src/backend/parser/parse_relation.c

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*-------------------------------------------------------------------------
 *
 * parse_relation.c
 *	  parser support routines dealing with relations
 *
 * Portions Copyright (c) 2006-2008, Greenplum inc
 * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.125 2006/10/04 00:29:56 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <ctype.h>

#include "catalog/catquery.h"
#include "access/genam.h"
#include "catalog/heap.h"
#include "access/heapam.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_exttable.h"
#include "catalog/pg_proc_callback.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_database.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/relation.h"                 /* CdbRelColumnInfo */
#include "optimizer/pathnode.h"             /* cdb_rte_find_pseudo_column() */
#include "parser/parsetree.h"
#include "parser/parse_coerce.h"
#include "parser/parse_expr.h"
#include "parser/parse_relation.h"
#include "parser/parse_type.h"
#include "utils/acl.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "utils/rangerrest.h"

/* GUC parameter */
bool		add_missing_from;

static RangeTblEntry *scanNameSpaceForRefname(ParseState *pstate,
						const char *refname);
static RangeTblEntry *scanNameSpaceForRelid(ParseState *pstate, Oid relid);
static LockingClause *getLockingClause(ParseState *pstate, char *refname);
static void expandRelation(Oid relid, Alias *eref,
			   int rtindex, int sublevels_up,
			   bool include_dropped,
			   List **colnames, List **colvars);
static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
				int rtindex, int sublevels_up,
				bool include_dropped,
				List **colnames, List **colvars);
static int	specialAttNum(const char *attname);
static void warnAutoRange(ParseState *pstate, RangeVar *relation,
			  int location);

static bool get_attisdropped(Oid relid, int attnum);
static RangeTblEntry *refnameRangeTblEntryHelper(ParseState *pstate, const char *refname, Oid relid, int *sublevels_up);
static RangeTblEntry *refnameRangeTblEntryHelperSchemaQualified(ParseState *pstate, Oid dboid, const char *schemaname, const char *refname, int *sublevels_up);

/*
 * refnameRangeTblEntry
 *	  Given a possibly-qualified refname, look to see if it matches any RTE.
 *	  If so, return a pointer to the RangeTblEntry; else return NULL.
 *
 *	  Optionally get RTE's nesting depth (0 = current) into *sublevels_up.
 *	  If sublevels_up is NULL, only consider items at the current nesting
 *	  level.
 *
 * An unqualified refname (schemaname == NULL) can match any RTE with matching
 * alias, or matching unqualified relname in the case of alias-less relation
 * RTEs.  It is possible that such a refname matches multiple RTEs in the
 * nearest nesting level that has a match; if so, we report an error via
 * ereport().
 *
 * A qualified refname (schemaname != NULL) can only match a relation RTE
 * that (a) has no alias and (b) is for the same relation identified by
 * schemaname.refname.	In this case we convert schemaname.refname to a
 * relation OID and search by relid, rather than by alias name.  This is
 * peculiar, but it's what SQL92 says to do.
 */
RangeTblEntry *
refnameRangeTblEntry(ParseState *pstate,
                                         const char *catalogname,
					 const char *schemaname,
					 const char *refname,
					 int location,
					 int *sublevels_up)
{
	Oid			relId = InvalidOid;

	if (sublevels_up)
	{
		*sublevels_up = 0;
	}
	
	if (NULL == catalogname && NULL == schemaname)
	{
		/* simple unqualified name: search the rangevars of the query */
		return refnameRangeTblEntryHelper(pstate, refname, InvalidOid /*relId*/, sublevels_up);
	}
	
	if (NULL != catalogname && NULL != schemaname)
	{
		/* fully qualified table name: catalog.schema.refname */
		Oid dboid = GetCatalogId(catalogname);
		Oid	namespaceId = LookupExplicitNamespace(schemaname, dboid);
		relId = get_relname_relid(refname, namespaceId);
		
		if (!OidIsValid(relId))
		{
			return NULL;
		}
		
		return refnameRangeTblEntryHelper(pstate, refname, relId, sublevels_up);
	}
		
	/* namespace-qualified name: schema.refname: consider both the current database and HCatalog */
	Assert(NULL != schemaname);

	Oid dboidCurrent = GetCatalogId(NULL /*catalogname*/);
	int slevelsUpHcatalog = 0;
	int slevelsUpCurrent = 0;
	
	int *pslevelsUpCurrent = NULL;
	int *pslevelsUpHcatalog = NULL;
	
	if (NULL != sublevels_up)
	{
		pslevelsUpCurrent = &slevelsUpCurrent;
		pslevelsUpHcatalog = &slevelsUpHcatalog;
	}
	
	RangeTblEntry *rteCurrent = refnameRangeTblEntryHelperSchemaQualified(pstate, dboidCurrent, schemaname, refname, pslevelsUpCurrent);
	RangeTblEntry *rteHcatalog = refnameRangeTblEntryHelperSchemaQualified(pstate, HcatalogDbOid, schemaname, refname, pslevelsUpHcatalog);
	
	if (NULL == rteCurrent && NULL == rteHcatalog)
	{
		return NULL;
	}
	if (NULL != rteCurrent && NULL != rteHcatalog)
	{
		ereport(ERROR,
					(errcode(ERRCODE_AMBIGUOUS_ALIAS),
					 errmsg("table reference \"%s.%s\" is ambiguous",
							schemaname, refname)));
	}
	if (NULL != rteCurrent)
	{
		if (NULL != sublevels_up)
		{
			*sublevels_up = *pslevelsUpCurrent;
		}
		return rteCurrent;
	}
	
	Assert(NULL != rteHcatalog);	
	if (NULL != sublevels_up)
	{
		*sublevels_up = *pslevelsUpHcatalog;
	}
	return rteHcatalog;
}

/*
 * refnameRangeTblEntryHelper
 *	  Given a refname an possibly resolved relid, look to see if it matches any RTE.
 *	  If so, return a pointer to the RangeTblEntry; else return NULL.
 *
 *	  Optionally get RTE's nesting depth (0 = current) into *sublevels_up.
 *	  If sublevels_up is NULL, only consider items at the current nesting
 *	  level.
 *
 *
 * The relid may have been resolved by the caller, in case a qualified refname (schemaname != NULL) 
 * was specified.
 */
RangeTblEntry *
refnameRangeTblEntryHelper(ParseState *pstate, const char *refname, Oid relId, int *sublevels_up)
{
	while (pstate != NULL)
	{
		RangeTblEntry *result = NULL;

		if (OidIsValid(relId))
		{
			result = scanNameSpaceForRelid(pstate, relId);
		}
		else
		{
			result = scanNameSpaceForRefname(pstate, refname);
		}

		if (result)
		{
			return result;
		}

		if (NULL == sublevels_up)
		{
			break;
		}
		
		(*sublevels_up)++;
		pstate = pstate->parentParseState;
	}
	
	return NULL;
}

/*
 * refnameRangeTblEntryHelperSchemaQualified
 *	  Given a schema-qualified refname and a dboid, look to see if it matches any RTE.
 *	  If so, return a pointer to the RangeTblEntry; else return NULL.
 *
 *	  Optionally get RTE's nesting depth (0 = current) into *sublevels_up.
 *	  If sublevels_up is NULL, only consider items at the current nesting
 *	  level.
 *
 */
RangeTblEntry *
refnameRangeTblEntryHelperSchemaQualified(ParseState *pstate, Oid dboid, const char *nspname, const char *refname, int *sublevels_up)
{
	Oid nspid = LookupNamespaceId(nspname, dboid);
	if (!OidIsValid(nspid))
	{
		return NULL;
	}
	Oid relid = get_relname_relid(refname, nspid);
	if (!OidIsValid(relid))
	{
		return NULL;
	}
	
	return refnameRangeTblEntryHelper(pstate, refname, relid, sublevels_up);
}

/*
 * Search the query's table namespace for an RTE matching the
 * given unqualified refname.  Return the RTE if a unique match, or NULL
 * if no match.  Raise error if multiple matches.
 */
static RangeTblEntry *
scanNameSpaceForRefname(ParseState *pstate, const char *refname)
{
	RangeTblEntry *result = NULL;
	ListCell   *l;

	foreach(l, pstate->p_relnamespace)
	{
		RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);

		if (strcmp(rte->eref->aliasname, refname) == 0)
		{
			if (result)
				ereport(ERROR,
						(errcode(ERRCODE_AMBIGUOUS_ALIAS),
						 errmsg("table reference \"%s\" is ambiguous",
								refname)));
			result = rte;
		}
	}
	return result;
}

/*
 * Search the query's table namespace for a relation RTE matching the
 * given relation OID.	Return the RTE if a unique match, or NULL
 * if no match.  Raise error if multiple matches (which shouldn't
 * happen if the namespace was checked correctly when it was created).
 *
 * See the comments for refnameRangeTblEntry to understand why this
 * acts the way it does.
 */
static RangeTblEntry *
scanNameSpaceForRelid(ParseState *pstate, Oid relid)
{
	RangeTblEntry *result = NULL;
	ListCell   *l;

	foreach(l, pstate->p_relnamespace)
	{
		RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);

		/* yes, the test for alias == NULL should be there... */
		if (rte->rtekind == RTE_RELATION &&
			rte->relid == relid &&
			rte->alias == NULL)
		{
			if (result)
				ereport(ERROR,
						(errcode(ERRCODE_AMBIGUOUS_ALIAS),
						 errmsg("table reference %u is ambiguous",
								relid)));
			result = rte;
		}
	}
	return result;
}

/*
 * Search the query's CTE namespace for a CTE matching the given unqualified
 * refname.  Return the CTE (and its levelsup count) if a match, or NULL
 * if no match.  We need not worry about multiple matches, since parse_cte.c
 * rejects WITH lists containing duplicate CTE names.
 */
CommonTableExpr *
scanNameSpaceForCTE(ParseState *pstate,
					const char *refname,
					Index *ctelevelsup)
{
	Assert(refname != NULL);

