Adding upstream version 14.5.upstream/14.5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3711 insertions, 0 deletions

diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
new file mode 100644
index 0000000..713ec0e
--- /dev/null
+++ b/src/backend/parser/parse_relation.c
@@ -0,0 +1,3711 @@
+/*-------------------------------------------------------------------------
+ *
+ * parse_relation.c
+ *	  parser support routines dealing with relations
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/parser/parse_relation.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <ctype.h>
+
+#include "access/htup_details.h"
+#include "access/relation.h"
+#include "access/sysattr.h"
+#include "access/table.h"
+#include "catalog/heap.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_type.h"
+#include "funcapi.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
+#include "parser/parse_enr.h"
+#include "parser/parse_relation.h"
+#include "parser/parse_type.h"
+#include "parser/parsetree.h"
+#include "storage/lmgr.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+#include "utils/rel.h"
+#include "utils/syscache.h"
+#include "utils/varlena.h"
+
+
+/*
+ * Support for fuzzily matching columns.
+ *
+ * This is for building diagnostic messages, where non-exact matching
+ * attributes are suggested to the user.  The struct's fields may be facets of
+ * a particular RTE, or of an entire range table, depending on context.
+ */
+typedef struct
+{
+	int			distance;		/* Weighted distance (lowest so far) */
+	RangeTblEntry *rfirst;		/* RTE of first */
+	AttrNumber	first;			/* Closest attribute so far */
+	RangeTblEntry *rsecond;		/* RTE of second */
+	AttrNumber	second;			/* Second closest attribute so far */
+} FuzzyAttrMatchState;
+
+#define MAX_FUZZY_DISTANCE				3
+
+
+static ParseNamespaceItem *scanNameSpaceForRefname(ParseState *pstate,
+												   const char *refname,
+												   int location);
+static ParseNamespaceItem *scanNameSpaceForRelid(ParseState *pstate, Oid relid,
+												 int location);
+static void check_lateral_ref_ok(ParseState *pstate, ParseNamespaceItem *nsitem,
+								 int location);
+static int	scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte,
+							 Alias *eref,
+							 const char *colname, int location,
+							 int fuzzy_rte_penalty,
+							 FuzzyAttrMatchState *fuzzystate);
+static void markRTEForSelectPriv(ParseState *pstate,
+								 int rtindex, AttrNumber col);
+static void expandRelation(Oid relid, Alias *eref,
+						   int rtindex, int sublevels_up,
+						   int location, bool include_dropped,
+						   List **colnames, List **colvars);
+static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
+							int count, int offset,
+							int rtindex, int sublevels_up,
+							int location, bool include_dropped,
+							List **colnames, List **colvars);
+static int	specialAttNum(const char *attname);
+static bool isQueryUsingTempRelation_walker(Node *node, void *context);
+
+
+/*
+ * refnameNamespaceItem
+ *	  Given a possibly-qualified refname, look to see if it matches any visible
+ *	  namespace item.  If so, return a pointer to the nsitem; else return NULL.
+ *
+ *	  Optionally get nsitem'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 item with matching
+ * alias, or matching unqualified relname in the case of alias-less relation
+ * items.  It is possible that such a refname matches multiple items 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 item
+ * 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 SQL says to do.
+ */
+ParseNamespaceItem *
+refnameNamespaceItem(ParseState *pstate,
+					 const char *schemaname,
+					 const char *refname,
+					 int location,
+					 int *sublevels_up)
+{
+	Oid			relId = InvalidOid;
+
+	if (sublevels_up)
+		*sublevels_up = 0;
+
+	if (schemaname != NULL)
+	{
+		Oid			namespaceId;
+
+		/*
+		 * We can use LookupNamespaceNoError() here because we are only
+		 * interested in finding existing RTEs.  Checking USAGE permission on
+		 * the schema is unnecessary since it would have already been checked
+		 * when the RTE was made.  Furthermore, we want to report "RTE not
+		 * found", not "no permissions for schema", if the name happens to
+		 * match a schema name the user hasn't got access to.
+		 */
+		namespaceId = LookupNamespaceNoError(schemaname);
+		if (!OidIsValid(namespaceId))
+			return NULL;
+		relId = get_relname_relid(refname, namespaceId);
+		if (!OidIsValid(relId))
+			return NULL;
+	}
+
+	while (pstate != NULL)
+	{
+		ParseNamespaceItem *result;
+
+		if (OidIsValid(relId))
+			result = scanNameSpaceForRelid(pstate, relId, location);
+		else
+			result = scanNameSpaceForRefname(pstate, refname, location);
+
+		if (result)
+			return result;
+
+		if (sublevels_up)
+			(*sublevels_up)++;
+		else
+			break;
+
+		pstate = pstate->parentParseState;
+	}
+	return NULL;
+}
+
+/*
+ * Search the query's table namespace for an item matching the
+ * given unqualified refname.  Return the nsitem if a unique match, or NULL
+ * if no match.  Raise error if multiple matches.
+ *
+ * Note: it might seem that we shouldn't have to worry about the possibility
+ * of multiple matches; after all, the SQL standard disallows duplicate table
+ * aliases within a given SELECT level.  Historically, however, Postgres has
+ * been laxer than that.  For example, we allow
+ *		SELECT ... FROM tab1 x CROSS JOIN (tab2 x CROSS JOIN tab3 y) z
+ * on the grounds that the aliased join (z) hides the aliases within it,
+ * therefore there is no conflict between the two RTEs named "x".  However,
+ * if tab3 is a LATERAL subquery, then from within the subquery both "x"es
+ * are visible.  Rather than rejecting queries that used to work, we allow
+ * this situation, and complain only if there's actually an ambiguous
+ * reference to "x".
+ */
+static ParseNamespaceItem *
+scanNameSpaceForRefname(ParseState *pstate, const char *refname, int location)
+{
+	ParseNamespaceItem *result = NULL;
+	ListCell   *l;
+
+	foreach(l, pstate->p_namespace)
+	{
+		ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(l);
+
+		/* Ignore columns-only items */
+		if (!nsitem->p_rel_visible)
+			continue;
+		/* If not inside LATERAL, ignore lateral-only items */
+		if (nsitem->p_lateral_only && !pstate->p_lateral_active)
+			continue;
+
+		if (strcmp(nsitem->p_names->aliasname, refname) == 0)
+		{
+			if (result)
+				ereport(ERROR,
+						(errcode(ERRCODE_AMBIGUOUS_ALIAS),
+						 errmsg("table reference \"%s\" is ambiguous",
+								refname),
+						 parser_errposition(pstate, location)));
+			check_lateral_ref_ok(pstate, nsitem, location);
+			result = nsitem;
+		}
+	}
+	return result;
+}
+
+/*
+ * Search the query's table namespace for a relation item matching the
+ * given relation OID.  Return the nsitem if a unique match, or NULL
+ * if no match.  Raise error if multiple matches.
+ *
+ * See the comments for refnameNamespaceItem to understand why this
+ * acts the way it does.
+ */
+static ParseNamespaceItem *
+scanNameSpaceForRelid(ParseState *pstate, Oid relid, int location)
+{
+	ParseNamespaceItem *result = NULL;
+	ListCell   *l;
+
+	foreach(l, pstate->p_namespace)
+	{
+		ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(l);
+		RangeTblEntry *rte = nsitem->p_rte;
+
+		/* Ignore columns-only items */
+		if (!nsitem->p_rel_visible)
+			continue;
+		/* If not inside LATERAL, ignore lateral-only items */
+		if (nsitem->p_lateral_only && !pstate->p_lateral_active)
+			continue;
+
+		/* 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),
+						 parser_errposition(pstate, location)));
+			check_lateral_ref_ok(pstate, nsitem, location);
+			result = nsitem;
+		}
+	}
+	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)
+{
+	Index		levelsup;
+
+	for (levelsup = 0;
+		 pstate != NULL;
+		 pstate = pstate->parentParseState, levelsup++)
+	{
+		ListCell   *lc;
+
+		foreach(lc, pstate->p_ctenamespace)
+		{
+			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
+
+			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;
+}
+
+/*
+ * Search the query's ephemeral named relation namespace for a relation
+ * matching the given unqualified refname.
+ */
+bool
+scanNameSpaceForENR(ParseState *pstate, const char *refname)
+{
+	return name_matches_visible_ENR(pstate, refname);
+}
+
+/*
+ * searchRangeTableForRel
+ *	  See if any RangeTblEntry could possibly match the RangeVar.
+ *	  If so, return a pointer to the RangeTblEntry; else return NULL.
+ *
+ * This is different from refnameNamespaceItem in that it considers every
+ * entry in the ParseState's rangetable(s), not only those that are currently
+ * visible in the p_namespace list(s).  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 errorMissingRTE.
+ *
+ * Notice that we consider both matches on actual relation (or CTE) name
+ * and matches on alias.
+ */
+static RangeTblEntry *
+searchRangeTableForRel(ParseState *pstate, RangeVar *relation)
+{
+	const char *refname = relation->relname;
+	Oid			relId = InvalidOid;
+	CommonTableExpr *cte = NULL;
+	bool		isenr = false;
+	Index		ctelevelsup = 0;
+	Index		levelsup;
+
+	/*
+	 * 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.
+	 *
+	 * NB: It's not critical that RangeVarGetRelid return the correct answer
+	 * here in the face of concurrent DDL.  If it doesn't, the worst case
+	 * scenario is a less-clear error message.  Also, the tables involved in
+	 * the query are already locked, which reduces the number of cases in
+	 * which surprising behavior can occur.  So we do the name lookup
+	 * unlocked.
+	 */
+	if (!relation->schemaname)
+	{
+		cte = scanNameSpaceForCTE(pstate, refname, &ctelevelsup);
+		if (!cte)
+			isenr = scanNameSpaceForENR(pstate, refname);
+	}
+
+	if (!cte && !isenr)
+		relId = RangeVarGetRelid(relation, NoLock, true);
+
+	/* Now look for RTEs matching either the relation/CTE/ENR or the alias */
+	for (levelsup = 0;
+		 pstate != NULL;
+		 pstate = pstate->parentParseState, levelsup++)
+	{
+		ListCell   *l;
+
+		foreach(l, pstate->p_rtable)
+		{
+			RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
+
+			if (rte->rtekind == RTE_RELATION &&
+				OidIsValid(relId) &&
+				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->rtekind == RTE_NAMEDTUPLESTORE &&
+				isenr &&
+				strcmp(rte->enrname, refname) == 0)
+				return rte;
+			if (strcmp(rte->eref->aliasname, refname) == 0)
+				return rte;
+		}
+	}
+	return NULL;
+}
+
+/*
+ * Check for relation-name conflicts between two namespace 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 SQL, 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).
+ *
+ * We ignore the lateral-only flags in the namespace items: the lists must
+ * not conflict, even when all items are considered visible.  However,
+ * columns-only items should be ignored.
+ */
+void
+checkNameSpaceConflicts(ParseState *pstate, List *namespace1,
+						List *namespace2)
+{
+	ListCell   *l1;
+
+	foreach(l1, namespace1)
+	{
+		ParseNamespaceItem *nsitem1 = (ParseNamespaceItem *) lfirst(l1);
+		RangeTblEntry *rte1 = nsitem1->p_rte;
+		const char *aliasname1 = nsitem1->p_names->aliasname;
+		ListCell   *l2;
+
+		if (!nsitem1->p_rel_visible)
+			continue;
+
+		foreach(l2, namespace2)
+		{
+			ParseNamespaceItem *nsitem2 = (ParseNamespaceItem *) lfirst(l2);
+			RangeTblEntry *rte2 = nsitem2->p_rte;
+			const char *aliasname2 = nsitem2->p_names->aliasname;
+
+			if (!nsitem2->p_rel_visible)
+				continue;
+			if (strcmp(aliasname2, 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 SQL rule */
+			ereport(ERROR,
+					(errcode(ERRCODE_DUPLICATE_ALIAS),
+					 errmsg("table name \"%s\" specified more than once",
+							aliasname1)));
+		}
+	}
+}
+
+/*
+ * Complain if a namespace item is currently disallowed as a LATERAL reference.
+ * This enforces both SQL:2008's rather odd idea of what to do with a LATERAL
+ * reference to the wrong side of an outer join, and our own prohibition on
+ * referencing the target table of an UPDATE or DELETE as a lateral reference
+ * in a FROM/USING clause.
+ *
+ * Note: the pstate should be the same query level the nsitem was found in.
+ *
+ * Convenience subroutine to avoid multiple copies of a rather ugly ereport.
+ */
+static void
+check_lateral_ref_ok(ParseState *pstate, ParseNamespaceItem *nsitem,
+					 int location)
+{
+	if (nsitem->p_lateral_only && !nsitem->p_lateral_ok)
+	{
+		/* SQL:2008 demands this be an error, not an invisible item */
+		RangeTblEntry *rte = nsitem->p_rte;
+		char	   *refname = nsitem->p_names->aliasname;
+
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+				 errmsg("invalid reference to FROM-clause entry for table \"%s\"",
+						refname),
+				 (pstate->p_target_nsitem != NULL &&
+				  rte == pstate->p_target_nsitem->p_rte) ?
+				 errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
+						 refname) :
+				 errdetail("The combining JOIN type must be INNER or LEFT for a LATERAL reference."),
+				 parser_errposition(pstate, location)));
+	}
+}
+
+/*
+ * Given an RT index and nesting depth, find the corresponding
+ * ParseNamespaceItem (there must be one).
