Simplify pg_upgrade C comment about what is preserved.

diff --git a/contrib/pg_upgrade/pg_upgrade.c b/contrib/pg_upgrade/pg_upgrade.c
index dd50eb85ccc08751da1675db4b82ebd5976151ad..9a5ef0fd205f01f7fb684d9f9ec8b36fc64df6e1 100644 (file)
--- a/contrib/pg_upgrade/pg_upgrade.c
+++ b/contrib/pg_upgrade/pg_upgrade.c
@@ -15,22 +15,16 @@
  *     oids are the same between old and new clusters.  This is important
  *     because toast oids are stored as toast pointers in user tables.
  *
- *     The only place where old/new relfilenode might not match is
- *     pg_largeobject, pg_largeobject_metadata, and its indexes,
- *     which can change their relfilenode values due to a cluster, reindex,
- *     or vacuum full.  (We don't create those so have no control over their
- *     new relfilenode values.)
- *
  *     FYI, while pg_class.oid and pg_class.relfilenode are intially the same
- *     in a cluster, but they can diverge due to cluster, reindex, or vacuum
- *     full.  The new cluster will again have matching pg_class.relfilenode
- *     and pg_class.oid values, but based on the old relfilenode value, so the
- *     old/new oids might differ.
+ *     in a cluster, but they can diverge due to CLUSTER, REINDEX, or VACUUM
+ *     FULL.  The new cluster will have matching pg_class.oid and
+ *     pg_class.relfilenode values and be based on the old oid value.  This can
+ *     cause the old and new pg_class.relfilenode values to differ.
  *
- *     We control all assignments of pg_type.oid because these oid are stored
+ *     We control all assignments of pg_type.oid because these oids are stored
  *     in user composite type values.
  *
- *     We control all assignments of pg_enum.oid because these oid are stored
+ *     We control all assignments of pg_enum.oid because these oids are stored
  *     in user tables as enum values.
  */