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#4 <signal handler called>
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#5 0x08383dcb in JOIN::print_explain (this=0xa0f0258, result=0x9ff0560,
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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:21264
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#6 0x081e8fa7 in st_select_lex::print_explain (this=0x9fd4818, output=0x9ff0560,
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explain_flags=0 '\000') at sql_lex.cc:3773
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#7 0x081e9109 in st_select_lex_unit::print_explain (this=0x9fd4524, output=0x9ff0560,
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explain_flags=0 '\000') at sql_lex.cc:3824
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#8 0x082bd29f in Show_explain_request::get_explain_data (arg=0x943d1694)
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at sql_class.cc:3042
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#9 0x0850ae24 in Apc_target::process_apc_requests (this=0x9fd433c) at my_apc.cc:255
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#10 0x0850a875 in Apc_target::disable (this=0x9fd433c) at my_apc.cc:83
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#11 0x08357d43 in JOIN::exec (this=0xa0f0258) at sql_select.cc:2134
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#12 0x0835ac4f in mysql_select (thd=0x9fd2d30, rref_pointer_array=0x9fd4958,
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tables=0xa0ef240, wild_num=1, fields=..., conds=0xa0f00a0, og_num=0, order=0x0,
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group=0x0, having=0x0, proc_param=0x0, select_options=2147764736, result=0xa0f0240,
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unit=0x9fd4524, select_lex=0x9fd4818) at sql_select.cc:3031
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#13 0x0835277f in handle_select (thd=0x9fd2d30, lex=0x9fd44c8, result=0xa0f0240,
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setup_tables_done_option=0) at sql_select.cc:332
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#14 0x082ed586 in execute_sqlcom_select (thd=0x9fd2d30, all_tables=0xa0ef240)
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at sql_parse.cc:5178
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#15 0x082e480b in mysql_execute_command (thd=0x9fd2d30) at sql_parse.cc:2285
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#16 0x082efbc1 in mysql_parse (thd=0x9fd2d30,
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rawbuf=0xa0ef078 "SELECT * FROM A WHERE ( 5, 78 ) IN ( SELECT `a1`, MAX(`a1`) FROM A GROUP BY `a1` )", length=82, found_semicolon=0x9438a234) at sql_parse.cc:6179
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#17 0x082e244b in dispatch_command (command=COM_QUERY, thd=0x9fd2d30, packet=0xa0e9709 "",
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packet_length=82) at sql_parse.cc:1229
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#18 0x082e18f5 in do_command (thd=0x9fd2d30) at sql_parse.cc:924
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#19 0x082de7e1 in handle_one_connection (arg=0x9fd2d30) at sql_connect.cc:1218
|
#20 0xb774bb25 in start_thread () from /lib/libpthread.so.0
|
bzr version-info
revision-id: psergey@askmonty.org-20120516162254-kxt6xh902iqb6rsc
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date: 2012-05-16 20:22:54 +0400
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revno: 3513
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The provided RQG test repeatedly runs the same query in one thread, and SHOW EXPLAIN for the first thread in another thread. It always fails within seconds after start when I run it.
Before server crashes, EXPLAIN result comes in two variants, I am not sure which one causes the problem, or maybe there is a third which does not reach the client:
1 PRIMARY <subquery2> const distinct_key distinct_key 8 1
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1 PRIMARY A ALL 20 Using join buffer (flat, BNL join)
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2 MATERIALIZED A index a1 4 20 Using index
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1 PRIMARY <subquery2> const distinct_key distinct_key 8 const,const 1
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1 PRIMARY A ALL 20 Using join buffer (flat, BNL join)
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2 MATERIALIZED A index a1 4 20 Using index
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Run RQG test 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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--basedir=<your basedir>
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RQG grammar (test.yy):
thread1_init:
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DROP TABLE IF EXISTS A; CREATE TABLE A ( `pk` INT NOT NULL PRIMARY KEY, `a1` INT NOT NULL, KEY(`a1`) ) ENGINE=MyISAM ; INSERT INTO A VALUES (1,5),(2,4),(3,6),(4,9),(5,2),(6,8),(7,4),(8,8),(9,0),(10,43),(11,23),(12,3),(13,45),(14,16),(15,2),(16,33),(17,2),(18,5),(19,9),(20,2);
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query:
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SELECT * FROM A WHERE ( 5, 78 ) IN ( SELECT `a1`, MAX(`a1`) FROM A GROUP BY `a1` ) ;
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thread2_init:
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SET @con_id = CONNECTION_ID()-1;
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thread2:
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SHOW EXPLAIN FOR @con_id ;
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