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mysqld: item.h:3759: virtual bool Item_cache::is_expensive_processor(uchar*): Assertion `example' failed. [ERROR] mysqld got signal 6 ;
#6 0x00007f896f21cd4d in __GI___assert_fail (assertion=0xcb12d3 "example", file=<optimized out>, line=3759, function=<optimized out>) at assert.c:81 #7 0x00000000005d0622 in Item_cache::is_expensive_processor (this=0x1c9d618, arg=0x0) at item.h:3759 #8 0x00000000005cbd97 in Item::walk (this=0x1c9d618, processor=&virtual Item::is_expensive_processor(unsigned char*), walk_subquery=false, arg=0x0) at item.h:985 #9 0x00000000005e3087 in Item_func::walk (this=0x1c96bd8, processor=&virtual table offset 632, walk_subquery=false, argument=0x0) at item_func.cc:276 #10 0x00000000005cc261 in Item::is_expensive (this=0x1c96bd8) at item.h:1277 #11 0x000000000075f5c5 in remove_eq_conds (thd=0x1bf4b10, cond=0x1c96bd8, cond_value=0x7f896651f0a8) at sql_select.cc:13182 #12 0x000000000075f00b in remove_eq_conds (thd=0x1bf4b10, cond=0x1c96d78, cond_value=0x1c98dd0) at sql_select.cc:13065 #13 0x000000000075eed4 in optimize_cond (join=0x1c98ab8, conds=0x1c96d78, join_list=0x1c95938, cond_value=0x1c98dd0, cond_equal=0x1c98f30) at sql_select.cc:13032 #14 0x000000000073f9c6 in JOIN::optimize (this=0x1c98ab8) at sql_select.cc:1016 #15 0x0000000000598191 in st_select_lex::optimize_unflattened_subqueries (this=0x1c94a58) at sql_lex.cc:3161 #16 0x00000000008351e5 in JOIN::optimize_unflattened_subqueries (this=0x1c98328) at opt_subselect.cc:4880 #17 0x0000000000741ac2 in JOIN::optimize (this=0x1c98328) at sql_select.cc:1554 #18 0x0000000000598191 in st_select_lex::optimize_unflattened_subqueries (this=0x1bf75d0) at sql_lex.cc:3161 #19 0x00000000008351e5 in JOIN::optimize_unflattened_subqueries (this=0x1c97778) at opt_subselect.cc:4880 #20 0x0000000000741ac2 in JOIN::optimize (this=0x1c97778) at sql_select.cc:1554 #21 0x0000000000746cf5 in mysql_select (thd=0x1bf4b10, rref_pointer_array=0x1bf7878, tables=0x1c94628, wild_num=1, fields=..., conds=0x1c97358, og_num=0, order=0x0, group=0x0, having=0x0, proc_param=0x0, select_options=2147764736, result=0x1c97728, unit=0x1bf70a8, select_lex=0x1bf75d0) at sql_select.cc:2969 #22 0x000000000073d7a3 in handle_select (thd=0x1bf4b10, lex=0x1bf7008, result=0x1c97728, setup_tables_done_option=0) at sql_select.cc:286 #23 0x00000000006c8c3b in execute_sqlcom_select (thd=0x1bf4b10, all_tables=0x1c94628) at sql_parse.cc:5157 #24 0x00000000006bf9fa in mysql_execute_command (thd=0x1bf4b10) at sql_parse.cc:2290 #25 0x00000000006cb693 in mysql_parse (thd=0x1bf4b10, rawbuf=0x1c7fab8 "SELECT * FROM t1 WHERE a1 IN ( \nSELECT a2 FROM t2 WHERE a2 IN ( \nSELECT a3 FROM t3 WHERE b2 = b1 AND b2 <= b1 ORDER BY b3 \n)\n)", length=126, found_semicolon=0x7f89665207e0) at sql_parse.cc:6158 #26 0x00000000006bd1a0 in dispatch_command (command=COM_QUERY, thd=0x1bf4b10, packet=0x1c62871 "SELECT * FROM t1 WHERE a1 IN ( \nSELECT a2 FROM t2 WHERE a2 IN ( \nSELECT a3 FROM t3 WHERE b2 = b1 AND b2 <= b1 ORDER BY b3 \n)\n)", packet_length=126) at sql_parse.cc:1228 #27 0x00000000006bc4b4 in do_command (thd=0x1bf4b10) at sql_parse.cc:923 #28 0x00000000006b8f0d in handle_one_connection (arg=0x1bf4b10) at sql_connect.cc:1218
Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (0x1c7fab8): SELECT * FROM t1 WHERE a1 IN ( SELECT a2 FROM t2 WHERE a2 IN ( SELECT a3 FROM t3 WHERE b2 = b1 AND b2 <= b1 ORDER BY b3 ) ) Connection ID (thread ID): 1 Status: NOT_KILLED
branch maria/5.3 revision-id: sanja@montyprogram.com-20121205190600-fzhla1o8ecu3hf20 date: 2012-12-05 21:06:00 +0200 revno: 3606
Reproducible on maria/5.3, maria/5.5 and maria/10.0. Not reproducible on maria/5.2.
