Adding upstream version 14.5.upstream/14.5upstream

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

1 files changed, 1002 insertions, 0 deletions

diff --git a/src/backend/optimizer/util/appendinfo.c b/src/backend/optimizer/util/appendinfo.c
new file mode 100644
index 0000000..af46f58
--- /dev/null
+++ b/src/backend/optimizer/util/appendinfo.c
@@ -0,0 +1,1002 @@
+/*-------------------------------------------------------------------------
+ *
+ * appendinfo.c
+ *	  Routines for mapping between append parent(s) and children
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/optimizer/path/appendinfo.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/htup_details.h"
+#include "access/table.h"
+#include "foreign/fdwapi.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
+#include "optimizer/appendinfo.h"
+#include "optimizer/pathnode.h"
+#include "parser/parsetree.h"
+#include "utils/lsyscache.h"
+#include "utils/rel.h"
+#include "utils/syscache.h"
+
+
+typedef struct
+{
+	PlannerInfo *root;
+	int			nappinfos;
+	AppendRelInfo **appinfos;
+} adjust_appendrel_attrs_context;
+
+static void make_inh_translation_list(Relation oldrelation,
+									  Relation newrelation,
+									  Index newvarno,
+									  AppendRelInfo *appinfo);
+static Node *adjust_appendrel_attrs_mutator(Node *node,
+											adjust_appendrel_attrs_context *context);
+
+
+/*
+ * make_append_rel_info
+ *	  Build an AppendRelInfo for the parent-child pair
+ */
+AppendRelInfo *
+make_append_rel_info(Relation parentrel, Relation childrel,
+					 Index parentRTindex, Index childRTindex)
+{
+	AppendRelInfo *appinfo = makeNode(AppendRelInfo);
+
+	appinfo->parent_relid = parentRTindex;
+	appinfo->child_relid = childRTindex;
+	appinfo->parent_reltype = parentrel->rd_rel->reltype;
+	appinfo->child_reltype = childrel->rd_rel->reltype;
+	make_inh_translation_list(parentrel, childrel, childRTindex, appinfo);
+	appinfo->parent_reloid = RelationGetRelid(parentrel);
+
+	return appinfo;
+}
+
+/*
+ * make_inh_translation_list
+ *	  Build the list of translations from parent Vars to child Vars for
+ *	  an inheritance child, as well as a reverse-translation array.
+ *
+ * The reverse-translation array has an entry for each child relation
+ * column, which is either the 1-based index of the corresponding parent
+ * column, or 0 if there's no match (that happens for dropped child columns,
+ * as well as child columns beyond those of the parent, which are allowed in
+ * traditional inheritance though not partitioning).
+ *
+ * For paranoia's sake, we match type/collation as well as attribute name.
+ */
+static void
+make_inh_translation_list(Relation oldrelation, Relation newrelation,
+						  Index newvarno,
+						  AppendRelInfo *appinfo)
+{
+	List	   *vars = NIL;
+	AttrNumber *pcolnos;
+	TupleDesc	old_tupdesc = RelationGetDescr(oldrelation);
+	TupleDesc	new_tupdesc = RelationGetDescr(newrelation);
+	Oid			new_relid = RelationGetRelid(newrelation);
+	int			oldnatts = old_tupdesc->natts;
+	int			newnatts = new_tupdesc->natts;
+	int			old_attno;
+	int			new_attno = 0;
+
+	/* Initialize reverse-translation array with all entries zero */
+	appinfo->num_child_cols = newnatts;
+	appinfo->parent_colnos = pcolnos =
+		(AttrNumber *) palloc0(newnatts * sizeof(AttrNumber));
+
+	for (old_attno = 0; old_attno < oldnatts; old_attno++)
+	{
+		Form_pg_attribute att;
+		char	   *attname;
+		Oid			atttypid;
+		int32		atttypmod;
+		Oid			attcollation;
+
+		att = TupleDescAttr(old_tupdesc, old_attno);
+		if (att->attisdropped)
+		{
+			/* Just put NULL into this list entry */
+			vars = lappend(vars, NULL);
+			continue;
+		}
+		attname = NameStr(att->attname);
+		atttypid = att->atttypid;
+		atttypmod = att->atttypmod;
+		attcollation = att->attcollation;
+
+		/*
+		 * When we are generating the "translation list" for the parent table
+		 * of an inheritance set, no need to search for matches.
+		 */
+		if (oldrelation == newrelation)
+		{
+			vars = lappend(vars, makeVar(newvarno,
+										 (AttrNumber) (old_attno + 1),
+										 atttypid,
+										 atttypmod,
+										 attcollation,
+										 0));
+			pcolnos[old_attno] = old_attno + 1;
+			continue;
+		}
+
+		/*
+		 * Otherwise we have to search for the matching column by name.
