partition.test produces valgrind errors in 5.3-based branches

[Sergey Petrunia]

partition.test produces valgrind errors in 5.3-based branches. There is no such failure in 5.2

worker[1] Using MTR_BUILD_THREAD 301, with reserved ports 13010..13019
main.partition [ fail ] Found warnings/errors in server log file!
        Test ended at 2010-06-24 23:58:36
mysqltest: Logging to ''.
mysqltest: Results saved in ''.
mysqltest: Connecting to server localhost:13010 (socket /home/psergey/dev2/maria-5.3-subqueries-r12-vg/mysql-test/var/tmp/mysqld.1.sock) as 'root', connection 'default', attempt 0 ...
mysqltest: ... Connected.
mysqltest: Start processing test commands from './include/check-warnings.test' ...
line
==5946== Thread 9:
==5946== Conditional jump or move depends on uninitialised value(s)
==5946== at 0x82F304C: JOIN_CACHE::write_record_data(unsigned char*, bool*) (sql_join_cache.cc:1075)
==5946== by 0x82F36B2: JOIN_CACHE::put_record() (sql_join_cache.cc:1234)
==5946== by 0x8324E60: sub_select_cache(JOIN*, st_join_table*, bool) (sql_select.cc:12936)
==5946== by 0x83247AF: evaluate_join_record(JOIN*, st_join_table*, int) (sql_select.cc:13316)
==5946== by 0x8324B0B: sub_select(JOIN*, st_join_table*, bool) (sql_select.cc:13133)
==5946== by 0x8332859: do_select(JOIN*, List<Item>*, st_table*, Procedure*) (sql_select.cc:12680)
==5946== by 0x83468AA: JOIN::exec() (sql_select.cc:2201)
==5946== by 0x8340DC1: 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:2396)
==5946== by 0x8346BDB: handle_select(THD*, st_lex*, select_result*, unsigned long) (sql_select.cc:279)
==5946== by 0x82AB34F: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:5133)
==5946== by 0x82AD549: mysql_execute_command(THD*) (sql_parse.cc:2318)
==5946== by 0x82B70D5: mysql_parse(THD*, char const*, unsigned int, char const**) (sql_parse.cc:6079)
==5946== by 0x82B7EB2: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1253)
==5946== by 0x82B945E: do_command(THD*) (sql_parse.cc:891)
==5946== by 0x82A344B: handle_one_connection (sql_connect.cc:1599)
==5946== by 0x406C4FE: start_thread (in /lib/tls/i686/cmov/libpthread-2.9.so)
==5946==
==5946== Conditional jump or move depends on uninitialised value(s)
==5946== at 0x82F249C: JOIN_CACHE::read_record_field(st_cache_field*, bool) (sql_join_cache.cc:1446)
==5946== by 0x82F2C26: JOIN_CACHE::read_all_record_fields() (sql_join_cache.cc:1384)
==5946== by 0x82F2D41: JOIN_CACHE::get_record() (sql_join_cache.cc:1276)
==5946== by 0x82F2392: JOIN_CACHE_BNL::join_matching_records(bool) (sql_join_cache.cc:1856)
==5946== by 0x82F065B: JOIN_CACHE::join_records(bool) (sql_join_cache.cc:1665)
==5946== by 0x8324D94: sub_select_cache(JOIN*, st_join_table*, bool) (sql_select.cc:12923)
==5946== by 0x8324974: sub_select(JOIN*, st_join_table*, bool) (sql_select.cc:13085)
==5946== by 0x8332882: do_select(JOIN*, List<Item>*, st_table*, Procedure*) (sql_select.cc:12682)
==5946== by 0x83468AA: JOIN::exec() (sql_select.cc:2201)
==5946== by 0x8340DC1: 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:2396)
==5946== by 0x8346BDB: handle_select(THD*, st_lex*, select_result*, unsigned long) (sql_select.cc:279)
==5946== by 0x82AB34F: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:5133)
==5946== by 0x82AD549: mysql_execute_command(THD*) (sql_parse.cc:2318)
==5946== by 0x82B70D5: mysql_parse(THD*, char const*, unsigned int, char const**) (sql_parse.cc:6079)
==5946== by 0x82B7EB2: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1253)
==5946== by 0x82B945E: do_command(THD*) (sql_parse.cc:891)
==5946==
==5946== Conditional jump or move depends on uninitialised value(s)
==5946== at 0x82F249C: JOIN_CACHE::read_record_field(st_cache_field*, bool) (sql_join_cache.cc:1446)
==5946== by 0x82F2C26: JOIN_CACHE::read_all_record_fields() (sql_join_cache.cc:1384)
==5946== by 0x82F2C6E: JOIN_CACHE::get_record_by_pos(unsigned char*) (sql_join_cache.cc:1308)
==5946== by 0x82F0323: JOIN_CACHE::restore_last_record() (sql_join_cache.cc:1614)
==5946== by 0x82F0829: JOIN_CACHE::join_records(bool) (sql_join_cache.cc:1737)
==5946== by 0x8324D94: sub_select_cache(JOIN*, st_join_table*, bool) (sql_select.cc:12923)
==5946== by 0x8324974: sub_select(JOIN*, st_join_table*, bool) (sql_select.cc:13085)
==5946== by 0x8332882: do_select(JOIN*, List<Item>*, st_table*, Procedure*) (sql_select.cc:12682)
==5946== by 0x83468AA: JOIN::exec() (sql_select.cc:2201)
==5946== by 0x8340DC1: 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:2396)
==5946== by 0x8346BDB: handle_select(THD*, st_lex*, select_result*, unsigned long) (sql_select.cc:279)
==5946== by 0x82AB34F: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:5133)
==5946== by 0x82AD549: mysql_execute_command(THD*) (sql_parse.cc:2318)
==5946== by 0x82B70D5: mysql_parse(THD*, char const*, unsigned int, char const**) (sql_parse.cc:6079)
==5946== by 0x82B7EB2: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1253)
==5946== by 0x82B945E: do_command(THD*) (sql_parse.cc:891)
^ Found warnings in /home/psergey/dev2/maria-5.3-subqueries-r12-vg/mysql-test/var/log/mysqld.1.err
mysqltest: ... Done processing test commands.
mysqltest: Test has succeeded!
ok