	Index levelsup;

	for (levelsup = 0;
		 pstate != NULL;
		 pstate = pstate->parentParseState, levelsup++)
	{
		ListCell *lc;

		foreach(lc, pstate->p_ctenamespace)
		{
			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
			Assert(cte != NULL && cte->ctename != NULL);

			if (strcmp(cte->ctename, refname) == 0)
			{
				*ctelevelsup = levelsup;
				return cte;
			}
		}
	}

	return NULL;
}

/*
 * Search for a possible "future CTE", that is one that is not yet in scope
 * according to the WITH scoping rules.  This has nothing to do with valid
 * SQL semantics, but it's important for error reporting purposes.
 */
static bool
isFutureCTE(ParseState *pstate, const char *refname)
{
	for (; pstate != NULL; pstate = pstate->parentParseState)
	{
		ListCell   *lc;

		foreach(lc, pstate->p_future_ctes)
		{
			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);

			if (strcmp(cte->ctename, refname) == 0)
				return true;
		}
	}
	return false;
}

/*
 * searchRangeTable
 *	  See if any RangeTblEntry could possibly match the RangeVar.
 *	  If so, return a pointer to the RangeTblEntry; else return NULL.
 *
 * This is different from refnameRangeTblEntry in that it considers every
 * entry in the ParseState's rangetable(s), not only those that are currently
 * visible in the p_relnamespace lists.  This behavior is invalid per the SQL
 * spec, and it may give ambiguous results (there might be multiple equally
 * valid matches, but only one will be returned).  This must be used ONLY
 * as a heuristic in giving suitable error messages.  See warnAutoRange.
 *
 * Notice that we consider both matches on actual relation name (or CTE) and matches
 * on alias.
 */
static RangeTblEntry *
searchRangeTable(ParseState *pstate, RangeVar *relation)
{
	Oid	relId = InvalidOid;
	const char *refname = relation->relname;
	CommonTableExpr *cte = NULL;
	Index ctelevelsup = 0;

	/*
	 * If it's an unqualified name, check for possible CTE matches. A CTE
	 * hides any real relation matches.  If no CTE, look for a matching
	 * relation.
	 */
	if (!relation->schemaname)
		cte = scanNameSpaceForCTE(pstate, refname, &ctelevelsup);
	if (!cte)
		relId = RangeVarGetRelid(relation, true, true /*allowHcatalog*/);

	Index levelsup = 0;
	while (pstate != NULL)
	{
		ListCell   *l;

		foreach(l, pstate->p_rtable)
		{
			RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);

			if (OidIsValid(relId) &&
				rte->rtekind == RTE_RELATION &&
				rte->relid == relId)
				return rte;

			if (rte->rtekind == RTE_CTE &&
				cte != NULL &&
				rte->ctelevelsup + levelsup == ctelevelsup &&
				strcmp(rte->ctename, refname) == 0)
				return rte;

			if (rte->eref != NULL &&
                rte->eref->aliasname != NULL &&
                strcmp(rte->eref->aliasname, refname) == 0)
				return rte;
		}

		pstate = pstate->parentParseState;
		levelsup++;
	}
	return NULL;
}

/*
 * Check for relation-name conflicts between two relnamespace lists.
 * Raise an error if any is found.
 *
 * Note: we assume that each given argument does not contain conflicts
 * itself; we just want to know if the two can be merged together.
 *
 * Per SQL92, two alias-less plain relation RTEs do not conflict even if
 * they have the same eref->aliasname (ie, same relation name), if they
 * are for different relation OIDs (implying they are in different schemas).
 */
void
checkNameSpaceConflicts(ParseState *pstate, List *namespace1,
						List *namespace2)
{
	ListCell   *l1;

	foreach(l1, namespace1)
	{
		RangeTblEntry *rte1 = (RangeTblEntry *) lfirst(l1);
		const char *aliasname1 = rte1->eref->aliasname;
		ListCell   *l2;

		foreach(l2, namespace2)
		{
			RangeTblEntry *rte2 = (RangeTblEntry *) lfirst(l2);

			if (strcmp(rte2->eref->aliasname, aliasname1) != 0)
				continue;		/* definitely no conflict */
			if (rte1->rtekind == RTE_RELATION && rte1->alias == NULL &&
				rte2->rtekind == RTE_RELATION && rte2->alias == NULL &&
				rte1->relid != rte2->relid)
				continue;		/* no conflict per SQL92 rule */
			ereport(ERROR,
					(errcode(ERRCODE_DUPLICATE_ALIAS),
					 errmsg("table name \"%s\" specified more than once",
							aliasname1)));
		}
	}
}

/*
 * given an RTE, return RT index (starting with 1) of the entry,
 * and optionally get its nesting depth (0 = current).	If sublevels_up
 * is NULL, only consider rels at the current nesting level.
 * Raises error if RTE not found.
 */
int
RTERangeTablePosn(ParseState *pstate, RangeTblEntry *rte, int *sublevels_up)
{
	int			index;
	ListCell   *l;

	if (sublevels_up)
		*sublevels_up = 0;

	while (pstate != NULL)
	{
		index = 1;
		foreach(l, pstate->p_rtable)
		{
			if (rte == (RangeTblEntry *) lfirst(l))
				return index;
			index++;
		}
		pstate = pstate->parentParseState;
		if (sublevels_up)
			(*sublevels_up)++;
		else
			break;
	}

	elog(ERROR, "RTE not found (internal error)");
	return 0;					/* keep compiler quiet */
}

/*
 * Given an RT index and nesting depth, find the corresponding RTE.
 * This is the inverse of RTERangeTablePosn.
 */
RangeTblEntry *
GetRTEByRangeTablePosn(ParseState *pstate,
					   int varno,
					   int sublevels_up)
{
	while (sublevels_up-- > 0)
	{
		pstate = pstate->parentParseState;
		Assert(pstate != NULL);
	}
	Assert(varno > 0 && varno <= list_length(pstate->p_rtable));
	return rt_fetch(varno, pstate->p_rtable);
}

/*
 * scanRTEForColumn
 *	  Search the column names of a single RTE for the given name.
 *	  If found, return an appropriate Var node, else return NULL.
 *	  If the name proves ambiguous within this RTE, raise error.
 *
 * Side effect: if we find a match, mark the RTE as requiring read access.
 * See comments in setTargetTable().
 *
 * NOTE: if the RTE is for a join, marking it as requiring read access does
 * nothing.  It might seem that we need to propagate the mark to all the
 * contained RTEs, but that is not necessary.  This is so because a join
 * expression can only appear in a FROM clause, and any table named in
 * FROM will be marked as requiring read access from the beginning.
 */
Node *
scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte, char *colname,
				 int location)
{
	Node	   *result = NULL;
	int			attnum = 0;
	ListCell   *c;

	/*
	 * Scan the user column names (or aliases) for a match. Complain if
	 * multiple matches.
	 *
	 * Note: eref->colnames may include entries for dropped columns, but those
	 * will be empty strings that cannot match any legal SQL identifier, so we
	 * don't bother to test for that case here.
	 *
	 * Should this somehow go wrong and we try to access a dropped column,
	 * we'll still catch it by virtue of the checks in
	 * get_rte_attribute_type(), which is called by make_var().  That routine
	 * has to do a cache lookup anyway, so the check there is cheap.
	 */
	foreach(c, rte->eref->colnames)
	{
		attnum++;
		if (strcmp(strVal(lfirst(c)), colname) == 0)
		{
			if (result)
				ereport(ERROR,
						(errcode(ERRCODE_AMBIGUOUS_COLUMN),
						 errmsg("column reference \"%s\" is ambiguous",
								colname),
						 errOmitLocation(true),
						 parser_errposition(pstate, location)));
			result = (Node *) make_var(pstate, rte, attnum, location);
			/* Require read access */
			rte->requiredPerms |= ACL_SELECT;
		}
	}

	/*
	 * If we have a unique match, return it.  Note that this allows a user
	 * alias to override a system column name (such as OID) without error.
	 */
	if (result)
		return result;

	/*
	 * If the RTE represents a real table, consider system column names.
	 */
	if (rte->rtekind == RTE_RELATION)
	{
		/* quick check to see if name could be a system column */
		attnum = specialAttNum(colname);
		if (attnum != InvalidAttrNumber)
		{
			/* now check to see if column actually is defined */
			if (caql_getcount(
						NULL,
						cql("SELECT COUNT(*) FROM pg_attribute "
							" WHERE attrelid = :1 "
							" AND attnum = :2 ",
							ObjectIdGetDatum(rte->relid),
							Int16GetDatum(attnum))))
			{
				result = (Node *) make_var(pstate, rte, attnum, location);
				/* Require read access */
				rte->requiredPerms |= ACL_SELECT;
			}
		}
	}

	return result;
}

/*
 * colNameToVar
 *	  Search for an unqualified column name.
 *	  If found, return the appropriate Var node (or expression).
 *	  If not found, return NULL.  If the name proves ambiguous, raise error.
 *	  If localonly is true, only names in the innermost query are considered.
 */
Node *
colNameToVar(ParseState *pstate, char *colname, bool localonly,
			 int location)
{
	Node	   *result = NULL;
	ParseState *orig_pstate = pstate;

	while (pstate != NULL)
	{
		ListCell   *l;

		foreach(l, pstate->p_varnamespace)
		{
			RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
			Node	   *newresult;

			/* use orig_pstate here to get the right sublevels_up */
			newresult = scanRTEForColumn(orig_pstate, rte, colname, location);

			if (newresult)
			{
				if (result)
					ereport(ERROR,
							(errcode(ERRCODE_AMBIGUOUS_COLUMN),
							 errmsg("column reference \"%s\" is ambiguous",
									colname),
							 errOmitLocation(true),
							 parser_errposition(orig_pstate, location)));
				result = newresult;
			}
		}

		if (result != NULL || localonly)
			break;				/* found, or don't want to look at parent */

		pstate = pstate->parentParseState;
	}

	return result;
}

/*
 * qualifiedNameToVar
 *	  Search for a qualified column name: either refname.colname or
 *	  schemaname.relname.colname.
 *
 *	  If found, return the appropriate Var node.
 *	  If not found, return NULL.  If the name proves ambiguous, raise error.
 */
Node *
qualifiedNameToVar(ParseState *pstate,
		           char *catalogname,
				   char *schemaname,
				   char *refname,
				   char *colname,
				   bool implicitRTEOK,
				   int location)
{
	RangeTblEntry *rte;
	int			sublevels_up;

	rte = refnameRangeTblEntry(pstate, catalogname, schemaname, refname, location, &sublevels_up);

	if (rte == NULL)
	{
		if (!implicitRTEOK)
			return NULL;
		rte = addImplicitRTE(pstate, makeRangeVar(catalogname, schemaname, refname, location),
							 location);
	}

	return scanRTEForColumn(pstate, rte, colname, location);
}

/*
 * buildRelationAliases
 *		Construct the eref column name list for a relation RTE.
 *		This code is also used for the case of a function RTE returning
 *		a named composite type.
 *
 * tupdesc: the physical column information
 * alias: the user-supplied alias, or NULL if none
 * eref: the eref Alias to store column names in
 *
 * eref->colnames is filled in.  Also, alias->colnames is rebuilt to insert
 * empty strings for any dropped columns, so that it will be one-to-one with
 * physical column numbers.
 */
static void
buildRelationAliases(TupleDesc tupdesc, Alias *alias, Alias *eref)
{
	int			maxattrs = tupdesc->natts;
	ListCell   *aliaslc;
	int			numaliases;
	int			varattno;
	int			numdropped = 0;