+ */
+ParseNamespaceItem *
+GetNSItemByRangeTablePosn(ParseState *pstate,
+						  int varno,
+						  int sublevels_up)
+{
+	ListCell   *lc;
+
+	while (sublevels_up-- > 0)
+	{
+		pstate = pstate->parentParseState;
+		Assert(pstate != NULL);
+	}
+	foreach(lc, pstate->p_namespace)
+	{
+		ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(lc);
+
+		if (nsitem->p_rtindex == varno)
+			return nsitem;
+	}
+	elog(ERROR, "nsitem not found (internal error)");
+	return NULL;				/* keep compiler quiet */
+}
+
+/*
+ * Given an RT index and nesting depth, find the corresponding RTE.
+ * (Note that the RTE need not be in the query's namespace.)
+ */
+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);
+}
+
+/*
+ * Fetch the CTE for a CTE-reference RTE.
+ *
+ * rtelevelsup is the number of query levels above the given pstate that the
+ * RTE came from.
+ */
+CommonTableExpr *
+GetCTEForRTE(ParseState *pstate, RangeTblEntry *rte, int rtelevelsup)
+{
+	Index		levelsup;
+	ListCell   *lc;
+
+	Assert(rte->rtekind == RTE_CTE);
+	levelsup = rte->ctelevelsup + rtelevelsup;
+	while (levelsup-- > 0)
+	{
+		pstate = pstate->parentParseState;
+		if (!pstate)			/* shouldn't happen */
+			elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
+	}
+	foreach(lc, pstate->p_ctenamespace)
+	{
+		CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
+
+		if (strcmp(cte->ctename, rte->ctename) == 0)
+			return cte;
+	}
+	/* shouldn't happen */
+	elog(ERROR, "could not find CTE \"%s\"", rte->ctename);
+	return NULL;				/* keep compiler quiet */
+}
+
+/*
+ * updateFuzzyAttrMatchState
+ *	  Using Levenshtein distance, consider if column is best fuzzy match.
+ */
+static void
+updateFuzzyAttrMatchState(int fuzzy_rte_penalty,
+						  FuzzyAttrMatchState *fuzzystate, RangeTblEntry *rte,
+						  const char *actual, const char *match, int attnum)
+{
+	int			columndistance;
+	int			matchlen;
+
+	/* Bail before computing the Levenshtein distance if there's no hope. */
+	if (fuzzy_rte_penalty > fuzzystate->distance)
+		return;
+
+	/*
+	 * Outright reject dropped columns, which can appear here with apparent
+	 * empty actual names, per remarks within scanRTEForColumn().
+	 */
+	if (actual[0] == '\0')
+		return;
+
+	/* Use Levenshtein to compute match distance. */
+	matchlen = strlen(match);
+	columndistance =
+		varstr_levenshtein_less_equal(actual, strlen(actual), match, matchlen,
+									  1, 1, 1,
+									  fuzzystate->distance + 1
+									  - fuzzy_rte_penalty,
+									  true);
+
+	/*
+	 * If more than half the characters are different, don't treat it as a
+	 * match, to avoid making ridiculous suggestions.
+	 */
+	if (columndistance > matchlen / 2)
+		return;
+
+	/*
+	 * From this point on, we can ignore the distinction between the RTE-name
+	 * distance and the column-name distance.
+	 */
+	columndistance += fuzzy_rte_penalty;
+
+	/*
+	 * If the new distance is less than or equal to that of the best match
+	 * found so far, update fuzzystate.
+	 */
+	if (columndistance < fuzzystate->distance)
+	{
+		/* Store new lowest observed distance for RTE */
+		fuzzystate->distance = columndistance;
+		fuzzystate->rfirst = rte;
+		fuzzystate->first = attnum;
+		fuzzystate->rsecond = NULL;
+		fuzzystate->second = InvalidAttrNumber;
+	}
+	else if (columndistance == fuzzystate->distance)
+	{
+		/*
+		 * This match distance may equal a prior match within this same range
+		 * table.  When that happens, the prior match may also be given, but
+		 * only if there is no more than two equally distant matches from the
+		 * RTE (in turn, our caller will only accept two equally distant
+		 * matches overall).
+		 */
+		if (AttributeNumberIsValid(fuzzystate->second))
+		{
+			/* Too many RTE-level matches */
+			fuzzystate->rfirst = NULL;
+			fuzzystate->first = InvalidAttrNumber;
+			fuzzystate->rsecond = NULL;
+			fuzzystate->second = InvalidAttrNumber;
+			/* Clearly, distance is too low a bar (for *any* RTE) */
+			fuzzystate->distance = columndistance - 1;
+		}
+		else if (AttributeNumberIsValid(fuzzystate->first))
+		{
+			/* Record as provisional second match for RTE */
+			fuzzystate->rsecond = rte;
+			fuzzystate->second = attnum;
+		}
+		else if (fuzzystate->distance <= MAX_FUZZY_DISTANCE)
+		{
+			/*
+			 * Record as provisional first match (this can occasionally occur
+			 * because previous lowest distance was "too low a bar", rather
+			 * than being associated with a real match)
+			 */
+			fuzzystate->rfirst = rte;
+			fuzzystate->first = attnum;
+		}
+	}
+}
+
+/*
+ * scanNSItemForColumn
+ *	  Search the column names of a single namespace item for the given name.
+ *	  If found, return an appropriate Var node, else return NULL.
+ *	  If the name proves ambiguous within this nsitem, raise error.
+ *
+ * Side effect: if we find a match, mark the corresponding RTE as requiring
+ * read access for the column.
+ */
+Node *
+scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
+					int sublevels_up, const char *colname, int location)
+{
+	RangeTblEntry *rte = nsitem->p_rte;
+	int			attnum;
+	Var		   *var;
+
+	/*
+	 * Scan the nsitem's column names (or aliases) for a match.  Complain if
+	 * multiple matches.
+	 */
+	attnum = scanRTEForColumn(pstate, rte, nsitem->p_names,
+							  colname, location,
+							  0, NULL);
+
+	if (attnum == InvalidAttrNumber)
+		return NULL;			/* Return NULL if no match */
+
+	/* In constraint check, no system column is allowed except tableOid */
+	if (pstate->p_expr_kind == EXPR_KIND_CHECK_CONSTRAINT &&
+		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+				 errmsg("system column \"%s\" reference in check constraint is invalid",
+						colname),
+				 parser_errposition(pstate, location)));
+
+	/* In generated column, no system column is allowed except tableOid */
+	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
+		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+				 errmsg("cannot use system column \"%s\" in column generation expression",
+						colname),
+				 parser_errposition(pstate, location)));
+
+	/* Found a valid match, so build a Var */
+	if (attnum > InvalidAttrNumber)
+	{
+		/* Get attribute data from the ParseNamespaceColumn array */
+		ParseNamespaceColumn *nscol = &nsitem->p_nscolumns[attnum - 1];
+
+		/* Complain if dropped column.  See notes in scanRTEForColumn. */
+		if (nscol->p_varno == 0)
+			ereport(ERROR,
+					(errcode(ERRCODE_UNDEFINED_COLUMN),
+					 errmsg("column \"%s\" of relation \"%s\" does not exist",
+							colname,
+							nsitem->p_names->aliasname)));
+
+		var = makeVar(nscol->p_varno,
+					  nscol->p_varattno,
+					  nscol->p_vartype,
+					  nscol->p_vartypmod,
+					  nscol->p_varcollid,
+					  sublevels_up);
+		/* makeVar doesn't offer parameters for these, so set them by hand: */
+		var->varnosyn = nscol->p_varnosyn;
+		var->varattnosyn = nscol->p_varattnosyn;
+	}
+	else
+	{
+		/* System column, so use predetermined type data */
+		const FormData_pg_attribute *sysatt;
+
+		sysatt = SystemAttributeDefinition(attnum);
+		var = makeVar(nsitem->p_rtindex,
+					  attnum,
+					  sysatt->atttypid,
+					  sysatt->atttypmod,
+					  sysatt->attcollation,
+					  sublevels_up);
+	}
+	var->location = location;
+
+	/* Require read access to the column */
+	markVarForSelectPriv(pstate, var);
+
+	return (Node *) var;
+}
+
+/*
+ * scanRTEForColumn
+ *	  Search the column names of a single RTE for the given name.
+ *	  If found, return the attnum (possibly negative, for a system column);
+ *	  else return InvalidAttrNumber.
+ *	  If the name proves ambiguous within this RTE, raise error.
+ *
+ * Actually, we only search the names listed in "eref".  This can be either
+ * rte->eref, in which case we are indeed searching all the column names,
+ * or for a join it can be rte->join_using_alias, in which case we are only
+ * considering the common column names (which are the first N columns of the
+ * join, so everything works).
+ *
+ * pstate and location are passed only for error-reporting purposes.
+ *
+ * Side effect: if fuzzystate is non-NULL, check non-system columns
+ * for an approximate match and update fuzzystate accordingly.
+ *
+ * Note: this is factored out of scanNSItemForColumn because error message
+ * creation may want to check RTEs that are not in the namespace.  To support
+ * that usage, minimize the number of validity checks performed here.  It's
+ * okay to complain about ambiguous-name cases, though, since if we are
+ * working to complain about an invalid name, we've already eliminated that.
+ */
+static int
+scanRTEForColumn(ParseState *pstate, RangeTblEntry *rte,
+				 Alias *eref,
+				 const char *colname, int location,
+				 int fuzzy_rte_penalty,
+				 FuzzyAttrMatchState *fuzzystate)
+{
+	int			result = InvalidAttrNumber;
+	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 check in scanNSItemForColumn().
+	 * Callers interested in finding match with shortest distance need to
+	 * defend against this directly, though.
+	 */
+	foreach(c, eref->colnames)
+	{
+		const char *attcolname = strVal(lfirst(c));
+
+		attnum++;
+		if (strcmp(attcolname, colname) == 0)
+		{
+			if (result)
+				ereport(ERROR,
+						(errcode(ERRCODE_AMBIGUOUS_COLUMN),
+						 errmsg("column reference \"%s\" is ambiguous",
+								colname),
+						 parser_errposition(pstate, location)));
+			result = attnum;
+		}
+
+		/* Update fuzzy match state, if provided. */
+		if (fuzzystate != NULL)
+			updateFuzzyAttrMatchState(fuzzy_rte_penalty, fuzzystate,
+									  rte, attcolname, colname, attnum);
+	}
+
+	/*
+	 * 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 relation, consider system column names.
+	 * Composites are only used for pseudo-relations like ON CONFLICT's
+	 * excluded.
+	 */
+	if (rte->rtekind == RTE_RELATION &&
+		rte->relkind != RELKIND_COMPOSITE_TYPE)
+	{
+		/* 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 (SearchSysCacheExists2(ATTNUM,
+									  ObjectIdGetDatum(rte->relid),
+									  Int16GetDatum(attnum)))
+				result = attnum;
+		}
+	}
+
+	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, const char *colname, bool localonly,
+			 int location)
+{
+	Node	   *result = NULL;
+	int			sublevels_up = 0;
+	ParseState *orig_pstate = pstate;
+
+	while (pstate != NULL)
+	{
+		ListCell   *l;
+
+		foreach(l, pstate->p_namespace)
+		{
+			ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(l);
+			Node	   *newresult;
+
+			/* Ignore table-only items */
+			if (!nsitem->p_cols_visible)
+				continue;
+			/* If not inside LATERAL, ignore lateral-only items */
+			if (nsitem->p_lateral_only && !pstate->p_lateral_active)
+				continue;
+
+			/* use orig_pstate here for consistency with other callers */
+			newresult = scanNSItemForColumn(orig_pstate, nsitem, sublevels_up,
+											colname, location);
+
+			if (newresult)
+			{
+				if (result)
+					ereport(ERROR,
+							(errcode(ERRCODE_AMBIGUOUS_COLUMN),
+							 errmsg("column reference \"%s\" is ambiguous",
+									colname),
+							 parser_errposition(pstate, location)));
+				check_lateral_ref_ok(pstate, nsitem, location);
+				result = newresult;
+			}
+		}
+
+		if (result != NULL || localonly)
+			break;				/* found, or don't want to look at parent */
+
+		pstate = pstate->parentParseState;
+		sublevels_up++;
+	}
+
+	return result;
+}
+
+/*
+ * searchRangeTableForCol
+ *	  See if any RangeTblEntry could possibly provide the given column name (or
+ *	  find the best match available).  Returns state with relevant details.
+ *
+ * This is different from colNameToVar in that it considers every entry in
+ * the ParseState's rangetable(s), not only those that are currently visible
+ * in the p_namespace list(s).  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 errorMissingColumn.
+ *
+ * This function is also different in that it will consider approximate
+ * matches -- if the user entered an alias/column pair that is only slightly
+ * different from a valid pair, we may be able to infer what they meant to
+ * type and provide a reasonable hint.
+ *
+ * The FuzzyAttrMatchState will have 'rfirst' pointing to the best RTE
+ * containing the most promising match for the alias and column name.  If
+ * the alias and column names match exactly, 'first' will be InvalidAttrNumber;
+ * otherwise, it will be the attribute number for the match.  In the latter
+ * case, 'rsecond' may point to a second, equally close approximate match,
+ * and 'second' will contain the attribute number for the second match.
