[MDEV-6736] [10.0] Valgrind warnings 'Invalid read' in subselect_engine::calc_const_tables with SQ in WHERE and HAVING, ORDER BY, materialization+semijoin - Jira

Details

Type: Bug
Status: Closed (View Workflow)
Priority: Minor
Resolution: Fixed
Affects Version/s: 10.0.13, 10.0(EOL)
Fix Version/s: 10.0.35
Component/s: Optimizer
Labels:
- optimizer
- valgrind

Sprint:
10.1.32

Description

CREATE TABLE t1 (a INT) ENGINE=MyISAM;

INSERT INTO t1 VALUES (3),(8);

CREATE TABLE t2 (b INT) ENGINE=MyISAM;

INSERT INTO t2 VALUES (2),(1);

SELECT a FROM t1

WHERE 9 IN ( SELECT MIN( a ) FROM t1 )

HAVING a <> ( SELECT COUNT(*) FROM t2 )

ORDER BY a;

==30848== Invalid read of size 1

==30848==    at 0x90E68F: subselect_engine::calc_const_tables(List<TABLE_LIST>&) (item_subselect.cc:4166)

==30848==    by 0x90E708: subselect_single_select_engine::upper_select_const_tables() (item_subselect.cc:4175)

==30848==    by 0x904F8B: Item_subselect::update_used_tables() (item_subselect.cc:888)

==30848==    by 0x8C917E: Item_func::update_used_tables() (item_func.cc:445)

==30848==    by 0x6B6F0A: JOIN::exec_inner() (sql_select.cc:2927)

==30848==    by 0x6B4CDB: JOIN::exec() (sql_select.cc:2369)

==30848==    by 0x6B8046: 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:3307)

==30848==    by 0x6AE640: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:372)

==30848==    by 0x683345: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:5269)

==30848==    by 0x67B646: mysql_execute_command(THD*) (sql_parse.cc:2552)

==30848==    by 0x685AD0: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:6415)

==30848==    by 0x6788E7: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1307)

==30848==    by 0x677C8C: do_command(THD*) (sql_parse.cc:1004)

==30848==    by 0x7941C9: do_handle_one_connection(THD*) (sql_connect.cc:1379)

==30848==    by 0x793F1C: handle_one_connection (sql_connect.cc:1293)

==30848==    by 0xCC9D29: pfs_spawn_thread (pfs.cc:1860)

==30848==  Address 0xdbe21dd is 2,269 bytes inside a block of size 4,772 free'd

==30848==    at 0x4C27BF4: free (vg_replace_malloc.c:469)

==30848==    by 0xE52CEE: free_memory (safemalloc.c:276)

==30848==    by 0xE529B2: sf_free (safemalloc.c:194)

==30848==    by 0xE41D2D: my_free (my_malloc.c:216)

==30848==    by 0xE362D9: free_root (my_alloc.c:385)

==30848==    by 0x6D96E1: free_tmp_table(THD*, TABLE*) (sql_select.cc:17081)

==30848==    by 0x91013E: subselect_hash_sj_engine::cleanup() (item_subselect.cc:5002)

==30848==    by 0x9034AB: Item_subselect::cleanup() (item_subselect.cc:152)

==30848==    by 0x90364A: Item_in_subselect::cleanup() (item_subselect.cc:189)

==30848==    by 0x6CB94E: st_join_table::cleanup() (sql_select.cc:11224)

==30848==    by 0x6CC748: JOIN::cleanup(bool) (sql_select.cc:11620)

==30848==    by 0x6CC35B: JOIN::join_free() (sql_select.cc:11507)

==30848==    by 0x6B68B7: JOIN::exec_inner() (sql_select.cc:2844)

==30848==    by 0x6B4CDB: JOIN::exec() (sql_select.cc:2369)

==30848==    by 0x6B8046: 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:3307)

==30848==    by 0x6AE640: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:372)

==30848== Invalid read of size 8

==30848==    at 0x90E69E: subselect_engine::calc_const_tables(List<TABLE_LIST>&) (item_subselect.cc:4167)

==30848==    by 0x90E708: subselect_single_select_engine::upper_select_const_tables() (item_subselect.cc:4175)

==30848==    by 0x904F8B: Item_subselect::update_used_tables() (item_subselect.cc:888)

==30848==    by 0x8C917E: Item_func::update_used_tables() (item_func.cc:445)

==30848==    by 0x6B6F0A: JOIN::exec_inner() (sql_select.cc:2927)

==30848==    by 0x6B4CDB: JOIN::exec() (sql_select.cc:2369)

==30848==    by 0x6B8046: 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:3307)

==30848==    by 0x6AE640: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:372)

==30848==    by 0x683345: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:5269)

==30848==    by 0x67B646: mysql_execute_command(THD*) (sql_parse.cc:2552)

==30848==    by 0x685AD0: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:6415)

==30848==    by 0x6788E7: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1307)

==30848==    by 0x677C8C: do_command(THD*) (sql_parse.cc:1004)

==30848==    by 0x7941C9: do_handle_one_connection(THD*) (sql_connect.cc:1379)

==30848==    by 0x793F1C: handle_one_connection (sql_connect.cc:1293)

==30848==    by 0xCC9D29: pfs_spawn_thread (pfs.cc:1860)

==30848==  Address 0xdbe21a0 is 2,208 bytes inside a block of size 4,772 free'd

==30848==    at 0x4C27BF4: free (vg_replace_malloc.c:469)

==30848==    by 0xE52CEE: free_memory (safemalloc.c:276)