+		 * There's no guarantee it'll have the same column position, because
+		 * of cases like ALTER TABLE ADD COLUMN and multiple inheritance.
+		 * However, in simple cases, the relative order of columns is mostly
+		 * the same in both relations, so try the column of newrelation that
+		 * follows immediately after the one that we just found, and if that
+		 * fails, let syscache handle it.
+		 */
+		if (new_attno >= newnatts ||
+			(att = TupleDescAttr(new_tupdesc, new_attno))->attisdropped ||
+			strcmp(attname, NameStr(att->attname)) != 0)
+		{
+			HeapTuple	newtup;
+
+			newtup = SearchSysCacheAttName(new_relid, attname);
+			if (!HeapTupleIsValid(newtup))
+				elog(ERROR, "could not find inherited attribute \"%s\" of relation \"%s\"",
+					 attname, RelationGetRelationName(newrelation));
+			new_attno = ((Form_pg_attribute) GETSTRUCT(newtup))->attnum - 1;
+			Assert(new_attno >= 0 && new_attno < newnatts);
+			ReleaseSysCache(newtup);
+
+			att = TupleDescAttr(new_tupdesc, new_attno);
+		}
+
+		/* Found it, check type and collation match */
+		if (atttypid != att->atttypid || atttypmod != att->atttypmod)
+			elog(ERROR, "attribute \"%s\" of relation \"%s\" does not match parent's type",
+				 attname, RelationGetRelationName(newrelation));
+		if (attcollation != att->attcollation)
+			elog(ERROR, "attribute \"%s\" of relation \"%s\" does not match parent's collation",
+				 attname, RelationGetRelationName(newrelation));
+
+		vars = lappend(vars, makeVar(newvarno,
+									 (AttrNumber) (new_attno + 1),
+									 atttypid,
+									 atttypmod,
+									 attcollation,
+									 0));
+		pcolnos[new_attno] = old_attno + 1;
+		new_attno++;
+	}
+
+	appinfo->translated_vars = vars;
+}
+
+/*
+ * adjust_appendrel_attrs
+ *	  Copy the specified query or expression and translate Vars referring to a
+ *	  parent rel to refer to the corresponding child rel instead.  We also
+ *	  update rtindexes appearing outside Vars, such as resultRelation and
+ *	  jointree relids.
+ *
+ * Note: this is only applied after conversion of sublinks to subplans,
+ * so we don't need to cope with recursion into sub-queries.
+ *
+ * Note: this is not hugely different from what pullup_replace_vars() does;
+ * maybe we should try to fold the two routines together.
+ */
+Node *
+adjust_appendrel_attrs(PlannerInfo *root, Node *node, int nappinfos,
+					   AppendRelInfo **appinfos)
+{
+	adjust_appendrel_attrs_context context;
+
+	context.root = root;
+	context.nappinfos = nappinfos;
+	context.appinfos = appinfos;
+
+	/* If there's nothing to adjust, don't call this function. */
+	Assert(nappinfos >= 1 && appinfos != NULL);
+
+	/* Should never be translating a Query tree. */
+	Assert(node == NULL || !IsA(node, Query));
+
+	return adjust_appendrel_attrs_mutator(node, &context);
+}
+
+static Node *
+adjust_appendrel_attrs_mutator(Node *node,
+							   adjust_appendrel_attrs_context *context)
+{
+	AppendRelInfo **appinfos = context->appinfos;
+	int			nappinfos = context->nappinfos;
+	int			cnt;
+
+	if (node == NULL)
+		return NULL;
+	if (IsA(node, Var))
+	{
+		Var		   *var = (Var *) copyObject(node);
+		AppendRelInfo *appinfo = NULL;
+
+		if (var->varlevelsup != 0)
+			return (Node *) var;	/* no changes needed */
+
+		for (cnt = 0; cnt < nappinfos; cnt++)
+		{
+			if (var->varno == appinfos[cnt]->parent_relid)
+			{
+				appinfo = appinfos[cnt];
+				break;
+			}
+		}
+
+		if (appinfo)
+		{
+			var->varno = appinfo->child_relid;
+			/* it's now a generated Var, so drop any syntactic labeling */
+			var->varnosyn = 0;
+			var->varattnosyn = 0;
+			if (var->varattno > 0)
+			{
+				Node	   *newnode;
+
+				if (var->varattno > list_length(appinfo->translated_vars))
+					elog(ERROR, "attribute %d of relation \"%s\" does not exist",
+						 var->varattno, get_rel_name(appinfo->parent_reloid));
+				newnode = copyObject(list_nth(appinfo->translated_vars,
+											  var->varattno - 1));
+				if (newnode == NULL)
+					elog(ERROR, "attribute %d of relation \"%s\" does not exist",
+						 var->varattno, get_rel_name(appinfo->parent_reloid));
+				return newnode;
+			}
+			else if (var->varattno == 0)
+			{
+				/*
+				 * Whole-row Var: if we are dealing with named rowtypes, we
+				 * can use a whole-row Var for the child table plus a coercion
+				 * step to convert the tuple layout to the parent's rowtype.
