCO_RLS_INSERT_CHECK:
				case WCO_RLS_UPDATE_CHECK:
					if (wco->polname != NULL)
						ereport(ERROR,
								(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
								 errmsg("new row violates row-level security policy \"%s\" for table \"%s\"",
										wco->polname, wco->relname)));
					else
						ereport(ERROR,
								(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
								 errmsg("new row violates row-level security policy for table \"%s\"",
										wco->relname)));
					break;
				case WCO_RLS_CONFLICT_CHECK:
					if (wco->polname != NULL)
						ereport(ERROR,
								(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
								 errmsg("new row violates row-level security policy \"%s\" (USING expression) for table \"%s\"",
										wco->polname, wco->relname)));
					else
						ereport(ERROR,
								(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
								 errmsg("new row violates row-level security policy (USING expression) for table \"%s\"",
										wco->relname)));
					break;
				default:
					elog(ERROR, "unrecognized WCO kind: %u", wco->kind);
					break;
			}
		}
	}
}

/*
 * ExecBuildSlotValueDescription -- construct a string representing a tuple
 *
 * This is intentionally very similar to BuildIndexValueDescription, but
 * unlike that function, we truncate long field values (to at most maxfieldlen
 * bytes).  That seems necessary here since heap field values could be very
 * long, whereas index entries typically aren't so wide.
 *
 * Also, unlike the case with index entries, we need to be prepared to ignore
 * dropped columns.  We used to use the slot's tuple descriptor to decode the
 * data, but the slot's descriptor doesn't identify dropped columns, so we
 * now need to be passed the relation's descriptor.
 *
 * Note that, like BuildIndexValueDescription, if the user does not have
 * permission to view any of the columns involved, a NULL is returned.  Unlike
 * BuildIndexValueDescription, if the user has access to view a subset of the
 * column involved, that subset will be returned with a key identifying which
 * columns they are.
 */
static char *
ExecBuildSlotValueDescription(Oid reloid,
							  TupleTableSlot *slot,
							  TupleDesc tupdesc,
							  Bitmapset *modifiedCols,
							  int maxfieldlen)
{
	StringInfoData buf;
	StringInfoData collist;
	bool		write_comma = false;
	bool		write_comma_collist = false;
	int			i;
	AclResult	aclresult;
	bool		table_perm = false;
	bool		any_perm = false;

	/*
	 * Check if RLS is enabled and should be active for the relation; if so,
	 * then don't return anything.  Otherwise, go through normal permission
	 * checks.
	 */
	if (check_enable_rls(reloid, InvalidOid, true) == RLS_ENABLED)
		return NULL;

	initStringInfo(&buf);

	appendStringInfoChar(&buf, '(');

	/*
	 * Check if the user has permissions to see the row.  Table-level SELECT
	 * allows access to all columns.  If the user does not have table-level
	 * SELECT then we check each column and include those the user has SELECT
	 * rights on.  Additionally, we always include columns the user provided
	 * data for.
	 */
	aclresult = pg_class_aclcheck(reloid, GetUserId(), ACL_SELECT);
	if (aclresult != ACLCHECK_OK)
	{
		/* Set up the buffer for the column list */
		initStringInfo(&collist);
		appendStringInfoChar(&collist, '(');
	}
	else
		table_perm = any_perm = true;

	/* Make sure the tuple is fully deconstructed */
	slot_getallattrs(slot);

	for (i = 0; i < tupdesc->natts; i++)
	{
		bool		column_perm = false;
		char	   *val;
		int			vallen;
		Form_pg_attribute att = TupleDescAttr(tupdesc, i);