Minimal optimizer_switch: in_to_exists=on
Also reproducible with the default optimizer_switch:
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
EXPLAIN also crashes.
Test case:
SET optimizer_switch = 'in_to_exists=on'; CREATE TABLE t1 (a1 INT, b1 TIME) ENGINE=MyISAM; INSERT INTO t1 VALUES (4,'21:22:34'),(6,'10:50:38'); CREATE TABLE t2 (a2 INT, b2 TIME) ENGINE=MyISAM; INSERT INTO t2 VALUES (8, '06:17:39'); CREATE TABLE t3 (a3 INT, b3 TIME) ENGINE=MyISAM; INSERT INTO t3 VALUES (1,'00:00:01'),(7,'00:00:02'); SELECT * FROM t1 WHERE a1 IN ( SELECT a2 FROM t2 WHERE a2 IN ( SELECT a3 FROM t3 WHERE b2 = b1 AND b2 <= b1 ORDER BY b3 ) );
It seems to be a debug-only assertion, no visible problems on a release build, and the scenario is an edge test case, so I'm setting it to Minor
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Analysis:
The following call stack shows that it is possible to set Item_cache::value_cached, and the relevant value
without setting Item_cache::example. Therefore the ASSERT is too specific, and need to include the case
when there is a cached value without an example.
#0 Item_cache_temporal::store_packed (this=0x7f02e4010060, val_arg=22659000000) at item.cc:8395
#1 0x00000000005fe1b9 in get_datetime_value (thd=0x3a4e298, item_arg=0x7f0359f26ea0, cache_arg=0x7f0359f26e98, warn_item=0x7f02e400a7d8, is_null=0x7f0359f26e74) at item_cmpfunc.cc:915
#2 0x00000000005c3f13 in resolve_const_item (thd=0x3a4e298, ref=0x7f02e400a968, comp_item=0x7f02e400a7d8) at item.cc:7987
#3 0x000000000075b8c3 in propagate_cond_constants (thd=0x3a4e298, save_list=0x7f0359f273d0, and_father=0x7f02e400adc8, cond=0x7f02e400a8d8) at sql_select.cc:12264
#4 0x000000000075b503 in propagate_cond_constants (thd=0x3a4e298, save_list=0x0, and_father=0x7f02e400adc8, cond=0x7f02e400adc8) at sql_select.cc:12227
#5 0x000000000075cd8a in optimize_cond (join=0x7f02e400c750, conds=0x7f02e400adc8, join_list=0x7f02e40089e0, cond_value=0x7f02e400ca38, cond_equal=0x7f02e400cb58) at sql_select.cc:13026
#6 0x000000000073c97c in JOIN::optimize (this=0x7f02e400c750) at sql_select.cc:1016
#7 0x00000000005976f1 in st_select_lex::optimize_unflattened_subqueries (this=0x3a50d30) at sql_lex.cc:3161
#8 0x0000000000832d63 in JOIN::optimize_unflattened_subqueries (this=0x7f02e400b4d8) at opt_subselect.cc:4880
#9 0x000000000073eac9 in JOIN::optimize (this=0x7f02e400b4d8) at sql_select.cc:1554
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