diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 54 |
1 files changed, 10 insertions, 44 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 094c7082b14..2372311d409 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -1500,7 +1500,6 @@ grouping_planner(PlannerInfo *root, bool inheritance_update, PathTarget *grouping_target; PathTarget *scanjoin_target; bool have_grouping; - bool scanjoin_target_parallel_safe = false; WindowFuncLists *wflists = NULL; List *activeWindows = NIL; List *rollup_lists = NIL; @@ -1731,14 +1730,6 @@ grouping_planner(PlannerInfo *root, bool inheritance_update, scanjoin_target = grouping_target; /* - * Check whether scan/join target is parallel safe ... unless there - * are no partial paths, in which case we don't care. - */ - if (current_rel->partial_pathlist && - !has_parallel_hazard((Node *) scanjoin_target->exprs, false)) - scanjoin_target_parallel_safe = true; - - /* * Forcibly apply scan/join target to all the Paths for the scan/join * rel. * @@ -1756,8 +1747,7 @@ grouping_planner(PlannerInfo *root, bool inheritance_update, Assert(subpath->param_info == NULL); path = apply_projection_to_path(root, current_rel, - subpath, scanjoin_target, - scanjoin_target_parallel_safe); + subpath, scanjoin_target); /* If we had to add a Result, path is different from subpath */ if (path != subpath) { @@ -1774,15 +1764,13 @@ grouping_planner(PlannerInfo *root, bool inheritance_update, * partial pathlist will expect partial paths for that rel to produce * the same output as complete paths ... and we just changed the * output for the complete paths, so we'll need to do the same thing - * for partial paths. + * for partial paths. But only parallel-safe expressions can be + * computed by partial paths. */ - if (scanjoin_target_parallel_safe) + if (current_rel->partial_pathlist && + !has_parallel_hazard((Node *) scanjoin_target->exprs, false)) { - /* - * Apply the scan/join target to each partial path. Otherwise, - * anything that attempts to use the partial paths for further - * upper planning may go wrong. - */ + /* Apply the scan/join target to each partial path */ foreach(lc, current_rel->partial_pathlist) { Path *subpath = (Path *) lfirst(lc); @@ -1792,36 +1780,14 @@ grouping_planner(PlannerInfo *root, bool inheritance_update, Assert(subpath->param_info == NULL); /* - * We can't use apply_projection_to_path() here, because there - * could already be pointers to these paths, and therefore we - * dare not modify them in place. Instead, we must use - * create_projection_path() unconditionally. + * Don't use apply_projection_to_path() here, because there + * could be other pointers to these paths, and therefore we + * mustn't modify them in place. */ newpath = (Path *) create_projection_path(root, current_rel, subpath, scanjoin_target); - - /* - * Although create_projection_path() inserts a ProjectionPath - * unconditionally, create_projection_plan() will only insert - * a Result node if the subpath is not projection-capable, so - * we should discount the cost of that node if it will not - * actually get inserted. (This is pretty grotty but we can - * improve it later if it seems important.) - */ - if (equal(scanjoin_target->exprs, subpath->pathtarget->exprs)) - { - /* at most we need a relabeling of the subpath */ - newpath->startup_cost = subpath->startup_cost; - newpath->total_cost = subpath->total_cost; - } - else if (is_projection_capable_path(subpath)) - { - /* need to project, but we don't need a Result */ - newpath->total_cost -= cpu_tuple_cost * subpath->rows; - } - lfirst(lc) = newpath; } } @@ -4231,7 +4197,7 @@ create_ordered_paths(PlannerInfo *root, /* Add projection step if needed */ if (path->pathtarget != target) path = apply_projection_to_path(root, ordered_rel, - path, target, false); + path, target); add_path(ordered_rel, path); } |