		/* ignore dropped columns */
		if (att->attisdropped)
			continue;

		if (!table_perm)
		{
			/*
			 * No table-level SELECT, so need to make sure they either have
			 * SELECT rights on the column or that they have provided the data
			 * for the column.  If not, omit this column from the error
			 * message.
			 */
			aclresult = pg_attribute_aclcheck(reloid, att->attnum,
											  GetUserId(), ACL_SELECT);
			if (bms_is_member(att->attnum - FirstLowInvalidHeapAttributeNumber,
							  modifiedCols) || aclresult == ACLCHECK_OK)
			{
				column_perm = any_perm = true;

				if (write_comma_collist)
					appendStringInfoString(&collist, ", ");
				else
					write_comma_collist = true;

				appendStringInfoString(&collist, NameStr(att->attname));
			}
		}

		if (table_perm || column_perm)
		{
			if (slot->tts_isnull[i])
				val = "null";
			else
			{
				Oid			foutoid;
				bool		typisvarlena;

				getTypeOutputInfo(att->atttypid,
								  &foutoid, &typisvarlena);
				val = OidOutputFunctionCall(foutoid, slot->tts_values[i]);
			}

			if (write_comma)
				appendStringInfoString(&buf, ", ");
			else
				write_comma = true;

			/* truncate if needed */
			vallen = strlen(val);
			if (vallen <= maxfieldlen)
				appendBinaryStringInfo(&buf, val, vallen);
			else
			{
				vallen = pg_mbcliplen(val, vallen, maxfieldlen);
				appendBinaryStringInfo(&buf, val, vallen);
				appendStringInfoString(&buf, "...");
			}
		}
	}

	/* If we end up with zero columns being returned, then return NULL. */
	if (!any_perm)
		return NULL;

	appendStringInfoChar(&buf, ')');

	if (!table_perm)
	{
		appendStringInfoString(&collist, ") = ");
		appendBinaryStringInfo(&collist, buf.data, buf.len);

		return collist.data;
	}

	return buf.data;
}


/*
 * ExecUpdateLockMode -- find the appropriate UPDATE tuple lock mode for a
 * given ResultRelInfo
 */
LockTupleMode
ExecUpdateLockMode(EState *estate, ResultRelInfo *relinfo)
{
	Bitmapset  *keyCols;
	Bitmapset  *updatedCols;

	/*
	 * Compute lock mode to use.  If columns that are part of the key have not
	 * been modified, then we can use a weaker lock, allowing for better
	 * concurrency.
	 */
	updatedCols = GetAllUpdatedColumns(relinfo, estate);
	keyCols = RelationGetIndexAttrBitmap(relinfo->ri_RelationDesc,
										 INDEX_ATTR_BITMAP_KEY);

	if (bms_overlap(keyCols, updatedCols))
		return LockTupleExclusive;

	return LockTupleNoKeyExclusive;
}

/*
 * ExecFindRowMark -- find the ExecRowMark struct for given rangetable index
 *
 * If no such struct, either return NULL or throw error depending on missing_ok
 */
ExecRowMark *
ExecFindRowMark(EState *estate, Index rti, bool missing_ok)
{
	if (rti > 0 && rti <= estate->es_range_table_size &&
		estate->es_rowmarks != NULL)
	{
		ExecRowMark *erm = estate->es_rowmarks[rti - 1];

		if (erm)
			return erm;
	}
	if (!missing_ok)
		elog(ERROR, "failed to find ExecRowMark for rangetable index %u", rti);
	return NULL;
}

/*
 * ExecBuildAuxRowMark -- create an ExecAuxRowMark struct
 *
 * Inputs are the underlying ExecRowMark struct and the targetlist of the
 * input plan node (not planstate node!).  We need the latter to find out
 * the column numbers of the resjunk columns.
 */
ExecAuxRowMark *
ExecBuildAuxRowMark(ExecRowMark *erm, List *targetlist)
{
	ExecAuxRowMark *aerm = (ExecAuxRowMark *) palloc0(sizeof(ExecAuxRowMark));
	char		resname[32];

	aerm->rowmark = erm;

	/* Look up the resjunk columns associated with this rowmark */
	if (erm->markType != ROW_MARK_COPY)
	{
		/* need ctid for all methods other than COPY */
		snprintf(resname, sizeof(resname), "ctid%u", erm->rowmarkId);
		aerm->ctidAttNo = ExecFindJunkAttributeInTlist(targetlist,
													   resname);
		if (!AttributeNumberIsValid(aerm->ctidAttNo))
			elog(ERROR, "could not find junk %s column", resname);
	}
	else
	{
		/* need wholerow if COPY */
		snprintf(resname, sizeof(resname), "wholerow%u", erm->rowmarkId);
		aerm->wholeAttNo = ExecFindJunkAttributeInTlist(targetlist,
														resname);
		if (!AttributeNumberIsValid(aerm->wholeAttNo))
			elog(ERROR, "could not find junk %s column", resname);
	}