+ */
+static FuzzyAttrMatchState *
+searchRangeTableForCol(ParseState *pstate, const char *alias, const char *colname,
+					   int location)
+{
+	ParseState *orig_pstate = pstate;
+	FuzzyAttrMatchState *fuzzystate = palloc(sizeof(FuzzyAttrMatchState));
+
+	fuzzystate->distance = MAX_FUZZY_DISTANCE + 1;
+	fuzzystate->rfirst = NULL;
+	fuzzystate->rsecond = NULL;
+	fuzzystate->first = InvalidAttrNumber;
+	fuzzystate->second = InvalidAttrNumber;
+
+	while (pstate != NULL)
+	{
+		ListCell   *l;
+
+		foreach(l, pstate->p_rtable)
+		{
+			RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
+			int			fuzzy_rte_penalty = 0;
+
+			/*
+			 * Typically, it is not useful to look for matches within join
+			 * RTEs; they effectively duplicate other RTEs for our purposes,
+			 * and if a match is chosen from a join RTE, an unhelpful alias is
+			 * displayed in the final diagnostic message.
+			 */
+			if (rte->rtekind == RTE_JOIN)
+				continue;
+
+			/*
+			 * If the user didn't specify an alias, then matches against one
+			 * RTE are as good as another.  But if the user did specify an
+			 * alias, then we want at least a fuzzy - and preferably an exact
+			 * - match for the range table entry.
+			 */
+			if (alias != NULL)
+				fuzzy_rte_penalty =
+					varstr_levenshtein_less_equal(alias, strlen(alias),
+												  rte->eref->aliasname,
+												  strlen(rte->eref->aliasname),
+												  1, 1, 1,
+												  MAX_FUZZY_DISTANCE + 1,
+												  true);
+
+			/*
+			 * Scan for a matching column; if we find an exact match, we're
+			 * done.  Otherwise, update fuzzystate.
+			 */
+			if (scanRTEForColumn(orig_pstate, rte, rte->eref, colname, location,
+								 fuzzy_rte_penalty, fuzzystate)
+				&& fuzzy_rte_penalty == 0)
+			{
+				fuzzystate->rfirst = rte;
+				fuzzystate->first = InvalidAttrNumber;
+				fuzzystate->rsecond = NULL;
+				fuzzystate->second = InvalidAttrNumber;
+				return fuzzystate;
+			}
+		}
+
+		pstate = pstate->parentParseState;
+	}
+
+	return fuzzystate;
+}
+
+/*
+ * markRTEForSelectPriv
+ *	   Mark the specified column of the RTE with index rtindex
+ *	   as requiring SELECT privilege
+ *
+ * col == InvalidAttrNumber means a "whole row" reference
+ */
+static void
+markRTEForSelectPriv(ParseState *pstate, int rtindex, AttrNumber col)
+{
+	RangeTblEntry *rte = rt_fetch(rtindex, pstate->p_rtable);
+
+	if (rte->rtekind == RTE_RELATION)
+	{
+		/* Make sure the rel as a whole is marked for SELECT access */
+		rte->requiredPerms |= ACL_SELECT;
+		/* Must offset the attnum to fit in a bitmapset */
+		rte->selectedCols = bms_add_member(rte->selectedCols,
+										   col - FirstLowInvalidHeapAttributeNumber);
+	}
+	else if (rte->rtekind == RTE_JOIN)
+	{
+		if (col == InvalidAttrNumber)
+		{
+			/*
+			 * A whole-row reference to a join has to be treated as whole-row
+			 * references to the two inputs.
+			 */
+			JoinExpr   *j;
+
+			if (rtindex > 0 && rtindex <= list_length(pstate->p_joinexprs))
+				j = list_nth_node(JoinExpr, pstate->p_joinexprs, rtindex - 1);
+			else
+				j = NULL;
+			if (j == NULL)
+				elog(ERROR, "could not find JoinExpr for whole-row reference");
+
+			/* Note: we can't see FromExpr here */
+			if (IsA(j->larg, RangeTblRef))
+			{
+				int			varno = ((RangeTblRef *) j->larg)->rtindex;
+
+				markRTEForSelectPriv(pstate, varno, InvalidAttrNumber);
+			}
+			else if (IsA(j->larg, JoinExpr))
+			{
+				int			varno = ((JoinExpr *) j->larg)->rtindex;
+
+				markRTEForSelectPriv(pstate, varno, InvalidAttrNumber);
+			}
+			else
+				elog(ERROR, "unrecognized node type: %d",
+					 (int) nodeTag(j->larg));
+			if (IsA(j->rarg, RangeTblRef))
+			{
+				int			varno = ((RangeTblRef *) j->rarg)->rtindex;
+
+				markRTEForSelectPriv(pstate, varno, InvalidAttrNumber);
+			}
+			else if (IsA(j->rarg, JoinExpr))
+			{
+				int			varno = ((JoinExpr *) j->rarg)->rtindex;
+
+				markRTEForSelectPriv(pstate, varno, InvalidAttrNumber);
+			}
+			else
+				elog(ERROR, "unrecognized node type: %d",
+					 (int) nodeTag(j->rarg));
+		}
+		else
+		{
+			/*
+			 * Join alias Vars for ordinary columns must refer to merged JOIN
+			 * USING columns.  We don't need to do anything here, because the
+			 * join input columns will also be referenced in the join's qual
+			 * clause, and will get marked for select privilege there.
+			 */
+		}
+	}
+	/* other RTE types don't require privilege marking */
+}
+
+/*
+ * markVarForSelectPriv
+ *	   Mark the RTE referenced by the Var as requiring SELECT privilege
+ *	   for the Var's column (the Var could be a whole-row Var, too)
+ */
+void
+markVarForSelectPriv(ParseState *pstate, Var *var)
+{
+	Index		lv;
+
+	Assert(IsA(var, Var));
+	/* Find the appropriate pstate if it's an uplevel Var */
+	for (lv = 0; lv < var->varlevelsup; lv++)
+		pstate = pstate->parentParseState;
+	markRTEForSelectPriv(pstate, var->varno, var->varattno);
+}
+
+/*
+ * buildRelationAliases
+ *		Construct the eref column name list for a relation RTE.
+ *		This code is also used for function RTEs.
+ *
+ * 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.
+ *
+ * It is an error for there to be more aliases present than required.
+ */
+static void
+buildRelationAliases(TupleDesc tupdesc, Alias *alias, Alias *eref)
+{
+	int			maxattrs = tupdesc->natts;
+	List	   *aliaslist;
+	ListCell   *aliaslc;
+	int			numaliases;
+	int			varattno;
+	int			numdropped = 0;
+
+	Assert(eref->colnames == NIL);
+
+	if (alias)
+	{
+		aliaslist = alias->colnames;
+		aliaslc = list_head(aliaslist);
+		numaliases = list_length(aliaslist);
+		/* We'll rebuild the alias colname list */
+		alias->colnames = NIL;
+	}
+	else
+	{
+		aliaslist = NIL;
+		aliaslc = NULL;
+		numaliases = 0;
+	}
+
+	for (varattno = 0; varattno < maxattrs; varattno++)
+	{
+		Form_pg_attribute attr = TupleDescAttr(tupdesc, 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(aliaslist, 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)));
+}
+
+/*
+ * chooseScalarFunctionAlias
+ *		Select the column alias for a function in 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 (as determined by FigureColname)
+ * alias: the user-supplied alias for the RTE, or NULL if none
+ * nfuncs: the number of functions appearing in the function RTE
+ *
+ * Note that the name we choose might be overridden later, if the user-given
+ * alias includes column alias names.  That's of no concern here.
+ */
+static char *
+chooseScalarFunctionAlias(Node *funcexpr, char *funcname,
+						  Alias *alias, int nfuncs)
+{
+	char	   *pname;
+
+	/*
+	 * 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)
+			return pname;
+	}
+
+	/*
+	 * If there's just one function in the RTE, and the user gave an RTE alias
+	 * name, use that name.  (This makes FROM func() AS foo use "foo" as the
+	 * column name as well as the table alias.)
+	 */
+	if (nfuncs == 1 && alias)
+		return alias->aliasname;
+
+	/*
+	 * Otherwise use the function name.
+	 */
+	return funcname;
+}
+
+/*
+ * buildNSItemFromTupleDesc
+ *		Build a ParseNamespaceItem, given a tupdesc describing the columns.
+ *
+ * rte: the new RangeTblEntry for the rel
+ * rtindex: its index in the rangetable list
+ * tupdesc: the physical column information
+ */
+static ParseNamespaceItem *
+buildNSItemFromTupleDesc(RangeTblEntry *rte, Index rtindex, TupleDesc tupdesc)
+{
+	ParseNamespaceItem *nsitem;
+	ParseNamespaceColumn *nscolumns;
+	int			maxattrs = tupdesc->natts;
+	int			varattno;
+
+	/* colnames must have the same number of entries as the nsitem */
+	Assert(maxattrs == list_length(rte->eref->colnames));
+
+	/* extract per-column data from the tupdesc */
+	nscolumns = (ParseNamespaceColumn *)
+		palloc0(maxattrs * sizeof(ParseNamespaceColumn));
+
+	for (varattno = 0; varattno < maxattrs; varattno++)
+	{
+		Form_pg_attribute attr = TupleDescAttr(tupdesc, varattno);
+
+		/* For a dropped column, just leave the entry as zeroes */
+		if (attr->attisdropped)
+			continue;
+
+		nscolumns[varattno].p_varno = rtindex;
+		nscolumns[varattno].p_varattno = varattno + 1;
+		nscolumns[varattno].p_vartype = attr->atttypid;
+		nscolumns[varattno].p_vartypmod = attr->atttypmod;
+		nscolumns[varattno].p_varcollid = attr->attcollation;
+		nscolumns[varattno].p_varnosyn = rtindex;
+		nscolumns[varattno].p_varattnosyn = varattno + 1;
+	}
+
+	/* ... and build the nsitem */
+	nsitem = (ParseNamespaceItem *) palloc(sizeof(ParseNamespaceItem));
+	nsitem->p_names = rte->eref;
+	nsitem->p_rte = rte;
+	nsitem->p_rtindex = rtindex;
+	nsitem->p_nscolumns = nscolumns;
+	/* set default visibility flags; might get changed later */
+	nsitem->p_rel_visible = true;
+	nsitem->p_cols_visible = true;
+	nsitem->p_lateral_only = false;
+	nsitem->p_lateral_ok = true;
+
+	return nsitem;
+}
+
+/*
+ * buildNSItemFromLists
+ *		Build a ParseNamespaceItem, given column type information in lists.
+ *
+ * rte: the new RangeTblEntry for the rel
+ * rtindex: its index in the rangetable list
+ * coltypes: per-column datatype OIDs
+ * coltypmods: per-column type modifiers
+ * colcollation: per-column collation OIDs
+ */
+static ParseNamespaceItem *
+buildNSItemFromLists(RangeTblEntry *rte, Index rtindex,
+					 List *coltypes, List *coltypmods, List *colcollations)
+{
+	ParseNamespaceItem *nsitem;
+	ParseNamespaceColumn *nscolumns;
+	int			maxattrs = list_length(coltypes);
+	int			varattno;
+	ListCell   *lct;
+	ListCell   *lcm;
+	ListCell   *lcc;
+
+	/* colnames must have the same number of entries as the nsitem */
+	Assert(maxattrs == list_length(rte->eref->colnames));
+
+	Assert(maxattrs == list_length(coltypmods));
+	Assert(maxattrs == list_length(colcollations));
+
+	/* extract per-column data from the lists */
+	nscolumns = (ParseNamespaceColumn *)
+		palloc0(maxattrs * sizeof(ParseNamespaceColumn));
+
+	varattno = 0;
+	forthree(lct, coltypes,
+			 lcm, coltypmods,
+			 lcc, colcollations)
+	{
+		nscolumns[varattno].p_varno = rtindex;
+		nscolumns[varattno].p_varattno = varattno + 1;
+		nscolumns[varattno].p_vartype = lfirst_oid(lct);
+		nscolumns[varattno].p_vartypmod = lfirst_int(lcm);
+		nscolumns[varattno].p_varcollid = lfirst_oid(lcc);
+		nscolumns[varattno].p_varnosyn = rtindex;
+		nscolumns[varattno].p_varattnosyn = varattno + 1;
+		varattno++;
+	}
+
+	/* ... and build the nsitem */
+	nsitem = (ParseNamespaceItem *) palloc(sizeof(ParseNamespaceItem));
+	nsitem->p_names = rte->eref;
+	nsitem->p_rte = rte;
+	nsitem->p_rtindex = rtindex;
+	nsitem->p_nscolumns = nscolumns;
+	/* set default visibility flags; might get changed later */
+	nsitem->p_rel_visible = true;
+	nsitem->p_cols_visible = true;
+	nsitem->p_lateral_only = false;
+	nsitem->p_lateral_ok = true;
+
+	return nsitem;
+}
+
+/*
+ * Open a table during parse analysis
+ *
+ * This is essentially just the same as table_openrv(), except that it caters
+ * to some parser-specific error reporting needs, notably that it arranges
+ * to include the RangeVar's parse location in any resulting error.
+ *
+ * Note: properly, lockmode should be declared LOCKMODE not int, but that
+ * would require importing storage/lock.h into parse_relation.h.  Since
+ * LOCKMODE is typedef'd as int anyway, that seems like overkill.
