[#MDEV-21495] Conditional jump or move depends on uninitialised value in sel_arg_range_seq

10.4 valgrind 2d4b6571
$ perl ./mtr --valgrind main.subselect_mat_cost

main.subselect_mat_cost [ fail ] Found warnings/errors in server log file!
Test ended at 2020-01-15 18:46:14
line
==7420== Thread 6:
==7420== Conditional jump or move depends on uninitialised value(s)
==7420== at 0xDF628B: sel_arg_range_seq_next(void, st_key_multi_range) (opt_range_mrr.cc:342)
==7420== by 0xDFC8C0: records_in_column_ranges(PARAM, unsigned int, SEL_ARG) (opt_range.cc:3189)
==7420== by 0xDFD50B: calculate_cond_selectivity_for_table(THD, TABLE, Item**) (opt_range.cc:3458)
==7420== by 0x961CF5: make_join_statistics(JOIN, List<TABLE_LIST>&, st_dynamic_array) (sql_select.cc:5435)
==7420== by 0x9561E1: JOIN::optimize_inner() (sql_select.cc:2235)
==7420== by 0x953B97: JOIN::optimize() (sql_select.cc:1598)
==7420== by 0x8D68E3: st_select_lex::optimize_unflattened_subqueries(bool) (sql_lex.cc:4187)
==7420== by 0xAFFFDF: JOIN::optimize_unflattened_subqueries() (opt_subselect.cc:5512)
==7420== by 0x958389: JOIN::optimize_stage2() (sql_select.cc:2797)
==7420== by 0x9562DF: JOIN::optimize_inner() (sql_select.cc:2261)
==7420== by 0x953B97: JOIN::optimize() (sql_select.cc:1598)
==7420== by 0x95F023: mysql_select(THD, 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:4633)
==7420== by 0x99C58B: mysql_explain_union(THD, st_select_lex_unit, select_result*) (sql_select.cc:26815)
==7420== by 0x914426: execute_sqlcom_select(THD, TABLE_LIST) (sql_parse.cc:6299)
==7420== by 0x909E02: mysql_execute_command(THD*) (sql_parse.cc:3899)
==7420== by 0x918962: mysql_parse(THD, char, unsigned int, Parser_state*, bool, bool) (sql_parse.cc:7901)

--source include/have_sequence.inc

CREATE TABLE t1(a INT, b INT);

INSERT INTO t1 SELECT seq, seq from seq_1_to_100;

set optimizer_use_condition_selectivity=4;

set use_stat_tables='preferably';

ANALYZE TABLE t1 PERSISTENT FOR ALL;

SELECT * from t1 WHERE a = 5 and b=5;

drop table t1;

(lldb) bt

* thread #2, stop reason = step over

  * frame #0: 0x00000001007b57f6 mysqld`calculate_cond_selectivity_for_table(thd=0x000062b00005b288, table=0x0000620000035108, cond=0x000062b000065168) at opt_range.cc:3447:53

    frame #1: 0x0000000100ebc3db mysqld`make_join_statistics(join=0x000062b000064d58, tables_list=0x000062b0000625c8, keyuse_array=0x000062b000065048) at sql_select.cc:5460:13

    frame #2: 0x0000000100ea2c5f mysqld`JOIN::optimize_inner(this=0x000062b000064d58) at sql_select.cc:2260:7

    frame #3: 0x0000000100e8d3e4 mysqld`JOIN::optimize(this=0x000062b000064d58) at sql_select.cc:1606:10

    frame #4: 0x0000000100e6e2b4 mysqld`mysql_select(thd=0x000062b00005b288, tables=0x000062b0000629b8, fields=0x000062b0000624d8, conds=0x000062b000063968, og_num=0, order=0x0000000000000000, group=0x0000000000000000, having=0x0000000000000000, proc_param=0x0000000000000000, select_options=2147748612, result=0x000062b000064478, unit=0x000062b00005f2c8, select_lex=0x000062b000062388) at sql_select.cc:4655:19

(lldb) p param.max_key_parts

(uint) $1 = 55299413

  seq->param->range_count++;

  seq->param->max_key_parts= MY_MAX(seq->param->max_key_parts, max_key_parts);

[MDEV-21495] Conditional jump or move depends on uninitialised value in sel_arg_range_seq_next Created: 2020-01-15 Updated: 2020-05-26 Resolved: 2020-05-26
Status:	Closed
Project:	MariaDB Server
Component/s:	Optimizer
Affects Version/s:	10.1, 10.2, 10.3, 10.4, 10.5
Fix Version/s:	10.5.4, 10.1.46, 10.2.33, 10.3.24, 10.4.14

[MDEV-21495] Conditional jump or move depends on uninitialised value in sel_arg_range_seq_next Created: 2020-01-15 Updated: 2020-05-26 Resolved: 2020-05-26