	Assert(eref->colnames == NIL);

	if (alias)
	{
		aliaslc = list_head(alias->colnames);
		numaliases = list_length(alias->colnames);
		/* We'll rebuild the alias colname list */
		alias->colnames = NIL;
	}
	else
	{
		aliaslc = NULL;
		numaliases = 0;
	}

	for (varattno = 0; varattno < maxattrs; varattno++)
	{
		Form_pg_attribute attr = tupdesc->attrs[varattno];
		Value	   *attrname;

		if (attr->attisdropped)
		{
			/* Always insert an empty string for a dropped column */
			attrname = makeString(pstrdup(""));
			if (aliaslc)
				alias->colnames = lappend(alias->colnames, attrname);
			numdropped++;
		}
		else if (aliaslc)
		{
			/* Use the next user-supplied alias */
			attrname = (Value *) lfirst(aliaslc);
			aliaslc = lnext(aliaslc);
			alias->colnames = lappend(alias->colnames, attrname);
		}
		else
		{
			attrname = makeString(pstrdup(NameStr(attr->attname)));
			/* we're done with the alias if any */
		}

		eref->colnames = lappend(eref->colnames, attrname);
	}

	/* Too many user-supplied aliases? */
	if (aliaslc)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
				 errmsg("table \"%s\" has %d columns available but %d columns specified",
						eref->aliasname, maxattrs - numdropped, numaliases)));
}

/*
 * buildScalarFunctionAlias
 *		Construct the eref column name list for a function RTE,
 *		when the function returns a scalar type (not composite or RECORD).
 *
 * funcexpr: transformed expression tree for the function call
 * funcname: function name (used only for error message)
 * alias: the user-supplied alias, or NULL if none
 * eref: the eref Alias to store column names in
 *
 * eref->colnames is filled in.
 */
static void
buildScalarFunctionAlias(Node *funcexpr, char *funcname,
						 Alias *alias, Alias *eref)
{
	char	   *pname;

	Assert(eref->colnames == NIL);

	/* Use user-specified column alias if there is one. */
	if (alias && alias->colnames != NIL)
	{
		if (list_length(alias->colnames) != 1)
			ereport(ERROR,
					(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
				  errmsg("too many column aliases specified for function %s",
						 funcname)));
		eref->colnames = copyObject(alias->colnames);
		return;
	}

	/*
	 * If the expression is a simple function call, and the function has a
	 * single OUT parameter that is named, use the parameter's name.
	 */
	if (funcexpr && IsA(funcexpr, FuncExpr))
	{
		pname = get_func_result_name(((FuncExpr *) funcexpr)->funcid);
		if (pname)
		{
			eref->colnames = list_make1(makeString(pname));
			return;
		}
	}

	/*
	 * Otherwise use the previously-determined alias (not necessarily the
	 * function name!)
	 */
	eref->colnames = list_make1(makeString(eref->aliasname));
}

/*
 * Open a table during parse analysis
 *
 * This is essentially the same as CdbOpenRelationRv, except that it caters
 * to some parser-specific error reporting needs.
 */
static Relation
parserOpenTable(ParseState *pstate, const RangeVar *relation,
				int lockmode, bool nowait, bool *lockUpgraded)
{
	Relation rel = NULL;
	
	PG_TRY();
	{
		rel = CdbOpenRelationRv(relation, lockmode, nowait, NULL);
	}
	PG_CATCH();
	{
		if (relation->schemaname == NULL &&
			isFutureCTE(pstate, relation->relname))
		{
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_TABLE),
					 errmsg("relation \"%s\" does not exist",
							relation->relname),
					 errdetail("There is a WITH item named \"%s\", but it cannot be referenced from this part of the query.",
							   relation->relname),
					 errhint("Re-order the WITH items to remove forward references.")));
		}

		PG_RE_THROW();
	}
	PG_END_TRY();

	return rel;
}

/*
 * Add an entry for a relation to the pstate's range table (p_rtable).
 *
 * If pstate is NULL, we just build an RTE and return it without adding it
 * to an rtable list.
 *
 * Note: formerly this checked for refname conflicts, but that's wrong.
 * Caller is responsible for checking for conflicts in the appropriate scope.
 */
RangeTblEntry *
addRangeTableEntry(ParseState *pstate,
				   RangeVar *relation,
				   Alias *alias,
				   bool inh,
				   bool inFromCl)
{
	RangeTblEntry		*rte	 = makeNode(RangeTblEntry);
	char				*refname = alias ? alias->aliasname : relation->relname;
	LOCKMODE             lockmode = AccessShareLock;
	bool                 nowait = false;
	LockingClause		*locking;
	Relation			 rel;
	
	/* 
	 * CDB: lock promotion around the locking clause is a little different
	 * from postgres to allow for required lock promotion for distributed
	 * tables.
	 */
	locking = getLockingClause(pstate, refname);
	if (locking)
	{
		lockmode = locking->forUpdate ? RowExclusiveLock : RowShareLock;
		nowait	 = locking->noWait;
	}
	rel = parserOpenTable(pstate, relation, lockmode, nowait, NULL);
	
	/*
	 * Get the rel's OID.  This access also ensures that we have an up-to-date
	 * relcache entry for the rel.	Since this is typically the first access
	 * to a rel in a statement, be careful to get the right access level
	 * depending on whether we're doing SELECT FOR UPDATE/SHARE.
	 */
	rte->relid = RelationGetRelid(rel);
	rte->alias = alias;
	rte->rtekind = RTE_RELATION;

	/* external tables don't allow inheritance */
	if(RelationIsExternal(rel))
		inh = false;

	/*
	 * Build the list of effective column names using user-supplied aliases
	 * and/or actual column names.
	 */
	rte->eref = makeAlias(refname, NIL);
	buildRelationAliases(rel->rd_att, alias, rte->eref);

	/*
	 * Drop the rel refcount, but keep the access lock till end of transaction
	 * so that the table can't be deleted or have its schema modified
	 * underneath us.
	 */
	heap_close(rel, NoLock);

	/*----------
	 * Flags:
	 * - this RTE should be expanded to include descendant tables,
	 * - this RTE is in the FROM clause,
	 * - this RTE should be checked for appropriate access rights.
	 *
	 * The initial default on access checks is always check-for-READ-access,
	 * which is the right thing for all except target tables.
	 *----------
	 */
	rte->inh = inh;
	rte->inFromCl = inFromCl;

	rte->requiredPerms = ACL_SELECT;
	rte->checkAsUser = InvalidOid;		/* not set-uid by default, either */

	/*
	 * Add completed RTE to pstate's range table list, but not to join list
	 * nor namespace --- caller must do that if appropriate.
	 */
	if (pstate != NULL)
		pstate->p_rtable = lappend(pstate->p_rtable, rte);

	return rte;
}

/*
 * Add an entry for a relation to the pstate's range table (p_rtable).
 *
 * This is just like addRangeTableEntry() except that it makes an RTE
 * given an already-open relation instead of a RangeVar reference.
 */
RangeTblEntry *
addRangeTableEntryForRelation(ParseState *pstate,
							  Relation rel,
							  Alias *alias,
							  bool inh,
							  bool inFromCl)
{
	RangeTblEntry *rte = makeNode(RangeTblEntry);
	char	   *refname = alias ? alias->aliasname : RelationGetRelationName(rel);

	rte->rtekind = RTE_RELATION;
	rte->alias = alias;
	rte->relid = RelationGetRelid(rel);

	/*
	 * Build the list of effective column names using user-supplied aliases
	 * and/or actual column names.
	 */
	rte->eref = makeAlias(refname, NIL);
	buildRelationAliases(rel->rd_att, alias, rte->eref);

	/*----------
	 * Flags:
	 * - this RTE should be expanded to include descendant tables,
	 * - this RTE is in the FROM clause,
	 * - this RTE should be checked for appropriate access rights.
	 *
	 * The initial default on access checks is always check-for-READ-access,
	 * which is the right thing for all except target tables.
	 *----------
	 */
	rte->inh = inh;
	rte->inFromCl = inFromCl;

	rte->requiredPerms = ACL_SELECT;
	rte->checkAsUser = InvalidOid;		/* not set-uid by default, either */

	/*
	 * Add completed RTE to pstate's range table list, but not to join list
	 * nor namespace --- caller must do that if appropriate.
	 */
	if (pstate != NULL)
		pstate->p_rtable = lappend(pstate->p_rtable, rte);

	return rte;
}

/*
 * Add an entry for a subquery to the pstate's range table (p_rtable).
 *
 * This is just like addRangeTableEntry() except that it makes a subquery RTE.
 * Note that an alias clause *must* be supplied.
 */
RangeTblEntry *
addRangeTableEntryForSubquery(ParseState *pstate,
							  Query *subquery,
							  Alias *alias,
							  bool inFromCl)
{
	RangeTblEntry *rte = makeNode(RangeTblEntry);
	char	   *refname = alias->aliasname;
	Alias	   *eref;
	int			numaliases;
	int			varattno;
	ListCell   *tlistitem;

	rte->rtekind = RTE_SUBQUERY;
	rte->relid = InvalidOid;
	rte->subquery = subquery;
	rte->alias = alias;

	eref = copyObject(alias);
	numaliases = list_length(eref->colnames);

	/* fill in any unspecified alias columns */
	varattno = 0;
	foreach(tlistitem, subquery->targetList)
	{
		TargetEntry *te = (TargetEntry *) lfirst(tlistitem);

		if (te->resjunk)
			continue;
		varattno++;
		Assert(varattno == te->resno);
		if (varattno > numaliases)
		{
			char	   *attrname;

			attrname = pstrdup(te->resname);
			eref->colnames = lappend(eref->colnames, makeString(attrname));
		}
	}
	if (varattno < numaliases)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
				 errmsg("table \"%s\" has %d columns available but %d columns specified",
						refname, varattno, numaliases)));

	rte->eref = eref;

