Attempting backtrace. You can use the following information to find out

==30029== 16 bytes in 1 blocks are definitely lost in loss record 1 of 29

==30029==    at 0x4C280F3: malloc (vg_replace_malloc.c:299)

==30029==    by 0x114A3EA: my_malloc (my_malloc.c:101)

==30029==    by 0x7C4991: String::real_alloc(unsigned long) (sql_string.cc:47)

==30029==    by 0x6EB4AA: String::String(unsigned int) (sql_string.h:148)

==30029==    by 0x9D50E0: Cached_item_str::Cached_item_str(THD*, Item*) (item_buff.cc:76)

==30029==    by 0x9D4EE0: new_Cached_item(THD*, Item*, bool) (item_buff.cc:50)

==30029==    by 0x8E616F: Group_bound_tracker::Group_bound_tracker(THD*, SQL_I_List<st_order>*) (item_windowfunc.h:21)

==30029==    by 0x8E7BD9: Frame_range_current_row_bottom::Frame_range_current_row_bottom(THD*, SQL_I_List<st_order>*, SQL_I_List<st_order>*) (sql_window.cc:1367)

==30029==    by 0x8E39BF: get_frame_cursor(THD*, Window_spec*, bool) (sql_window.cc:2223)

==30029==    by 0x8E4ABA: get_window_functions_required_cursors(THD*, List<Item_window_func>&, List<Cursor_manager>*) (sql_window.cc:2475)

==30029==    by 0x8E550C: Window_func_runner::exec(THD*, TABLE*, SORT_INFO*) (sql_window.cc:2736)

==30029==    by 0x8E5650: Window_funcs_sort::exec(JOIN*, bool) (sql_window.cc:2767)

==30029==    by 0x8E5B4E: Window_funcs_computation::exec(JOIN*, bool) (sql_window.cc:2893)

==30029==    by 0x78DC02: AGGR_OP::end_send() (sql_select.cc:26668)

==30029==    by 0x778ABD: sub_select_postjoin_aggr(JOIN*, st_join_table*, bool) (sql_select.cc:18477)

==30029==    by 0x778DE7: sub_select(JOIN*, st_join_table*, bool) (sql_select.cc:18713)

create table t1 (id int, n1 int);

insert into t1 values (1,1),(2,1),(3,2),(4,4);

select max(n1) over (partition by 'abc') from t1;

create table t1 (a int, b int);

insert into t1 values (1,3), (2,2), (3,1), (1,3), (2,2), (3,1);

select  lag(a) over (order by null desc), sum(a) over (order by null) from t1;