diff options
Diffstat (limited to 'sql/sql_window.cc')
| -rw-r--r-- | sql/sql_window.cc | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/sql/sql_window.cc b/sql/sql_window.cc index 5d929101e10..15045924e83 100644 --- a/sql/sql_window.cc +++ b/sql/sql_window.cc @@ -2509,7 +2509,8 @@ bool Window_funcs_sort::exec(JOIN *join) bool Window_funcs_sort::setup(THD *thd, SQL_SELECT *sel, - List_iterator<Item_window_func> &it) + List_iterator<Item_window_func> &it, + JOIN_TAB *join_tab) { Window_spec *spec; Item_window_func *win_func= it.peek(); @@ -2547,6 +2548,27 @@ bool Window_funcs_sort::setup(THD *thd, SQL_SELECT *sel, ORDER* sort_order= concat_order_lists(thd->mem_root, spec->partition_list->first, spec->order_list->first); + if (sort_order == NULL) // No partition or order by clause. + { + /* TODO(cvicentiu) This is used as a way to allow an empty OVER () + clause for window functions. However, a better approach is + to not call Filesort at all in this case and just read whatever order + the temporary table has. + Due to cursors not working for out_of_memory cases (yet!), we have to run + filesort to generate a sort buffer of the results. + In this case we sort by the first field of the temporary table. + We should have this field available, even if it is a window_function + field. We don't care of the particular sorting result in this case. + */ + ORDER *order= (ORDER *)alloc_root(thd->mem_root, sizeof(ORDER)); + memset(order, 0, sizeof(*order)); + Item *item= new (thd->mem_root) Item_field(thd, join_tab->table->field[0]); + order->item= (Item **)alloc_root(thd->mem_root, 2 * sizeof(Item *)); + order->item[1]= NULL; + order->item[0]= item; + order->field= join_tab->table->field[0]; + sort_order= order; + } filesort= new (thd->mem_root) Filesort(sort_order, HA_POS_ERROR, true, NULL); /* Apply the same condition that the subsequent sort has. */ @@ -2574,7 +2596,7 @@ bool Window_funcs_computation::setup(THD *thd, while (iter.peek()) { if (!(srt= new Window_funcs_sort()) || - srt->setup(thd, sel, iter)) + srt->setup(thd, sel, iter, tab)) { return true; } |