	/* if child rel, need tableoid */
	if (erm->rti != erm->prti)
	{
		snprintf(resname, sizeof(resname), "tableoid%u", erm->rowmarkId);
		aerm->toidAttNo = ExecFindJunkAttributeInTlist(targetlist,
													   resname);
		if (!AttributeNumberIsValid(aerm->toidAttNo))
			elog(ERROR, "could not find junk %s column", resname);
	}

	return aerm;
}


/*
 * EvalPlanQual logic --- recheck modified tuple(s) to see if we want to
 * process the updated version under READ COMMITTED rules.
 *
 * See backend/executor/README for some info about how this works.
 */


/*
 * Check the updated version of a tuple to see if we want to process it under
 * READ COMMITTED rules.
 *
 *	epqstate - state for EvalPlanQual rechecking
 *	relation - table containing tuple
 *	rti - rangetable index of table containing tuple
 *	inputslot - tuple for processing - this can be the slot from
 *		EvalPlanQualSlot(), for the increased efficiency.
 *
 * This tests whether the tuple in inputslot still matches the relevant
 * quals. For that result to be useful, typically the input tuple has to be
 * last row version (otherwise the result isn't particularly useful) and
 * locked (otherwise the result might be out of date). That's typically
 * achieved by using table_tuple_lock() with the
 * TUPLE_LOCK_FLAG_FIND_LAST_VERSION flag.
 *
 * Returns a slot containing the new candidate update/delete tuple, or
 * NULL if we determine we shouldn't process the row.
 */
TupleTableSlot *
EvalPlanQual(EPQState *epqstate, Relation relation,
			 Index rti, TupleTableSlot *inputslot)
{
	TupleTableSlot *slot;
	TupleTableSlot *testslot;

	Assert(rti > 0);

	/*
	 * Need to run a recheck subquery.  Initialize or reinitialize EPQ state.
	 */
	EvalPlanQualBegin(epqstate);

	/*
	 * Callers will often use the EvalPlanQualSlot to store the tuple to avoid
	 * an unnecessary copy.
	 */
	testslot = EvalPlanQualSlot(epqstate, relation, rti);
	if (testslot != inputslot)
		ExecCopySlot(testslot, inputslot);

	/*
	 * Run the EPQ query.  We assume it will return at most one tuple.
	 */
	slot = EvalPlanQualNext(epqstate);

	/*
	 * If we got a tuple, force the slot to materialize the tuple so that it
	 * is not dependent on any local state in the EPQ query (in particular,
	 * it's highly likely that the slot contains references to any pass-by-ref
	 * datums that may be present in copyTuple).  As with the next step, this
	 * is to guard against early re-use of the EPQ query.
	 */
	if (!TupIsNull(slot))
		ExecMaterializeSlot(slot);

	/*
	 * Clear out the test tuple.  This is needed in case the EPQ query is
	 * re-used to test a tuple for a different relation.  (Not clear that can
	 * really happen, but let's be safe.)
	 */
	ExecClearTuple(testslot);

	return slot;
}

/*
 * EvalPlanQualInit -- initialize during creation of a plan state node
 * that might need to invoke EPQ processing.
 *
 * Note: subplan/auxrowmarks can be NULL/NIL if they will be set later
 * with EvalPlanQualSetPlan.
 */
void
EvalPlanQualInit(EPQState *epqstate, EState *parentestate,
				 Plan *subplan, List *auxrowmarks, int epqParam)
{
	Index		rtsize = parentestate->es_range_table_size;

	/* initialize data not changing over EPQState's lifetime */
	epqstate->parentestate = parentestate;
	epqstate->epqParam = epqParam;

