From 0c444a70f2a79d4d7ef6f1af057909839e5b2097 Mon Sep 17 00:00:00 2001 From: David Rowley Date: Thu, 15 Feb 2024 18:01:28 +1300 Subject: [PATCH] Simplify PathKey checking code pathkeys_useful_for_ordering() contained some needless checks to return 0 when either root->query_pathkeys or pathkeys lists were empty. This is already handled by pathkeys_count_contained_in(), so let's have it do the work instead of having redundant checks. Similarly, in pathkeys_useful_for_grouping(), checking pathkeys is an empty list just before looping over it isn't required. Technically, neither is the list empty check for group_pathkeys, but I felt a bit more work would have to be done to get the equivalent behavior if we'd left it up to the foreach loop to call list_member_ptr(). This was noticed by Andy while he was reviewing a patch to improve the UNION planner. Since that patch adds another function similar to pathkeys_useful_for_ordering() and since I wasn't planning to copy these redundant checks over to the new function, let's adjust the existing code so that both functions will be consistent. Author: Andy Fan Discussion: https://postgr.es/m/87o7cti48f.fsf@163.com --- src/backend/optimizer/path/pathkeys.c | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c index bcc1b7a9ebe..da6f457a3bf 100644 --- a/src/backend/optimizer/path/pathkeys.c +++ b/src/backend/optimizer/path/pathkeys.c @@ -2143,12 +2143,6 @@ pathkeys_useful_for_ordering(PlannerInfo *root, List *pathkeys) { int n_common_pathkeys; - if (root->query_pathkeys == NIL) - return 0; /* no special ordering requested */ - - if (pathkeys == NIL) - return 0; /* unordered path */ - (void) pathkeys_count_contained_in(root->query_pathkeys, pathkeys, &n_common_pathkeys); @@ -2184,10 +2178,6 @@ pathkeys_useful_for_grouping(PlannerInfo *root, List *pathkeys) if (root->group_pathkeys == NIL) return 0; - /* unordered path */ - if (pathkeys == NIL) - return 0; - /* walk the pathkeys and search for matching group key */ foreach(key, pathkeys) { -- 2.39.5