#2  0x000000000088a866 in handle_fatal_signal (sig=11) at signal_handler.cc:272
#3  <signal handler called>
#4  0x00000000007a8914 in JOIN::print_explain (this=0x7fcc440158f8, result=0x22ccba8, 
    on_the_fly=true, need_tmp_table=false, need_order=false, distinct=false, message=0x0)
    at sql_select.cc:21294
#5  0x00000000005d5fdf in st_select_lex::print_explain (this=0x7fcc4d46ce08, 
    output=0x22ccba8) at sql_lex.cc:3758
#6  0x00000000005d613e in st_select_lex_unit::print_explain (this=0x7fcc4d46c900, 
    output=0x22ccba8) at sql_lex.cc:3807
#7  0x00000000006cca6c in Show_explain_request::get_explain_data (arg=0x7fcc351bcba0)
    at sql_class.cc:3042
#8  0x000000000095b035 in Apc_target::process_apc_requests (this=0x7fcc4d46c670)
    at my_apc.cc:255
#9  0x00000000006c88dc in THD::check_killed (this=0x7fcc4d46a358) at sql_class.cc:1904
#10 0x0000000000868fdd in find_all_keys (param=0x7fcc352042f0, select=0x0, 
    sort_keys=0x7fcc4403d288, sort_keys_buf=0x7fcc4403d2f0 "", 
    buffpek_pointers=0x7fcc35203fd0, tempfile=0x7fcc35204160, indexfile=0x0)
    at filesort.cc:591
#11 0x0000000000867e7d in filesort (thd=0x7fcc4d46a358, table=0x7fcc4403ad50, 
    sortorder=0x7fcc4401a3a8, s_length=1, select=0x0, max_rows=18446744073709551615, 
    sort_positions=false, examined_rows=0x7fcc352044e8) at filesort.cc:244
#12 0x00000000007a2008 in create_sort_index (thd=0x7fcc4d46a358, join=0x7fcc440158f8, 
    order=0x21fa168, filesort_limit=18446744073709551615, 
    select_limit=18446744073709551615, is_order_by=false) at sql_select.cc:18731
#13 0x000000000077a558 in JOIN::exec_inner (this=0x7fcc440158f8) at sql_select.cc:2751
#14 0x0000000000777cd3 in JOIN::exec (this=0x7fcc440158f8) at sql_select.cc:2125
#15 0x000000000077b125 in mysql_select (thd=0x7fcc4d46a358, 
    rref_pointer_array=0x7fcc4d46d060, tables=0x21f8568, wild_num=0, fields=..., conds=
    0x0, og_num=1, order=0x0, group=0x21fa168, having=0x0, proc_param=0x0, 
    select_options=2147764736, result=0x21fa248, unit=0x7fcc4d46c900, 
    select_lex=0x7fcc4d46ce08) at sql_select.cc:3023
#16 0x0000000000771c0a in handle_select (thd=0x7fcc4d46a358, lex=0x7fcc4d46c860, 
    result=0x21fa248, setup_tables_done_option=0) at sql_select.cc:332
#17 0x0000000000700181 in execute_sqlcom_select (thd=0x7fcc4d46a358, 
    all_tables=0x21f8568) at sql_parse.cc:5178
#18 0x00000000006f70c7 in mysql_execute_command (thd=0x7fcc4d46a358) at sql_parse.cc:2285
#19 0x0000000000702b5c in mysql_parse (thd=0x7fcc4d46a358, 
---Type <return> to continue, or q <return> to quit---
    rawbuf=0x21f8310 "SELECT alias.a FROM A, ( SELECT * FROM A ) AS alias GROUP BY alias.a", length=68, found_semicolon=0x7fcc35205c98) at sql_parse.cc:6179
#20 0x00000000006f4876 in dispatch_command (command=COM_QUERY, thd=0x7fcc4d46a358, 
    packet=0x7fcc4d472559 "SELECT alias.a FROM A, ( SELECT * FROM A ) AS alias GROUP BY alias.a", packet_length=68) at sql_parse.cc:1229
#21 0x00000000006f3baa in do_command (thd=0x7fcc4d46a358) at sql_parse.cc:924
#22 0x00000000006f09ee in handle_one_connection (arg=0x7fcc4d46a358)
    at sql_connect.cc:1218

Query (0x21f8310): SELECT alias.a FROM A, ( SELECT * FROM A ) AS alias GROUP BY alias.a
Connection ID (thread ID): 5
Status: NOT_KILLED

index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on

revision-id: psergey@askmonty.org-20120426031831-0iujnre01v3tlwkf
date: 2012-04-26 08:48:31 +0530
build-date: 2012-05-01 04:17:19 +0300
revno: 3504

thread1_init:
  CREATE TABLE A ( a INT ) ENGINE=MyISAM; INSERT INTO A VALUES (1),(2),(1),(4),(2);

thread2_init:
  SET @con_id = CONNECTION_ID()-1;

query:
  SELECT alias.a FROM A, ( SELECT * FROM A ) AS alias GROUP BY alias.a ;

thread2:
  SHOW EXPLAIN FOR @con_id;

perl ./runall.pl \
--queries=100M \
--threads=2 \
--duration=600 \
--grammar=1.yy \
--skip-gendata \
--basedir=<basedir> \ 
--vardir=<vardir>