+				 * Otherwise we have to generate a RowExpr.
+				 */
+				if (OidIsValid(appinfo->child_reltype))
+				{
+					Assert(var->vartype == appinfo->parent_reltype);
+					if (appinfo->parent_reltype != appinfo->child_reltype)
+					{
+						ConvertRowtypeExpr *r = makeNode(ConvertRowtypeExpr);
+
+						r->arg = (Expr *) var;
+						r->resulttype = appinfo->parent_reltype;
+						r->convertformat = COERCE_IMPLICIT_CAST;
+						r->location = -1;
+						/* Make sure the Var node has the right type ID, too */
+						var->vartype = appinfo->child_reltype;
+						return (Node *) r;
+					}
+				}
+				else
+				{
+					/*
+					 * Build a RowExpr containing the translated variables.
+					 *
+					 * In practice var->vartype will always be RECORDOID here,
+					 * so we need to come up with some suitable column names.
+					 * We use the parent RTE's column names.
+					 *
+					 * Note: we can't get here for inheritance cases, so there
+					 * is no need to worry that translated_vars might contain
+					 * some dummy NULLs.
+					 */
+					RowExpr    *rowexpr;
+					List	   *fields;
+					RangeTblEntry *rte;
+
+					rte = rt_fetch(appinfo->parent_relid,
+								   context->root->parse->rtable);
+					fields = copyObject(appinfo->translated_vars);
+					rowexpr = makeNode(RowExpr);
+					rowexpr->args = fields;
+					rowexpr->row_typeid = var->vartype;
+					rowexpr->row_format = COERCE_IMPLICIT_CAST;
+					rowexpr->colnames = copyObject(rte->eref->colnames);
+					rowexpr->location = -1;
+
+					return (Node *) rowexpr;
+				}
+			}
+			/* system attributes don't need any other translation */
+		}
+		else if (var->varno == ROWID_VAR)
+		{
+			/*
+			 * If it's a ROWID_VAR placeholder, see if we've reached a leaf
+			 * target rel, for which we can translate the Var to a specific
+			 * instantiation.  We should never be asked to translate to a set
+			 * of relids containing more than one leaf target rel, so the
+			 * answer will be unique.  If we're still considering non-leaf
+			 * inheritance levels, return the ROWID_VAR Var as-is.
+			 */
+			Relids		leaf_result_relids = context->root->leaf_result_relids;
+			Index		leaf_relid = 0;
+
+			for (cnt = 0; cnt < nappinfos; cnt++)
+			{
+				if (bms_is_member(appinfos[cnt]->child_relid,
+								  leaf_result_relids))
+				{
+					if (leaf_relid)
+						elog(ERROR, "cannot translate to multiple leaf relids");
+					leaf_relid = appinfos[cnt]->child_relid;
+				}
+			}
+
+			if (leaf_relid)
+			{
+				RowIdentityVarInfo *ridinfo = (RowIdentityVarInfo *)
+				list_nth(context->root->row_identity_vars, var->varattno - 1);
+
+				if (bms_is_member(leaf_relid, ridinfo->rowidrels))
+				{
+					/* Substitute the Var given in the RowIdentityVarInfo */
+					var = copyObject(ridinfo->rowidvar);
+					/* ... but use the correct relid */
+					var->varno = leaf_relid;
+					/* varnosyn in the RowIdentityVarInfo is probably wrong */
+					var->varnosyn = 0;
+					var->varattnosyn = 0;
+				}
+				else
+				{
+					/*
+					 * This leaf rel can't return the desired value, so
+					 * substitute a NULL of the correct type.
