lo_comments.patch

diff --git a/src/backend/catalog/aclchk.c b/src/backend/catalog/aclchk.c
index 809df7a..b0aea41 100644
--- a/src/backend/catalog/aclchk.c
+++ b/src/backend/catalog/aclchk.c
@@ -4261,9 +4261,8 @@ pg_language_ownercheck(Oid lan_oid, Oid roleid)
 /*
  * Ownership check for a largeobject (specified by OID)
  *
- * Note that we have no candidate to call this routine with a certain
- * snapshot except for SnapshotNow, so we don't provide an interface
- * with _snapshot() version now.
+ * This is only used for operations like ALTER LARGE OBJECT that are always
+ * relative to SnapshotNow.
  */
 bool
 pg_largeobject_ownercheck(Oid lobj_oid, Oid roleid)
diff --git a/src/backend/catalog/pg_largeobject.c b/src/backend/catalog/pg_largeobject.c
index ada5b88..dfbf350 100644
--- a/src/backend/catalog/pg_largeobject.c
+++ b/src/backend/catalog/pg_largeobject.c
@@ -79,10 +79,8 @@ LargeObjectCreate(Oid loid)
 }
 
 /*
- * Drop a large object having the given LO identifier.
- *
- * When we drop a large object, it is necessary to drop both of metadata
- * and data pages in same time.
+ * Drop a large object having the given LO identifier.  Both the data pages
+ * and metadata must be dropped.
  */
 void
 LargeObjectDrop(Oid loid)
@@ -191,13 +189,12 @@ LargeObjectAlterOwner(Oid loid, Oid newOwnerId)
 		if (!superuser())
 		{
 			/*
-			 * The 'lo_compat_privileges' is not checked here, because we
-			 * don't have any access control features in the 8.4.x series
-			 * or earlier release.
-			 * So, it is not a place we can define a compatible behavior.
+			 * lo_compat_privileges is not checked here, because ALTER
+			 * LARGE OBJECT ... OWNER did not exist at all prior to
+			 * PostgreSQL 8.5.
+			 *
+			 * We must be the owner of the existing object.
 			 */
-
-			/* Otherwise, must be owner of the existing object */
 			if (!pg_largeobject_ownercheck(loid, GetUserId()))
 				ereport(ERROR,
 						(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -251,9 +248,8 @@ LargeObjectAlterOwner(Oid loid, Oid newOwnerId)
 /*
  * LargeObjectExists
  *
- * Currently, we don't use system cache to contain metadata of
- * large objects, because massive number of large objects can
- * consume not a small amount of process local memory.
+ * We don't use the system cache to for large object metadata, for fear of
+ * using too much local memory.
  *
  * Note that LargeObjectExists always scans the system catalog
  * with SnapshotNow, so it is unavailable to use to check
diff --git a/src/backend/commands/comment.c b/src/backend/commands/comment.c
index 8f8ecc7..ece2a30 100644
--- a/src/backend/commands/comment.c
+++ b/src/backend/commands/comment.c
@@ -1449,7 +1449,7 @@ CommentLargeObject(List *qualname, char *comment)
 	 *
 	 * See the comment in the inv_create() which describes
 	 * the reason why LargeObjectRelationId is used instead
-	 * of the LargeObjectMetadataRelationId.
+	 * of LargeObjectMetadataRelationId.
 	 */
 	CreateComments(loid, LargeObjectRelationId, 0, comment);
 }
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index c799b13..22b8ea7 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1229,9 +1229,9 @@ static struct config_bool ConfigureNamesBool[] =
 
 	{
 		{"lo_compat_privileges", PGC_SUSET, COMPAT_OPTIONS_PREVIOUS,
-			gettext_noop("Enables backward compatibility in privilege checks on large objects"),
-			gettext_noop("When turned on, privilege checks on large objects perform "
-						 "with backward compatibility as 8.4.x or earlier releases.")
+			gettext_noop("Enables backward compatibility mode for privilege checks on large objects"),
+			gettext_noop("Skips privilege checks when reading or modifying large objects, "
+						 "for compatibility with PostgreSQL releases prior to 8.5.")
 		},
 		&lo_compat_privileges,
 		false, NULL, NULL