	/*----------
	 * Flags:
	 * - this RTE should be expanded to include descendant tables,
	 * - this RTE is in the FROM clause,
	 * - this RTE should be checked for appropriate access rights.
	 *
	 * Subqueries are never checked for access rights.
	 *----------
	 */
	rte->inh = false;			/* never true for subqueries */
	rte->inFromCl = inFromCl;

	rte->requiredPerms = 0;
	rte->checkAsUser = InvalidOid;

	/*
	 * Add completed RTE to pstate's range table list, but not to join list
	 * nor namespace --- caller must do that if appropriate.
	 */
	if (pstate != NULL)
		pstate->p_rtable = lappend(pstate->p_rtable, rte);

	return rte;
}

/*
 * Add an entry for a function to the pstate's range table (p_rtable).
 *
 * This is just like addRangeTableEntry() except that it makes a function RTE.
 */
RangeTblEntry *
addRangeTableEntryForFunction(ParseState *pstate,
							  char *funcname,
							  Node *funcexpr,
							  RangeFunction *rangefunc,
							  bool inFromCl)
{
	RangeTblEntry *rte = makeNode(RangeTblEntry);
	TypeFuncClass functypclass;
	Oid			funcrettype;
	Oid         funcDescribe = InvalidOid;
	TupleDesc	tupdesc;
	Alias	   *alias = rangefunc->alias;
	List	   *coldeflist = rangefunc->coldeflist;
	Alias	   *eref;

	rte->rtekind = RTE_FUNCTION;
	rte->relid = InvalidOid;
	rte->subquery = NULL;
	rte->funcexpr = funcexpr;
	rte->funccoltypes = NIL;
	rte->funccoltypmods = NIL;
	rte->alias = alias;

	eref = makeAlias(alias ? alias->aliasname : funcname, NIL);
	rte->eref = eref;

	/*
	 * If the function has TABLE value expressions in its arguments then it must
	 * be planned as a TableFunctionScan instead of a normal FunctionScan.  We
	 * mark this here because this is where we know that the function is being
	 * used as a RangeTableEntry.
	 */
	if (funcexpr && IsA(funcexpr, FuncExpr))
	{
		FuncExpr		*func = (FuncExpr *) funcexpr;

		if (func->args && IsA(func->args, List))
		{
			ListCell		*arg;

			foreach(arg, (List*) func->args)
			{
				Node *n = (Node *) lfirst(arg);
				if (IsA(n, TableValueExpr))
				{
					TableValueExpr *input = (TableValueExpr *) n;

					/* 
					 * Currently only support single TABLE value expression.
					 *
					 * Note: this shouldn't be possible given that we don't
					 * allow it at function creation so the function parser
					 * should have already errored due to type mismatch.
					 */
					Assert(IsA(input->subquery, Query));
					if (rte->subquery != NULL)
						ereport(ERROR, 
								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
								 errmsg("functions over multiple TABLE value "
										"expressions not supported")));

					/*
					 * Convert RTE to a TableFunctionScan over the specified
					 * input 
					 */
					rte->rtekind = RTE_TABLEFUNCTION;
					rte->subquery = (Query *) input->subquery;

					/* 
					 * Mark function as a table function so that the second pass
					 * check, parseCheckTableFunctions(), can correctly detect
					 * that it is a valid TABLE value expression.
					 */
					func->is_tablefunc = true;

					/*
					 * We do not break from the loop here because we want to
					 * keep looping to guard against multiple TableValueExpr
					 * arguments.
					 */
				}
			}
		}
	}

	/*
	 * Now determine if the function returns a simple or composite type.
	 */
	functypclass = get_expr_result_type(funcexpr,
										&funcrettype,
										&tupdesc);

	/*
	 * Handle dynamic type resolution for functions with DESCRIBE callbacks.
	 */
	if (functypclass == TYPEFUNC_RECORD && IsA(funcexpr, FuncExpr))
	{
		FuncExpr *func = (FuncExpr *) funcexpr;
		Datum     d;
		int       i;

		Insist(TypeSupportsDescribe(funcrettype));

		funcDescribe = lookupProcCallback(func->funcid, PROMETHOD_DESCRIBE);
		if (OidIsValid(funcDescribe))
		{
			FmgrInfo	flinfo;
			FunctionCallInfoData fcinfo;

			/*
			 * Describe functions have the signature  d(internal) => internal
			 * where the parameter is the untransformed FuncExpr node and the result
			 * is a tuple descriptor. Its context is RangeTblEntry which has
			 * funcuserdata field to store arbitrary binary data to transport
			 * to executor.
			 */
			rte->funcuserdata = NULL;
			fmgr_info(funcDescribe, &flinfo);
			InitFunctionCallInfoData(fcinfo, &flinfo, 1, (Node *) rte, NULL);
			fcinfo.arg[0] = PointerGetDatum(funcexpr);
			fcinfo.argnull[0] = false;

			d = FunctionCallInvoke(&fcinfo);
			if (fcinfo.isnull)
				elog(ERROR, "function %u returned NULL", flinfo.fn_oid);
			tupdesc = (TupleDesc) DatumGetPointer(d);

			/* 
			 * Might want to improve this API so the describe method return 
			 * value is somehow verifiable 
			 */
			if (tupdesc != NULL)
			{
				functypclass = TYPEFUNC_COMPOSITE;
				for (i = 0; i < tupdesc->natts; i++)
				{
					Form_pg_attribute attr = tupdesc->attrs[i];

					rte->funccoltypes	= lappend_oid(rte->funccoltypes, 
													  attr->atttypid);
					rte->funccoltypmods = lappend_int(rte->funccoltypmods, 
													  attr->atttypmod);
				}
			}
		}
	}

	/*
	 * A coldeflist is required if the function returns RECORD and hasn't got
	 * a predetermined record type, and is prohibited otherwise.
	 */
	if (coldeflist != NIL)
	{
		if (functypclass != TYPEFUNC_RECORD)
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("a column definition list is only allowed for functions returning \"record\""),
							   errOmitLocation(true)));
	}
	else
	{
		if (functypclass == TYPEFUNC_RECORD)
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("a column definition list is required for functions returning \"record\""),
							   errOmitLocation(true)));
	}

	if (functypclass == TYPEFUNC_COMPOSITE)
	{
		/* Composite data type, e.g. a table's row type */
		Assert(tupdesc);
		/* Build the column alias list */
		buildRelationAliases(tupdesc, alias, eref);
	}
	else if (functypclass == TYPEFUNC_SCALAR)
	{
		/* Base data type, i.e. scalar */
		buildScalarFunctionAlias(funcexpr, funcname, alias, eref);
	}
	else if (functypclass == TYPEFUNC_RECORD)
	{
		ListCell   *col;

		/*
		 * Use the column definition list to form the alias list and
		 * funccoltypes/funccoltypmods lists.
		 */
		foreach(col, coldeflist)
		{
			ColumnDef  *n = (ColumnDef *) lfirst(col);
			char	   *attrname;
			Oid			attrtype;
			int32		attrtypmod;

			attrname = pstrdup(n->colname);
			if (n->typname->setof)
				ereport(ERROR,
						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
						 errmsg("column \"%s\" cannot be declared SETOF",
								attrname),
										   errOmitLocation(true)));
			eref->colnames = lappend(eref->colnames, makeString(attrname));
			attrtype = typenameTypeId(pstate, n->typname);
			attrtypmod = n->typname->typmod;
			rte->funccoltypes = lappend_oid(rte->funccoltypes, attrtype);
			rte->funccoltypmods = lappend_int(rte->funccoltypmods, attrtypmod);
		}
	}
	else
		ereport(ERROR,
				(errcode(ERRCODE_DATATYPE_MISMATCH),
			 errmsg("function \"%s\" in FROM has unsupported return type %s",
					funcname, format_type_be(funcrettype)),
							   errOmitLocation(true)));

	/*----------
	 * Flags:
	 * - this RTE should be expanded to include descendant tables,
	 * - this RTE is in the FROM clause,
	 * - this RTE should be checked for appropriate access rights.
	 *
	 * Functions are never checked for access rights (at least, not by
	 * the RTE permissions mechanism).
	 *----------
	 */
	rte->inh = false;			/* never true for functions */
	rte->inFromCl = inFromCl;

	rte->requiredPerms = 0;
	rte->checkAsUser = InvalidOid;

	/*
	 * Add completed RTE to pstate's range table list, but not to join list
	 * nor namespace --- caller must do that if appropriate.
	 */
	if (pstate != NULL)
		pstate->p_rtable = lappend(pstate->p_rtable, rte);

	return rte;
}

/*
 * Add an entry for a VALUES list to the pstate's range table (p_rtable).
 *
 * This is much like addRangeTableEntry() except that it makes a values RTE.
 */
RangeTblEntry *
addRangeTableEntryForValues(ParseState *pstate,
							List *exprs,
							Alias *alias,
							bool inFromCl)
{
	RangeTblEntry *rte = makeNode(RangeTblEntry);
	char	   *refname = alias ? alias->aliasname : pstrdup("*VALUES*");
	Alias	   *eref;
	int			numaliases;
	int			numcolumns;

	rte->rtekind = RTE_VALUES;
	rte->relid = InvalidOid;
	rte->subquery = NULL;
	rte->values_lists = exprs;
	rte->alias = alias;

	eref = alias ? copyObject(alias) : makeAlias(refname, NIL);

	/* fill in any unspecified alias columns */
	numcolumns = list_length((List *) linitial(exprs));
	numaliases = list_length(eref->colnames);
	while (numaliases < numcolumns)
	{
		char		attrname[64];

		numaliases++;
		snprintf(attrname, sizeof(attrname), "column%d", numaliases);
		eref->colnames = lappend(eref->colnames,
								 makeString(pstrdup(attrname)));
	}
	if (numcolumns < numaliases)
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
				 errmsg("VALUES lists \"%s\" have %d columns available but %d columns specified",
						refname, numcolumns, numaliases),
								   errOmitLocation(true)));

	rte->eref = eref;

	/*----------
	 * Flags:
	 * - this RTE should be expanded to include descendant tables,
	 * - this RTE is in the FROM clause,
	 * - this RTE should be checked for appropriate access rights.
	 *
	 * Subqueries are never checked for access rights.
	 *----------
	 */
	rte->inh = false;			/* never true for values RTEs */
	rte->inFromCl = inFromCl;
	rte->requiredPerms = 0;
	rte->checkAsUser = InvalidOid;

