Valgrind warnings in mark_as_null_row with materialization+semijoin, STRAIGHT_JOIN, impossible WHERE

[Elena Stepanova]

==25752== Thread 5:
==25752== Invalid write of size 1
==25752== at 0x832D957: mark_as_null_row(st_table*) (mysql_priv.h:2642)
==25752== by 0x836A845: return_zero_rows(JOIN*, select_result*, List<TABLE_LIST>&, List<Item>&, bool, unsigned long long, char const*, Item*) (sql_select.cc:10437)
==25752== by 0x8356936: JOIN::exec() (sql_select.cc:2160)
==25752== by 0x83590D0: mysql_select(THD*, Item***, TABLE_LIST*, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) (sql_select.cc:2931)
==25752== by 0x8350DEA: handle_select(THD*, st_lex*, select_result*, unsigned long) (sql_select.cc:284)
==25752== by 0x82EC2BC: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:5151)
==25752== by 0x82E3698: mysql_execute_command(THD*) (sql_parse.cc:2284)
==25752== by 0x82EE8F7: mysql_parse(THD*, char*, unsigned int, char const**) (sql_parse.cc:6152)
==25752== by 0x82E12D8: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1228)
==25752== by 0x82E0782: do_command(THD*) (sql_parse.cc:923)
==25752== by 0x82DD708: handle_one_connection (sql_connect.cc:1193)
==25752== by 0x40C9B24: start_thread (in /lib/libpthread-2.11.2.so)
==25752== by 0x42F534D: clone (in /lib/libc-2.11.2.so)
==25752== Address 0x59d0220 is 1,680 bytes inside a block of size 2,956 free'd
==25752== at 0x4026996: free (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==25752== by 0x87C2E73: _myfree (safemalloc.c:337)
==25752== by 0x87C21D0: free_root (my_alloc.c:366)
==25752== by 0x8373FB5: free_tmp_table(THD*, st_table*) (sql_select.cc:14862)
==25752== by 0x836906A: st_join_table::cleanup() (sql_select.cc:9783)
==25752== by 0x8369A70: JOIN::cleanup(bool) (sql_select.cc:10095)
==25752== by 0x836979C: JOIN::join_free() (sql_select.cc:10015)
==25752== by 0x836A819: return_zero_rows(JOIN*, select_result*, List<TABLE_LIST>&, List<Item>&, bool, unsigned long long, char const*, Item*) (sql_select.cc:10430)
==25752== by 0x8356936: JOIN::exec() (sql_select.cc:2160)
==25752== by 0x83590D0: mysql_select(THD*, Item***, TABLE_LIST*, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) (sql_select.cc:2931)
==25752== by 0x8350DEA: handle_select(THD*, st_lex*, select_result*, unsigned long) (sql_select.cc:284)
==25752== by 0x82EC2BC: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:5151)
==25752== by 0x82E3698: mysql_execute_command(THD*) (sql_parse.cc:2284)
==25752== by 0x82EE8F7: mysql_parse(THD*, char*, unsigned int, char const**) (sql_parse.cc:6152)
==25752== by 0x82E12D8: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1228)
==25752== by 0x82E0782: do_command(THD*) (sql_parse.cc:923)
==25752==

==25752== Invalid read of size 4
==25752== at 0x832D961: mark_as_null_row(st_table*) (mysql_priv.h:2643)
==25752== by 0x836A845: return_zero_rows(JOIN*, select_result*, List<TABLE_LIST>&, List<Item>&, bool, unsigned long long, char const*, Item*) (sql_select.cc:10437)
,,,

==25752== Invalid read of size 4
==25752== at 0x832D978: mark_as_null_row(st_table*) (mysql_priv.h:2644)
==25752== by 0x836A845: return_zero_rows(JOIN*, select_result*, List<TABLE_LIST>&, List<Item>&, bool, unsigned long long, char const*, Item*) (sql_select.cc:10437)
...

==25752== Invalid write of size 1
==25752== at 0x4028C78: memset (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==25752== by 0x832D99C: mark_as_null_row(st_table*) (mysql_priv.h:2644)
==25752== by 0x836A845: return_zero_rows(JOIN*, select_result*, List<TABLE_LIST>&, List<Item>&, bool, unsigned long long, char const*, Item*) (sql_select.cc:10437)
...

stack trace from bzr version-info
revision-id: <email address hidden>
date: 2012-02-01 17:48:45 -0800
build-date: 2012-02-02 20:40:47 +0400
revno: 3405

Also reproducible on current revno 3421.

EXPLAIN:

id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <subquery2> system NULL NULL NULL NULL 1 100.00
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00
2 MATERIALIZED NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
Warnings:
Note 1003 select straight_join min(`test`.`t1`.`a`) AS `MIN(a)` from <materialize> (select `test`.`t1`.`a` from `test`.`t1` where 0) join `test`.`t1` where 1

Full 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
Minimal optimizer_switch: materialization=on,semijoin=on

Test case:

SET optimizer_switch='materialization=on,semijoin=on';

CREATE TABLE t1 ( a INT );
INSERT INTO t1 VALUES (0),(8);

SELECT STRAIGHT_JOIN MIN(a) FROM t1
WHERE a IN (
    SELECT a FROM t1
    WHERE 'condition'='impossible'
  );

[Elena Stepanova (elenst)]

Fix released with 5.3.5-ga.