 - saving '/home/psergey/dev2/maria-5.3-subqueries-r12-vg/mysql-test/var/log/main.partition/' to '/home/psergey/dev2/maria-5.3-subqueries-r12-vg/mysql-test/var/log/main.partition/'
------------------------------------------------------------
The servers were restarted 0 times
Spent 0.000 of 104 seconds executing testcases
mysql-test-run: WARNING: Got errors/warnings while running tests, please examine '/home/psergey/dev2/maria-5.3-subqueries-r12-vg/mysql-test/var/log/warnings' for details.

Failed 1/1 tests, 0.00% were successful.

Failing test(s): main.partition

The log files in var/log may give you some hint of what went wrong.

If you want to report this error, please read first the documentation
at http://dev.mysql.com/doc/mysql/en/mysql-test-suite.html

mysql-test-run: *** ERROR: there were failing test cases
psergey@pslp2:~/dev2/maria-5.3-subqueries-r12-vg/mysql-test$

[Sergey Petrunia (sergefp)]

The simplest testcase:

--disable_warnings
drop table if exists t1, t2;
--enable_warnings

CREATE TABLE t1 (
  a INT DEFAULT NULL,
  b DOUBLE DEFAULT NULL,
  c INT DEFAULT NULL,
  KEY idx2(b,a)
) engine=myisam PARTITION BY HASH(c) PARTITIONS 3;

INSERT INTO t1 VALUES (6,8,9);
INSERT INTO t1 VALUES (6,8,10);

SELECT 1 FROM t1 JOIN t1 AS t2 USING (a);
# FOR UPDATE - is not necessary.

drop table t1;

[Sergey Petrunia (sergefp)]

The EXPLAIN of the query causing the warning:

MySQL [jun28]> explain SELECT 1 FROM t1 JOIN t1 AS t2 USING (a);
+----+-------------+-------+-------+---------------+------+---------+------+------+---------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+-------+---------------+------+---------+------+------+---------------------------------------------+
| 1 | SIMPLE | t1 | index | NULL | idx2 | 14 | NULL | 2 | Using index |
| 1 | SIMPLE | t2 | index | NULL | idx2 | 14 | NULL | 2 | Using where; Using index; Using join buffer |
+----+-------------+-------+-------+---------------+------+---------+------+------+---------------------------------------------+
2 rows in set (0.03 sec)

[Sergey Petrunia (sergefp)]

Upon investigation, discovered the following:

The failure occurs when trying to read the value of t1.c from join buffer. It
is wrong that t1.c is present in the join buffer, because
- it is not really needed by the query
- EXPLAIN shows "Using index" for table t1 (and that is correct, the
  executor really uses HA_EXTRA_KEYREAD for table t1), so we don't
  really have the value of t1.c

Table t1's data structures are not self-consistent with regards to t1.c:

(gdb) p this
  $21 = (TABLE * const) 0xa707470
(gdb) p this->alias
  $22 = 0xa6df300 "t1"
(gdb) p/x this->read_set->last_word_mask
  $23 = 0xfffffff8
(gdb) p/x *(this->read_set->last_word_ptr)
  $24 = 0x5
(gdb) p this->covering_keys
  $25 = {map = 1}

that is, the index idx2 is considered covering, even though it doesn't include
t1.c which is in the read set.

[Sergey Petrunia (sergefp)]

For some reason, lp:~mysql/mysql-server/mysql-trunk/ doesn't produce the valgrind warning, although it has the same problem - "index only" read is used, and a non-indexed column is put into join buffer.

[Timour Katchaounov (timour)]

There is no longer a valgrind warning with the latest 5.3 as of 14-06-2011.
Sergey, could you please re-verify in GDB whether the internal state is
correct or not. I think the test case should be added to the regression suite.

[Sergey Petrunia (sergefp)]

Checked against revision-id:<email address hidden>. The data structures are still not self-consistent, in the same way as it was mentioned in comment #3.

[Sergey Petrunia (sergefp)]

The valgrind warning can no longer be repeated. Pushed a testcase.