	/*
	 * Allocate space to reference a slot for each potential rti - do so now
	 * rather than in EvalPlanQualBegin(), as done for other dynamically
	 * allocated resources, so EvalPlanQualSlot() can be used to hold tuples
	 * that *may* need EPQ later, without forcing the overhead of
	 * EvalPlanQualBegin().
	 */
	epqstate->tuple_table = NIL;
	epqstate->relsubs_slot = (TupleTableSlot **)
		palloc0(rtsize * sizeof(TupleTableSlot *));

	/* ... and remember data that EvalPlanQualBegin will need */
	epqstate->plan = subplan;
	epqstate->arowMarks = auxrowmarks;

	/* ... and mark the EPQ state inactive */
	epqstate->origslot = NULL;
	epqstate->recheckestate = NULL;
	epqstate->recheckplanstate = NULL;
	epqstate->relsubs_rowmark = NULL;
	epqstate->relsubs_done = NULL;
}

/*
 * EvalPlanQualSetPlan -- set or change subplan of an EPQState.
 *
 * We need this so that ModifyTable can deal with multiple subplans.
 */
void
EvalPlanQualSetPlan(EPQState *epqstate, Plan *subplan, List *auxrowmarks)
{
	/* If we have a live EPQ query, shut it down */
	EvalPlanQualEnd(epqstate);
	/* And set/change the plan pointer */
	epqstate->plan = subplan;
	/* The rowmarks depend on the plan, too */
	epqstate->arowMarks = auxrowmarks;
}

/*
 * Return, and create if necessary, a slot for an EPQ test tuple.
 *
 * Note this only requires EvalPlanQualInit() to have been called,
 * EvalPlanQualBegin() is not necessary.
 */
TupleTableSlot *
EvalPlanQualSlot(EPQState *epqstate,
				 Relation relation, Index rti)
{
	TupleTableSlot **slot;

	Assert(relation);
	Assert(rti > 0 && rti <= epqstate->parentestate->es_range_table_size);
	slot = &epqstate->relsubs_slot[rti - 1];

	if (*slot == NULL)
	{
		MemoryContext oldcontext;

		oldcontext = MemoryContextSwitchTo(epqstate->parentestate->es_query_cxt);
		*slot = table_slot_create(relation, &epqstate->tuple_table);
		MemoryContextSwitchTo(oldcontext);
	}

	return *slot;
}

/*
 * Fetch the current row value for a non-locked relation, identified by rti,
 * that needs to be scanned by an EvalPlanQual operation.  origslot must have
 * been set to contain the current result row (top-level row) that we need to
 * recheck.  Returns true if a substitution tuple was found, false if not.
 */
bool
EvalPlanQualFetchRowMark(EPQState *epqstate, Index rti, TupleTableSlot *slot)
{
	ExecAuxRowMark *earm = epqstate->relsubs_rowmark[rti - 1];
	ExecRowMark *erm = earm->rowmark;
	Datum		datum;
	bool		isNull;

	Assert(earm != NULL);
	Assert(epqstate->origslot != NULL);

	if (RowMarkRequiresRowShareLock(erm->markType))
		elog(ERROR, "EvalPlanQual doesn't support locking rowmarks");

	/* if child rel, must check whether it produced this row */
	if (erm->rti != erm->prti)
	{
		Oid			tableoid;

		datum = ExecGetJunkAttribute(epqstate->origslot,
									 earm->toidAttNo,
									 &isNull);
		/* non-locked rels could be on the inside of outer joins */
		if (isNull)
			return false;

		tableoid = DatumGetObjectId(datum);

		Assert(OidIsValid(erm->relid));
		if (tableoid != erm->relid)
		{
			/* this child is inactive right now */
			return false;
		}
	}

	if (erm->markType == ROW_MARK_REFERENCE)
	{
		Assert(erm->relation != NULL);

		/* fetch the tuple's ctid */
		datum = ExecGetJunkAttribute(epqstate->origslot,
									 earm->ctidAttNo,
									 &isNull);
		/* non-locked rels could be on the inside of outer joins */
		if (isNull)
			return false;

