CREATE RULE "_RETURN" and toast tables

diff --git a/src/backend/rewrite/rewriteDefine.c b/src/backend/rewrite/rewriteDefine.c
index b37f36b..7e7b16a 100644
--- a/src/backend/rewrite/rewriteDefine.c
+++ b/src/backend/rewrite/rewriteDefine.c
@@ -16,6 +16,9 @@
 
 #include "access/heapam.h"
 #include "access/htup_details.h"
+#include "access/transam.h"
+#include "access/multixact.h"
+#include "access/xact.h"
 #include "catalog/catalog.h"
 #include "catalog/dependency.h"
 #include "catalog/heap.h"
@@ -500,30 +503,101 @@ DefineQueryRewrite(char *rulename,
 							replace);
 
 		/*
-		 * Set pg_class 'relhasrules' field TRUE for event relation. If
-		 * appropriate, also modify the 'relkind' field to show that the
-		 * relation is now a view.
+		 * Set pg_class 'relhasrules' field TRUE for event relation.
 		 *
 		 * Important side effect: an SI notice is broadcast to force all
 		 * backends (including me!) to update relcache entries with the new
 		 * rule.
 		 */
-		SetRelationRuleStatus(event_relid, true, RelisBecomingView);
+		SetRelationRuleStatus(event_relid, true);
 	}
 
-	/*
-	 * If the relation is becoming a view, delete the storage files associated
-	 * with it.  Also, get rid of any system attribute entries in pg_attribute,
-	 * because a view shouldn't have any of those.
+	/* ---------------------------------------------------------------------
+	 * If the relation is becoming a view
+	 * - delete the associated storage files
+	 * - get rid of any system attributes in pg_attribute, a view shouldn't
+         have any of those
+	 * - remove the toast table, there is no need for it anymore, and its
+         presence would make vacuum slightly more complicated
+	 * - set relkind to RELKIND_VIEW
+	 * - adjust other pg_class attributes to be appropriate for a view
 	 *
 	 * NB: we had better have AccessExclusiveLock to do this ...
-	 *
-	 * XXX what about getting rid of its TOAST table?  For now, we don't.
+	 * ---------------------------------------------------------------------
 	 */
 	if (RelisBecomingView)
 	{
+		Relation	relationRelation;
+		Oid			toastrelid;
+		HeapTuple	classTup;
+		Form_pg_class classForm;
+
+		relationRelation = heap_open(RelationRelationId, RowExclusiveLock);
+		toastrelid = event_relation->rd_rel->reltoastrelid;
+
+		/* drop storage while table still looks like a table  */
 		RelationDropStorage(event_relation);
 		DeleteSystemAttributeTuples(event_relid);
+
+		/*
+		 * Now drop the toast table which is not needed anymore, the pg_class
+		 * entry is adapted below.
+		 */
+		if (toastrelid != InvalidOid)
+		{
+			ObjectAddress toastobject;
+
+			/*
+			 * delete the dependency of the main relation to the toast relation
+			 * so we can delete the toast relation without also deleting what
+			 * is becoming the view.
+			 */
+			deleteDependencyRecordsFor(RelationRelationId, toastrelid,
+									   false);
+
+			/* make deletion of dependency record visible */
+			CommandCounterIncrement();
+
+			/* now drop toast table, including index */
+			toastobject.classId = RelationRelationId;
+			toastobject.objectId = toastrelid;
+			toastobject.objectSubId = 0;
+			performDeletion(&toastobject, DROP_RESTRICT, PERFORM_DELETION_INTERNAL);
+		}
+
+		/*
+		 * Fixup pg_class entry to look like a normal view's, including setting
+		 * the correct relkind and removal of reltoastrelid, reltoastidxid of
+		 * the toast table we potentially removed above.
+		 */
+
+		/*
+		 * SetRelationRuleStatus may have updated the pg_class row, so make
+		 * current version visible before we fetch the current tuple.
+		 */
+		CommandCounterIncrement();
+
+		classTup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(event_relid));
+		if (!HeapTupleIsValid(classTup))
+			elog(ERROR, "cache lookup failed for relation %u", event_relid);
+
+		classForm = (Form_pg_class) GETSTRUCT(classTup);
+		classForm->reltablespace = InvalidOid;
+		classForm->relpages = 0;
+		classForm->reltuples = 0;
+		classForm->relallvisible = 0;
+		classForm->reltoastrelid = InvalidOid;
+		classForm->reltoastidxid = InvalidOid;
+		classForm->relkind = RELKIND_VIEW;
+		classForm->relhasoids = false;
+		classForm->relfrozenxid = InvalidTransactionId;
+		classForm->relminmxid = InvalidMultiXactId;
+
+		simple_heap_update(relationRelation, &classTup->t_self, classTup);
+		CatalogUpdateIndexes(relationRelation, classTup);
+
+		heap_freetuple(classTup);
+		heap_close(relationRelation, RowExclusiveLock);
 	}
 
