Update new pg_upgrade comment about pre-8.4 TOAST tables.

diff --git a/contrib/pg_upgrade/info.c b/contrib/pg_upgrade/info.c
index ad7edc4e7933f6426806f046696b6b490dd083ae..fe060ff326a5aa2431fdc17813e1645fd8349a8f 100644 (file)
--- a/contrib/pg_upgrade/info.c
+++ b/contrib/pg_upgrade/info.c
@@ -54,7 +54,11 @@ gen_db_file_maps(DbInfo *old_db, DbInfo *new_db,
                        pg_log(PG_FATAL, "Mismatch of relation id: database \"%s\", old relid %d, new relid %d\n",
                        old_db->db_name, old_rel->reloid, new_rel->reloid);
 
-               /* toast names were not renamed to match their relfilenodes in pre-8.4 */
+               /*
+                *      In pre-8.4, TOAST table names change during CLUSTER;  in >= 8.4
+                *      TOAST relation names always use the heap tables oid, hence we
+                *      cannot check relation names when upgrading from pre-8.4.
+                */
                if (GET_MAJOR_VERSION(old_cluster.major_version) >= 804 &&
                        (strcmp(old_rel->nspname, new_rel->nspname) != 0 ||
                     strcmp(old_rel->relname, new_rel->relname) != 0))