+					 */
+					return (Node *) makeNullConst(var->vartype,
+												  var->vartypmod,
+												  var->varcollid);
+				}
+			}
+		}
+		return (Node *) var;
+	}
+	if (IsA(node, CurrentOfExpr))
+	{
+		CurrentOfExpr *cexpr = (CurrentOfExpr *) copyObject(node);
+
+		for (cnt = 0; cnt < nappinfos; cnt++)
+		{
+			AppendRelInfo *appinfo = appinfos[cnt];
+
+			if (cexpr->cvarno == appinfo->parent_relid)
+			{
+				cexpr->cvarno = appinfo->child_relid;
+				break;
+			}
+		}
+		return (Node *) cexpr;
+	}
+	if (IsA(node, PlaceHolderVar))
+	{
+		/* Copy the PlaceHolderVar node with correct mutation of subnodes */
+		PlaceHolderVar *phv;
+
+		phv = (PlaceHolderVar *) expression_tree_mutator(node,
+														 adjust_appendrel_attrs_mutator,
+														 (void *) context);
+		/* now fix PlaceHolderVar's relid sets */
+		if (phv->phlevelsup == 0)
+			phv->phrels = adjust_child_relids(phv->phrels, context->nappinfos,
+											  context->appinfos);
+		return (Node *) phv;
+	}
+	/* Shouldn't need to handle planner auxiliary nodes here */
+	Assert(!IsA(node, SpecialJoinInfo));
+	Assert(!IsA(node, AppendRelInfo));
+	Assert(!IsA(node, PlaceHolderInfo));
+	Assert(!IsA(node, MinMaxAggInfo));
+
+	/*
+	 * We have to process RestrictInfo nodes specially.  (Note: although
+	 * set_append_rel_pathlist will hide RestrictInfos in the parent's
+	 * baserestrictinfo list from us, it doesn't hide those in joininfo.)
+	 */
+	if (IsA(node, RestrictInfo))
+	{
+		RestrictInfo *oldinfo = (RestrictInfo *) node;
+		RestrictInfo *newinfo = makeNode(RestrictInfo);
+
+		/* Copy all flat-copiable fields */
+		memcpy(newinfo, oldinfo, sizeof(RestrictInfo));
+
+		/* Recursively fix the clause itself */
+		newinfo->clause = (Expr *)
+			adjust_appendrel_attrs_mutator((Node *) oldinfo->clause, context);
+
+		/* and the modified version, if an OR clause */
+		newinfo->orclause = (Expr *)
+			adjust_appendrel_attrs_mutator((Node *) oldinfo->orclause, context);
+
+		/* adjust relid sets too */
+		newinfo->clause_relids = adjust_child_relids(oldinfo->clause_relids,
+													 context->nappinfos,
+													 context->appinfos);
+		newinfo->required_relids = adjust_child_relids(oldinfo->required_relids,
+													   context->nappinfos,
+													   context->appinfos);
+		newinfo->outer_relids = adjust_child_relids(oldinfo->outer_relids,
+													context->nappinfos,
+													context->appinfos);
+		newinfo->nullable_relids = adjust_child_relids(oldinfo->nullable_relids,
+													   context->nappinfos,
+													   context->appinfos);
+		newinfo->left_relids = adjust_child_relids(oldinfo->left_relids,
+												   context->nappinfos,
+												   context->appinfos);
+		newinfo->right_relids = adjust_child_relids(oldinfo->right_relids,
+													context->nappinfos,
+													context->appinfos);
+
+		/*
+		 * Reset cached derivative fields, since these might need to have
+		 * different values when considering the child relation.  Note we
+		 * don't reset left_ec/right_ec: each child variable is implicitly
+		 * equivalent to its parent, so still a member of the same EC if any.
+		 */
+		newinfo->eval_cost.startup = -1;
+		newinfo->norm_selec = -1;
+		newinfo->outer_selec = -1;
+		newinfo->left_em = NULL;
+		newinfo->right_em = NULL;
+		newinfo->scansel_cache = NIL;
+		newinfo->left_bucketsize = -1;
+		newinfo->right_bucketsize = -1;
+		newinfo->left_mcvfreq = -1;
+		newinfo->right_mcvfreq = -1;
+
+		return (Node *) newinfo;
+	}
+
+	/*
+	 * NOTE: we do not need to recurse into sublinks, because they should
+	 * already have been converted to subplans before we see them.
+	 */
+	Assert(!IsA(node, SubLink));
+	Assert(!IsA(node, Query));
+	/* We should never see these Query substructures, either. */
+	Assert(!IsA(node, RangeTblRef));
+	Assert(!IsA(node, JoinExpr));
+
+	return expression_tree_mutator(node, adjust_appendrel_attrs_mutator,
+								   (void *) context);
+}
+
+/*
+ * adjust_appendrel_attrs_multilevel
+ *	  Apply Var translations from a toplevel appendrel parent down to a child.
+ *
+ * In some cases we need to translate expressions referencing a parent relation
+ * to reference an appendrel child that's multiple levels removed from it.
