Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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None
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None
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None
Description
#4 0x00000000007a85b6 in JOIN::print_explain (this=0x1d40278, result=0x1cb3ab8,
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explain_flags=0 '\000', on_the_fly=true, need_tmp_table=false, need_order=false,
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distinct=false, message=0x0) at sql_select.cc:21247
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#5 0x00000000005d6106 in st_select_lex::print_explain (this=0x1cf24b0, output=0x1cb3ab8,
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explain_flags=0 '\000') at sql_lex.cc:3769
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#6 0x00000000005d6279 in st_select_lex_unit::print_explain (this=0x1d3baf0, output=0x1cb3ab8,
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explain_flags=0 '\000') at sql_lex.cc:3820
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#7 0x00000000005d6172 in st_select_lex::print_explain (this=0x1cf14a0, output=0x1cb3ab8,
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explain_flags=0 '\000') at sql_lex.cc:3784
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#8 0x00000000005d6279 in st_select_lex_unit::print_explain (this=0x1cf17f0, output=0x1cb3ab8,
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explain_flags=0 '\000') at sql_lex.cc:3820
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#9 0x00000000005d6172 in st_select_lex::print_explain (this=0x1ce4c68, output=0x1cb3ab8,
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explain_flags=0 '\000') at sql_lex.cc:3784
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#10 0x00000000005d6279 in st_select_lex_unit::print_explain (this=0x1ce4760, output=0x1cb3ab8,
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explain_flags=0 '\000') at sql_lex.cc:3820
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#11 0x00000000006ccbb1 in Show_explain_request::get_explain_data (arg=0x7f093ae47ba0)
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at sql_class.cc:3042
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#12 0x000000000095b261 in Apc_target::process_apc_requests (this=0x1ce44d0) at my_apc.cc:255
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#13 0x00000000006c8a1c in THD::check_killed (this=0x1ce21b8) at sql_class.cc:1904
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#14 0x000000000079a59f in evaluate_join_record (join=0x1d3d488, join_tab=0x1d42f58, error=0)
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at sql_select.cc:15829
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#15 0x000000000079a204 in sub_select (join=0x1d3d488, join_tab=0x1d42f58, end_of_records=false)
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at sql_select.cc:15744
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#16 0x00000000007999d5 in do_select (join=0x1d3d488, fields=0x1d3d818, table=0x0, procedure=0x0)
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at sql_select.cc:15405
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#17 0x000000000077aa3a in JOIN::exec_inner (this=0x1d3d488) at sql_select.cc:2810
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#18 0x0000000000777e1d in JOIN::exec (this=0x1d3d488) at sql_select.cc:2125
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#19 0x0000000000685dbb in subselect_single_select_engine::exec (this=0x1d3c900)
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at item_subselect.cc:3006
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#20 0x000000000067eae9 in Item_subselect::exec (this=0x1d3c7e8) at item_subselect.cc:587
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#21 0x0000000000680143 in Item_singlerow_subselect::val_int (this=0x1d3c7e8)
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at item_subselect.cc:1101
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#22 0x000000000063a6a6 in Arg_comparator::compare_int_signed (this=0x1d3ca00)
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at item_cmpfunc.cc:1167
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#23 0x000000000061b590 in Arg_comparator::compare (this=0x1d3ca00) at item_cmpfunc.h:72
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#24 0x000000000063c5a6 in Item_func_eq::val_int (this=0x1d3c940) at item_cmpfunc.cc:1851
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#25 0x000000000079a63e in evaluate_join_record (join=0x1d3cb78, join_tab=0x1d415a8, error=0)
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at sql_select.cc:15840
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#26 0x000000000079a204 in sub_select (join=0x1d3cb78, join_tab=0x1d415a8, end_of_records=false)
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at sql_select.cc:15744
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#27 0x00000000007999d5 in do_select (join=0x1d3cb78, fields=0x1ce4d70, table=0x0, procedure=0x0)
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at sql_select.cc:15405
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#28 0x000000000077aa3a in JOIN::exec_inner (this=0x1d3cb78) at sql_select.cc:2810
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#29 0x0000000000777e1d in JOIN::exec (this=0x1d3cb78) at sql_select.cc:2125
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#30 0x000000000077b2d3 in mysql_select (thd=0x1ce21b8, rref_pointer_array=0x1ce4ec0,
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tables=0x1cf0f88, wild_num=1, fields=..., conds=0x1d3c940, og_num=0, order=0x0, group=0x0,
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having=0x0, proc_param=0x0, select_options=2147764736, result=0x1d3cb58, unit=0x1ce4760,
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select_lex=0x1ce4c68) at sql_select.cc:3031
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#31 0x0000000000771d4e in handle_select (thd=0x1ce21b8, lex=0x1ce46c0, result=0x1d3cb58,
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setup_tables_done_option=0) at sql_select.cc:332
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#32 0x00000000007002c5 in execute_sqlcom_select (thd=0x1ce21b8, all_tables=0x1cf0f88)
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at sql_parse.cc:5178
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#33 0x00000000006f720b in mysql_execute_command (thd=0x1ce21b8) at sql_parse.cc:2285
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#34 0x0000000000702ca0 in mysql_parse (thd=0x1ce21b8,