+ */
+Relation
+parserOpenTable(ParseState *pstate, const RangeVar *relation, int lockmode)
+{
+	Relation	rel;
+	ParseCallbackState pcbstate;
+
+	setup_parser_errposition_callback(&pcbstate, pstate, relation->location);
+	rel = table_openrv_extended(relation, lockmode, true);
+	if (rel == NULL)
+	{
+		if (relation->schemaname)
+			ereport(ERROR,
+					(errcode(ERRCODE_UNDEFINED_TABLE),
+					 errmsg("relation \"%s.%s\" does not exist",
+							relation->schemaname, relation->relname)));
+		else
+		{
+			/*
+			 * An unqualified name might have been meant as a reference to
+			 * some not-yet-in-scope CTE.  The bare "does not exist" message
+			 * has proven remarkably unhelpful for figuring out such problems,
+			 * so we take pains to offer a specific hint.
+			 */
+			if (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("Use WITH RECURSIVE, or re-order the WITH items to remove forward references.")));
+			else
+				ereport(ERROR,
+						(errcode(ERRCODE_UNDEFINED_TABLE),
+						 errmsg("relation \"%s\" does not exist",
+								relation->relname)));
+		}
+	}
+	cancel_parser_errposition_callback(&pcbstate);
+	return rel;
+}
+
+/*
+ * Add an entry for a relation to the pstate's range table (p_rtable).
+ * Then, construct and return a ParseNamespaceItem for the new RTE.
+ *
+ * We do not link the ParseNamespaceItem into the pstate here; it's the
+ * caller's job to do that in the appropriate way.
+ *
+ * Note: formerly this checked for refname conflicts, but that's wrong.
+ * Caller is responsible for checking for conflicts in the appropriate scope.
+ */
+ParseNamespaceItem *
+addRangeTableEntry(ParseState *pstate,
+				   RangeVar *relation,
+				   Alias *alias,
+				   bool inh,
+				   bool inFromCl)
+{
+	RangeTblEntry *rte = makeNode(RangeTblEntry);
+	char	   *refname = alias ? alias->aliasname : relation->relname;
+	LOCKMODE	lockmode;
+	Relation	rel;
+	ParseNamespaceItem *nsitem;
+
+	Assert(pstate != NULL);
+
+	rte->rtekind = RTE_RELATION;
+	rte->alias = alias;
+
+	/*
+	 * Identify the type of lock we'll need on this relation.  It's not the
+	 * query's target table (that case is handled elsewhere), so we need
+	 * either RowShareLock if it's locked by FOR UPDATE/SHARE, or plain
+	 * AccessShareLock otherwise.
+	 */
+	lockmode = isLockedRefname(pstate, refname) ? RowShareLock : AccessShareLock;
+
+	/*
+	 * 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, we must open the rel with the proper lockmode.
+	 */
+	rel = parserOpenTable(pstate, relation, lockmode);
+	rte->relid = RelationGetRelid(rel);
+	rte->relkind = rel->rd_rel->relkind;
+	rte->rellockmode = lockmode;
+
+	/*
+	 * 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);
+
+	/*
+	 * Set flags and access permissions.
+	 *
+	 * The initial default on access checks is always check-for-READ-access,
+	 * which is the right thing for all except target tables.
+	 */
+	rte->lateral = false;
+	rte->inh = inh;
+	rte->inFromCl = inFromCl;
+
+	rte->requiredPerms = ACL_SELECT;
+	rte->checkAsUser = InvalidOid;	/* not set-uid by default, either */
+	rte->selectedCols = NULL;
+	rte->insertedCols = NULL;
+	rte->updatedCols = NULL;
+	rte->extraUpdatedCols = NULL;
+
+	/*
+	 * Add completed RTE to pstate's range table list, so that we know its
+	 * index.  But we don't add it to the join list --- caller must do that if
+	 * appropriate.
+	 */
+	pstate->p_rtable = lappend(pstate->p_rtable, rte);
+
+	/*
+	 * Build a ParseNamespaceItem, but don't add it to the pstate's namespace
+	 * list --- caller must do that if appropriate.
+	 */
+	nsitem = buildNSItemFromTupleDesc(rte, list_length(pstate->p_rtable),
+									  rel->rd_att);
+
+	/*
+	 * 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.
+	 */
+	table_close(rel, NoLock);
+
+	return nsitem;
+}
+
+/*
+ * Add an entry for a relation to the pstate's range table (p_rtable).
+ * Then, construct and return a ParseNamespaceItem for the new RTE.
+ *
+ * This is just like addRangeTableEntry() except that it makes an RTE
+ * given an already-open relation instead of a RangeVar reference.
+ *
+ * lockmode is the lock type required for query execution; it must be one
+ * of AccessShareLock, RowShareLock, or RowExclusiveLock depending on the
+ * RTE's role within the query.  The caller must hold that lock mode
+ * or a stronger one.
+ *
+ * Note: properly, lockmode should be declared LOCKMODE not int, but that
+ * would require importing storage/lock.h into parse_relation.h.  Since
+ * LOCKMODE is typedef'd as int anyway, that seems like overkill.
+ */
+ParseNamespaceItem *
+addRangeTableEntryForRelation(ParseState *pstate,
+							  Relation rel,
+							  int lockmode,
+							  Alias *alias,
+							  bool inh,
+							  bool inFromCl)
+{
+	RangeTblEntry *rte = makeNode(RangeTblEntry);
+	char	   *refname = alias ? alias->aliasname : RelationGetRelationName(rel);
+
+	Assert(pstate != NULL);
+
+	Assert(lockmode == AccessShareLock ||
+		   lockmode == RowShareLock ||
+		   lockmode == RowExclusiveLock);
+	Assert(CheckRelationLockedByMe(rel, lockmode, true));
+
+	rte->rtekind = RTE_RELATION;
+	rte->alias = alias;
+	rte->relid = RelationGetRelid(rel);
+	rte->relkind = rel->rd_rel->relkind;
+	rte->rellockmode = lockmode;
+
+	/*
+	 * 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);
+
+	/*
+	 * Set flags and access permissions.
+	 *
+	 * The initial default on access checks is always check-for-READ-access,
+	 * which is the right thing for all except target tables.
+	 */
+	rte->lateral = false;
+	rte->inh = inh;
+	rte->inFromCl = inFromCl;
+
+	rte->requiredPerms = ACL_SELECT;
+	rte->checkAsUser = InvalidOid;	/* not set-uid by default, either */
+	rte->selectedCols = NULL;
+	rte->insertedCols = NULL;
+	rte->updatedCols = NULL;
+	rte->extraUpdatedCols = NULL;
+
+	/*
+	 * Add completed RTE to pstate's range table list, so that we know its
+	 * index.  But we don't add it to the join list --- caller must do that if
+	 * appropriate.
+	 */
+	pstate->p_rtable = lappend(pstate->p_rtable, rte);
+
+	/*
+	 * Build a ParseNamespaceItem, but don't add it to the pstate's namespace
+	 * list --- caller must do that if appropriate.
+	 */
+	return buildNSItemFromTupleDesc(rte, list_length(pstate->p_rtable),
+									rel->rd_att);
+}
+
+/*
+ * Add an entry for a subquery to the pstate's range table (p_rtable).
+ * Then, construct and return a ParseNamespaceItem for the new RTE.
+ *
+ * This is much like addRangeTableEntry() except that it makes a subquery RTE.
+ * Note that an alias clause *must* be supplied.
+ */
+ParseNamespaceItem *
+addRangeTableEntryForSubquery(ParseState *pstate,
+							  Query *subquery,
+							  Alias *alias,
+							  bool lateral,
+							  bool inFromCl)
+{
+	RangeTblEntry *rte = makeNode(RangeTblEntry);
+	char	   *refname = alias->aliasname;
+	Alias	   *eref;
+	int			numaliases;
+	List	   *coltypes,
+			   *coltypmods,
+			   *colcollations;
+	int			varattno;
+	ListCell   *tlistitem;
+
+	Assert(pstate != NULL);
+
+	rte->rtekind = RTE_SUBQUERY;
+	rte->subquery = subquery;
+	rte->alias = alias;
+
+	eref = copyObject(alias);
+	numaliases = list_length(eref->colnames);
+
+	/* fill in any unspecified alias columns, and extract column type info */
+	coltypes = coltypmods = colcollations = NIL;
+	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));
+		}
+		coltypes = lappend_oid(coltypes,
+							   exprType((Node *) te->expr));
+		coltypmods = lappend_int(coltypmods,
+								 exprTypmod((Node *) te->expr));
+		colcollations = lappend_oid(colcollations,
+									exprCollation((Node *) te->expr));
+	}
+	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;
+
+	/*
+	 * Set flags and access permissions.
+	 *
+	 * Subqueries are never checked for access rights.
+	 */
+	rte->lateral = lateral;
+	rte->inh = false;			/* never true for subqueries */
+	rte->inFromCl = inFromCl;
+
+	rte->requiredPerms = 0;
+	rte->checkAsUser = InvalidOid;
+	rte->selectedCols = NULL;
+	rte->insertedCols = NULL;
+	rte->updatedCols = NULL;
+	rte->extraUpdatedCols = NULL;
+
+	/*
+	 * Add completed RTE to pstate's range table list, so that we know its
+	 * index.  But we don't add it to the join list --- caller must do that if
+	 * appropriate.
+	 */
+	pstate->p_rtable = lappend(pstate->p_rtable, rte);
+
+	/*
+	 * Build a ParseNamespaceItem, but don't add it to the pstate's namespace
+	 * list --- caller must do that if appropriate.
+	 */
+	return buildNSItemFromLists(rte, list_length(pstate->p_rtable),
+								coltypes, coltypmods, colcollations);
+}
+
+/*
+ * Add an entry for a function (or functions) to the pstate's range table
+ * (p_rtable).  Then, construct and return a ParseNamespaceItem for the new RTE.
+ *
+ * This is much like addRangeTableEntry() except that it makes a function RTE.
+ */
+ParseNamespaceItem *
+addRangeTableEntryForFunction(ParseState *pstate,
+							  List *funcnames,
+							  List *funcexprs,
+							  List *coldeflists,
+							  RangeFunction *rangefunc,
+							  bool lateral,
+							  bool inFromCl)
+{
+	RangeTblEntry *rte = makeNode(RangeTblEntry);
+	Alias	   *alias = rangefunc->alias;
+	Alias	   *eref;
+	char	   *aliasname;
+	int			nfuncs = list_length(funcexprs);
+	TupleDesc  *functupdescs;
+	TupleDesc	tupdesc;
+	ListCell   *lc1,
+			   *lc2,
+			   *lc3;
+	int			i;
+	int			j;
+	int			funcno;
+	int			natts,
+				totalatts;
+
+	Assert(pstate != NULL);
+
+	rte->rtekind = RTE_FUNCTION;
+	rte->relid = InvalidOid;
+	rte->subquery = NULL;
+	rte->functions = NIL;		/* we'll fill this list below */
+	rte->funcordinality = rangefunc->ordinality;
+	rte->alias = alias;
+
+	/*
+	 * Choose the RTE alias name.  We default to using the first function's
+	 * name even when there's more than one; which is maybe arguable but beats
+	 * using something constant like "table".
+	 */
+	if (alias)
+		aliasname = alias->aliasname;
+	else
+		aliasname = linitial(funcnames);
+
+	eref = makeAlias(aliasname, NIL);
+	rte->eref = eref;
+
+	/* Process each function ... */
+	functupdescs = (TupleDesc *) palloc(nfuncs * sizeof(TupleDesc));
+
+	totalatts = 0;
+	funcno = 0;
+	forthree(lc1, funcexprs, lc2, funcnames, lc3, coldeflists)
+	{
+		Node	   *funcexpr = (Node *) lfirst(lc1);
+		char	   *funcname = (char *) lfirst(lc2);
+		List	   *coldeflist = (List *) lfirst(lc3);
+		RangeTblFunction *rtfunc = makeNode(RangeTblFunction);
+		TypeFuncClass functypclass;
+		Oid			funcrettype;
+
+		/* Initialize RangeTblFunction node */
+		rtfunc->funcexpr = funcexpr;
+		rtfunc->funccolnames = NIL;
+		rtfunc->funccoltypes = NIL;
+		rtfunc->funccoltypmods = NIL;
+		rtfunc->funccolcollations = NIL;
+		rtfunc->funcparams = NULL;	/* not set until planning */
+
+		/*
+		 * Now determine if the function returns a simple or composite type.
+		 */
+		functypclass = get_expr_result_type(funcexpr,
+											&funcrettype,
+											&tupdesc);
+
+		/*
+		 * A coldeflist is required if the function returns RECORD and hasn't
+		 * got a predetermined record type, and is prohibited otherwise.  This
+		 * can be a bit confusing, so we expend some effort on delivering a
+		 * relevant error message.
+		 */
+		if (coldeflist != NIL)
+		{
+			switch (functypclass)
+			{
+				case TYPEFUNC_RECORD:
+					/* ok */
+					break;
+				case TYPEFUNC_COMPOSITE:
+				case TYPEFUNC_COMPOSITE_DOMAIN:
+
+					/*
+					 * If the function's raw result type is RECORD, we must
+					 * have resolved it using its OUT parameters.  Otherwise,
+					 * it must have a named composite type.