+ */
+Node *
+adjust_appendrel_attrs_multilevel(PlannerInfo *root, Node *node,
+								  Relids child_relids,
+								  Relids top_parent_relids)
+{
+	AppendRelInfo **appinfos;
+	Bitmapset  *parent_relids = NULL;
+	int			nappinfos;
+	int			cnt;
+
+	Assert(bms_num_members(child_relids) == bms_num_members(top_parent_relids));
+
+	appinfos = find_appinfos_by_relids(root, child_relids, &nappinfos);
+
+	/* Construct relids set for the immediate parent of given child. */
+	for (cnt = 0; cnt < nappinfos; cnt++)
+	{
+		AppendRelInfo *appinfo = appinfos[cnt];
+
+		parent_relids = bms_add_member(parent_relids, appinfo->parent_relid);
+	}
+
+	/* Recurse if immediate parent is not the top parent. */
+	if (!bms_equal(parent_relids, top_parent_relids))
+		node = adjust_appendrel_attrs_multilevel(root, node, parent_relids,
+												 top_parent_relids);
+
+	/* Now translate for this child */
+	node = adjust_appendrel_attrs(root, node, nappinfos, appinfos);
+
+	pfree(appinfos);
+
+	return node;
+}
+
+/*
+ * Substitute child relids for parent relids in a Relid set.  The array of
+ * appinfos specifies the substitutions to be performed.
+ */
+Relids
+adjust_child_relids(Relids relids, int nappinfos, AppendRelInfo **appinfos)
+{
+	Bitmapset  *result = NULL;
+	int			cnt;
+
+	for (cnt = 0; cnt < nappinfos; cnt++)
+	{
+		AppendRelInfo *appinfo = appinfos[cnt];
+
+		/* Remove parent, add child */
+		if (bms_is_member(appinfo->parent_relid, relids))
+		{
+			/* Make a copy if we are changing the set. */
+			if (!result)
+				result = bms_copy(relids);
+
+			result = bms_del_member(result, appinfo->parent_relid);
+			result = bms_add_member(result, appinfo->child_relid);
+		}
+	}
+
+	/* If we made any changes, return the modified copy. */
+	if (result)
+		return result;
+
+	/* Otherwise, return the original set without modification. */
+	return relids;
+}
+
+/*
+ * Replace any relid present in top_parent_relids with its child in
+ * child_relids. Members of child_relids can be multiple levels below top
+ * parent in the partition hierarchy.
+ */
+Relids
+adjust_child_relids_multilevel(PlannerInfo *root, Relids relids,
+							   Relids child_relids, Relids top_parent_relids)
+{
+	AppendRelInfo **appinfos;
+	int			nappinfos;
+	Relids		parent_relids = NULL;
+	Relids		result;
+	Relids		tmp_result = NULL;
+	int			cnt;
+
+	/*
+	 * If the given relids set doesn't contain any of the top parent relids,
+	 * it will remain unchanged.
+	 */
+	if (!bms_overlap(relids, top_parent_relids))
+		return relids;
+
+	appinfos = find_appinfos_by_relids(root, child_relids, &nappinfos);
+
+	/* Construct relids set for the immediate parent of the given child. */
+	for (cnt = 0; cnt < nappinfos; cnt++)
+	{
+		AppendRelInfo *appinfo = appinfos[cnt];
+
+		parent_relids = bms_add_member(parent_relids, appinfo->parent_relid);
+	}
+
+	/* Recurse if immediate parent is not the top parent. */
+	if (!bms_equal(parent_relids, top_parent_relids))
+	{
+		tmp_result = adjust_child_relids_multilevel(root, relids,
+													parent_relids,
+													top_parent_relids);
+		relids = tmp_result;
+	}
+
+	result = adjust_child_relids(relids, nappinfos, appinfos);
+
+	/* Free memory consumed by any intermediate result. */
+	if (tmp_result)
+		bms_free(tmp_result);
+	bms_free(parent_relids);
+	pfree(appinfos);
+
+	return result;
+}
+
+/*
+ * adjust_inherited_attnums
+ *	  Translate an integer list of attribute numbers from parent to child.
+ */
+List *
+adjust_inherited_attnums(List *attnums, AppendRelInfo *context)
+{
+	List	   *result = NIL;
+	ListCell   *lc;
+
+	/* This should only happen for an inheritance case, not UNION ALL */
+	Assert(OidIsValid(context->parent_reloid));
+
+	/* Look up each attribute in the AppendRelInfo's translated_vars list */
+	foreach(lc, attnums)
+	{
+		AttrNumber	parentattno = lfirst_int(lc);
+		Var		   *childvar;
+
+		/* Look up the translation of this column: it must be a Var */
+		if (parentattno <= 0 ||
+			parentattno > list_length(context->translated_vars))
+			elog(ERROR, "attribute %d of relation \"%s\" does not exist",
+				 parentattno, get_rel_name(context->parent_reloid));
+		childvar = (Var *) list_nth(context->translated_vars, parentattno - 1);
+		if (childvar == NULL || !IsA(childvar, Var))
+			elog(ERROR, "attribute %d of relation \"%s\" does not exist",
+				 parentattno, get_rel_name(context->parent_reloid));
+
+		result = lappend_int(result, childvar->varattno);
+	}
+	return result;
+}
+
+/*
+ * adjust_inherited_attnums_multilevel
+ *	  As above, but traverse multiple inheritance levels as needed.
