diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 079bd0bfdfd..c0bdc77d390 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -2758,8 +2758,9 @@ remove_useless_groupby_columns(PlannerInfo *root) * * In principle it might be interesting to consider other orderings of the * GROUP BY elements, which could match the sort ordering of other - * possible plans (eg an indexscan) and thereby reduce cost. We don't - * bother with that, though. Hashed grouping will frequently win anyway. + * possible plans (eg an indexscan) and thereby reduce cost. However, we + * don't yet have sufficient information to do that here, so that's left until + * later in planning. See get_useful_group_keys_orderings(). * * Note: we need no comparable processing of the distinctClause because * the parser already enforced that that matches ORDER BY. |