main.sum_distinct-big fails with Assertion `m_buffer_end == __null || end <= m_buffer_end'

$ perl ./mtr main.sum_distinct-big --mem

mysqld: /data/src/10.5-bug/sql/sql_sort.h:106: void Merge_chunk::set_buffer_end(uchar*): Assertion `m_buffer_end == __null || end <= m_buffer_end' failed.

200121  2:48:57 [ERROR] mysqld got signal 6 ;

#7  0x00007f4e8c65df12 in __GI___assert_fail (assertion=0x5628401ed508 "m_buffer_end == __null || end <= m_buffer_end", file=0x5628401ed4e0 "/data/src/10.5-bug/sql/sql_sort.h", line=106, function=0x5628401ed660 <Merge_chunk::set_buffer_end(unsigned char*)::__PRETTY_FUNCTION__> "void Merge_chunk::set_buffer_end(uchar*)") at assert.c:101

#8  0x000056283f5c69b9 in Merge_chunk::set_buffer_end (this=0x7f4e5823ff38, end=0x7f4e5807c9b0 "\370\061") at /data/src/10.5-bug/sql/sql_sort.h:106

#9  0x000056283f5c595d in merge_walk (merge_buffer=0x7f4e58079b30 "", merge_buffer_size=16384, key_length=8, begin=0x7f4e5823fdb0, end=0x7f4e58240018, walk_action=0x56283f8a3912 <item_sum_distinct_walk(void*, element_count, void*)>, walk_action_arg=0x7f4e58016b98, compare=0x56283f8a38b6 <simple_raw_key_cmp(void*, void const*, void const*)>, compare_arg=0x7f4e58016bd0, file=0x7f4e58018078, with_counters=false) at /data/src/10.5-bug/sql/uniques.cc:532

#10 0x000056283f5c604c in Unique::walk (this=0x7f4e58018048, table=0x7f4e58016cb0, action=0x56283f8a3912 <item_sum_distinct_walk(void*, element_count, void*)>, walk_action_arg=0x7f4e58016b98) at /data/src/10.5-bug/sql/uniques.cc:673

#11 0x000056283f8a4be8 in Aggregator_distinct::endup (this=0x7f4e58016b98) at /data/src/10.5-bug/sql/item_sum.cc:1088

#12 0x000056283f8a786e in Item_sum_sum::val_str (this=0x7f4e58013b18, str=0x7f4e81a120a0) at /data/src/10.5-bug/sql/item_sum.cc:1715

#13 0x000056283f6a245b in Type_handler::Item_send_str (this=0x562840efb440 <type_handler_newdecimal>, item=0x7f4e58013b18, protocol=0x7f4e580010c8, buf=0x7f4e81a12070) at /data/src/10.5-bug/sql/sql_type.cc:7138

#14 0x000056283f5de606 in Type_handler_decimal_result::Item_send (this=0x562840efb440 <type_handler_newdecimal>, item=0x7f4e58013b18, protocol=0x7f4e580010c8, buf=0x7f4e81a12070) at /data/src/10.5-bug/sql/sql_type.h:4628

#15 0x000056283f33f056 in Item::send (this=0x7f4e58013b18, protocol=0x7f4e580010c8, buffer=0x7f4e81a12070) at /data/src/10.5-bug/sql/item.h:1046

#16 0x000056283f338e5f in Protocol::send_result_set_row (this=0x7f4e580010c8, row_items=0x7f4e58015138) at /data/src/10.5-bug/sql/protocol.cc:1035

#17 0x000056283f3ee137 in select_send::send_data (this=0x7f4e58014d60, items=...) at /data/src/10.5-bug/sql/sql_class.cc:3021

#18 0x000056283f501cdd in select_result_sink::send_data_with_check (this=0x7f4e58014d60, items=..., u=0x7f4e58004a48, sent=0) at /data/src/10.5-bug/sql/sql_class.h:5140

#19 0x000056283f4e95a1 in end_send_group (join=0x7f4e58014d88, join_tab=0x7f4e580163a0, end_of_records=true) at /data/src/10.5-bug/sql/sql_select.cc:21717

#20 0x000056283f4e5b09 in sub_select (join=0x7f4e58014d88, join_tab=0x7f4e58015ff8, end_of_records=true) at /data/src/10.5-bug/sql/sql_select.cc:20325

#21 0x000056283f4e5231 in do_select (join=0x7f4e58014d88, procedure=0x0) at /data/src/10.5-bug/sql/sql_select.cc:19916

#22 0x000056283f4b986d in JOIN::exec_inner (this=0x7f4e58014d88) at /data/src/10.5-bug/sql/sql_select.cc:4457

#23 0x000056283f4b8999 in JOIN::exec (this=0x7f4e58014d88) at /data/src/10.5-bug/sql/sql_select.cc:4238

#24 0x000056283f4ba0ca in mysql_select (thd=0x7f4e58000b00, tables=0x7f4e58013da0, fields=..., conds=0x0, og_num=0, order=0x0, group=0x0, having=0x0, proc_param=0x0, select_options=2147748608, result=0x7f4e58014d60, unit=0x7f4e58004a48, select_lex=0x7f4e58013568) at /data/src/10.5-bug/sql/sql_select.cc:4662

#25 0x000056283f4a9c5a in handle_select (thd=0x7f4e58000b00, lex=0x7f4e58004988, result=0x7f4e58014d60, setup_tables_done_option=0) at /data/src/10.5-bug/sql/sql_select.cc:428

#26 0x000056283f46f6ab in execute_sqlcom_select (thd=0x7f4e58000b00, all_tables=0x7f4e58013da0) at /data/src/10.5-bug/sql/sql_parse.cc:6219

#27 0x000056283f46572c in mysql_execute_command (thd=0x7f4e58000b00) at /data/src/10.5-bug/sql/sql_parse.cc:3904

#28 0x000056283f47436c in mysql_parse (thd=0x7f4e58000b00, rawbuf=0x7f4e580134b8 "SELECT SUM(DISTINCT id) sm FROM t2", length=34, parser_state=0x7f4e81a13570, is_com_multi=false, is_next_command=false) at /data/src/10.5-bug/sql/sql_parse.cc:7988

#29 0x000056283f45f42f in dispatch_command (command=COM_QUERY, thd=0x7f4e58000b00, packet=0x7f4e58093791 "", packet_length=34, is_com_multi=false, is_next_command=false) at /data/src/10.5-bug/sql/sql_parse.cc:1846

#30 0x000056283f45db89 in do_command (thd=0x7f4e58000b00) at /data/src/10.5-bug/sql/sql_parse.cc:1364

#31 0x000056283f5fdf15 in do_handle_one_connection (connect=0x56284299af00, put_in_cache=true) at /data/src/10.5-bug/sql/sql_connect.cc:1422

#32 0x000056283f5fdc44 in handle_one_connection (arg=0x56284299af00) at /data/src/10.5-bug/sql/sql_connect.cc:1319

#33 0x000056283fb58f3f in pfs_spawn_thread (arg=0x56284299ab50) at /data/src/10.5-bug/storage/perfschema/pfs.cc:1862

#34 0x00007f4e8e1d34a4 in start_thread (arg=0x7f4e81a14700) at pthread_create.c:456

#35 0x00007f4e8c71ad0f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:97

commit f52bf92014efae6a1da9c2f26a7e3792ed5f5396

Author: Varun Gupta

Date:   Tue Jan 21 01:37:47 2020 +0530

    MDEV-21263: Allow packed values of non-sorted fields in the sort buffer