diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 93dca7a..1d6f774 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -32,6 +32,7 @@
 #include "access/xlogutils.h"
 #include "catalog/catalog.h"
 #include "catalog/namespace.h"
+#include "catalog/pg_enum.h"
 #include "catalog/storage.h"
 #include "commands/async.h"
 #include "commands/tablecmds.h"
@@ -2126,6 +2127,7 @@ CommitTransaction(void)
 	smgrDoPendingDeletes(true);

 	AtCommit_Notify();
+	AtEOXact_Enum();
 	AtEOXact_GUC(true, 1);
 	AtEOXact_SPI(true);
 	AtEOXact_on_commit_actions(true);
@@ -2405,6 +2407,7 @@ PrepareTransaction(void)

 	/* PREPARE acts the same as COMMIT as far as GUC is concerned */
 	AtEOXact_GUC(true, 1);
+	AtEOXact_Enum();
 	AtEOXact_SPI(true);
 	AtEOXact_on_commit_actions(true);
 	AtEOXact_Namespace(true, false);
@@ -2606,6 +2609,7 @@ AbortTransaction(void)
 							 false, true);
 		smgrDoPendingDeletes(false);

+		AtEOXact_Enum();
 		AtEOXact_GUC(false, 1);
 		AtEOXact_SPI(false);
 		AtEOXact_on_commit_actions(false);
diff --git a/src/backend/catalog/pg_enum.c b/src/backend/catalog/pg_enum.c
index fe61d4d..3056f68 100644
--- a/src/backend/catalog/pg_enum.c
+++ b/src/backend/catalog/pg_enum.c
@@ -28,6 +28,8 @@
 #include "utils/builtins.h"
 #include "utils/catcache.h"
 #include "utils/fmgroids.h"
+#include "utils/hsearch.h"
+#include "utils/memutils.h"
 #include "utils/syscache.h"
 #include "utils/tqual.h"

@@ -38,6 +40,8 @@ Oid			binary_upgrade_next_pg_enum_oid = InvalidOid;
 static void RenumberEnumType(Relation pg_enum, HeapTuple *existing, int nelems);
 static int	sort_order_cmp(const void *p1, const void *p2);

+/* hash table of values added in the current transaction by AddEnumLabel */
+static HTAB *enum_blacklist = NULL;

 /*
  * EnumValuesCreate
@@ -460,8 +464,49 @@ restart:
 	heap_freetuple(enum_tup);

 	heap_close(pg_enum, RowExclusiveLock);
+
+	/* Set up the blacklist hash if required */
+	if (enum_blacklist == NULL)
+	{
+		HASHCTL     hash_ctl;
+		memset(&hash_ctl, 0, sizeof(hash_ctl));
+		hash_ctl.keysize = sizeof(Oid);
+		hash_ctl.entrysize = sizeof(Oid);
+		hash_ctl.hcxt = TopTransactionContext;
+		enum_blacklist = hash_create("Enum blacklist for current transaction",
+						   32,
+						   &hash_ctl,
+						   HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
+
+	}
+
+	/* Add the new value to the blacklist */
+	(void) hash_search(enum_blacklist, &newOid, HASH_ENTER, NULL);
 }

+/* Test if the enum is on the blacklist */
+bool
+EnumBlacklisted(Oid enum_id)
+{
+	bool found;
+
+	if (enum_blacklist == NULL)
+		return false;
+
+	(void) hash_search(enum_blacklist, &enum_id, HASH_FIND, &found);
+	return found;
+}
+
+/*
+ * Clean up the blacklist hash at the end of the transaction. The memory will
+ * have been deallocated, so all we need to do is set the pointer back to
+ * NULL for the next transaction.
+ */
+void
+AtEOXact_Enum(void)
+{
+	enum_blacklist = NULL;
+}

 /*
  * RenameEnumLabel
diff --git a/src/backend/utils/adt/enum.c b/src/backend/utils/adt/enum.c
index 973397c..a7ba3d0 100644
--- a/src/backend/utils/adt/enum.c
+++ b/src/backend/utils/adt/enum.c
@@ -76,6 +76,10 @@ check_safe_enum_use(HeapTuple enumval_tup)
 		TransactionIdDidCommit(xmin))
 		return;

+	/* Check if the enum value is blacklisted. If not, it's safe */
+	if (! EnumBlacklisted(HeapTupleGetOid(enumval_tup)))
+		return;
+
 	/* It is a new enum value, so check to see if the whole enum is new */
 	en = (Form_pg_enum) GETSTRUCT(enumval_tup);
 	enumtyp_tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(en->enumtypid));
diff --git a/src/include/catalog/pg_enum.h b/src/include/catalog/pg_enum.h
index 5938ba5..dff3d2f 100644
--- a/src/include/catalog/pg_enum.h
+++ b/src/include/catalog/pg_enum.h
@@ -69,5 +69,7 @@ extern void AddEnumLabel(Oid enumTypeOid, const char *newVal,
 			 bool skipIfExists);
 extern void RenameEnumLabel(Oid enumTypeOid,
 				const char *oldVal, const char *newVal);
+extern bool EnumBlacklisted(Oid enum_id);
+extern void AtEOXact_Enum(void);

 #endif							/* PG_ENUM_H */
diff --git a/src/test/regress/expected/enum.out b/src/test/regress/expected/enum.out
index 0e60304..96345e4 100644
--- a/src/test/regress/expected/enum.out
+++ b/src/test/regress/expected/enum.out
@@ -648,6 +648,29 @@ SELECT enum_range(null::bogus);
 (1 row)

 ROLLBACK;
+-- check that we don't forbid anything except use of a new value on an
+-- existing enum
+BEGIN;
+CREATE ROLE newowner;
+CREATE TYPE bogus AS ENUM('good','bad','ugly');
+ALTER TYPE bogus OWNER TO newowner;
+select enum_range(null::bogus);
+   enum_range    
+-----------------
+ {good,bad,ugly}
+(1 row)
+
+ROLLBACK;
+BEGIN;
+CREATE ROLE newowner;
+ALTER TYPE rainbow OWNER TO newowner;
+select enum_range(null::rainbow);
+                enum_range                 
+-------------------------------------------
+ {crimson,orange,yellow,green,blue,purple}
+(1 row)
+
+ROLLBACK;
 --
 -- Cleanup
 --
diff --git a/src/test/regress/sql/enum.sql b/src/test/regress/sql/enum.sql
index d7e8714..2129f64 100644
--- a/src/test/regress/sql/enum.sql
+++ b/src/test/regress/sql/enum.sql
@@ -311,6 +311,22 @@ ALTER TYPE bogus ADD VALUE 'ugly';
 SELECT enum_range(null::bogus);
 ROLLBACK;

+-- check that we don't forbid anything except use of a new value on an
+-- existing enum
+
+BEGIN;
+CREATE ROLE newowner;
+CREATE TYPE bogus AS ENUM('good','bad','ugly');
+ALTER TYPE bogus OWNER TO newowner;
+select enum_range(null::bogus);
+ROLLBACK;
+
+BEGIN;
+CREATE ROLE newowner;
+ALTER TYPE rainbow OWNER TO newowner;
+select enum_range(null::rainbow);
+ROLLBACK;
+
 --
 -- Cleanup
 --