diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 395e75f768..6cab35126b 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -1361,6 +1361,7 @@ vac_update_datfrozenxid(void)
 	MultiXactId lastSaneMinMulti;
 	bool		bogus = false;
 	bool		dirty = false;
+	ScanKeyData key[1];
 
 	/*
 	 * Restrict this task to one backend per database.  This avoids race
@@ -1479,10 +1480,24 @@ vac_update_datfrozenxid(void)
 	/* Now fetch the pg_database tuple we need to update. */
 	relation = table_open(DatabaseRelationId, RowExclusiveLock);
 
-	/* Fetch a copy of the tuple to scribble on */
-	tuple = SearchSysCacheCopy1(DATABASEOID, ObjectIdGetDatum(MyDatabaseId));
+	/*
+	 * Get the pg_database tuple to scribble on, and do not rely on
+	 * the syscache to avoid problem with toasted values.
+	 */
+	ScanKeyInit(&key[0],
+				Anum_pg_database_oid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(MyDatabaseId));
+
+	scan = systable_beginscan(relation, DatabaseOidIndexId, true,
+							  NULL, 1, key);
+	tuple = systable_getnext(scan);
+	tuple = heap_copytuple(tuple);
+	systable_endscan(scan);
+
 	if (!HeapTupleIsValid(tuple))
 		elog(ERROR, "could not find tuple for database %u", MyDatabaseId);
+
 	dbform = (Form_pg_database) GETSTRUCT(tuple);
 
 	/*