MWL#253: Valgrind warnings 'Use of uninitialised value' and 'Invalid read' in get_column_range_cardinality

==19269== Thread 4:

==19269== Use of uninitialised value of size 8

==19269==    at 0xD35BEB: my_strnxfrm_simple (ctype-simple.c:86)

==19269==    by 0x7CD8EC: Field_str::middle_point_pos(Field*, Field*) (field.cc:6206)

==19269==    by 0x6AAAC3: get_column_range_cardinality(Field*, st_key_range*, st_key_range*) (sql_statistics.cc:3403)

==19269==    by 0x8F69C4: records_in_column_ranges(PARAM*, unsigned int, SEL_ARG*) (opt_range.cc:3306)

==19269==    by 0x8F6D50: calculate_cond_selectivity_for_table(THD*, TABLE*, Item*) (opt_range.cc:3385)

==19269==    by 0x65087E: make_join_statistics(JOIN*, List<TABLE_LIST>&, Item*, st_dynamic_array*) (sql_select.cc:3839)

==19269==    by 0x647A3C: JOIN::optimize_inner() (sql_select.cc:1306)

==19269==    by 0x6469E7: JOIN::optimize() (sql_select.cc:1008)

==19269==    by 0x64E69C: 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:3220)

==19269==    by 0x644E52: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:376)

==19269==    by 0x61C303: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4797)

==19269==    by 0x614903: mysql_execute_command(THD*) (sql_parse.cc:2266)

==19269==    by 0x61EBA5: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:5920)

==19269==    by 0x611C27: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1091)

==19269==    by 0x610E55: do_command(THD*) (sql_parse.cc:810)

==19269==    by 0x729CC7: do_handle_one_connection(THD*) (sql_connect.cc:1266)

==19269== Invalid read of size 1

==19269==    at 0xD35BE1: my_strnxfrm_simple (ctype-simple.c:86)

==19269==    by 0x7CDA62: Field_str::middle_point_pos(Field*, Field*) (field.cc:6212)

==19269==    by 0x6AAAC3: get_column_range_cardinality(Field*, st_key_range*, st_key_range*) (sql_statistics.cc:3403)

==19269==    by 0x8F69C4: records_in_column_ranges(PARAM*, unsigned int, SEL_ARG*) (opt_range.cc:3306)

==19269==    by 0x8F6D50: calculate_cond_selectivity_for_table(THD*, TABLE*, Item*) (opt_range.cc:3385)

==19269==    by 0x65087E: make_join_statistics(JOIN*, List<TABLE_LIST>&, Item*, st_dynamic_array*) (sql_select.cc:3839)

==19269==    by 0x647A3C: JOIN::optimize_inner() (sql_select.cc:1306)

==19269==    by 0x6469E7: JOIN::optimize() (sql_select.cc:1008)

==19269==    by 0x64E69C: 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:3220)

==19269==    by 0x644E52: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:376)

==19269==    by 0x61C303: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4797)

==19269==    by 0x614903: mysql_execute_command(THD*) (sql_parse.cc:2266)

==19269==    by 0x61EBA5: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:5920)

==19269==    by 0x611C27: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1091)

==19269==    by 0x610E55: do_command(THD*) (sql_parse.cc:810)

==19269==    by 0x729CC7: do_handle_one_connection(THD*) (sql_connect.cc:1266)

==19269==  Address 0x1194efc0 is 0 bytes after a block of size 48 alloc'd

==19269==    at 0x4C2B6CD: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)

==19269==    by 0xCFFFCE: my_malloc (my_malloc.c:99)

==19269==    by 0xCF0E84: alloc_root (my_alloc.c:180)

==19269==    by 0x6A7319: create_min_max_statistical_fields_for_table_share(THD*, TABLE_SHARE*) (sql_statistics.cc:1721)

==19269==    by 0x6A7BC0: alloc_statistics_for_table_share(THD*, TABLE_SHARE*, bool) (sql_statistics.cc:2000)

==19269==    by 0x5B76F2: open_and_process_table(THD*, LEX*, TABLE_LIST*, unsigned int*, unsigned int, Prelocking_strategy*, bool, Open_table_context*, st_mem_root*) (sql_base.cc:4646)

==19269==    by 0x5B8428: open_tables(THD*, TABLE_LIST**, unsigned int*, unsigned int, Prelocking_strategy*) (sql_base.cc:5062)

==19269==    by 0x5B92C2: open_and_lock_tables(THD*, TABLE_LIST*, bool, unsigned int, Prelocking_strategy*) (sql_base.cc:5667)

==19269==    by 0x5AC212: open_and_lock_tables(THD*, TABLE_LIST*, bool, unsigned int) (sql_base.h:532)

==19269==    by 0x61C06B: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4755)

==19269==    by 0x614903: mysql_execute_command(THD*) (sql_parse.cc:2266)

==19269==    by 0x61EBA5: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:5920)

==19269==    by 0x611C27: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1091)

==19269==    by 0x610E55: do_command(THD*) (sql_parse.cc:810)

==19269==    by 0x729CC7: do_handle_one_connection(THD*) (sql_connect.cc:1266)

==19269==    by 0x7296B2: handle_one_connection (sql_connect.cc:1181)

revision-id: igor@askmonty.org-20130404211131-w3aybgqc80g7aiaq

revno: 3516

branch-nick: maria-10.0-mwl253

SET use_stat_tables = PREFERABLY;

SET optimizer_use_condition_selectivity=3;

CREATE TABLE t1 (a VARCHAR(1));

INSERT INTO t1 VALUES ('x'),('y');

ANALYZE TABLE t1;

FLUSH TABLES;

SELECT * FROM t1 WHERE a <= 'w';

EXPLAIN EXTENDED

SELECT * FROM t1 WHERE a <= 'w';

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where

Warnings:

Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where (`test`.`t1`.`a` <= 'w')