	/*
	 * Add completed RTE to pstate's range table list, but not to join list
	 * nor namespace --- caller must do that if appropriate.
	 */
	if (pstate != NULL)
		pstate->p_rtable = lappend(pstate->p_rtable, rte);

	return rte;
}

/*
 * Add an entry for a join to the pstate's range table (p_rtable).
 *
 * This is much like addRangeTableEntry() except that it makes a join RTE.
 */
RangeTblEntry *
addRangeTableEntryForJoin(ParseState *pstate,
						  List *colnames,
						  JoinType jointype,
						  List *aliasvars,
						  Alias *alias,
						  bool inFromCl)
{
	RangeTblEntry *rte = makeNode(RangeTblEntry);
	Alias	   *eref;
	int			numaliases;

	/*
	 * Fail if join has too many columns --- we must be able to reference
	 * any of the columns with an AttrNumber.
	 */
	if (list_length(aliasvars) > MaxAttrNumber)
		ereport(ERROR,
				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
				 errmsg("joins can have at most %d columns",
						MaxAttrNumber)));

	rte->rtekind = RTE_JOIN;
	rte->relid = InvalidOid;
	rte->subquery = NULL;
	rte->jointype = jointype;
	rte->joinaliasvars = aliasvars;
	rte->alias = alias;

	/* transform any Vars of type UNKNOWNOID if we can */
	fixup_unknown_vars_in_exprlist(pstate, rte->joinaliasvars);

	eref = alias ? (Alias *) copyObject(alias) : makeAlias("unnamed_join", NIL);
	numaliases = list_length(eref->colnames);

	/* fill in any unspecified alias columns */
	if (numaliases < list_length(colnames))
		eref->colnames = list_concat(eref->colnames,
									 list_copy_tail(colnames, numaliases));

	rte->eref = eref;

	/*----------
	 * Flags:
	 * - this RTE should be expanded to include descendant tables,
	 * - this RTE is in the FROM clause,
	 * - this RTE should be checked for appropriate access rights.
	 *
	 * Joins are never checked for access rights.
	 *----------
	 */
	rte->inh = false;			/* never true for joins */
	rte->inFromCl = inFromCl;

	rte->requiredPerms = 0;
	rte->checkAsUser = InvalidOid;

	/*
	 * Add completed RTE to pstate's range table list, but not to join list
	 * nor namespace --- caller must do that if appropriate.
	 */
	if (pstate != NULL)
		pstate->p_rtable = lappend(pstate->p_rtable, rte);

	return rte;
}

/*
 * Add an entry for a CTE to the pstate's range table (p_rtable).
 *
 * This is just like addRangeTableEntry() except that it makes a CTE RTE.
 */
RangeTblEntry *
addRangeTableEntryForCTE(ParseState *pstate,
						 CommonTableExpr *cte,
						 Index levelsup,
						 RangeVar *rangeVar,
						 bool inFromCl)
{
	RangeTblEntry *rte = makeNode(RangeTblEntry);

	rte->rtekind = RTE_CTE;
	rte->ctename = cte->ctename;
	rte->ctelevelsup = levelsup;

	/* Self-reference if and only if CTE's parse analysis isn't completed */
	rte->self_reference = !IsA(cte->ctequery, Query);
	Assert(cte->cterecursive || !rte->self_reference);
	/* Bump the CTE's refcount if this isn't a self-reference */
	if (!rte->self_reference)
		cte->cterefcount++;

	/* Currently, we only support SELECT in WITH query */
	AssertImply(IsA(cte->ctequery, Query),
				((Query *) cte->ctequery)->commandType == CMD_SELECT);

	rte->ctecoltypes = cte->ctecoltypes;
	rte->ctecoltypmods = cte->ctecoltypmods;

	rte->alias = rangeVar->alias;
	char *refname = rte->alias ? rte->alias->aliasname : cte->ctename;
	Alias *eref;

	if (rte->alias)
		eref = copyObject(rte->alias);
	else
		eref = makeAlias(refname, NIL);
	int numaliases = list_length(eref->colnames);

	/* fill in any unspecified alias columns */
	int varattno = 0;
	ListCell *lc;
	foreach(lc, cte->ctecolnames)
	{
		varattno++;
		if (varattno > numaliases)
			eref->colnames = lappend(eref->colnames, lfirst(lc));
	}
	if (varattno < numaliases)
	{
		ereport(ERROR,
				(errcode(ERRCODE_SYNTAX_ERROR),
				 errmsg(ERRMSG_GP_WITH_COLUMNS_MISMATCH, refname)));
	}

	rte->eref = eref;

	/*----------
	 * Flags:
	 * - this RTE should be expanded to include descendant tables,
	 * - this RTE is in the FROM clause,
	 * - this RTE should be checked for appropriate access rights.
	 *
	 * Subqueries are never checked for access rights.
	 *----------
	 */
	rte->inh = false;			/* never true for subqueries */
	rte->inFromCl = inFromCl;

	rte->requiredPerms = 0;
	rte->checkAsUser = InvalidOid;

	/*
	 * Add completed RTE to pstate's range table list, but not to join list
	 * nor namespace --- caller must do that if appropriate.
	 */
	if (pstate != NULL)
		pstate->p_rtable = lappend(pstate->p_rtable, rte);

	return rte;
}


/*
 * Has the specified refname been selected FOR UPDATE/FOR SHARE?
 *
 * Note: we pay no attention to whether it's FOR UPDATE vs FOR SHARE.
 */
static LockingClause*
getLockingClause(ParseState *pstate, char *refname)
{
	/* Outer loop to check parent query levels as well as this one */
	while (pstate != NULL)
	{
		ListCell   *l;

		foreach(l, pstate->p_locking_clause)
		{
			LockingClause *lc = (LockingClause *) lfirst(l);

			if (lc->lockedRels == NIL)
			{
				return lc;  				/* all tables used in query */
			}
			else
			{
				/* just the named tables */
				ListCell	*l2;
				foreach(l2, lc->lockedRels)
				{
					char	*rname = strVal(lfirst(l2));

					if (strcmp(refname, rname) == 0)
						return lc;         /* refname matched */
				}
			}
		}
		pstate = pstate->parentParseState;
	}

	return NULL;
}

/*
 * isSimplyUpdatableRelation
 *
 * The oid must reference a normal, heap relation. This disallows
 * AO, AO/CO, external tables, views, etc.
 */
bool
isSimplyUpdatableRelation(Oid relid)
{
	if (OidIsValid(relid))
	{
		cqContext		*pcqCtx;
		HeapTuple		 tuple;

		pcqCtx = caql_beginscan(
				NULL,
				cql("SELECT * FROM pg_class "
					" WHERE oid = :1 ",
					ObjectIdGetDatum(relid)));

		tuple = caql_getnext(pcqCtx);

		if (!HeapTupleIsValid(tuple))
			elog(ERROR, "cache lookup failed for relation %u", relid);
		Form_pg_class rel = (Form_pg_class) GETSTRUCT(tuple);
		bool is_heap_tuple = rel->relkind == RELKIND_RELATION &&
							 rel->relstorage == RELSTORAGE_HEAP;

		caql_endscan(pcqCtx);
		return is_heap_tuple;
	}
	return false;
}

/*
 * extractSimplyUpdatableRTEIndex
 *  given a range table associated with a simply updatable range table,
 *    return the desired RangeTblEntry
 *
 * NOTE: The range table *MUST* belong to a simply updatable query.
 * 
 * The semantics of a simply updatable query demand a range table consisting
 * of exactly one logical table. Thus, for the simple case of a one-element
 * range table, we quickly return the index for the lone RTE.
 * However, we must also cope with inheritance, where an RTE requesting 
 * inheritance may have been expanded out into its child relations. In this
 * case, we seek to return the parent RTE.
 */
Index
extractSimplyUpdatableRTEIndex(List *rtable) 
{
	Assert(list_length(rtable) > 0);
	if (list_length(rtable) == 1)
		return 1;

	/* 
	 * This better be an inheritance case. 
	 * Find the RTE with inh = true. 
	 * Furthermore, we Insist that no other RTEs have inh = true. 
	 */
	Index 			temp, ret = 0;
	ListCell        *lc;
	foreach_with_count (lc, rtable, temp)
	{
		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
		if (rte->inh)
		{
			Insist(ret == 0);	/* to be simply updatable, there cannot be more than 1 parent table */
			ret = temp + 1;		/* the temp counter is zero indexed */
		}
	}
	Insist(ret != 0);
	return ret;
}

/*
 * Add the given RTE as a top-level entry in the pstate's join list
 * and/or name space lists.  (We assume caller has checked for any
 * namespace conflicts.)
 */
void
addRTEtoQuery(ParseState *pstate, RangeTblEntry *rte,
			  bool addToJoinList,
			  bool addToRelNameSpace, bool addToVarNameSpace)
{
	if (addToJoinList)
	{
		int			rtindex = RTERangeTablePosn(pstate, rte, NULL);
		RangeTblRef *rtr = makeNode(RangeTblRef);

		rtr->rtindex = rtindex;
		pstate->p_joinlist = lappend(pstate->p_joinlist, rtr);
	}
	if (addToRelNameSpace)
		pstate->p_relnamespace = lappend(pstate->p_relnamespace, rte);
	if (addToVarNameSpace)
		pstate->p_varnamespace = lappend(pstate->p_varnamespace, rte);
}

/*
 * Add a POSTQUEL-style implicit RTE.
 *
 * We assume caller has already checked that there is no RTE or join with
 * a conflicting name.
 */
RangeTblEntry *
addImplicitRTE(ParseState *pstate, RangeVar *relation, int location)
{
	RangeTblEntry *rte;

	/* issue warning or error as needed */
	warnAutoRange(pstate, relation, location);