		/* fetch requests on foreign tables must be passed to their FDW */
		if (erm->relation->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
		{
			FdwRoutine *fdwroutine;
			bool		updated = false;

			fdwroutine = GetFdwRoutineForRelation(erm->relation, false);
			/* this should have been checked already, but let's be safe */
			if (fdwroutine->RefetchForeignRow == NULL)
				ereport(ERROR,
						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
						 errmsg("cannot lock rows in foreign table \"%s\"",
								RelationGetRelationName(erm->relation))));

			fdwroutine->RefetchForeignRow(epqstate->recheckestate,
										  erm,
										  datum,
										  slot,
										  &updated);
			if (TupIsNull(slot))
				elog(ERROR, "failed to fetch tuple for EvalPlanQual recheck");

			/*
			 * Ideally we'd insist on updated == false here, but that assumes
			 * that FDWs can track that exactly, which they might not be able
			 * to.  So just ignore the flag.
			 */
			return true;
		}
		else
		{
			/* ordinary table, fetch the tuple */
			if (!table_tuple_fetch_row_version(erm->relation,
											   (ItemPointer) DatumGetPointer(datum),
											   SnapshotAny, slot))
				elog(ERROR, "failed to fetch tuple for EvalPlanQual recheck");
			return true;
		}
	}
	else
	{
		Assert(erm->markType == ROW_MARK_COPY);

		/* fetch the whole-row Var for the relation */
		datum = ExecGetJunkAttribute(epqstate->origslot,
									 earm->wholeAttNo,
									 &isNull);
		/* non-locked rels could be on the inside of outer joins */
		if (isNull)
			return false;

		ExecStoreHeapTupleDatum(datum, slot);
		return true;
	}
}

/*
 * Fetch the next row (if any) from EvalPlanQual testing
 *
 * (In practice, there should never be more than one row...)
 */
TupleTableSlot *
EvalPlanQualNext(EPQState *epqstate)
{
	MemoryContext oldcontext;
	TupleTableSlot *slot;

	oldcontext = MemoryContextSwitchTo(epqstate->recheckestate->es_query_cxt);
	slot = ExecProcNode(epqstate->recheckplanstate);
	MemoryContextSwitchTo(oldcontext);

	return slot;
}

/*
 * Initialize or reset an EvalPlanQual state tree
 */
void
EvalPlanQualBegin(EPQState *epqstate)
{
	EState	   *parentestate = epqstate->parentestate;
	EState	   *recheckestate = epqstate->recheckestate;

	if (recheckestate == NULL)
	{
		/* First time through, so create a child EState */
		EvalPlanQualStart(epqstate, epqstate->plan);
	}
	else
	{
		/*
		 * We already have a suitable child EPQ tree, so just reset it.
		 */
		Index		rtsize = parentestate->es_range_table_size;
		PlanState  *rcplanstate = epqstate->recheckplanstate;

		MemSet(epqstate->relsubs_done, 0, rtsize * sizeof(bool));

		/* Recopy current values of parent parameters */
		if (parentestate->es_plannedstmt->paramExecTypes != NIL)
		{
			int			i;

			/*
			 * Force evaluation of any InitPlan outputs that could be needed
			 * by the subplan, just in case they got reset since
			 * EvalPlanQualStart (see comments therein).
			 */
			ExecSetParamPlanMulti(rcplanstate->plan->extParam,
								  GetPerTupleExprContext(parentestate));

			i = list_length(parentestate->es_plannedstmt->paramExecTypes);

			while (--i >= 0)
			{
				/* copy value if any, but not execPlan link */
				recheckestate->es_param_exec_vals[i].value =
					parentestate->es_param_exec_vals[i].value;
				recheckestate->es_param_exec_vals[i].isnull =
					parentestate->es_param_exec_vals[i].isnull;
			}
		}

		/*
		 * Mark child plan tree as needing rescan at all scan nodes.  The
		 * first ExecProcNode will take care of actually doing the rescan.
		 */
		rcplanstate->chgParam = bms_add_member(rcplanstate->chgParam,
											   epqstate->epqParam);
	}
}