+ */
+List *
+adjust_inherited_attnums_multilevel(PlannerInfo *root, List *attnums,
+									Index child_relid, Index top_parent_relid)
+{
+	AppendRelInfo *appinfo = root->append_rel_array[child_relid];
+
+	if (!appinfo)
+		elog(ERROR, "child rel %d not found in append_rel_array", child_relid);
+
+	/* Recurse if immediate parent is not the top parent. */
+	if (appinfo->parent_relid != top_parent_relid)
+		attnums = adjust_inherited_attnums_multilevel(root, attnums,
+													  appinfo->parent_relid,
+													  top_parent_relid);
+
+	/* Now translate for this child */
+	return adjust_inherited_attnums(attnums, appinfo);
+}
+
+/*
+ * get_translated_update_targetlist
+ *	  Get the processed_tlist of an UPDATE query, translated as needed to
+ *	  match a child target relation.
+ *
+ * Optionally also return the list of target column numbers translated
+ * to this target relation.  (The resnos in processed_tlist MUST NOT be
+ * relied on for this purpose.)
+ */
+void
+get_translated_update_targetlist(PlannerInfo *root, Index relid,
+								 List **processed_tlist, List **update_colnos)
+{
+	/* This is pretty meaningless for commands other than UPDATE. */
+	Assert(root->parse->commandType == CMD_UPDATE);
+	if (relid == root->parse->resultRelation)
+	{
+		/*
+		 * Non-inheritance case, so it's easy.  The caller might be expecting
+		 * a tree it can scribble on, though, so copy.
+		 */
+		*processed_tlist = copyObject(root->processed_tlist);
+		if (update_colnos)
+			*update_colnos = copyObject(root->update_colnos);
+	}
+	else
+	{
+		Assert(bms_is_member(relid, root->all_result_relids));
+		*processed_tlist = (List *)
+			adjust_appendrel_attrs_multilevel(root,
+											  (Node *) root->processed_tlist,
+											  bms_make_singleton(relid),
+											  bms_make_singleton(root->parse->resultRelation));
+		if (update_colnos)
+			*update_colnos =
+				adjust_inherited_attnums_multilevel(root, root->update_colnos,
+													relid,
+													root->parse->resultRelation);
+	}
+}
+
+/*
+ * find_appinfos_by_relids
+ * 		Find AppendRelInfo structures for all relations specified by relids.
+ *
+ * The AppendRelInfos are returned in an array, which can be pfree'd by the
+ * caller. *nappinfos is set to the number of entries in the array.
+ */
+AppendRelInfo **
+find_appinfos_by_relids(PlannerInfo *root, Relids relids, int *nappinfos)
+{
+	AppendRelInfo **appinfos;
+	int			cnt = 0;
+	int			i;
+
+	*nappinfos = bms_num_members(relids);
+	appinfos = (AppendRelInfo **) palloc(sizeof(AppendRelInfo *) * *nappinfos);
+
+	i = -1;
+	while ((i = bms_next_member(relids, i)) >= 0)
+	{
+		AppendRelInfo *appinfo = root->append_rel_array[i];
+
+		if (!appinfo)
+			elog(ERROR, "child rel %d not found in append_rel_array", i);
+
+		appinfos[cnt++] = appinfo;
+	}
+	return appinfos;
+}
+
+
+/*****************************************************************************
+ *
+ *		ROW-IDENTITY VARIABLE MANAGEMENT
+ *
+ * This code lacks a good home, perhaps.  We choose to keep it here because
+ * adjust_appendrel_attrs_mutator() is its principal co-conspirator.  That
+ * function does most of what is needed to expand ROWID_VAR Vars into the
+ * right things.
+ *
+ *****************************************************************************/
+
+/*
+ * add_row_identity_var
+ *	  Register a row-identity column to be used in UPDATE/DELETE.
+ *
+ * The Var must be equal(), aside from varno, to any other row-identity
+ * column with the same rowid_name.  Thus, for example, "wholerow"
+ * row identities had better use vartype == RECORDOID.
+ *
+ * rtindex is currently redundant with rowid_var->varno, but we specify
+ * it as a separate parameter in case this is ever generalized to support
+ * non-Var expressions.  (We could reasonably handle expressions over
+ * Vars of the specified rtindex, but for now that seems unnecessary.)
