pg_upgrade: Mention that we preserve database OIDs in a comment.

nathan-bossart · nathan-bossart · commit e2665efd0f4d · 2025-04-09T14:27:08.000-05:00
Oversight in commit aa01051. Reported-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/4055696.1744134682%40sss.pgh.pa.us
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
@@ -32,6 +32,9 @@
  *	We control all assignments of pg_authid.oid for historical reasons (the
  *	oids used to be stored in pg_largeobject_metadata, which is now copied via
  *	SQL commands), that might change at some point in the future.
+ *
+ *	We control all assignments of pg_database.oid because we want the directory
+ *	names to match between the old and new cluster.
  */
 
 