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rawbuf=0x1cf0d00 "SELECT * FROM C WHERE a = ( SELECT MAX(a) FROM C\nWHERE pk = ( SELECT MAX(pk) FROM C WHERE pk = 3 ) )", length=100, found_semicolon=0x7f093ae00c98) at sql_parse.cc:6179
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#35 0x00000000006f49ba in dispatch_command (command=COM_QUERY, thd=0x1ce21b8, packet=0x1ce6359 "",
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packet_length=101) at sql_parse.cc:1229
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#36 0x00000000006f3cee in do_command (thd=0x1ce21b8) at sql_parse.cc:924
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#37 0x00000000006f0b32 in handle_one_connection (arg=0x1ce21b8) at sql_connect.cc:1218
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bzr version-info
revision-id: psergey@askmonty.org-20120514183900-rvddjradoeiynwif
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date: 2012-05-14 22:39:00 +0400
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revno: 3510
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Normal EXPLAIN from the before executing the query:
id select_type table type possible_keys key key_len ref rows filtered
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Extra
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1 PRIMARY C ALL NULL NULL NULL NULL 32768 100.00 Using where
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2 SUBQUERY C const PRIMARY PRIMARY 4 const 1 100.00 Using where
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3 SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL Select tables
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optimized away
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Warnings:
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Note 1003 select `test`.`C`.`pk` AS `pk`,`test`.`C`.`a` AS `a` from `test`.`C` where (`test`.`C`.`a` = (select max(`test`.`C`.`a`) from `test`.`C` where (`test`.`C`.`pk` = (select max(`test`.`C`.`pk`) from `test`.`C` where multiple equal(3, `test`.`C`.`pk`)))))
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Reproducible with the default optimizer_switch as well as with all OFFs except for in_to_exists which is required to execute the query.
MTR test case:
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CREATE TABLE C (pk INT PRIMARY KEY AUTO_INCREMENT, a INT ) ENGINE=MyISAM ;
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INSERT INTO C (a) VALUES
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(4),(6),(7),(1),(0),(7),(7),(1),
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(5),(2),(0),(1),(8),(1),(1),(9);
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INSERT INTO C SELECT NULL, a FROM C;
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INSERT INTO C SELECT NULL, a FROM C;
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INSERT INTO C SELECT NULL, a FROM C;
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INSERT INTO C SELECT NULL, a FROM C;
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INSERT INTO C SELECT NULL, a FROM C;
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INSERT INTO C SELECT NULL, a FROM C;
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INSERT INTO C SELECT NULL, a FROM C;
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INSERT INTO C SELECT NULL, a FROM C;
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INSERT INTO C SELECT NULL, a FROM C;
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INSERT INTO C SELECT NULL, a FROM C;
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INSERT INTO C SELECT NULL, a FROM C;
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--connect (con1,localhost,root,,)
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--let $con_id = `SELECT CONNECTION_ID()`
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--send
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SELECT * FROM C WHERE a = ( SELECT MAX(a) FROM C
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WHERE pk = ( SELECT MAX(pk) FROM C WHERE pk = 3 ) ) ;
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--connection default
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--let $run = 100
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while ($run)
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{
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--error 0,1220
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--eval SHOW EXPLAIN FOR $con_id
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--dec $run
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}
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--connection con1
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--reap
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In case you cannot reproduce it with the MTR case, you might want to try RQG.
RQG grammar (test.yy):
query_init:
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CREATE TABLE C (`pk` INT PRIMARY KEY, `a` INT ) ENGINE=MyISAM ; INSERT INTO C
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VALUES (1,4),(2,62),(3,7),(4,1),(5,0),(6,7),(7,7),(8,1),(9,7),(10,1),
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(11,5),(12,2),(13,0),(14,1),(15,8),(16,1),(17,1),(18,9),(19,1),(20,5) ;
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thread2:
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SHOW EXPLAIN FOR @con_id ;
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thread2_init:
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SET @con_id = CONNECTION_ID()-1;
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query:
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SELECT * FROM C WHERE `a` = ( SELECT MAX(`a`) FROM C
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WHERE `pk` = ( SELECT MAX(`pk`) FROM C WHERE `pk` = 3 ) ) ;
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Run as:
perl runall.pl \
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--threads=2 \
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--duration=600 \
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--queries=100M \
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--skip-gendata \
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--grammar=test.yy \
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--basedir1=<your basedir> \
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--vardir1=<your vardir>
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Attachments
Issue Links
- relates to
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MDEV-165 MWL#182: Explain running statements: finish coding, submit for review
- Closed