/*
 * Start execution of an EvalPlanQual plan tree.
 *
 * This is a cut-down version of ExecutorStart(): we copy some state from
 * the top-level estate rather than initializing it fresh.
 */
static void
EvalPlanQualStart(EPQState *epqstate, Plan *planTree)
{
	EState	   *parentestate = epqstate->parentestate;
	Index		rtsize = parentestate->es_range_table_size;
	EState	   *rcestate;
	MemoryContext oldcontext;
	ListCell   *l;

	epqstate->recheckestate = rcestate = CreateExecutorState();

	oldcontext = MemoryContextSwitchTo(rcestate->es_query_cxt);

	/* signal that this is an EState for executing EPQ */
	rcestate->es_epq_active = epqstate;

	/*
	 * Child EPQ EStates share the parent's copy of unchanging state such as
	 * the snapshot, rangetable, and external Param info.  They need their own
	 * copies of local state, including a tuple table, es_param_exec_vals,
	 * result-rel info, etc.
	 */
	rcestate->es_direction = ForwardScanDirection;
	rcestate->es_snapshot = parentestate->es_snapshot;
	rcestate->es_crosscheck_snapshot = parentestate->es_crosscheck_snapshot;
	rcestate->es_range_table = parentestate->es_range_table;
	rcestate->es_range_table_size = parentestate->es_range_table_size;
	rcestate->es_relations = parentestate->es_relations;
	rcestate->es_queryEnv = parentestate->es_queryEnv;
	rcestate->es_rowmarks = parentestate->es_rowmarks;
	rcestate->es_plannedstmt = parentestate->es_plannedstmt;
	rcestate->es_junkFilter = parentestate->es_junkFilter;
	rcestate->es_output_cid = parentestate->es_output_cid;

	/*
	 * ResultRelInfos needed by subplans are initialized from scratch when the
	 * subplans themselves are initialized.
	 */
	rcestate->es_result_relations = NULL;
	/* es_trig_target_relations must NOT be copied */
	rcestate->es_top_eflags = parentestate->es_top_eflags;
	rcestate->es_instrument = parentestate->es_instrument;
	/* es_auxmodifytables must NOT be copied */

	/*
	 * The external param list is simply shared from parent.  The internal
	 * param workspace has to be local state, but we copy the initial values
	 * from the parent, so as to have access to any param values that were
	 * already set from other parts of the parent's plan tree.
	 */
	rcestate->es_param_list_info = parentestate->es_param_list_info;
	if (parentestate->es_plannedstmt->paramExecTypes != NIL)
	{
		int			i;

		/*
		 * Force evaluation of any InitPlan outputs that could be needed by
		 * the subplan.  (With more complexity, maybe we could postpone this
		 * till the subplan actually demands them, but it doesn't seem worth
		 * the trouble; this is a corner case already, since usually the
		 * InitPlans would have been evaluated before reaching EvalPlanQual.)
		 *
		 * This will not touch output params of InitPlans that occur somewhere
		 * within the subplan tree, only those that are attached to the
		 * ModifyTable node or above it and are referenced within the subplan.
		 * That's OK though, because the planner would only attach such
		 * InitPlans to a lower-level SubqueryScan node, and EPQ execution
		 * will not descend into a SubqueryScan.
		 *
		 * The EState's per-output-tuple econtext is sufficiently short-lived
		 * for this, since it should get reset before there is any chance of
		 * doing EvalPlanQual again.
		 */
		ExecSetParamPlanMulti(planTree->extParam,
							  GetPerTupleExprContext(parentestate));

		/* now make the internal param workspace ... */
		i = list_length(parentestate->es_plannedstmt->paramExecTypes);
		rcestate->es_param_exec_vals = (ParamExecData *)
			palloc0(i * sizeof(ParamExecData));
		/* ... and copy down all values, whether really needed or not */
		while (--i >= 0)
		{
			/* copy value if any, but not execPlan link */
			rcestate->es_param_exec_vals[i].value =
				parentestate->es_param_exec_vals[i].value;
			rcestate->es_param_exec_vals[i].isnull =
				parentestate->es_param_exec_vals[i].isnull;
		}
	}