+					 */
+					if (exprType(funcexpr) == RECORDOID)
+						ereport(ERROR,
+								(errcode(ERRCODE_SYNTAX_ERROR),
+								 errmsg("a column definition list is redundant for a function with OUT parameters"),
+								 parser_errposition(pstate,
+													exprLocation((Node *) coldeflist))));
+					else
+						ereport(ERROR,
+								(errcode(ERRCODE_SYNTAX_ERROR),
+								 errmsg("a column definition list is redundant for a function returning a named composite type"),
+								 parser_errposition(pstate,
+													exprLocation((Node *) coldeflist))));
+					break;
+				default:
+					ereport(ERROR,
+							(errcode(ERRCODE_SYNTAX_ERROR),
+							 errmsg("a column definition list is only allowed for functions returning \"record\""),
+							 parser_errposition(pstate,
+												exprLocation((Node *) coldeflist))));
+					break;
+			}
+		}
+		else
+		{
+			if (functypclass == TYPEFUNC_RECORD)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("a column definition list is required for functions returning \"record\""),
+						 parser_errposition(pstate, exprLocation(funcexpr))));
+		}
+
+		if (functypclass == TYPEFUNC_COMPOSITE ||
+			functypclass == TYPEFUNC_COMPOSITE_DOMAIN)
+		{
+			/* Composite data type, e.g. a table's row type */
+			Assert(tupdesc);
+		}
+		else if (functypclass == TYPEFUNC_SCALAR)
+		{
+			/* Base data type, i.e. scalar */
+			tupdesc = CreateTemplateTupleDesc(1);
+			TupleDescInitEntry(tupdesc,
+							   (AttrNumber) 1,
+							   chooseScalarFunctionAlias(funcexpr, funcname,
+														 alias, nfuncs),
+							   funcrettype,
+							   exprTypmod(funcexpr),
+							   0);
+			TupleDescInitEntryCollation(tupdesc,
+										(AttrNumber) 1,
+										exprCollation(funcexpr));
+		}
+		else if (functypclass == TYPEFUNC_RECORD)
+		{
+			ListCell   *col;
+
+			/*
+			 * Use the column definition list to construct a tupdesc and fill
+			 * in the RangeTblFunction's lists.  Limit number of columns to
+			 * MaxHeapAttributeNumber, because CheckAttributeNamesTypes will.
+			 */
+			if (list_length(coldeflist) > MaxHeapAttributeNumber)
+				ereport(ERROR,
+						(errcode(ERRCODE_TOO_MANY_COLUMNS),
+						 errmsg("column definition lists can have at most %d entries",
+								MaxHeapAttributeNumber),
+						 parser_errposition(pstate,
+											exprLocation((Node *) coldeflist))));
+			tupdesc = CreateTemplateTupleDesc(list_length(coldeflist));
+			i = 1;
+			foreach(col, coldeflist)
+			{
+				ColumnDef  *n = (ColumnDef *) lfirst(col);
+				char	   *attrname;
+				Oid			attrtype;
+				int32		attrtypmod;
+				Oid			attrcollation;
+
+				attrname = n->colname;
+				if (n->typeName->setof)
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+							 errmsg("column \"%s\" cannot be declared SETOF",
+									attrname),
+							 parser_errposition(pstate, n->location)));
+				typenameTypeIdAndMod(pstate, n->typeName,
+									 &attrtype, &attrtypmod);
+				attrcollation = GetColumnDefCollation(pstate, n, attrtype);
+				TupleDescInitEntry(tupdesc,
+								   (AttrNumber) i,
+								   attrname,
+								   attrtype,
+								   attrtypmod,
+								   0);
+				TupleDescInitEntryCollation(tupdesc,
+											(AttrNumber) i,
+											attrcollation);
+				rtfunc->funccolnames = lappend(rtfunc->funccolnames,
+											   makeString(pstrdup(attrname)));
+				rtfunc->funccoltypes = lappend_oid(rtfunc->funccoltypes,
+												   attrtype);
+				rtfunc->funccoltypmods = lappend_int(rtfunc->funccoltypmods,
+													 attrtypmod);
+				rtfunc->funccolcollations = lappend_oid(rtfunc->funccolcollations,
+														attrcollation);
+
+				i++;
+			}
+
+			/*
+			 * Ensure that the coldeflist defines a legal set of names (no
+			 * duplicates, but we needn't worry about system column names) and
+			 * datatypes.  Although we mostly can't allow pseudo-types, it
+			 * seems safe to allow RECORD and RECORD[], since values within
+			 * those type classes are self-identifying at runtime, and the
+			 * coldeflist doesn't represent anything that will be visible to
+			 * other sessions.
+			 */
+			CheckAttributeNamesTypes(tupdesc, RELKIND_COMPOSITE_TYPE,
+									 CHKATYPE_ANYRECORD);
+		}
+		else
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg("function \"%s\" in FROM has unsupported return type %s",
+							funcname, format_type_be(funcrettype)),
+					 parser_errposition(pstate, exprLocation(funcexpr))));
+
+		/* Finish off the RangeTblFunction and add it to the RTE's list */
+		rtfunc->funccolcount = tupdesc->natts;
+		rte->functions = lappend(rte->functions, rtfunc);
+
+		/* Save the tupdesc for use below */
+		functupdescs[funcno] = tupdesc;
+		totalatts += tupdesc->natts;
+		funcno++;
+	}
+
+	/*
+	 * If there's more than one function, or we want an ordinality column, we
+	 * have to produce a merged tupdesc.
+	 */
+	if (nfuncs > 1 || rangefunc->ordinality)
+	{
+		if (rangefunc->ordinality)
+			totalatts++;
+
+		/* Disallow more columns than will fit in a tuple */
+		if (totalatts > MaxTupleAttributeNumber)
+			ereport(ERROR,
+					(errcode(ERRCODE_TOO_MANY_COLUMNS),
+					 errmsg("functions in FROM can return at most %d columns",
+							MaxTupleAttributeNumber),
+					 parser_errposition(pstate,
+										exprLocation((Node *) funcexprs))));
+
+		/* Merge the tuple descs of each function into a composite one */
+		tupdesc = CreateTemplateTupleDesc(totalatts);
+		natts = 0;
+		for (i = 0; i < nfuncs; i++)
+		{
+			for (j = 1; j <= functupdescs[i]->natts; j++)
+				TupleDescCopyEntry(tupdesc, ++natts, functupdescs[i], j);
+		}
+
+		/* Add the ordinality column if needed */
+		if (rangefunc->ordinality)
+		{
+			TupleDescInitEntry(tupdesc,
+							   (AttrNumber) ++natts,
+							   "ordinality",
+							   INT8OID,
+							   -1,
+							   0);
+			/* no need to set collation */
+		}
+
+		Assert(natts == totalatts);
+	}
+	else
+	{
+		/* We can just use the single function's tupdesc as-is */
+		tupdesc = functupdescs[0];
+	}
+
+	/* Use the tupdesc while assigning column aliases for the RTE */
+	buildRelationAliases(tupdesc, alias, eref);
+
+	/*
+	 * Set flags and access permissions.
+	 *
+	 * Functions are never checked for access rights (at least, not by the RTE
+	 * permissions mechanism).
+	 */
+	rte->lateral = lateral;
+	rte->inh = false;			/* never true for functions */
+	rte->inFromCl = inFromCl;
+
+	rte->requiredPerms = 0;
+	rte->checkAsUser = InvalidOid;
+	rte->selectedCols = NULL;
+	rte->insertedCols = NULL;
+	rte->updatedCols = NULL;
+	rte->extraUpdatedCols = NULL;
+
+	/*
+	 * Add completed RTE to pstate's range table list, so that we know its
+	 * index.  But we don't add it to the join list --- caller must do that if
+	 * appropriate.
+	 */
+	pstate->p_rtable = lappend(pstate->p_rtable, rte);
+
+	/*
+	 * Build a ParseNamespaceItem, but don't add it to the pstate's namespace
+	 * list --- caller must do that if appropriate.
+	 */
+	return buildNSItemFromTupleDesc(rte, list_length(pstate->p_rtable),
+									tupdesc);
+}
+
+/*
+ * Add an entry for a table function to the pstate's range table (p_rtable).
+ * Then, construct and return a ParseNamespaceItem for the new RTE.
+ *
+ * This is much like addRangeTableEntry() except that it makes a tablefunc RTE.
+ */
+ParseNamespaceItem *
+addRangeTableEntryForTableFunc(ParseState *pstate,
+							   TableFunc *tf,
+							   Alias *alias,
+							   bool lateral,
+							   bool inFromCl)
+{
+	RangeTblEntry *rte = makeNode(RangeTblEntry);
+	char	   *refname = alias ? alias->aliasname : pstrdup("xmltable");
+	Alias	   *eref;
+	int			numaliases;
+
+	Assert(pstate != NULL);
+
+	/* Disallow more columns than will fit in a tuple */
+	if (list_length(tf->colnames) > MaxTupleAttributeNumber)
+		ereport(ERROR,
+				(errcode(ERRCODE_TOO_MANY_COLUMNS),
+				 errmsg("functions in FROM can return at most %d columns",
+						MaxTupleAttributeNumber),
+				 parser_errposition(pstate,
+									exprLocation((Node *) tf))));
+	Assert(list_length(tf->coltypes) == list_length(tf->colnames));
+	Assert(list_length(tf->coltypmods) == list_length(tf->colnames));
+	Assert(list_length(tf->colcollations) == list_length(tf->colnames));
+
+	rte->rtekind = RTE_TABLEFUNC;
+	rte->relid = InvalidOid;
+	rte->subquery = NULL;
+	rte->tablefunc = tf;
+	rte->coltypes = tf->coltypes;
+	rte->coltypmods = tf->coltypmods;
+	rte->colcollations = tf->colcollations;
+	rte->alias = alias;
+
+	eref = alias ? copyObject(alias) : makeAlias(refname, NIL);
+	numaliases = list_length(eref->colnames);
+
+	/* fill in any unspecified alias columns */
+	if (numaliases < list_length(tf->colnames))
+		eref->colnames = list_concat(eref->colnames,
+									 list_copy_tail(tf->colnames, numaliases));
+
+	if (numaliases > list_length(tf->colnames))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+				 errmsg("%s function has %d columns available but %d columns specified",
+						"XMLTABLE", list_length(tf->colnames), numaliases)));
+
+	rte->eref = eref;
+
+	/*
+	 * Set flags and access permissions.
+	 *
+	 * Tablefuncs are never checked for access rights (at least, not by the
+	 * RTE permissions mechanism).
+	 */
+	rte->lateral = lateral;
+	rte->inh = false;			/* never true for tablefunc RTEs */
+	rte->inFromCl = inFromCl;
+
+	rte->requiredPerms = 0;
+	rte->checkAsUser = InvalidOid;
+	rte->selectedCols = NULL;
+	rte->insertedCols = NULL;
+	rte->updatedCols = NULL;
+	rte->extraUpdatedCols = NULL;
+
+	/*
+	 * Add completed RTE to pstate's range table list, so that we know its
+	 * index.  But we don't add it to the join list --- caller must do that if
+	 * appropriate.
+	 */
+	pstate->p_rtable = lappend(pstate->p_rtable, rte);
+
+	/*
+	 * Build a ParseNamespaceItem, but don't add it to the pstate's namespace
+	 * list --- caller must do that if appropriate.
+	 */
+	return buildNSItemFromLists(rte, list_length(pstate->p_rtable),
+								rte->coltypes, rte->coltypmods,
+								rte->colcollations);
+}
+
+/*
+ * Add an entry for a VALUES list to the pstate's range table (p_rtable).
+ * Then, construct and return a ParseNamespaceItem for the new RTE.
+ *
+ * This is much like addRangeTableEntry() except that it makes a values RTE.
+ */
+ParseNamespaceItem *
+addRangeTableEntryForValues(ParseState *pstate,
+							List *exprs,
+							List *coltypes,
+							List *coltypmods,
+							List *colcollations,
+							Alias *alias,
+							bool lateral,
+							bool inFromCl)
+{
+	RangeTblEntry *rte = makeNode(RangeTblEntry);
+	char	   *refname = alias ? alias->aliasname : pstrdup("*VALUES*");
+	Alias	   *eref;
+	int			numaliases;
+	int			numcolumns;
+
+	Assert(pstate != NULL);
+
+	rte->rtekind = RTE_VALUES;
+	rte->relid = InvalidOid;
+	rte->subquery = NULL;
+	rte->values_lists = exprs;
+	rte->coltypes = coltypes;
+	rte->coltypmods = coltypmods;
+	rte->colcollations = colcollations;
+	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)));
+
+	rte->eref = eref;
+
+	/*
+	 * Set flags and access permissions.
+	 *
+	 * Subqueries are never checked for access rights.
+	 */
+	rte->lateral = lateral;
+	rte->inh = false;			/* never true for values RTEs */
+	rte->inFromCl = inFromCl;
+
+	rte->requiredPerms = 0;
+	rte->checkAsUser = InvalidOid;
+	rte->selectedCols = NULL;
+	rte->insertedCols = NULL;
+	rte->updatedCols = NULL;
+	rte->extraUpdatedCols = NULL;
+
+	/*
+	 * Add completed RTE to pstate's range table list, so that we know its
+	 * index.  But we don't add it to the join list --- caller must do that if
+	 * appropriate.
+	 */
+	pstate->p_rtable = lappend(pstate->p_rtable, rte);
+
+	/*
+	 * Build a ParseNamespaceItem, but don't add it to the pstate's namespace
+	 * list --- caller must do that if appropriate.
+	 */
+	return buildNSItemFromLists(rte, list_length(pstate->p_rtable),
+								rte->coltypes, rte->coltypmods,
+								rte->colcollations);
+}
+
+/*
+ * Add an entry for a join to the pstate's range table (p_rtable).
+ * Then, construct and return a ParseNamespaceItem for the new RTE.
+ *
+ * This is much like addRangeTableEntry() except that it makes a join RTE.
+ * Also, it's more convenient for the caller to construct the
+ * ParseNamespaceColumn array, so we pass that in.
