Cosmetic improvements in setup of planner's per-RTE arrays.

Merge setup_append_rel_array into setup_simple_rel_arrays.  There's no
particularly good reason to keep them separate, and it's inconsistent
with the lack of separation in expand_planner_arrays.  The only apparent
benefit was that the fast path for trivial queries in query_planner()
doesn't need to set up the append_rel_array; but all we're saving there
is an if-test and NULL assignment, which surely ought to be negligible.

Also improve some obsolete comments.

Discussion: https://postgr.es/m/17220.1565301350@sss.pgh.pa.us

1 files changed, 4 insertions, 5 deletions

diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index e3c579ee44..13b147d85d 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -204,17 +204,16 @@ struct PlannerInfo
 
 	/*
 	 * simple_rte_array is the same length as simple_rel_array and holds
-	 * pointers to the associated rangetable entries.  This lets us avoid
-	 * rt_fetch(), which can be a bit slow once large inheritance sets have
-	 * been expanded.
+	 * pointers to the associated rangetable entries.  Using this is a shade
+	 * faster than using rt_fetch(), mostly due to fewer indirections.
 	 */
 	RangeTblEntry **simple_rte_array;	/* rangetable as an array */
 
 	/*
 	 * append_rel_array is the same length as the above arrays, and holds
 	 * pointers to the corresponding AppendRelInfo entry indexed by
-	 * child_relid, or NULL if none.  The array itself is not allocated if
-	 * append_rel_list is empty.
+	 * child_relid, or NULL if the rel is not an appendrel child.  The array
+	 * itself is not allocated if append_rel_list is empty.
 	 */
 	struct AppendRelInfo **append_rel_array;