 	/* Close rel, but keep lock till commit... */
diff --git a/src/backend/rewrite/rewriteSupport.c b/src/backend/rewrite/rewriteSupport.c
index 4729560..8af960a 100644
--- a/src/backend/rewrite/rewriteSupport.c
+++ b/src/backend/rewrite/rewriteSupport.c
@@ -42,7 +42,6 @@ IsDefinedRewriteRule(Oid owningRel, const char *ruleName)
 /*
  * SetRelationRuleStatus
  *		Set the value of the relation's relhasrules field in pg_class;
- *		if the relation is becoming a view, also adjust its relkind.
  *
  * NOTE: caller must be holding an appropriate lock on the relation.
  *
@@ -53,8 +52,7 @@ IsDefinedRewriteRule(Oid owningRel, const char *ruleName)
  * row.
  */
 void
-SetRelationRuleStatus(Oid relationId, bool relHasRules,
-					  bool relIsBecomingView)
+SetRelationRuleStatus(Oid relationId, bool relHasRules)
 {
 	Relation	relationRelation;
 	HeapTuple	tuple;
@@ -69,13 +67,10 @@ SetRelationRuleStatus(Oid relationId, bool relHasRules,
 		elog(ERROR, "cache lookup failed for relation %u", relationId);
 	classForm = (Form_pg_class) GETSTRUCT(tuple);
 
-	if (classForm->relhasrules != relHasRules ||
-		(relIsBecomingView && classForm->relkind != RELKIND_VIEW))
+	if (classForm->relhasrules != relHasRules)
 	{
 		/* Do the update */
 		classForm->relhasrules = relHasRules;
-		if (relIsBecomingView)
-			classForm->relkind = RELKIND_VIEW;
 
 		simple_heap_update(relationRelation, &tuple->t_self, tuple);
 
diff --git a/src/include/rewrite/rewriteSupport.h b/src/include/rewrite/rewriteSupport.h
index ed40602..70de400 100644
--- a/src/include/rewrite/rewriteSupport.h
+++ b/src/include/rewrite/rewriteSupport.h
@@ -19,8 +19,7 @@
 
 extern bool IsDefinedRewriteRule(Oid owningRel, const char *ruleName);
 
-extern void SetRelationRuleStatus(Oid relationId, bool relHasRules,
-					  bool relIsBecomingView);
+extern void SetRelationRuleStatus(Oid relationId, bool relHasRules);
 
 extern Oid	get_rewrite_oid(Oid relid, const char *rulename, bool missing_ok);
 extern Oid get_rewrite_oid_without_relid(const char *rulename,
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 4226aad..4e58972 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -2316,25 +2316,47 @@ drop view fooview;
 --
 -- test conversion of table to view (needed to load some pg_dump files)
 --
-create table fooview (x int, y text);
-select xmin, * from fooview;
+create table fooview_toast (x int, y text);
+select xmin, * from fooview_toast;
  xmin | x | y 
 ------+---+---
 (0 rows)
 
-create rule "_RETURN" as on select to fooview do instead
+create rule "_RETURN" as on select to fooview_toast do instead
   select 1 as x, 'aaa'::text as y;
-select * from fooview;
+select * from fooview_toast;
  x |  y  
 ---+-----
  1 | aaa
 (1 row)
 
-select xmin, * from fooview;  -- fail, views don't have such a column
+select xmin, * from fooview_toast;  -- fail, views don't have such a column
 ERROR:  column "xmin" does not exist
-LINE 1: select xmin, * from fooview;
+LINE 1: select xmin, * from fooview_toast;
                ^
-drop view fooview;
+BEGIN;
+create table fooview_toast_onetx (x int, y text);
+create rule "_RETURN" as on select to fooview_toast_onetx do instead
+  select 1 as x, 'aaa'::text as y;
+COMMIT;
+select * from fooview_toast_onetx;
+ x |  y  
+---+-----
+ 1 | aaa
+(1 row)
+
+create table fooview_notoast (x int);
+create rule "_RETURN" as on select to fooview_notoast do instead
+  select 1 as x;
+select * from fooview_notoast;
+ x 
+---
+ 1
+(1 row)
+
+drop view fooview_toast;
+drop view fooview_toast_onetx;
+drop view fooview_notoast;
 --
 -- check for planner problems with complex inherited UPDATES
 --
diff --git a/src/test/regress/sql/rules.sql b/src/test/regress/sql/rules.sql
index b8d67ae..1173055 100644
--- a/src/test/regress/sql/rules.sql
+++ b/src/test/regress/sql/rules.sql
@@ -863,16 +863,33 @@ drop view fooview;
 -- test conversion of table to view (needed to load some pg_dump files)
 --
 
-create table fooview (x int, y text);
-select xmin, * from fooview;
+create table fooview_toast (x int, y text);
+select xmin, * from fooview_toast;
 
-create rule "_RETURN" as on select to fooview do instead
+create rule "_RETURN" as on select to fooview_toast do instead
   select 1 as x, 'aaa'::text as y;
 
-select * from fooview;
-select xmin, * from fooview;  -- fail, views don't have such a column
+select * from fooview_toast;
+select xmin, * from fooview_toast;  -- fail, views don't have such a column
 
-drop view fooview;
+BEGIN;
+create table fooview_toast_onetx (x int, y text);
+
+create rule "_RETURN" as on select to fooview_toast_onetx do instead
+  select 1 as x, 'aaa'::text as y;
+COMMIT;
+
+select * from fooview_toast_onetx;
+
+create table fooview_notoast (x int);
+create rule "_RETURN" as on select to fooview_notoast do instead
+  select 1 as x;
+
+select * from fooview_notoast;
+
+drop view fooview_toast;
+drop view fooview_toast_onetx;
+drop view fooview_notoast;
 
 --
 -- check for planner problems with complex inherited UPDATES