+ */
+ParseNamespaceItem *
+addRangeTableEntryForJoin(ParseState *pstate,
+						  List *colnames,
+						  ParseNamespaceColumn *nscolumns,
+						  JoinType jointype,
+						  int nummergedcols,
+						  List *aliasvars,
+						  List *leftcols,
+						  List *rightcols,
+						  Alias *join_using_alias,
+						  Alias *alias,
+						  bool inFromCl)
+{
+	RangeTblEntry *rte = makeNode(RangeTblEntry);
+	Alias	   *eref;
+	int			numaliases;
+	ParseNamespaceItem *nsitem;
+
+	Assert(pstate != NULL);
+
+	/*
+	 * 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->joinmergedcols = nummergedcols;
+	rte->joinaliasvars = aliasvars;
+	rte->joinleftcols = leftcols;
+	rte->joinrightcols = rightcols;
+	rte->join_using_alias = join_using_alias;
+	rte->alias = alias;
+
+	eref = 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));
+
+	if (numaliases > list_length(colnames))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+				 errmsg("join expression \"%s\" has %d columns available but %d columns specified",
+						eref->aliasname, list_length(colnames), numaliases)));
+
+	rte->eref = eref;
+
+	/*
+	 * Set flags and access permissions.
+	 *
+	 * Joins are never checked for access rights.
+	 */
+	rte->lateral = false;
+	rte->inh = false;			/* never true for joins */
+	rte->inFromCl = inFromCl;
+
+	rte->requiredPerms = 0;
+	rte->checkAsUser = InvalidOid;
+	rte->selectedCols = NULL;
+	rte->insertedCols = NULL;
+	rte->updatedCols = NULL;
+	rte->extraUpdatedCols = NULL;
+
+	/*
+	 * Add completed RTE to pstate's range table list, so that we know its
+	 * index.  But we don't add it to the join list --- caller must do that if
+	 * appropriate.
+	 */
+	pstate->p_rtable = lappend(pstate->p_rtable, rte);
+
+	/*
+	 * Build a ParseNamespaceItem, but don't add it to the pstate's namespace
+	 * list --- caller must do that if appropriate.
+	 */
+	nsitem = (ParseNamespaceItem *) palloc(sizeof(ParseNamespaceItem));
+	nsitem->p_names = rte->eref;
+	nsitem->p_rte = rte;
+	nsitem->p_rtindex = list_length(pstate->p_rtable);
+	nsitem->p_nscolumns = nscolumns;
+	/* set default visibility flags; might get changed later */
+	nsitem->p_rel_visible = true;
+	nsitem->p_cols_visible = true;
+	nsitem->p_lateral_only = false;
+	nsitem->p_lateral_ok = true;
+
+	return nsitem;
+}
+
+/*
+ * Add an entry for a CTE reference to the pstate's range table (p_rtable).
+ * Then, construct and return a ParseNamespaceItem for the new RTE.
+ *
+ * This is much like addRangeTableEntry() except that it makes a CTE RTE.
+ */
+ParseNamespaceItem *
+addRangeTableEntryForCTE(ParseState *pstate,
+						 CommonTableExpr *cte,
+						 Index levelsup,
+						 RangeVar *rv,
+						 bool inFromCl)
+{
+	RangeTblEntry *rte = makeNode(RangeTblEntry);
+	Alias	   *alias = rv->alias;
+	char	   *refname = alias ? alias->aliasname : cte->ctename;
+	Alias	   *eref;
+	int			numaliases;
+	int			varattno;
+	ListCell   *lc;
+	int			n_dontexpand_columns = 0;
+	ParseNamespaceItem *psi;
+
+	Assert(pstate != NULL);
+
+	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++;
+
+	/*
+	 * We throw error if the CTE is INSERT/UPDATE/DELETE without RETURNING.
+	 * This won't get checked in case of a self-reference, but that's OK
+	 * because data-modifying CTEs aren't allowed to be recursive anyhow.
+	 */
+	if (IsA(cte->ctequery, Query))
+	{
+		Query	   *ctequery = (Query *) cte->ctequery;
+
+		if (ctequery->commandType != CMD_SELECT &&
+			ctequery->returningList == NIL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("WITH query \"%s\" does not have a RETURNING clause",
+							cte->ctename),
+					 parser_errposition(pstate, rv->location)));
+	}
+
+	rte->coltypes = list_copy(cte->ctecoltypes);
+	rte->coltypmods = list_copy(cte->ctecoltypmods);
+	rte->colcollations = list_copy(cte->ctecolcollations);
+
+	rte->alias = alias;
+	if (alias)
+		eref = copyObject(alias);
+	else
+		eref = makeAlias(refname, NIL);
+	numaliases = list_length(eref->colnames);
+
+	/* fill in any unspecified alias columns */
+	varattno = 0;
+	foreach(lc, cte->ctecolnames)
+	{
+		varattno++;
+		if (varattno > numaliases)
+			eref->colnames = lappend(eref->colnames, lfirst(lc));
+	}
+	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;
+
+	if (cte->search_clause)
+	{
+		rte->eref->colnames = lappend(rte->eref->colnames, makeString(cte->search_clause->search_seq_column));
+		if (cte->search_clause->search_breadth_first)
+			rte->coltypes = lappend_oid(rte->coltypes, RECORDOID);
+		else
+			rte->coltypes = lappend_oid(rte->coltypes, RECORDARRAYOID);
+		rte->coltypmods = lappend_int(rte->coltypmods, -1);
+		rte->colcollations = lappend_oid(rte->colcollations, InvalidOid);
+
+		n_dontexpand_columns += 1;
+	}
+
+	if (cte->cycle_clause)
+	{
+		rte->eref->colnames = lappend(rte->eref->colnames, makeString(cte->cycle_clause->cycle_mark_column));
+		rte->coltypes = lappend_oid(rte->coltypes, cte->cycle_clause->cycle_mark_type);
+		rte->coltypmods = lappend_int(rte->coltypmods, cte->cycle_clause->cycle_mark_typmod);
+		rte->colcollations = lappend_oid(rte->colcollations, cte->cycle_clause->cycle_mark_collation);
+
+		rte->eref->colnames = lappend(rte->eref->colnames, makeString(cte->cycle_clause->cycle_path_column));
+		rte->coltypes = lappend_oid(rte->coltypes, RECORDARRAYOID);
+		rte->coltypmods = lappend_int(rte->coltypmods, -1);
+		rte->colcollations = lappend_oid(rte->colcollations, InvalidOid);
+
+		n_dontexpand_columns += 2;
+	}
+
+	/*
+	 * Set flags and access permissions.
+	 *
+	 * Subqueries are never checked for access rights.
+	 */
+	rte->lateral = false;
+	rte->inh = false;			/* never true for subqueries */
+	rte->inFromCl = inFromCl;
+
+	rte->requiredPerms = 0;
+	rte->checkAsUser = InvalidOid;
+	rte->selectedCols = NULL;
+	rte->insertedCols = NULL;
+	rte->updatedCols = NULL;
+	rte->extraUpdatedCols = NULL;
+
+	/*
+	 * Add completed RTE to pstate's range table list, so that we know its
+	 * index.  But we don't add it to the join list --- caller must do that if
+	 * appropriate.
+	 */
+	pstate->p_rtable = lappend(pstate->p_rtable, rte);
+
+	/*
+	 * Build a ParseNamespaceItem, but don't add it to the pstate's namespace
+	 * list --- caller must do that if appropriate.
+	 */
+	psi = buildNSItemFromLists(rte, list_length(pstate->p_rtable),
+							   rte->coltypes, rte->coltypmods,
+							   rte->colcollations);
+
+	/*
+	 * The columns added by search and cycle clauses are not included in star
+	 * expansion in queries contained in the CTE.
+	 */
+	if (rte->ctelevelsup > 0)
+		for (int i = 0; i < n_dontexpand_columns; i++)
+			psi->p_nscolumns[list_length(psi->p_names->colnames) - 1 - i].p_dontexpand = true;
+
+	return psi;
+}
+
+/*
+ * Add an entry for an ephemeral named relation reference to the pstate's
+ * range table (p_rtable).
+ * Then, construct and return a ParseNamespaceItem for the new RTE.
+ *
+ * It is expected that the RangeVar, which up until now is only known to be an
+ * ephemeral named relation, will (in conjunction with the QueryEnvironment in
+ * the ParseState), create a RangeTblEntry for a specific *kind* of ephemeral
+ * named relation, based on enrtype.
+ *
+ * This is much like addRangeTableEntry() except that it makes an RTE for an
+ * ephemeral named relation.
+ */
+ParseNamespaceItem *
+addRangeTableEntryForENR(ParseState *pstate,
+						 RangeVar *rv,
+						 bool inFromCl)
+{
+	RangeTblEntry *rte = makeNode(RangeTblEntry);
+	Alias	   *alias = rv->alias;
+	char	   *refname = alias ? alias->aliasname : rv->relname;
+	EphemeralNamedRelationMetadata enrmd;
+	TupleDesc	tupdesc;
+	int			attno;
+
+	Assert(pstate != NULL);
+	enrmd = get_visible_ENR(pstate, rv->relname);
+	Assert(enrmd != NULL);
+
+	switch (enrmd->enrtype)
+	{
+		case ENR_NAMED_TUPLESTORE:
+			rte->rtekind = RTE_NAMEDTUPLESTORE;
+			break;
+
+		default:
+			elog(ERROR, "unexpected enrtype: %d", enrmd->enrtype);
+			return NULL;		/* for fussy compilers */
+	}
+
+	/*
+	 * Record dependency on a relation.  This allows plans to be invalidated
+	 * if they access transition tables linked to a table that is altered.
+	 */
+	rte->relid = enrmd->reliddesc;
+
+	/*
+	 * Build the list of effective column names using user-supplied aliases
+	 * and/or actual column names.
+	 */
+	tupdesc = ENRMetadataGetTupDesc(enrmd);
+	rte->eref = makeAlias(refname, NIL);
+	buildRelationAliases(tupdesc, alias, rte->eref);
+
+	/* Record additional data for ENR, including column type info */
+	rte->enrname = enrmd->name;
+	rte->enrtuples = enrmd->enrtuples;
+	rte->coltypes = NIL;
+	rte->coltypmods = NIL;
+	rte->colcollations = NIL;
+	for (attno = 1; attno <= tupdesc->natts; ++attno)
+	{
+		Form_pg_attribute att = TupleDescAttr(tupdesc, attno - 1);
+
+		if (att->attisdropped)
+		{
+			/* Record zeroes for a dropped column */
+			rte->coltypes = lappend_oid(rte->coltypes, InvalidOid);
+			rte->coltypmods = lappend_int(rte->coltypmods, 0);
+			rte->colcollations = lappend_oid(rte->colcollations, InvalidOid);
+		}
+		else
+		{
+			/* Let's just make sure we can tell this isn't dropped */
+			if (att->atttypid == InvalidOid)
+				elog(ERROR, "atttypid is invalid for non-dropped column in \"%s\"",
+					 rv->relname);
+			rte->coltypes = lappend_oid(rte->coltypes, att->atttypid);
+			rte->coltypmods = lappend_int(rte->coltypmods, att->atttypmod);
+			rte->colcollations = lappend_oid(rte->colcollations,
+											 att->attcollation);
+		}
+	}
+
+	/*
+	 * Set flags and access permissions.
+	 *
+	 * ENRs are never checked for access rights.
+	 */
+	rte->lateral = false;
+	rte->inh = false;			/* never true for ENRs */
+	rte->inFromCl = inFromCl;
+
+	rte->requiredPerms = 0;
+	rte->checkAsUser = InvalidOid;
+	rte->selectedCols = NULL;
+
+	/*
+	 * Add completed RTE to pstate's range table list, so that we know its
+	 * index.  But we don't add it to the join list --- caller must do that if
+	 * appropriate.
+	 */
+	pstate->p_rtable = lappend(pstate->p_rtable, rte);
+
+	/*
+	 * Build a ParseNamespaceItem, but don't add it to the pstate's namespace
+	 * list --- caller must do that if appropriate.
+	 */
+	return buildNSItemFromTupleDesc(rte, list_length(pstate->p_rtable),
+									tupdesc);
+}
+
+
+/*
+ * Has the specified refname been selected FOR UPDATE/FOR SHARE?
+ *
+ * This is used when we have not yet done transformLockingClause, but need
+ * to know the correct lock to take during initial opening of relations.
+ *
+ * Note: we pay no attention to whether it's FOR UPDATE vs FOR SHARE,
+ * since the table-level lock is the same either way.
+ */
+bool
+isLockedRefname(ParseState *pstate, const char *refname)
+{
+	ListCell   *l;
+
+	/*
+	 * If we are in a subquery specified as locked FOR UPDATE/SHARE from
+	 * parent level, then act as though there's a generic FOR UPDATE here.
+	 */
+	if (pstate->p_locked_from_parent)
+		return true;
+
+	foreach(l, pstate->p_locking_clause)
+	{
+		LockingClause *lc = (LockingClause *) lfirst(l);
+
+		if (lc->lockedRels == NIL)
+		{
+			/* all tables used in query */
+			return true;
+		}
+		else
+		{
+			/* just the named tables */
+			ListCell   *l2;
+
+			foreach(l2, lc->lockedRels)
+			{
+				RangeVar   *thisrel = (RangeVar *) lfirst(l2);
+
+				if (strcmp(refname, thisrel->relname) == 0)
+					return true;
+			}
+		}
+	}
+	return false;
+}
+
+/*
+ * Add the given nsitem/RTE as a top-level entry in the pstate's join list
+ * and/or namespace list.  (We assume caller has checked for any
+ * namespace conflicts.)  The nsitem is always marked as unconditionally
+ * visible, that is, not LATERAL-only.
