Update obsolete comment.

Noted by Justin Pryzby, though I chose to just rip out the stale text,
as it's in no way relevant to this particular function.

Discussion: https://postgr.es/m/20200212182337.GZ1412@telsasoft.com

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index e9d7a7ff79bc7df3ebcdaba14a38e3cdef3d3a50..11ce1bb40468084cd14568003a1a0b7a96a27673 100644 (file)
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -1522,8 +1522,8 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 /*
  * Get a list of tables that the current user owns and
  * have indisclustered set.  Return the list in a List * of RelToCluster
- * with the tableOid and the indexOid on which the table is already
- * clustered.
+ * (stored in the specified memory context), each one giving the tableOid
+ * and the indexOid on which the table is already clustered.
  */
 static List *
 get_tables_to_cluster(MemoryContext cluster_context)
@@ -1539,9 +1539,7 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
        /*
         * Get all indexes that have indisclustered set and are owned by
-        * appropriate user. System relations or nailed-in relations cannot ever
-        * have indisclustered set, because CLUSTER will refuse to set it when
-        * called with one of them as argument.
+        * appropriate user.
         */
        indRelation = table_open(IndexRelationId, AccessShareLock);
        ScanKeyInit(&entry,