	/*
	 * Note that we set inFromCl true, so that the RTE will be listed
	 * explicitly if the parsetree is ever decompiled by ruleutils.c. This
	 * provides a migration path for views/rules that were originally written
	 * with implicit-RTE syntax.
	 */
	rte = addRangeTableEntry(pstate, relation, NULL, false, true);
	/* Add to joinlist and relnamespace, but not varnamespace */
	addRTEtoQuery(pstate, rte, true, true, false);

	return rte;
}

/*
 * expandRTE -- expand the columns of a rangetable entry
 *
 * This creates lists of an RTE's column names (aliases if provided, else
 * real names) and Vars for each column.  Only user columns are considered.
 * If include_dropped is FALSE then dropped columns are omitted from the
 * results.  If include_dropped is TRUE then empty strings and NULL constants
 * (not Vars!) are returned for dropped columns.
 *
 * rtindex and sublevels_up are the varno and varlevelsup values to use
 * in the created Vars.  Ordinarily rtindex should match the actual position
 * of the RTE in its rangetable.
 *
 * The output lists go into *colnames and *colvars.
 * If only one of the two kinds of output list is needed, pass NULL for the
 * output pointer for the unwanted one.
 */
void
expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
		int location, bool include_dropped,
		  List **colnames, List **colvars)
{
	int			varattno;

	if (colnames)
		*colnames = NIL;
	if (colvars)
		*colvars = NIL;

	switch (rte->rtekind)
	{
		case RTE_RELATION:
			/* Ordinary relation RTE */
			expandRelation(rte->relid, rte->eref, rtindex, sublevels_up,
						   include_dropped, colnames, colvars);
			break;
		case RTE_SUBQUERY:
			{
				/* Subquery RTE */
				ListCell   *aliasp_item = list_head(rte->eref->colnames);
				ListCell   *tlistitem;

				varattno = 0;
				foreach(tlistitem, rte->subquery->targetList)
				{
					TargetEntry *te = (TargetEntry *) lfirst(tlistitem);

					if (te->resjunk)
						continue;
					varattno++;
					Assert(varattno == te->resno);

					if (colnames)
					{
						/* Assume there is one alias per target item */
						char	   *label = strVal(lfirst(aliasp_item));

						*colnames = lappend(*colnames, makeString(pstrdup(label)));
						aliasp_item = lnext(aliasp_item);
					}

					if (colvars)
					{
						Var		   *varnode;

						varnode = makeVar(rtindex, varattno,
										  exprType((Node *) te->expr),
										  exprTypmod((Node *) te->expr),
										  sublevels_up);

						*colvars = lappend(*colvars, varnode);
					}
				}
			}
			break;
		case RTE_CTE:
			{
				ListCell *aliasp_item = list_head(rte->eref->colnames);
				ListCell *lct;
				ListCell *lcm;

				varattno = 0;
				forboth(lct, rte->ctecoltypes,
						lcm, rte->ctecoltypmods)
				{
					Oid coltype = lfirst_oid(lct);
					int32 coltypmod = lfirst_int(lcm);

					varattno++;

					if (colnames)
					{
						/* Assume there is one alias per output column */
						Assert(IsA(lfirst(aliasp_item), String));
						char *label = strVal(lfirst(aliasp_item));

						*colnames = lappend(*colnames, makeString(pstrdup(label)));
						aliasp_item = lnext(aliasp_item);
					}

					if (colvars)
					{
						Var	*varnode;

						varnode = makeVar(rtindex, varattno,
										  coltype, coltypmod,
										  sublevels_up);
						*colvars = lappend(*colvars, varnode);
					}
				}
			}
			break;
			
		case RTE_TABLEFUNCTION:
		case RTE_FUNCTION:
			{
				/* Function RTE */
				TypeFuncClass functypclass;
				Oid			funcrettype;
				TupleDesc	tupdesc;

				functypclass = get_expr_result_type(rte->funcexpr,
													&funcrettype,
													&tupdesc);
				if (functypclass == TYPEFUNC_COMPOSITE)
				{
					/* Composite data type, e.g. a table's row type */
					Assert(tupdesc);
					expandTupleDesc(tupdesc, rte->eref, rtindex, sublevels_up,
									include_dropped, colnames, colvars);
				}
				else if (functypclass == TYPEFUNC_SCALAR)
				{
					/* Base data type, i.e. scalar */
					if (colnames)
						*colnames = lappend(*colnames,
											linitial(rte->eref->colnames));

					if (colvars)
					{
						Var		   *varnode;

						varnode = makeVar(rtindex, 1,
										  funcrettype, -1,
										  sublevels_up);

						*colvars = lappend(*colvars, varnode);
					}
				}
				else if (functypclass == TYPEFUNC_RECORD)
				{
					if (colnames)
						*colnames = copyObject(rte->eref->colnames);
					if (colvars)
					{
						ListCell   *l1;
						ListCell   *l2;
						int			attnum = 0;

						forboth(l1, rte->funccoltypes, l2, rte->funccoltypmods)
						{
							Oid			attrtype = lfirst_oid(l1);
							int32		attrtypmod = lfirst_int(l2);
							Var		   *varnode;

							attnum++;
							varnode = makeVar(rtindex,
											  attnum,
											  attrtype,
											  attrtypmod,
											  sublevels_up);
							*colvars = lappend(*colvars, varnode);
						}
					}
				}
				else
				{
					/* addRangeTableEntryForFunction should've caught this */
					elog(ERROR, "function in FROM has unsupported return type");
				}
			}
			break;
		case RTE_VALUES:
			{
				/* Values RTE */
				ListCell   *aliasp_item = list_head(rte->eref->colnames);
				ListCell   *lc;

				varattno = 0;
				foreach(lc, (List *) linitial(rte->values_lists))
				{
					Node	   *col = (Node *) lfirst(lc);

					varattno++;
					if (colnames)
					{
						/* Assume there is one alias per column */
						char	   *label = strVal(lfirst(aliasp_item));

						*colnames = lappend(*colnames,
											makeString(pstrdup(label)));
						aliasp_item = lnext(aliasp_item);
					}

					if (colvars)
					{
						Var		   *varnode;

						varnode = makeVar(rtindex, varattno,
										  exprType(col),
										  exprTypmod(col),
										  sublevels_up);
						*colvars = lappend(*colvars, varnode);
					}
				}
			}
			break;
		case RTE_JOIN:
			{
				/* Join RTE */
				ListCell   *colname;
				ListCell   *aliasvar;

				Assert(list_length(rte->eref->colnames) == list_length(rte->joinaliasvars));

				varattno = 0;
				forboth(colname, rte->eref->colnames, aliasvar, rte->joinaliasvars)
				{
					Node	   *avar = (Node *) lfirst(aliasvar);

					varattno++;

					/*
					 * During ordinary parsing, there will never be any
					 * deleted columns in the join; but we have to check since
					 * this routine is also used by the rewriter, and joins
					 * found in stored rules might have join columns for
					 * since-deleted columns.  This will be signaled by a NULL
					 * Const in the alias-vars list.
					 */
					if (IsA(avar, Const))
					{
						if (include_dropped)
						{
							if (colnames)
								*colnames = lappend(*colnames,
													makeString(pstrdup("")));
							if (colvars)
								*colvars = lappend(*colvars,
												   copyObject(avar));
						}
						continue;
					}

					if (colnames)
					{
						char	   *label = strVal(lfirst(colname));

						*colnames = lappend(*colnames,
											makeString(pstrdup(label)));
					}

					if (colvars)
					{
						Var		   *varnode;

						varnode = makeVar(rtindex, varattno,
										  exprType(avar),
										  exprTypmod(avar),
										  sublevels_up);

						*colvars = lappend(*colvars, varnode);
					}
				}
			}
			break;
		default:
			elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
	}
}

/*
 * expandRelation -- expandRTE subroutine
 */
static void
expandRelation(Oid relid, Alias *eref, int rtindex, int sublevels_up,
			   bool include_dropped,
			   List **colnames, List **colvars)
{
	Relation	rel;

	/* Get the tupledesc and turn it over to expandTupleDesc */
	rel = relation_open(relid, AccessShareLock);
	expandTupleDesc(rel->rd_att, eref, rtindex, sublevels_up, include_dropped,
					colnames, colvars);
	relation_close(rel, AccessShareLock);
}

/*
 * expandTupleDesc -- expandRTE subroutine
 */
static void
expandTupleDesc(TupleDesc tupdesc, Alias *eref,
				int rtindex, int sublevels_up,
				bool include_dropped,
				List **colnames, List **colvars)
{
	int			maxattrs = tupdesc->natts;
	int			numaliases = list_length(eref->colnames);
	int			varattno;

	for (varattno = 0; varattno < maxattrs; varattno++)
	{
		Form_pg_attribute attr = tupdesc->attrs[varattno];

		if (attr->attisdropped)
		{
			if (include_dropped)
			{
				if (colnames)
					*colnames = lappend(*colnames, makeString(pstrdup("")));
				if (colvars)
				{
					/*
					 * can't use atttypid here, but it doesn't really matter
					 * what type the Const claims to be.
					 */
					*colvars = lappend(*colvars, makeNullConst(INT4OID, -1));
				}
			}
			continue;
		}

		if (colnames)
		{
			char	   *label;

			if (varattno < numaliases)
				label = strVal(list_nth(eref->colnames, varattno));
			else
				label = NameStr(attr->attname);
			*colnames = lappend(*colnames, makeString(pstrdup(label)));
		}

		if (colvars)
		{
			Var		   *varnode;

			varnode = makeVar(rtindex, attr->attnum,
							  attr->atttypid, attr->atttypmod,
							  sublevels_up);

			*colvars = lappend(*colvars, varnode);
		}
	}
}

/*
 * expandRelAttrs -
 *	  Workhorse for "*" expansion: produce a list of targetentries
 *	  for the attributes of the rte
 *
 * As with expandRTE, rtindex/sublevels_up determine the varno/varlevelsup
 * fields of the Vars produced.  pstate->p_next_resno determines the resnos
 * assigned to the TLEs.
 */
List *
expandRelAttrs(ParseState *pstate, RangeTblEntry *rte,
			   int rtindex, int sublevels_up, int location)
{
	List	   *names,
			   *vars;
	ListCell   *name,
			   *var;
	List	   *te_list = NIL;

	expandRTE(rte, rtindex, sublevels_up, location, false,
			  &names, &vars);

	forboth(name, names, var, vars)
	{
		char	   *label = strVal(lfirst(name));
		Node	   *varnode = (Node *) lfirst(var);
		TargetEntry *te;

		te = makeTargetEntry((Expr *) varnode,
							 (AttrNumber) pstate->p_next_resno++,
							 label,
							 false);
		te_list = lappend(te_list, te);
	}

