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Adjust reltarget assignment for UPPERREL_PARTIAL_DISTINCT rel

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A comment in grouping_planner() claimed that the PlannerInfo
upper_targets array was not used in core code.  However, the code that
generated the paths for the UPPERREL_PARTIAL_DISTINCT rel made that
comment untrue.

Here we adjust the create_distinct_paths() function signature to pass
down the PathTarget the same as is done for create_grouping_paths(),
thus making the aforementioned comment true again.

In passing adjust the order of the upper_targets[] assignments.  These
seem to be following the reverse enum order apart from
UPPERREL_PARTIAL_DISTINCT.

Also, update the header comment for generate_gather_paths() to mention
the function is also used to create gather paths for partial distinct
paths.

Author: Richard Guo, David Rowley
Discussion: https://postgr.es/m/CAMbWs48u9VoVOouJsys1qOaC9WVGVmBa+wT1dx8KvxF5GPzezA@mail.gmail.com
This commit is contained in:
David Rowley
2024-02-07 21:22:34 +13:00
parent aa5edbe379
commit 902900b308
2 changed files with 18 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
src/backend/optimizer/path/allpaths.c
View File

@ -3053,10 +3053,10 @@ set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
* *
* If we're generating paths for a scan or join relation, override_rows will * If we're generating paths for a scan or join relation, override_rows will
* be false, and we'll just use the relation's size estimate. When we're * be false, and we'll just use the relation's size estimate. When we're
* being called for a partially-grouped path, though, we need to override * being called for a partially-grouped or partially-distinct path, though, we
* the rowcount estimate. (It's not clear that the particular value we're * need to override the rowcount estimate. (It's not clear that the
* using here is actually best, but the underlying rel has no estimate so * particular value we're using here is actually best, but the underlying rel
* we must do something.) * has no estimate so we must do something.)
*/ */
void void
generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows) generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)

22
src/backend/optimizer/plan/planner.c
View File

@ -190,10 +190,12 @@ static void create_one_window_path(PlannerInfo *root,
WindowFuncLists *wflists, WindowFuncLists *wflists,
List *activeWindows); List *activeWindows);
static RelOptInfo *create_distinct_paths(PlannerInfo *root, static RelOptInfo *create_distinct_paths(PlannerInfo *root,
RelOptInfo *input_rel); RelOptInfo *input_rel,
PathTarget *target);
static void create_partial_distinct_paths(PlannerInfo *root, static void create_partial_distinct_paths(PlannerInfo *root,
RelOptInfo *input_rel, RelOptInfo *input_rel,
RelOptInfo *final_distinct_rel); RelOptInfo *final_distinct_rel,
PathTarget *target);
static RelOptInfo *create_final_distinct_paths(PlannerInfo *root, static RelOptInfo *create_final_distinct_paths(PlannerInfo *root,
RelOptInfo *input_rel, RelOptInfo *input_rel,
RelOptInfo *distinct_rel); RelOptInfo *distinct_rel);
@ -1644,8 +1646,8 @@ grouping_planner(PlannerInfo *root, double tuple_fraction)
*/ */
root->upper_targets[UPPERREL_FINAL] = final_target; root->upper_targets[UPPERREL_FINAL] = final_target;
root->upper_targets[UPPERREL_ORDERED] = final_target; root->upper_targets[UPPERREL_ORDERED] = final_target;
root->upper_targets[UPPERREL_PARTIAL_DISTINCT] = sort_input_target;
root->upper_targets[UPPERREL_DISTINCT] = sort_input_target; root->upper_targets[UPPERREL_DISTINCT] = sort_input_target;
root->upper_targets[UPPERREL_PARTIAL_DISTINCT] = sort_input_target;
root->upper_targets[UPPERREL_WINDOW] = sort_input_target; root->upper_targets[UPPERREL_WINDOW] = sort_input_target;
root->upper_targets[UPPERREL_GROUP_AGG] = grouping_target; root->upper_targets[UPPERREL_GROUP_AGG] = grouping_target;
@ -1695,7 +1697,8 @@ grouping_planner(PlannerInfo *root, double tuple_fraction)
if (parse->distinctClause) if (parse->distinctClause)
{ {
current_rel = create_distinct_paths(root, current_rel = create_distinct_paths(root,
current_rel); current_rel,
sort_input_target);
} }
} /* end of if (setOperations) */ } /* end of if (setOperations) */
@ -4568,12 +4571,14 @@ create_one_window_path(PlannerInfo *root,
* Build a new upperrel containing Paths for SELECT DISTINCT evaluation. * Build a new upperrel containing Paths for SELECT DISTINCT evaluation.
* *
* input_rel: contains the source-data Paths * input_rel: contains the source-data Paths
* target: the pathtarget for the result Paths to compute
* *
* Note: input paths should already compute the desired pathtarget, since * Note: input paths should already compute the desired pathtarget, since
* Sort/Unique won't project anything. * Sort/Unique won't project anything.
*/ */
static RelOptInfo * static RelOptInfo *
create_distinct_paths(PlannerInfo *root, RelOptInfo *input_rel) create_distinct_paths(PlannerInfo *root, RelOptInfo *input_rel,
PathTarget *target)
{ {
RelOptInfo *distinct_rel; RelOptInfo *distinct_rel;
@ -4601,7 +4606,7 @@ create_distinct_paths(PlannerInfo *root, RelOptInfo *input_rel)
create_final_distinct_paths(root, input_rel, distinct_rel); create_final_distinct_paths(root, input_rel, distinct_rel);
/* now build distinct paths based on input_rel's partial_pathlist */ /* now build distinct paths based on input_rel's partial_pathlist */
create_partial_distinct_paths(root, input_rel, distinct_rel); create_partial_distinct_paths(root, input_rel, distinct_rel, target);
/* Give a helpful error if we failed to create any paths */ /* Give a helpful error if we failed to create any paths */
if (distinct_rel->pathlist == NIL) if (distinct_rel->pathlist == NIL)
@ -4643,7 +4648,8 @@ create_distinct_paths(PlannerInfo *root, RelOptInfo *input_rel)
*/ */
static void static void
create_partial_distinct_paths(PlannerInfo *root, RelOptInfo *input_rel, create_partial_distinct_paths(PlannerInfo *root, RelOptInfo *input_rel,
RelOptInfo *final_distinct_rel) RelOptInfo *final_distinct_rel,
PathTarget *target)
{ {
RelOptInfo *partial_distinct_rel; RelOptInfo *partial_distinct_rel;
Query *parse; Query *parse;
@ -4664,7 +4670,7 @@ create_partial_distinct_paths(PlannerInfo *root, RelOptInfo *input_rel,
partial_distinct_rel = fetch_upper_rel(root, UPPERREL_PARTIAL_DISTINCT, partial_distinct_rel = fetch_upper_rel(root, UPPERREL_PARTIAL_DISTINCT,
NULL); NULL);
partial_distinct_rel->reltarget = root->upper_targets[UPPERREL_PARTIAL_DISTINCT]; partial_distinct_rel->reltarget = target;
partial_distinct_rel->consider_parallel = input_rel->consider_parallel; partial_distinct_rel->consider_parallel = input_rel->consider_parallel;
/* /*