diff options
Diffstat (limited to 'src/backend/parser/parse_agg.c')
| -rw-r--r-- | src/backend/parser/parse_agg.c | 58 |
1 files changed, 54 insertions, 4 deletions
diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c index fd08b9eeff0..899327aaf4e 100644 --- a/src/backend/parser/parse_agg.c +++ b/src/backend/parser/parse_agg.c @@ -1071,7 +1071,7 @@ parseCheckAggregates(ParseState *pstate, Query *qry) * The limit of 4096 is arbitrary and exists simply to avoid resource * issues from pathological constructs. */ - List *gsets = expand_grouping_sets(qry->groupingSets, 4096); + List *gsets = expand_grouping_sets(qry->groupingSets, qry->groupDistinct, 4096); if (!gsets) ereport(ERROR, @@ -1735,6 +1735,33 @@ cmp_list_len_asc(const ListCell *a, const ListCell *b) return (la > lb) ? 1 : (la == lb) ? 0 : -1; } +/* list_sort comparator to sort sub-lists by length and contents */ +static int +cmp_list_len_contents_asc(const ListCell *a, const ListCell *b) +{ + int res = cmp_list_len_asc(a, b); + + if (res == 0) + { + List *la = (List *) lfirst(a); + List *lb = (List *) lfirst(b); + ListCell *lca; + ListCell *lcb; + + forboth(lca, la, lcb, lb) + { + int va = intVal(lca); + int vb = intVal(lcb); + if (va > vb) + return 1; + if (va < vb) + return -1; + } + } + + return res; +} + /* * Expand a groupingSets clause to a flat list of grouping sets. * The returned list is sorted by length, shortest sets first. @@ -1743,7 +1770,7 @@ cmp_list_len_asc(const ListCell *a, const ListCell *b) * some consistency checks. */ List * -expand_grouping_sets(List *groupingSets, int limit) +expand_grouping_sets(List *groupingSets, bool groupDistinct, int limit) { List *expanded_groups = NIL; List *result = NIL; @@ -1801,8 +1828,31 @@ expand_grouping_sets(List *groupingSets, int limit) result = new_result; } - /* Now sort the lists by length */ - list_sort(result, cmp_list_len_asc); + /* Now sort the lists by length and deduplicate if necessary */ + if (!groupDistinct || list_length(result) < 2) + list_sort(result, cmp_list_len_asc); + else + { + ListCell *cell; + List *prev; + + /* Sort each groupset individually */ + foreach(cell, result) + list_sort(lfirst(cell), list_int_cmp); + + /* Now sort the list of groupsets by length and contents */ + list_sort(result, cmp_list_len_contents_asc); + + /* Finally, remove duplicates */ + prev = list_nth_node(List, result, 0); + for_each_from(cell, result, 1) + { + if (equal(lfirst(cell), prev)) + foreach_delete_current(result, cell); + else + prev = lfirst(cell); + } + } return result; } |