	/*
	 * Initialize private state information for each SubPlan.  We must do this
	 * before running ExecInitNode on the main query tree, since
	 * ExecInitSubPlan expects to be able to find these entries. Some of the
	 * SubPlans might not be used in the part of the plan tree we intend to
	 * run, but since it's not easy to tell which, we just initialize them
	 * all.
	 */
	Assert(rcestate->es_subplanstates == NIL);
	foreach(l, parentestate->es_plannedstmt->subplans)
	{
		Plan	   *subplan = (Plan *) lfirst(l);
		PlanState  *subplanstate;

		subplanstate = ExecInitNode(subplan, rcestate, 0);
		rcestate->es_subplanstates = lappend(rcestate->es_subplanstates,
											 subplanstate);
	}

	/*
	 * Build an RTI indexed array of rowmarks, so that
	 * EvalPlanQualFetchRowMark() can efficiently access the to be fetched
	 * rowmark.
	 */
	epqstate->relsubs_rowmark = (ExecAuxRowMark **)
		palloc0(rtsize * sizeof(ExecAuxRowMark *));
	foreach(l, epqstate->arowMarks)
	{
		ExecAuxRowMark *earm = (ExecAuxRowMark *) lfirst(l);

		epqstate->relsubs_rowmark[earm->rowmark->rti - 1] = earm;
	}

	/*
	 * Initialize per-relation EPQ tuple states to not-fetched.
	 */
	epqstate->relsubs_done = (bool *)
		palloc0(rtsize * sizeof(bool));

	/*
	 * Initialize the private state information for all the nodes in the part
	 * of the plan tree we need to run.  This opens files, allocates storage
	 * and leaves us ready to start processing tuples.
	 */
	epqstate->recheckplanstate = ExecInitNode(planTree, rcestate, 0);

	MemoryContextSwitchTo(oldcontext);
}

/*
 * EvalPlanQualEnd -- shut down at termination of parent plan state node,
 * or if we are done with the current EPQ child.
 *
 * This is a cut-down version of ExecutorEnd(); basically we want to do most
 * of the normal cleanup, but *not* close result relations (which we are
 * just sharing from the outer query).  We do, however, have to close any
 * result and trigger target relations that got opened, since those are not
 * shared.  (There probably shouldn't be any of the latter, but just in
 * case...)
 */
void
EvalPlanQualEnd(EPQState *epqstate)
{
	EState	   *estate = epqstate->recheckestate;
	Index		rtsize;
	MemoryContext oldcontext;
	ListCell   *l;

	rtsize = epqstate->parentestate->es_range_table_size;

	/*
	 * We may have a tuple table, even if EPQ wasn't started, because we allow
	 * use of EvalPlanQualSlot() without calling EvalPlanQualBegin().
	 */
	if (epqstate->tuple_table != NIL)
	{
		memset(epqstate->relsubs_slot, 0,
			   rtsize * sizeof(TupleTableSlot *));
		ExecResetTupleTable(epqstate->tuple_table, true);
		epqstate->tuple_table = NIL;
	}

	/* EPQ wasn't started, nothing further to do */
	if (estate == NULL)
		return;

	oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);

	ExecEndNode(epqstate->recheckplanstate);

	foreach(l, estate->es_subplanstates)
	{
		PlanState  *subplanstate = (PlanState *) lfirst(l);

		ExecEndNode(subplanstate);
	}

	/* throw away the per-estate tuple table, some node may have used it */
	ExecResetTupleTable(estate->es_tupleTable, false);

	/* Close any result and trigger target relations attached to this EState */
	ExecCloseResultRelations(estate);

	MemoryContextSwitchTo(oldcontext);

	FreeExecutorState(estate);

	/* Mark EPQState idle */
	epqstate->origslot = NULL;
	epqstate->recheckestate = NULL;
	epqstate->recheckplanstate = NULL;
	epqstate->relsubs_rowmark = NULL;
	epqstate->relsubs_done = NULL;
}