+ */
+void
+add_row_identity_var(PlannerInfo *root, Var *orig_var,
+					 Index rtindex, const char *rowid_name)
+{
+	TargetEntry *tle;
+	Var		   *rowid_var;
+	RowIdentityVarInfo *ridinfo;
+	ListCell   *lc;
+
+	/* For now, the argument must be just a Var of the given rtindex */
+	Assert(IsA(orig_var, Var));
+	Assert(orig_var->varno == rtindex);
+	Assert(orig_var->varlevelsup == 0);
+
+	/*
+	 * If we're doing non-inherited UPDATE/DELETE, there's little need for
+	 * ROWID_VAR shenanigans.  Just shove the presented Var into the
+	 * processed_tlist, and we're done.
+	 */
+	if (rtindex == root->parse->resultRelation)
+	{
+		tle = makeTargetEntry((Expr *) orig_var,
+							  list_length(root->processed_tlist) + 1,
+							  pstrdup(rowid_name),
+							  true);
+		root->processed_tlist = lappend(root->processed_tlist, tle);
+		return;
+	}
+
+	/*
+	 * Otherwise, rtindex should reference a leaf target relation that's being
+	 * added to the query during expand_inherited_rtentry().
+	 */
+	Assert(bms_is_member(rtindex, root->leaf_result_relids));
+	Assert(root->append_rel_array[rtindex] != NULL);
+
+	/*
+	 * We have to find a matching RowIdentityVarInfo, or make one if there is
+	 * none.  To allow using equal() to match the vars, change the varno to
+	 * ROWID_VAR, leaving all else alone.
+	 */
+	rowid_var = copyObject(orig_var);
+	/* This could eventually become ChangeVarNodes() */
+	rowid_var->varno = ROWID_VAR;
+
+	/* Look for an existing row-id column of the same name */
+	foreach(lc, root->row_identity_vars)
+	{
+		ridinfo = (RowIdentityVarInfo *) lfirst(lc);
+		if (strcmp(rowid_name, ridinfo->rowidname) != 0)
+			continue;
+		if (equal(rowid_var, ridinfo->rowidvar))
+		{
+			/* Found a match; we need only record that rtindex needs it too */
+			ridinfo->rowidrels = bms_add_member(ridinfo->rowidrels, rtindex);
+			return;
+		}
+		else
+		{
+			/* Ooops, can't handle this */
+			elog(ERROR, "conflicting uses of row-identity name \"%s\"",
+				 rowid_name);
+		}
+	}
+
+	/* No request yet, so add a new RowIdentityVarInfo */
+	ridinfo = makeNode(RowIdentityVarInfo);
+	ridinfo->rowidvar = copyObject(rowid_var);
+	/* for the moment, estimate width using just the datatype info */
+	ridinfo->rowidwidth = get_typavgwidth(exprType((Node *) rowid_var),
+										  exprTypmod((Node *) rowid_var));
+	ridinfo->rowidname = pstrdup(rowid_name);
+	ridinfo->rowidrels = bms_make_singleton(rtindex);
+
+	root->row_identity_vars = lappend(root->row_identity_vars, ridinfo);
+
+	/* Change rowid_var into a reference to this row_identity_vars entry */
+	rowid_var->varattno = list_length(root->row_identity_vars);
+
+	/* Push the ROWID_VAR reference variable into processed_tlist */
+	tle = makeTargetEntry((Expr *) rowid_var,
+						  list_length(root->processed_tlist) + 1,
+						  pstrdup(rowid_name),
+						  true);
+	root->processed_tlist = lappend(root->processed_tlist, tle);
+}
+
+/*
+ * add_row_identity_columns
+ *
+ * This function adds the row identity columns needed by the core code.
+ * FDWs might call add_row_identity_var() for themselves to add nonstandard
+ * columns.  (Duplicate requests are fine.)
+ */
+void
+add_row_identity_columns(PlannerInfo *root, Index rtindex,
+						 RangeTblEntry *target_rte,
+						 Relation target_relation)
+{
+	CmdType		commandType = root->parse->commandType;
+	char		relkind = target_relation->rd_rel->relkind;
+	Var		   *var;
+
+	Assert(commandType == CMD_UPDATE || commandType == CMD_DELETE);
+
+	if (relkind == RELKIND_RELATION ||
+		relkind == RELKIND_MATVIEW ||
+		relkind == RELKIND_PARTITIONED_TABLE)
+	{
+		/*
+		 * Emit CTID so that executor can find the row to update or delete.
+		 */
+		var = makeVar(rtindex,
+					  SelfItemPointerAttributeNumber,
+					  TIDOID,
+					  -1,
+					  InvalidOid,
+					  0);
+		add_row_identity_var(root, var, rtindex, "ctid");
+	}
+	else if (relkind == RELKIND_FOREIGN_TABLE)
+	{
+		/*
+		 * Let the foreign table's FDW add whatever junk TLEs it wants.