+ */
+void
+addNSItemToQuery(ParseState *pstate, ParseNamespaceItem *nsitem,
+				 bool addToJoinList,
+				 bool addToRelNameSpace, bool addToVarNameSpace)
+{
+	if (addToJoinList)
+	{
+		RangeTblRef *rtr = makeNode(RangeTblRef);
+
+		rtr->rtindex = nsitem->p_rtindex;
+		pstate->p_joinlist = lappend(pstate->p_joinlist, rtr);
+	}
+	if (addToRelNameSpace || addToVarNameSpace)
+	{
+		/* Set the new nsitem's visibility flags correctly */
+		nsitem->p_rel_visible = addToRelNameSpace;
+		nsitem->p_cols_visible = addToVarNameSpace;
+		nsitem->p_lateral_only = false;
+		nsitem->p_lateral_ok = true;
+		pstate->p_namespace = lappend(pstate->p_namespace, nsitem);
+	}
+}
+
+/*
+ * 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, sublevels_up, and location are the varno, varlevelsup, and location
+ * 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, location,
+						   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);
+
+					/*
+					 * In scenarios where columns have been added to a view
+					 * since the outer query was originally parsed, there can
+					 * be more items in the subquery tlist than the outer
+					 * query expects.  We should ignore such extra column(s)
+					 * --- compare the behavior for composite-returning
+					 * functions, in the RTE_FUNCTION case below.
+					 */
+					if (!aliasp_item)
+						break;
+
+					if (colnames)
+					{
+						char	   *label = strVal(lfirst(aliasp_item));
+
+						*colnames = lappend(*colnames, makeString(pstrdup(label)));
+					}
+
+					if (colvars)
+					{
+						Var		   *varnode;
+
+						varnode = makeVar(rtindex, varattno,
+										  exprType((Node *) te->expr),
+										  exprTypmod((Node *) te->expr),
+										  exprCollation((Node *) te->expr),
+										  sublevels_up);
+						varnode->location = location;
+
+						*colvars = lappend(*colvars, varnode);
+					}
+
+					aliasp_item = lnext(rte->eref->colnames, aliasp_item);
+				}
+			}
+			break;
+		case RTE_FUNCTION:
+			{
+				/* Function RTE */
+				int			atts_done = 0;
+				ListCell   *lc;
+
+				foreach(lc, rte->functions)
+				{
+					RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
+					TypeFuncClass functypclass;
+					Oid			funcrettype;
+					TupleDesc	tupdesc;
+
+					functypclass = get_expr_result_type(rtfunc->funcexpr,
+														&funcrettype,
+														&tupdesc);
+					if (functypclass == TYPEFUNC_COMPOSITE ||
+						functypclass == TYPEFUNC_COMPOSITE_DOMAIN)
+					{
+						/* Composite data type, e.g. a table's row type */
+						Assert(tupdesc);
+						expandTupleDesc(tupdesc, rte->eref,
+										rtfunc->funccolcount, atts_done,
+										rtindex, sublevels_up, location,
+										include_dropped, colnames, colvars);
+					}
+					else if (functypclass == TYPEFUNC_SCALAR)
+					{
+						/* Base data type, i.e. scalar */
+						if (colnames)
+							*colnames = lappend(*colnames,
+												list_nth(rte->eref->colnames,
+														 atts_done));
+
+						if (colvars)
+						{
+							Var		   *varnode;
+
+							varnode = makeVar(rtindex, atts_done + 1,
+											  funcrettype,
+											  exprTypmod(rtfunc->funcexpr),
+											  exprCollation(rtfunc->funcexpr),
+											  sublevels_up);
+							varnode->location = location;
+
+							*colvars = lappend(*colvars, varnode);
+						}
+					}
+					else if (functypclass == TYPEFUNC_RECORD)
+					{
+						if (colnames)
+						{
+							List	   *namelist;
+
+							/* extract appropriate subset of column list */
+							namelist = list_copy_tail(rte->eref->colnames,
+													  atts_done);
+							namelist = list_truncate(namelist,
+													 rtfunc->funccolcount);
+							*colnames = list_concat(*colnames, namelist);
+						}
+
+						if (colvars)
+						{
+							ListCell   *l1;
+							ListCell   *l2;
+							ListCell   *l3;
+							int			attnum = atts_done;
+
+							forthree(l1, rtfunc->funccoltypes,
+									 l2, rtfunc->funccoltypmods,
+									 l3, rtfunc->funccolcollations)
+							{
+								Oid			attrtype = lfirst_oid(l1);
+								int32		attrtypmod = lfirst_int(l2);
+								Oid			attrcollation = lfirst_oid(l3);
+								Var		   *varnode;
+
+								attnum++;
+								varnode = makeVar(rtindex,
+												  attnum,
+												  attrtype,
+												  attrtypmod,
+												  attrcollation,
+												  sublevels_up);
+								varnode->location = location;
+								*colvars = lappend(*colvars, varnode);
+							}
+						}
+					}
+					else
+					{
+						/* addRangeTableEntryForFunction should've caught this */
+						elog(ERROR, "function in FROM has unsupported return type");
+					}
+					atts_done += rtfunc->funccolcount;
+				}
+
+				/* Append the ordinality column if any */
+				if (rte->funcordinality)
+				{
+					if (colnames)
+						*colnames = lappend(*colnames,
+											llast(rte->eref->colnames));
+
+					if (colvars)
+					{
+						Var		   *varnode = makeVar(rtindex,
+													  atts_done + 1,
+													  INT8OID,
+													  -1,
+													  InvalidOid,
+													  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.  While this function is
+					 * also used by the rewriter and planner, they do not
+					 * currently call it on any JOIN RTEs.  Therefore, this
+					 * next bit is dead code, but it seems prudent to handle
+					 * the case correctly anyway.
+					 */
+					if (avar == NULL)
+					{
+						if (include_dropped)
+						{
+							if (colnames)
+								*colnames = lappend(*colnames,
+													makeString(pstrdup("")));
+							if (colvars)
+							{
+								/*
+								 * Can't use join's column type here (it might
+								 * be dropped!); but it doesn't really matter
+								 * what type the Const claims to be.
+								 */
+								*colvars = lappend(*colvars,
+												   makeNullConst(INT4OID, -1,
+																 InvalidOid));
+							}
+						}
+						continue;
+					}
+
+					if (colnames)
+					{
+						char	   *label = strVal(lfirst(colname));
+
+						*colnames = lappend(*colnames,
+											makeString(pstrdup(label)));
+					}
+
+					if (colvars)
+					{
+						Var		   *varnode;
+
+						/*
+						 * If the joinaliasvars entry is a simple Var, just
+						 * copy it (with adjustment of varlevelsup and
+						 * location); otherwise it is a JOIN USING column and
+						 * we must generate a join alias Var.  This matches
+						 * the results that expansion of "join.*" by
+						 * expandNSItemVars would have produced, if we had
+						 * access to the ParseNamespaceItem for the join.
+						 */
+						if (IsA(avar, Var))
+						{
+							varnode = copyObject((Var *) avar);
+							varnode->varlevelsup = sublevels_up;
+						}
+						else
+							varnode = makeVar(rtindex, varattno,
+											  exprType(avar),
+											  exprTypmod(avar),
+											  exprCollation(avar),
+											  sublevels_up);
+						varnode->location = location;
+
+						*colvars = lappend(*colvars, varnode);
+					}
+				}
+			}
+			break;
+		case RTE_TABLEFUNC:
+		case RTE_VALUES:
+		case RTE_CTE:
+		case RTE_NAMEDTUPLESTORE:
+			{
+				/* Tablefunc, Values, CTE, or ENR RTE */
+				ListCell   *aliasp_item = list_head(rte->eref->colnames);
+				ListCell   *lct;
+				ListCell   *lcm;
+				ListCell   *lcc;
+
+				varattno = 0;
+				forthree(lct, rte->coltypes,
+						 lcm, rte->coltypmods,
+						 lcc, rte->colcollations)
+				{
+					Oid			coltype = lfirst_oid(lct);
+					int32		coltypmod = lfirst_int(lcm);
+					Oid			colcoll = lfirst_oid(lcc);
+
+					varattno++;
+
+					if (colnames)
+					{
+						/* Assume there is one alias per output column */
+						if (OidIsValid(coltype))
+						{
+							char	   *label = strVal(lfirst(aliasp_item));
+
+							*colnames = lappend(*colnames,
+												makeString(pstrdup(label)));
+						}
+						else if (include_dropped)
+							*colnames = lappend(*colnames,
+												makeString(pstrdup("")));
+
+						aliasp_item = lnext(rte->eref->colnames, aliasp_item);
+					}
+
+					if (colvars)
+					{
+						if (OidIsValid(coltype))
+						{
+							Var		   *varnode;
+
+							varnode = makeVar(rtindex, varattno,
+											  coltype, coltypmod, colcoll,
+											  sublevels_up);
+							varnode->location = location;
+
+							*colvars = lappend(*colvars, varnode);
+						}
+						else if (include_dropped)
+						{
+							/*
+							 * It doesn't really matter what type the Const
+							 * claims to be.
+							 */
+							*colvars = lappend(*colvars,
+											   makeNullConst(INT4OID, -1,
+															 InvalidOid));
+						}
+					}
+				}
+			}
+			break;
+		case RTE_RESULT:
+			/* These expose no columns, so nothing to do */
+			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,
+			   int location, 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, rel->rd_att->natts, 0,
+					rtindex, sublevels_up,
+					location, include_dropped,
+					colnames, colvars);
+	relation_close(rel, AccessShareLock);
+}
+
+/*
+ * expandTupleDesc -- expandRTE subroutine
+ *
+ * Generate names and/or Vars for the first "count" attributes of the tupdesc,
+ * and append them to colnames/colvars.  "offset" is added to the varattno
+ * that each Var would otherwise have, and we also skip the first "offset"
+ * entries in eref->colnames.  (These provisions allow use of this code for
+ * an individual composite-returning function in an RTE_FUNCTION RTE.)
+ */
+static void
+expandTupleDesc(TupleDesc tupdesc, Alias *eref, int count, int offset,
+				int rtindex, int sublevels_up,
+				int location, bool include_dropped,
+				List **colnames, List **colvars)
+{
+	ListCell   *aliascell;
+	int			varattno;
+
+	aliascell = (offset < list_length(eref->colnames)) ?
+		list_nth_cell(eref->colnames, offset) : NULL;
+
+	Assert(count <= tupdesc->natts);
+	for (varattno = 0; varattno < count; varattno++)
+	{
+		Form_pg_attribute attr = TupleDescAttr(tupdesc, 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, InvalidOid));
+				}
+			}
+			if (aliascell)
+				aliascell = lnext(eref->colnames, aliascell);
+			continue;
+		}
+
+		if (colnames)
+		{
+			char	   *label;
+
+			if (aliascell)
+			{
+				label = strVal(lfirst(aliascell));
+				aliascell = lnext(eref->colnames, aliascell);
+			}
+			else
+			{
+				/* If we run out of aliases, use the underlying name */
+				label = NameStr(attr->attname);
+			}
+			*colnames = lappend(*colnames, makeString(pstrdup(label)));
+		}
+
+		if (colvars)
+		{
+			Var		   *varnode;
+
+			varnode = makeVar(rtindex, varattno + offset + 1,
+							  attr->atttypid, attr->atttypmod,
+							  attr->attcollation,
+							  sublevels_up);
+			varnode->location = location;
+
+			*colvars = lappend(*colvars, varnode);
+		}
+	}
+}
+
+/*
+ * expandNSItemVars
+ *	  Produce a list of Vars, and optionally a list of column names,
+ *	  for the non-dropped columns of the nsitem.
+ *
+ * The emitted Vars are marked with the given sublevels_up and location.
+ *
+ * If colnames isn't NULL, a list of String items for the columns is stored
+ * there; note that it's just a subset of the RTE's eref list, and hence
+ * the list elements mustn't be modified.
+ */
+List *
+expandNSItemVars(ParseNamespaceItem *nsitem,
+				 int sublevels_up, int location,
+				 List **colnames)
+{
+	List	   *result = NIL;
+	int			colindex;
+	ListCell   *lc;
+
+	if (colnames)
+		*colnames = NIL;
+	colindex = 0;
+	foreach(lc, nsitem->p_names->colnames)
+	{
+		Value	   *colnameval = (Value *) lfirst(lc);
+		const char *colname = strVal(colnameval);
+		ParseNamespaceColumn *nscol = nsitem->p_nscolumns + colindex;
+
+		if (nscol->p_dontexpand)
+		{
+			/* skip */
+		}
+		else if (colname[0])
+		{
+			Var		   *var;
+
+			Assert(nscol->p_varno > 0);
+			var = makeVar(nscol->p_varno,
+						  nscol->p_varattno,
+						  nscol->p_vartype,
+						  nscol->p_vartypmod,
+						  nscol->p_varcollid,
+						  sublevels_up);
+			/* makeVar doesn't offer parameters for these, so set by hand: */
+			var->varnosyn = nscol->p_varnosyn;
+			var->varattnosyn = nscol->p_varattnosyn;
+			var->location = location;
+			result = lappend(result, var);
+			if (colnames)
+				*colnames = lappend(*colnames, colnameval);
+		}
+		else
+		{
+			/* dropped column, ignore */
+			Assert(nscol->p_varno == 0);
+		}
+		colindex++;
+	}
+	return result;
+}
+
+/*
+ * expandNSItemAttrs -
+ *	  Workhorse for "*" expansion: produce a list of targetentries
+ *	  for the attributes of the nsitem
+ *
+ * pstate->p_next_resno determines the resnos assigned to the TLEs.
