diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 014e80c30e6..a4d523dcb0f 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -214,6 +214,7 @@ static List *postprocess_setop_tlist(List *new_tlist, List *orig_tlist); static void optimize_window_clauses(PlannerInfo *root, WindowFuncLists *wflists); static List *select_active_windows(PlannerInfo *root, WindowFuncLists *wflists); +static void name_active_windows(List *activeWindows); static PathTarget *make_window_input_target(PlannerInfo *root, PathTarget *final_target, List *activeWindows); @@ -1539,7 +1540,11 @@ grouping_planner(PlannerInfo *root, double tuple_fraction, */ optimize_window_clauses(root, wflists); + /* Extract the list of windows actually in use. */ activeWindows = select_active_windows(root, wflists); + + /* Make sure they all have names, for EXPLAIN's use. */ + name_active_windows(activeWindows); } else parse->hasWindowFuncs = false; @@ -5915,6 +5920,52 @@ select_active_windows(PlannerInfo *root, WindowFuncLists *wflists) } /* + * name_active_windows + * Ensure all active windows have unique names. + * + * The parser will have checked that user-assigned window names are unique + * within the Query. Here we assign made-up names to any unnamed + * WindowClauses for the benefit of EXPLAIN. (We don't want to do this + * at parse time, because it'd mess up decompilation of views.) + * + * activeWindows: result of select_active_windows + */ +static void +name_active_windows(List *activeWindows) +{ + int next_n = 1; + char newname[16]; + ListCell *lc; + + foreach(lc, activeWindows) + { + WindowClause *wc = lfirst_node(WindowClause, lc); + + /* Nothing to do if it has a name already. */ + if (wc->name) + continue; + + /* Select a name not currently present in the list. */ + for (;;) + { + ListCell *lc2; + + snprintf(newname, sizeof(newname), "w%d", next_n++); + foreach(lc2, activeWindows) + { + WindowClause *wc2 = lfirst_node(WindowClause, lc2); + + if (wc2->name && strcmp(wc2->name, newname) == 0) + break; /* matched */ + } + if (lc2 == NULL) + break; /* reached the end with no match */ + } + wc->name = pstrdup(newname); + } +} + +/* * common_prefix_cmp * QSort comparison function for WindowClauseSortData * |