	Assert(name == NULL && var == NULL);		/* lists not the same length? */

	return te_list;
}

/*
 * get_rte_attribute_name
 *		Get an attribute name from a RangeTblEntry
 *
 * This is unlike get_attname() because we use aliases if available.
 * In particular, it will work on an RTE for a subselect or join, whereas
 * get_attname() only works on real relations.
 *
 * "*" is returned if the given attnum is InvalidAttrNumber --- this case
 * occurs when a Var represents a whole tuple of a relation.
 */
const char *
get_rte_attribute_name(RangeTblEntry *rte, AttrNumber attnum)
{
    const char *name;

	if (attnum == InvalidAttrNumber)
		return "*";

	/*
	 * If there is a user-written column alias, use it.
	 */
	if (rte->alias &&
		attnum > 0 && attnum <= list_length(rte->alias->colnames))
		return strVal(list_nth(rte->alias->colnames, attnum - 1));

    /*
     * CDB: Pseudo columns have negative attribute numbers below the
     * lowest system attribute number.
     */
    if (attnum <= FirstLowInvalidHeapAttributeNumber)
    {
        CdbRelColumnInfo   *rci = cdb_rte_find_pseudo_column(rte, attnum);

        if (!rci)
            goto bogus;
        return rci->colname;
    }

    /*
	 * If the RTE is a relation, go to the system catalogs not the
	 * eref->colnames list.  This is a little slower but it will give the
	 * right answer if the column has been renamed since the eref list was
	 * built (which can easily happen for rules).
	 */
	if (rte->rtekind == RTE_RELATION)
		return get_relid_attribute_name(rte->relid, attnum);

	/*
	 * Otherwise use the column name from eref.  There should always be one.
	 */
	if (rte->eref != NULL &&
        attnum > 0 &&
        attnum <= list_length(rte->eref->colnames))
		return strVal(list_nth(rte->eref->colnames, attnum - 1));

    /* CDB: Get name of sysattr even if relid is no good (e.g. SubqueryScan) */
    if (attnum < 0 &&
        attnum > FirstLowInvalidHeapAttributeNumber)
    {
		Form_pg_attribute att_tup = SystemAttributeDefinition(attnum, true);

		return NameStr(att_tup->attname);
    }

bogus:
	/* else caller gave us a bogus attnum */
    name = (rte->eref && rte->eref->aliasname) ? rte->eref->aliasname
                                               : "*BOGUS*";
    ereport(WARNING, (errcode(ERRCODE_INTERNAL_ERROR),
                      errmsg_internal("invalid attnum %d for rangetable entry %s",
                                      attnum, name) ));
	return "*BOGUS*";
}

static bool get_attisdropped(Oid relid, int attnum)
{
	HeapTuple			 tp;
	Form_pg_attribute	 att_tup;
	bool				 result = false;
	cqContext			*pcqCtx;

	/* SELECT attisdropped FROM pg_attribute */

	pcqCtx = caql_beginscan(
			NULL,
			cql("SELECT * FROM pg_attribute "
				" WHERE attrelid = :1 "
				" AND attnum = :2 ",
				ObjectIdGetDatum(relid),
				Int16GetDatum(attnum)));

	tp = caql_getnext(pcqCtx);

	if (!HeapTupleIsValid(tp))		/* shouldn't happen */
		elog(ERROR, "cache lookup failed for attribute %d of relation %u",
			 attnum, relid);
	att_tup = (Form_pg_attribute) GETSTRUCT(tp);
	result	= att_tup->attisdropped;

	caql_endscan(pcqCtx);

	return (result);
}

/*
 * get_rte_attribute_type
 *		Get attribute type information from a RangeTblEntry
 */
void
get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
					   Oid *vartype, int32 *vartypmod)
{
	switch (rte->rtekind)
	{
		case RTE_RELATION:
			{
				/* Plain relation RTE --- get the attribute's type info */
				HeapTuple	tp;
				Form_pg_attribute att_tup;
				cqContext  *pcqCtx;

				pcqCtx = caql_beginscan(
						NULL,
						cql("SELECT * FROM pg_attribute "
							" WHERE attrelid = :1 "
							" AND attnum = :2 ",
							ObjectIdGetDatum(rte->relid),
							Int16GetDatum(attnum)));

				tp = caql_getnext(pcqCtx);

				if (!HeapTupleIsValid(tp))		/* shouldn't happen */
					elog(ERROR, "cache lookup failed for attribute %d of relation %u",
						 attnum, rte->relid);
				att_tup = (Form_pg_attribute) GETSTRUCT(tp);

				/*
				 * If dropped column, pretend it ain't there.  See notes in
				 * scanRTEForColumn.
				 */
				if (att_tup->attisdropped)
					ereport(ERROR,
							(errcode(ERRCODE_UNDEFINED_COLUMN),
					errmsg("column \"%s\" of relation \"%s\" does not exist",
						   NameStr(att_tup->attname),
						   get_rel_name(rte->relid)),
					errOmitLocation(true)));
				*vartype = att_tup->atttypid;
				*vartypmod = att_tup->atttypmod;

				caql_endscan(pcqCtx);
			}
			break;
		case RTE_SUBQUERY:
			{
				/* Subselect RTE --- get type info from subselect's tlist */
				TargetEntry *te = get_tle_by_resno(rte->subquery->targetList,
												   attnum);

				if (te == NULL || te->resjunk)
					elog(ERROR, "subquery %s does not have attribute %d",
						 rte->eref->aliasname, attnum);
				*vartype = exprType((Node *) te->expr);
				*vartypmod = exprTypmod((Node *) te->expr);
			}
			break;
		case RTE_TABLEFUNCTION:
		case RTE_FUNCTION:
			{
				/* Function RTE */
				TypeFuncClass functypclass;
				Oid			funcrettype;
				TupleDesc	tupdesc;

				functypclass = get_expr_result_type(rte->funcexpr,
													&funcrettype,
													&tupdesc);

				if (functypclass == TYPEFUNC_COMPOSITE)
				{
					/* Composite data type, e.g. a table's row type */
					Form_pg_attribute att_tup;

					Assert(tupdesc);
					/* this is probably a can't-happen case */
					if (attnum < 1 || attnum > tupdesc->natts)
						ereport(ERROR,
								(errcode(ERRCODE_UNDEFINED_COLUMN),
						errmsg("column %d of relation \"%s\" does not exist",
							   attnum,
							   rte->eref->aliasname)));

					att_tup = tupdesc->attrs[attnum - 1];

					/*
					 * If dropped column, pretend it ain't there.  See notes
					 * in scanRTEForColumn.
					 */
					if (att_tup->attisdropped)
						ereport(ERROR,
								(errcode(ERRCODE_UNDEFINED_COLUMN),
								 errmsg("column \"%s\" of relation \"%s\" does not exist",
										NameStr(att_tup->attname),
										rte->eref->aliasname)));
					*vartype = att_tup->atttypid;
					*vartypmod = att_tup->atttypmod;
				}
				else if (functypclass == TYPEFUNC_SCALAR)
				{
					/* Base data type, i.e. scalar */
					*vartype = funcrettype;
					*vartypmod = -1;
				}
				else if (functypclass == TYPEFUNC_RECORD)
				{
					*vartype = list_nth_oid(rte->funccoltypes, attnum - 1);
					*vartypmod = list_nth_int(rte->funccoltypmods, attnum - 1);
				}
				else
				{
					/* addRangeTableEntryForFunction should've caught this */
					elog(ERROR, "function in FROM has unsupported return type");
				}
			}
			break;
		case RTE_VALUES:
			{
				/* Values RTE --- get type info from first sublist */
				List	   *collist = (List *) linitial(rte->values_lists);
				Node	   *col;

				if (attnum < 1 || attnum > list_length(collist))
					elog(ERROR, "values list %s does not have attribute %d",
						 rte->eref->aliasname, attnum);
				col = (Node *) list_nth(collist, attnum - 1);
				*vartype = exprType(col);
				*vartypmod = exprTypmod(col);
			}
			break;
		case RTE_JOIN:
			{
				/*
				 * Join RTE --- get type info from join RTE's alias variable
				 */
				Node	   *aliasvar;

				Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
				aliasvar = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
				*vartype = exprType(aliasvar);
				*vartypmod = exprTypmod(aliasvar);
			}
			break;
		case RTE_CTE:
			{
				/* CTE RTE --- get type info from lists in the RTE */
				Assert(attnum > 0 && attnum <= list_length(rte->ctecoltypes));
				*vartype = list_nth_oid(rte->ctecoltypes, attnum - 1);
				*vartypmod = list_nth_int(rte->ctecoltypmods, attnum - 1);
			}
			break;
		default:
			elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
	}
}

/*
 * get_rte_attribute_is_dropped
 *		Check whether attempted attribute ref is to a dropped column
 */
bool
get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum)
{
	bool		result;

	switch (rte->rtekind)
	{
		case RTE_RELATION:
			{
				result = get_attisdropped(rte->relid, attnum);
			}
			break;
		case RTE_SUBQUERY:
		case RTE_VALUES:
		case RTE_CTE:
			/* Subselect and Values RTEs never have dropped columns */
			result = false;
			break;
		case RTE_JOIN:
			{
				/*
				 * A join RTE would not have dropped columns when constructed,
				 * but one in a stored rule might contain columns that were
				 * dropped from the underlying tables, if said columns are
				 * nowhere explicitly referenced in the rule.  This will be
				 * signaled to us by a NULL Const in the joinaliasvars list.
				 */
				Var		   *aliasvar;

				if (attnum <= 0 ||
					attnum > list_length(rte->joinaliasvars))
					elog(ERROR, "invalid varattno %d", attnum);
				aliasvar = (Var *) list_nth(rte->joinaliasvars, attnum - 1);

				result = IsA(aliasvar, Const);
			}
			break;
		case RTE_TABLEFUNCTION:
		case RTE_FUNCTION:
			{
				/* Function RTE */
				Oid			funcrettype = exprType(rte->funcexpr);
				Oid			funcrelid = typeidTypeRelid(funcrettype);

				if (OidIsValid(funcrelid))
				{
					/*
					 * Composite data type, i.e. a table's row type
					 *
					 * Same as ordinary relation RTE
					 */
					result = get_attisdropped(funcrelid, attnum);
				}
				else
				{
					/*
					 * Must be a base data type, i.e. scalar
					 */
					result = false;
				}
			}
			break;
		default:
			elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
			result = false;		/* keep compiler quiet */
	}