+ * The referenced columns are marked as requiring SELECT access.
+ */
+List *
+expandNSItemAttrs(ParseState *pstate, ParseNamespaceItem *nsitem,
+				  int sublevels_up, int location)
+{
+	RangeTblEntry *rte = nsitem->p_rte;
+	List	   *names,
+			   *vars;
+	ListCell   *name,
+			   *var;
+	List	   *te_list = NIL;
+
+	vars = expandNSItemVars(nsitem, sublevels_up, location, &names);
+
+	/*
+	 * Require read access to the table.  This is normally redundant with the
+	 * markVarForSelectPriv calls below, but not if the table has zero
+	 * columns.  We need not do anything if the nsitem is for a join: its
+	 * component tables will have been marked ACL_SELECT when they were added
+	 * to the rangetable.  (This step changes things only for the target
+	 * relation of UPDATE/DELETE, which cannot be under a join.)
+	 */
+	if (rte->rtekind == RTE_RELATION)
+		rte->requiredPerms |= ACL_SELECT;
+
+	forboth(name, names, var, vars)
+	{
+		char	   *label = strVal(lfirst(name));
+		Var		   *varnode = (Var *) lfirst(var);
+		TargetEntry *te;
+
+		te = makeTargetEntry((Expr *) varnode,
+							 (AttrNumber) pstate->p_next_resno++,
+							 label,
+							 false);
+		te_list = lappend(te_list, te);
+
+		/* Require read access to each column */
+		markVarForSelectPriv(pstate, varnode);
+	}
+
+	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.
+ *
+ * It is caller's responsibility to not call this on a dropped attribute.
+ * (You will get some answer for such cases, but it might not be sensible.)
+ */
+char *
+get_rte_attribute_name(RangeTblEntry *rte, AttrNumber attnum)
+{
+	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));
+
+	/*
+	 * 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_attname(rte->relid, attnum, false);
+
+	/*
+	 * Otherwise use the column name from eref.  There should always be one.
+	 */
+	if (attnum > 0 && attnum <= list_length(rte->eref->colnames))
+		return strVal(list_nth(rte->eref->colnames, attnum - 1));
+
+	/* else caller gave us a bogus attnum */
+	elog(ERROR, "invalid attnum %d for rangetable entry %s",
+		 attnum, rte->eref->aliasname);
+	return NULL;				/* keep compiler quiet */
+}
+
+/*
+ * 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:
+			{
+				/*
+				 * Plain relation RTE --- get the attribute's catalog entry
+				 */
+				HeapTuple	tp;
+				Form_pg_attribute att_tup;
+
+				tp = SearchSysCache2(ATTNUM,
+									 ObjectIdGetDatum(rte->relid),
+									 Int16GetDatum(attnum));
+				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);
+				result = att_tup->attisdropped;
+				ReleaseSysCache(tp);
+			}
+			break;
+		case RTE_SUBQUERY:
+		case RTE_TABLEFUNC:
+		case RTE_VALUES:
+		case RTE_CTE:
+
+			/*
+			 * Subselect, Table Functions, Values, CTE RTEs never have dropped
+			 * columns
+			 */
+			result = false;
+			break;
+		case RTE_NAMEDTUPLESTORE:
+			{
+				/* Check dropped-ness by testing for valid coltype */
+				if (attnum <= 0 ||
+					attnum > list_length(rte->coltypes))
+					elog(ERROR, "invalid varattno %d", attnum);
+				result = !OidIsValid((list_nth_oid(rte->coltypes, attnum - 1)));
+			}
+			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 pointer 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 = (aliasvar == NULL);
+			}
+			break;
+		case RTE_FUNCTION:
+			{
+				/* Function RTE */
+				ListCell   *lc;
+				int			atts_done = 0;
+
+				/*
+				 * Dropped attributes are only possible with functions that
+				 * return named composite types.  In such a case we have to
+				 * look up the result type to see if it currently has this
+				 * column dropped.  So first, loop over the funcs until we
+				 * find the one that covers the requested column.
+				 */
+				foreach(lc, rte->functions)
+				{
+					RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
+
+					if (attnum > atts_done &&
+						attnum <= atts_done + rtfunc->funccolcount)
+					{
+						TupleDesc	tupdesc;
+
+						tupdesc = get_expr_result_tupdesc(rtfunc->funcexpr,
+														  true);
+						if (tupdesc)
+						{
+							/* Composite data type, e.g. a table's row type */
+							Form_pg_attribute att_tup;
+
+							Assert(tupdesc);
+							Assert(attnum - atts_done <= tupdesc->natts);
+							att_tup = TupleDescAttr(tupdesc,
+													attnum - atts_done - 1);
+							return att_tup->attisdropped;
+						}
+						/* Otherwise, it can't have any dropped columns */
+						return false;
+					}
+					atts_done += rtfunc->funccolcount;
+				}
+
+				/* If we get here, must be looking for the ordinality column */
+				if (rte->funcordinality && attnum == atts_done + 1)
+					return false;
+
+				/* this probably can't happen ... */
+				ereport(ERROR,
+						(errcode(ERRCODE_UNDEFINED_COLUMN),
+						 errmsg("column %d of relation \"%s\" does not exist",
+								attnum,
+								rte->eref->aliasname)));
+				result = false; /* keep compiler quiet */
+			}
+			break;
+		case RTE_RESULT:
+			/* this probably can't happen ... */
+			ereport(ERROR,
+					(errcode(ERRCODE_UNDEFINED_COLUMN),
+					 errmsg("column %d of relation \"%s\" does not exist",
+							attnum,
+							rte->eref->aliasname)));
+			result = false;		/* keep compiler quiet */
+			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_parse_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
+ *	table_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 < RelationGetNumberOfAttributes(rd); i++)
+	{
+		Form_pg_attribute att = TupleDescAttr(rd->rd_att, i);
+
+		if (namestrcmp(&(att->attname), attname) == 0 && !att->attisdropped)
+			return i + 1;
+	}
+
+	if (sysColOK)
+	{
+		if ((i = specialAttNum(attname)) != InvalidAttrNumber)
+			return i;
+	}
+
+	/* on failure */
+	return InvalidAttrNumber;
+}
+
+/* specialAttNum()
+ *
+ * Check attribute name to see if it is "special", e.g. "xmin".
+ * - thomas 2000-02-07
+ *
+ * Note: this only discovers whether the name could be a system attribute.
+ * Caller needs to ensure that it really is an attribute of the rel.
+ */
+static int
+specialAttNum(const char *attname)
+{
+	const FormData_pg_attribute *sysatt;
+
+	sysatt = SystemAttributeByName(attname);
+	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
+ *	table_open()'ed.  Use the cache version get_atttype()
+ *	for access to non-opened relations.
+ */
+const NameData *
+attnumAttName(Relation rd, int attid)
+{
+	if (attid <= 0)
+	{
+		const FormData_pg_attribute *sysatt;
+
+		sysatt = SystemAttributeDefinition(attid);
+		return &sysatt->attname;
+	}
+	if (attid > rd->rd_att->natts)
+		elog(ERROR, "invalid attribute number %d", attid);
+	return &TupleDescAttr(rd->rd_att, attid - 1)->attname;
+}
+
+/*
+ * given attribute id, return type of that attribute
+ *
+ *	This should only be used if the relation is already
+ *	table_open()'ed.  Use the cache version get_atttype()
+ *	for access to non-opened relations.
+ */
+Oid
+attnumTypeId(Relation rd, int attid)
+{
+	if (attid <= 0)
+	{
+		const FormData_pg_attribute *sysatt;
+
+		sysatt = SystemAttributeDefinition(attid);
+		return sysatt->atttypid;
+	}
+	if (attid > rd->rd_att->natts)
+		elog(ERROR, "invalid attribute number %d", attid);
+	return TupleDescAttr(rd->rd_att, attid - 1)->atttypid;
+}
+
+/*
+ * given attribute id, return collation of that attribute
+ *
+ *	This should only be used if the relation is already table_open()'ed.
+ */
+Oid
+attnumCollationId(Relation rd, int attid)
+{
+	if (attid <= 0)
+	{
+		/* All system attributes are of noncollatable types. */
+		return InvalidOid;
+	}
+	if (attid > rd->rd_att->natts)
+		elog(ERROR, "invalid attribute number %d", attid);
+	return TupleDescAttr(rd->rd_att, attid - 1)->attcollation;
+}
+
+/*
+ * Generate a suitable error about a missing RTE.
+ *
+ * Since this is a very common type of error, we work rather hard to
+ * produce a helpful message.
+ */
+void
+errorMissingRTE(ParseState *pstate, RangeVar *relation)
+{
+	RangeTblEntry *rte;
+	const char *badAlias = NULL;
+
+	/*
+	 * Check to see if there are any potential matches in the query's
+	 * rangetable.  (Note: cases involving a bad schema name in the RangeVar
+	 * will throw error immediately here.  That seems OK.)
+	 */
+	rte = searchRangeTableForRel(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)
+	{
+		ParseNamespaceItem *nsitem;
+		int			sublevels_up;
+
+		nsitem = refnameNamespaceItem(pstate, NULL, rte->eref->aliasname,
+									  relation->location,
+									  &sublevels_up);
+		if (nsitem && nsitem->p_rte == rte)
+			badAlias = rte->eref->aliasname;
+	}
+
+	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)),
+				 parser_errposition(pstate, relation->location)));
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_TABLE),
+				 errmsg("missing FROM-clause entry for table \"%s\"",
+						relation->relname),
+				 parser_errposition(pstate, relation->location)));
+}
+
+/*
+ * Generate a suitable error about a missing column.
+ *
+ * Since this is a very common type of error, we work rather hard to
+ * produce a helpful message.
+ */
+void
+errorMissingColumn(ParseState *pstate,
+				   const char *relname, const char *colname, int location)
+{
+	FuzzyAttrMatchState *state;
+	char	   *closestfirst = NULL;
+
+	/*
+	 * Search the entire rtable looking for possible matches.  If we find one,
+	 * emit a hint about it.
+	 *
+	 * TODO: improve this code (and also errorMissingRTE) to mention using
+	 * LATERAL if appropriate.
+	 */
+	state = searchRangeTableForCol(pstate, relname, colname, location);
+
+	/*
+	 * Extract closest col string for best match, if any.
+	 *
+	 * Infer an exact match referenced despite not being visible from the fact
+	 * that an attribute number was not present in state passed back -- this
+	 * is what is reported when !closestfirst.  There might also be an exact
+	 * match that was qualified with an incorrect alias, in which case
+	 * closestfirst will be set (so hint is the same as generic fuzzy case).
+	 */
+	if (state->rfirst && AttributeNumberIsValid(state->first))
+		closestfirst = strVal(list_nth(state->rfirst->eref->colnames,
+									   state->first - 1));
+
+	if (!state->rsecond)
+	{
+		/*
+		 * Handle case where there is zero or one column suggestions to hint,
+		 * including exact matches referenced but not visible.
+		 */
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 relname ?
+				 errmsg("column %s.%s does not exist", relname, colname) :
+				 errmsg("column \"%s\" does not exist", colname),
+				 state->rfirst ? closestfirst ?
+				 errhint("Perhaps you meant to reference the column \"%s.%s\".",
+						 state->rfirst->eref->aliasname, closestfirst) :
+				 errhint("There is a column named \"%s\" in table \"%s\", but it cannot be referenced from this part of the query.",
+						 colname, state->rfirst->eref->aliasname) : 0,
+				 parser_errposition(pstate, location)));
+	}
+	else
+	{
+		/* Handle case where there are two equally useful column hints */
+		char	   *closestsecond;
+
+		closestsecond = strVal(list_nth(state->rsecond->eref->colnames,
+										state->second - 1));
+
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 relname ?
+				 errmsg("column %s.%s does not exist", relname, colname) :
+				 errmsg("column \"%s\" does not exist", colname),
+				 errhint("Perhaps you meant to reference the column \"%s.%s\" or the column \"%s.%s\".",
+						 state->rfirst->eref->aliasname, closestfirst,
+						 state->rsecond->eref->aliasname, closestsecond),
+				 parser_errposition(pstate, location)));
+	}
+}
+
+
+/*
+ * Examine a fully-parsed query, and return true iff any relation underlying
+ * the query is a temporary relation (table, view, or materialized view).
+ */
+bool
+isQueryUsingTempRelation(Query *query)
+{
+	return isQueryUsingTempRelation_walker((Node *) query, NULL);
+}
+
+static bool
+isQueryUsingTempRelation_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
+
+		foreach(rtable, query->rtable)
+		{
+			RangeTblEntry *rte = lfirst(rtable);
+
+			if (rte->rtekind == RTE_RELATION)
+			{
+				Relation	rel = table_open(rte->relid, AccessShareLock);
+				char		relpersistence = rel->rd_rel->relpersistence;
+
+				table_close(rel, AccessShareLock);
+				if (relpersistence == RELPERSISTENCE_TEMP)
+					return true;
+			}
+		}
+
+		return query_tree_walker(query,
+								 isQueryUsingTempRelation_walker,
+								 context,
+								 QTW_IGNORE_JOINALIASES);
+	}
+
+	return expression_tree_walker(node,
+								  isQueryUsingTempRelation_walker,
+								  context);
+}