+		 */
+		FdwRoutine *fdwroutine;
+
+		fdwroutine = GetFdwRoutineForRelation(target_relation, false);
+
+		if (fdwroutine->AddForeignUpdateTargets != NULL)
+			fdwroutine->AddForeignUpdateTargets(root, rtindex,
+												target_rte, target_relation);
+
+		/*
+		 * For UPDATE, we need to make the FDW fetch unchanged columns by
+		 * asking it to fetch a whole-row Var.  That's because the top-level
+		 * targetlist only contains entries for changed columns, but
+		 * ExecUpdate will need to build the complete new tuple.  (Actually,
+		 * we only really need this in UPDATEs that are not pushed to the
+		 * remote side, but it's hard to tell if that will be the case at the
+		 * point when this function is called.)
+		 *
+		 * We will also need the whole row if there are any row triggers, so
+		 * that the executor will have the "old" row to pass to the trigger.
+		 * Alas, this misses system columns.
+		 */
+		if (commandType == CMD_UPDATE ||
+			(target_relation->trigdesc &&
+			 (target_relation->trigdesc->trig_delete_after_row ||
+			  target_relation->trigdesc->trig_delete_before_row)))
+		{
+			var = makeVar(rtindex,
+						  InvalidAttrNumber,
+						  RECORDOID,
+						  -1,
+						  InvalidOid,
+						  0);
+			add_row_identity_var(root, var, rtindex, "wholerow");
+		}
+	}
+}
+
+/*
+ * distribute_row_identity_vars
+ *
+ * After we have finished identifying all the row identity columns
+ * needed by an inherited UPDATE/DELETE query, make sure that these
+ * columns will be generated by all the target relations.
+ *
+ * This is more or less like what build_base_rel_tlists() does,
+ * except that it would not understand what to do with ROWID_VAR Vars.
+ * Since that function runs before inheritance relations are expanded,
+ * it will never see any such Vars anyway.
+ */
+void
+distribute_row_identity_vars(PlannerInfo *root)
+{
+	Query	   *parse = root->parse;
+	int			result_relation = parse->resultRelation;
+	RangeTblEntry *target_rte;
+	RelOptInfo *target_rel;
+	ListCell   *lc;
+
+	/* There's nothing to do if this isn't an inherited UPDATE/DELETE. */
+	if (parse->commandType != CMD_UPDATE && parse->commandType != CMD_DELETE)
+	{
+		Assert(root->row_identity_vars == NIL);
+		return;
+	}
+	target_rte = rt_fetch(result_relation, parse->rtable);
+	if (!target_rte->inh)
+	{
+		Assert(root->row_identity_vars == NIL);
+		return;
+	}
+
+	/*
+	 * Ordinarily, we expect that leaf result relation(s) will have added some
+	 * ROWID_VAR Vars to the query.  However, it's possible that constraint
+	 * exclusion suppressed every leaf relation.  The executor will get upset
+	 * if the plan has no row identity columns at all, even though it will
+	 * certainly process no rows.  Handle this edge case by re-opening the top
+	 * result relation and adding the row identity columns it would have used,
+	 * as preprocess_targetlist() would have done if it weren't marked "inh".
+	 * (This is a bit ugly, but it seems better to confine the ugliness and
+	 * extra cycles to this unusual corner case.)  We needn't worry about
+	 * fixing the rel's reltarget, as that won't affect the finished plan.
+	 */
+	if (root->row_identity_vars == NIL)
+	{
+		Relation	target_relation;
+
+		target_relation = table_open(target_rte->relid, NoLock);
+		add_row_identity_columns(root, result_relation,
+								 target_rte, target_relation);
+		table_close(target_relation, NoLock);
+		return;
+	}
+
+	/*
+	 * Dig through the processed_tlist to find the ROWID_VAR reference Vars,
+	 * and forcibly copy them into the reltarget list of the topmost target
+	 * relation.  That's sufficient because they'll be copied to the
+	 * individual leaf target rels (with appropriate translation) later,
+	 * during appendrel expansion --- see set_append_rel_size().
+	 */
+	target_rel = find_base_rel(root, result_relation);
+
+	foreach(lc, root->processed_tlist)
+	{
+		TargetEntry *tle = lfirst(lc);
+		Var		   *var = (Var *) tle->expr;
+
+		if (var && IsA(var, Var) && var->varno == ROWID_VAR)
+		{
+			target_rel->reltarget->exprs =
+				lappend(target_rel->reltarget->exprs, copyObject(var));
+			/* reltarget cost and width will be computed later */
+		}
+	}
+}