diff options
Diffstat (limited to 'src/backend/optimizer/path/pathkeys.c')
| -rw-r--r-- | src/backend/optimizer/path/pathkeys.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c index 8b04d40d36d..879dcb4608e 100644 --- a/src/backend/optimizer/path/pathkeys.c +++ b/src/backend/optimizer/path/pathkeys.c @@ -2154,14 +2154,31 @@ right_merge_direction(PlannerInfo *root, PathKey *pathkey) * Because we the have the possibility of incremental sort, a prefix list of * keys is potentially useful for improving the performance of the requested * ordering. Thus we return 0, if no valuable keys are found, or the number - * of leading keys shared by the list and the requested ordering.. + * of leading keys shared by the list and the requested ordering. */ static int pathkeys_useful_for_ordering(PlannerInfo *root, List *pathkeys) { int n_common_pathkeys; - (void) pathkeys_count_contained_in(root->query_pathkeys, pathkeys, + (void) pathkeys_count_contained_in(root->sort_pathkeys, pathkeys, + &n_common_pathkeys); + + return n_common_pathkeys; +} + +/* + * pathkeys_useful_for_windowing + * Count the number of pathkeys that are useful for meeting the + * query's desired sort order for window function evaluation. + */ +static int +pathkeys_useful_for_windowing(PlannerInfo *root, List *pathkeys) +{ + int n_common_pathkeys; + + (void) pathkeys_count_contained_in(root->window_pathkeys, + pathkeys, &n_common_pathkeys); return n_common_pathkeys; @@ -2278,6 +2295,9 @@ truncate_useless_pathkeys(PlannerInfo *root, nuseful2 = pathkeys_useful_for_ordering(root, pathkeys); if (nuseful2 > nuseful) nuseful = nuseful2; + nuseful2 = pathkeys_useful_for_windowing(root, pathkeys); + if (nuseful2 > nuseful) + nuseful = nuseful2; nuseful2 = pathkeys_useful_for_grouping(root, pathkeys); if (nuseful2 > nuseful) nuseful = nuseful2; |