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Trim ORDER BY/DISTINCT aggregate pathkeys in gather_grouping_paths 

Similar to d8a295389, trim off any PathKeys which are for ORDER BY /
DISTINCT aggregate functions from the PathKey List for the Gather Merge
paths created by gather_grouping_paths().  These additional PathKeys are
not valid to use after grouping has taken place as these PathKeys belong
to columns which are inputs to an aggregate function and, therefore are
unavailable after aggregation.

Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/cf63174c-8c89-3953-cb49-48f41f74941a@gmail.com
Backpatch-through: 16, where 1349d2790 was added
This commit is contained in:
David Rowley 2024-03-15 11:54:36 +13:00
parent 4665cebc8a
commit 4169850f0b
1 changed files with 15 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
src/backend/optimizer/plan/planner.c
View File

@ -7320,6 +7320,17 @@ gather_grouping_paths(PlannerInfo *root, RelOptInfo *rel)
{
ListCell *lc;
Path *cheapest_partial_path;
List *groupby_pathkeys;
/*
* This occurs after any partial aggregation has taken place, so trim off
* any pathkeys added for ORDER BY / DISTINCT aggregates.
*/
if (list_length(root->group_pathkeys) > root->num_groupby_pathkeys)
groupby_pathkeys = list_copy_head(root->group_pathkeys,
root->num_groupby_pathkeys);
else
groupby_pathkeys = root->group_pathkeys;
/* Try Gather for unordered paths and Gather Merge for ordered ones. */
generate_useful_gather_paths(root, rel, true);
@ -7334,7 +7345,7 @@ gather_grouping_paths(PlannerInfo *root, RelOptInfo *rel)
int presorted_keys;
double total_groups;
is_sorted = pathkeys_count_contained_in(root->group_pathkeys,
is_sorted = pathkeys_count_contained_in(groupby_pathkeys,
path->pathkeys,
&presorted_keys);
@ -7360,13 +7371,13 @@ gather_grouping_paths(PlannerInfo *root, RelOptInfo *rel)
*/
if (presorted_keys == 0 || !enable_incremental_sort)
path = (Path *) create_sort_path(root, rel, path,
root->group_pathkeys,
groupby_pathkeys,
-1.0);
else
path = (Path *) create_incremental_sort_path(root,
rel,
path,
root->group_pathkeys,
groupby_pathkeys,
presorted_keys,
-1.0);
@ -7375,7 +7386,7 @@ gather_grouping_paths(PlannerInfo *root, RelOptInfo *rel)
rel,
path,
rel->reltarget,
root->group_pathkeys,
groupby_pathkeys,
NULL,
&total_groups);