	return result;
}

/*
 * Given a targetlist and a resno, return the matching TargetEntry
 *
 * Returns NULL if resno is not present in list.
 *
 * Note: we need to search, rather than just indexing with list_nth(),
 * because not all tlists are sorted by resno.
 */
TargetEntry *
get_tle_by_resno(List *tlist, AttrNumber resno)
{
	ListCell   *l;

	foreach(l, tlist)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(l);

		if (tle->resno == resno)
			return tle;
	}
	return NULL;
}

/*
 * Given a Query and rangetable index, return relation's RowMarkClause if any
 *
 * Returns NULL if relation is not selected FOR UPDATE/SHARE
 */
RowMarkClause *
get_rowmark(Query *qry, Index rtindex)
{
	ListCell   *l;

	foreach(l, qry->rowMarks)
	{
		RowMarkClause *rc = (RowMarkClause *) lfirst(l);

		if (rc->rti == rtindex)
			return rc;
	}
	return NULL;
}

/*
 *	given relation and att name, return attnum of variable
 *
 *	Returns InvalidAttrNumber if the attr doesn't exist (or is dropped).
 *
 *	This should only be used if the relation is already
 *	heap_open()'ed.  Use the cache version get_attnum()
 *	for access to non-opened relations.
 */
int
attnameAttNum(Relation rd, const char *attname, bool sysColOK)
{
	int			i;

	for (i = 0; i < rd->rd_rel->relnatts; i++)
	{
		Form_pg_attribute att = rd->rd_att->attrs[i];

		if (namestrcmp(&(att->attname), attname) == 0 && !att->attisdropped)
			return i + 1;
	}

	if (sysColOK)
	{
		if ((i = specialAttNum(attname)) != InvalidAttrNumber)
		{
			if (i != ObjectIdAttributeNumber || rd->rd_rel->relhasoids)
				return i;
		}
	}

	/* on failure */
	return InvalidAttrNumber;
}

/* specialAttNum()
 *
 * Check attribute name to see if it is "special", e.g. "oid".
 * - thomas 2000-02-07
 *
 * Note: this only discovers whether the name could be a system attribute.
 * Caller needs to verify that it really is an attribute of the rel,
 * at least in the case of "oid", which is now optional.
 */
static int
specialAttNum(const char *attname)
{
	Form_pg_attribute sysatt;

	sysatt = SystemAttributeByName(attname,
								   true /* "oid" will be accepted */ );
	if (sysatt != NULL)
		return sysatt->attnum;
	return InvalidAttrNumber;
}


/*
 * given attribute id, return name of that attribute
 *
 *	This should only be used if the relation is already
 *	heap_open()'ed.  Use the cache version get_atttype()
 *	for access to non-opened relations.
 */
Name
attnumAttName(Relation rd, int attid)
{
	if (attid <= 0)
	{
		Form_pg_attribute sysatt;

		sysatt = SystemAttributeDefinition(attid, rd->rd_rel->relhasoids);
		return &sysatt->attname;
	}
	if (attid > rd->rd_att->natts)
		elog(ERROR, "invalid attribute number %d", attid);
	return &rd->rd_att->attrs[attid - 1]->attname;
}

/*
 * given attribute id, return type of that attribute
 *
 *	This should only be used if the relation is already
 *	heap_open()'ed.  Use the cache version get_atttype()
 *	for access to non-opened relations.
 */
Oid
attnumTypeId(Relation rd, int attid)
{
	if (attid <= 0)
	{
		Form_pg_attribute sysatt;

		sysatt = SystemAttributeDefinition(attid, rd->rd_rel->relhasoids);
		return sysatt->atttypid;
	}
	if (attid > rd->rd_att->natts)
		elog(ERROR, "invalid attribute number %d", attid);
	return rd->rd_att->attrs[attid - 1]->atttypid;
}

/*
 * Generate a warning or error about an implicit RTE, if appropriate.
 *
 * If ADD_MISSING_FROM is not enabled, raise an error. Otherwise, emit
 * a warning.
 */
static void
warnAutoRange(ParseState *pstate, RangeVar *relation, int location)
{
	RangeTblEntry *rte;
	int			sublevels_up;
	const char *badAlias = NULL;

	/*
	 * Check to see if there are any potential matches in the query's
	 * rangetable.	This affects the message we provide.
	 */
	rte = searchRangeTable(pstate, relation);

	/*
	 * If we found a match that has an alias and the alias is visible in the
	 * namespace, then the problem is probably use of the relation's real name
	 * instead of its alias, ie "SELECT foo.* FROM foo f". This mistake is
	 * common enough to justify a specific hint.
	 *
	 * If we found a match that doesn't meet those criteria, assume the
	 * problem is illegal use of a relation outside its scope, as in the
	 * MySQL-ism "SELECT ... FROM a, b LEFT JOIN c ON (a.x = c.y)".
	 */
	if (rte && rte->alias &&
		strcmp(rte->eref->aliasname, relation->relname) != 0 &&
		refnameRangeTblEntry(pstate, NULL /*catalogname*/, NULL, rte->eref->aliasname, location,
							 &sublevels_up) == rte)
		badAlias = rte->eref->aliasname;

	if (!add_missing_from)
	{
		if (rte)
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_TABLE),
			errmsg("invalid reference to FROM-clause entry for table \"%s\"",
				   relation->relname),
					 (badAlias ?
			errhint("Perhaps you meant to reference the table alias \"%s\".",
					badAlias) :
					  errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
							  rte->eref->aliasname)),
					  errOmitLocation(true),
					 parser_errposition(pstate, location)));
		else
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_TABLE),
					 (pstate->parentParseState ?
			 errmsg("missing FROM-clause entry in subquery for table \"%s\"",
					relation->relname) :
					  errmsg("missing FROM-clause entry for table \"%s\"",
							 relation->relname)),
					  errOmitLocation(true),
					 parser_errposition(pstate, location)));
	}
	else
	{
		/* just issue a warning */
		ereport(NOTICE,
				(errcode(ERRCODE_UNDEFINED_TABLE),
				 (pstate->parentParseState ?
				  errmsg("adding missing FROM-clause entry in subquery for table \"%s\"",
						 relation->relname) :
				  errmsg("adding missing FROM-clause entry for table \"%s\"",
						 relation->relname)),
				 (badAlias ?
			errhint("Perhaps you meant to reference the table alias \"%s\".",
					badAlias) :
				  (rte ?
				   errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
						   rte->eref->aliasname) : 0)),
					errOmitLocation(true),
				 parser_errposition(pstate, location)));
	}
}

/*
 * ExecCheckRTPerms
 *		Check access permissions for all relations listed in a range table.
 */
void
ExecCheckRTPerms(List *rangeTable)
{
	if (aclType == HAWQ_ACL_RANGER)
	{
		if(rangeTable!=NULL)
			ExecCheckRTPermsWithRanger(rangeTable);
		return;
	}
	ListCell   *l;
	foreach(l, rangeTable)
	{
		ExecCheckRTEPerms((RangeTblEntry *) lfirst(l));
	}
}

/*
 * ExecCheckRTPerms
 *   Batch implementation: Check access permissions for all relations
 *   listed in a range table with acl_type is ranger.
 */
void
ExecCheckRTPermsWithRanger(List *rangeTable)
{
	List *ranger_check_args = NIL;
	ListCell *l;
	foreach(l, rangeTable)
	{

		AclMode requiredPerms;
		Oid relOid;
		Oid userid;
		RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);

		if (rte->rtekind != RTE_RELATION)
			continue;
		requiredPerms = rte->requiredPerms;
		if (requiredPerms == 0)
			continue;
		bool ret = fallBackToNativeCheck(ACL_KIND_CLASS, rte->relid, GetUserId(), ACL_NO_RIGHTS);
		if (ret) {
			ExecCheckRTEPerms((RangeTblEntry *) lfirst(l));
			continue;
		}

		relOid = rte->relid;
		userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();

		RangerPrivilegeArgs *ranger_check_arg = (RangerPrivilegeArgs *) palloc(sizeof(RangerPrivilegeArgs));
		ranger_check_arg->objkind = ACL_KIND_CLASS;
		ranger_check_arg->object_oid = relOid;
		ranger_check_arg->roleid = userid;
		ranger_check_arg->mask = requiredPerms;
		ranger_check_arg->how = ACLMASK_ALL;
		ranger_check_args = lappend(ranger_check_args, ranger_check_arg);

	}

	if (ranger_check_args == NIL)
		return;

	/* ranger ACL check with package Oids */
	List *aclresults = NIL;
	aclresults = pg_rangercheck_batch(ranger_check_args);
	if (aclresults == NIL)
	{
		elog(ERROR, "ACL check failed\n");
		return;
	}

	/* check result */
	StringInfoData acl_fail_msg;
	bool acl_allok = true;

	ListCell *result;
	foreach(result, aclresults)
	{
		RangerPrivilegeResults *result_ptr = (RangerPrivilegeResults *) lfirst(result);
		if(result_ptr->result != RANGERCHECK_OK)
		{
			if (acl_allok)
			{
				initStringInfo(&acl_fail_msg);
				appendStringInfo(&acl_fail_msg, "permission denied for relation(s): ");
			}
			else
			{
				appendStringInfo(&acl_fail_msg, ", ");
			}
			acl_allok = false;

			/* collect all acl fail relations */
			Oid relOid = result_ptr->relOid;
			const char *rel_name = get_rel_name_partition(relOid);
			const char *namespace_name = get_namespace_name(get_rel_namespace(relOid));
			appendStringInfo(&acl_fail_msg, "%s.%s", namespace_name, rel_name);
		}
	}

	if (ranger_check_args)
	{
		list_free_deep(ranger_check_args);
		ranger_check_args = NIL;
	}
	if (aclresults)
	{
		list_free_deep(aclresults);
		aclresults = NIL;
	}

	if (!acl_allok)
	{
		errstart(ERROR, __FILE__, __LINE__, PG_FUNCNAME_MACRO, TEXTDOMAIN);
		errmsg("%s", acl_fail_msg.data),
		pfree(acl_fail_msg.data);
		errfinish(errOmitLocation(true));
	}
}

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

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

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

	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, so use aclmask not aclcheck.
	 */
	if (pg_class_aclmask(relOid, userid, requiredPerms, ACLMASK_ALL)
			!= requiredPerms) {
		/*
		 * If the table is a partition, return an error message that includes
		 * the name of the parent table.
		 */
		const char *rel_name = get_rel_name_partition(relOid);
		aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS, rel_name);
	}
}