==30848==    by 0xE529B2: sf_free (safemalloc.c:194)

==30848==    by 0xE41D2D: my_free (my_malloc.c:216)

==30848==    by 0xE362D9: free_root (my_alloc.c:385)

==30848==    by 0x6D96E1: free_tmp_table(THD*, TABLE*) (sql_select.cc:17081)

==30848==    by 0x91013E: subselect_hash_sj_engine::cleanup() (item_subselect.cc:5002)

==30848==    by 0x9034AB: Item_subselect::cleanup() (item_subselect.cc:152)

==30848==    by 0x90364A: Item_in_subselect::cleanup() (item_subselect.cc:189)

==30848==    by 0x6CB94E: st_join_table::cleanup() (sql_select.cc:11224)

==30848==    by 0x6CC748: JOIN::cleanup(bool) (sql_select.cc:11620)

==30848==    by 0x6CC35B: JOIN::join_free() (sql_select.cc:11507)

==30848==    by 0x6B68B7: JOIN::exec_inner() (sql_select.cc:2844)

==30848==    by 0x6B4CDB: JOIN::exec() (sql_select.cc:2369)

==30848==    by 0x6B8046: 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:3307)

==30848==    by 0x6AE640: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:372)

Stack trace from:

revision-id: elenst@montyprogram.com-20140911232154-8kfkykep1qtsn8fi

revno: 4393

branch-nick: 10.0

EXPLAIN:

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	PRIMARY	<subquery2>	const	distinct_key	distinct_key	4	const	1	100.00	Using temporary; Using filesort

1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (flat, BNL join)

3	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away

2	MATERIALIZED	t1	ALL	NULL	NULL	NULL	NULL	2	100.00

Warnings:

Note	1003	select `test`.`t1`.`a` AS `a` from  <materialize> (select min(`test`.`t1`.`a`) from `test`.`t1`) join `test`.`t1` where (`<subquery2>`.`MIN( a )` = 9) having (`test`.`t1`.`a` <> (select count(0) from `test`.`t2`)) order by `test`.`t1`.`a`

Minimal optimizer_switch: materialization=on,semijoin=on

Attachments

Issue Links

relates to

MDEV-17616 ASAN heap-use-after-free in subselect_engine::calc_const_tables on 2nd execution of PS

Closed

Activity

Ascending order - Click to sort in descending order

Elena Stepanova added a comment - 2018-01-19 16:16

Still reproducible on 10.0, but not on 10.1/10.2.

10.0 4b8cd4536a2c ASAN
==25219==ERROR: AddressSanitizer: heap-use-after-free on address 0x6210000671dd at pc 0xd3eb47 bp 0x7f2d15797c60 sp 0x7f2d15797c58
READ of size 1 at 0x6210000671dd thread T5
#0 0xd3eb46 in subselect_engine::calc_const_tables(List<TABLE_LIST>&) /data/src/10.0/sql/item_subselect.cc:4242
#1 0xd3ec22 in subselect_single_select_engine::upper_select_const_tables() /data/src/10.0/sql/item_subselect.cc:4251
#2 0xd2009a in Item_subselect::update_used_tables() /data/src/10.0/sql/item_subselect.cc:902
#3 0xc71a4d in Item_func::update_used_tables() /data/src/10.0/sql/item_func.cc:446
#4 0x7dad09 in JOIN::exec_inner() /data/src/10.0/sql/sql_select.cc:2937
#5 0x7dd343 in JOIN::exec() /data/src/10.0/sql/sql_select.cc:2379
#6 0x7d24a6 in 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) /data/src/10.0/sql/sql_select.cc:3318
#7 0x7d2ad6 in handle_select(THD, LEX, select_result*, unsigned long) /data/src/10.0/sql/sql_select.cc:373
#8 0x6b566c in execute_sqlcom_select /data/src/10.0/sql/sql_parse.cc:5293
#9 0x6ccea8 in mysql_execute_command(THD*) /data/src/10.0/sql/sql_parse.cc:2553
#10 0x6e19f7 in mysql_parse(THD, char, unsigned int, Parser_state*) /data/src/10.0/sql/sql_parse.cc:6569
#11 0x6e5616 in dispatch_command(enum_server_command, THD, char, unsigned int) /data/src/10.0/sql/sql_parse.cc:1296
#12 0x6e9f0f in do_command(THD*) /data/src/10.0/sql/sql_parse.cc:999
#13 0x975c3b in do_handle_one_connection(THD*) /data/src/10.0/sql/sql_connect.cc:1377
#14 0x975ea2 in handle_one_connection /data/src/10.0/sql/sql_connect.cc:1292
#15 0x11a95d4 in pfs_spawn_thread /data/src/10.0/storage/perfschema/pfs.cc:1861
#16 0x7f2d1fdb2493 in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x7493)
#17 0x7f2d1e16b93e in __clone (/lib/x86_64-linux-gnu/libc.so.6+0xe893e)

0x6210000671dd is located 2269 bytes inside of 4772-byte region [0x621000066900,0x621000067ba4)
freed by thread T5 here:
#0 0x7f2d2001c527 in __interceptor_free (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x54527)
#1 0x18e68b3 in free_memory /data/src/10.0/mysys/safemalloc.c:276

previously allocated by thread T5 here:
#0 0x7f2d2001c73f in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x5473f)
#1 0x18e6986 in sf_malloc /data/src/10.0/mysys/safemalloc.c:115
#2 0x19c964a (/data/bld/10.0-asan/bin/mysqld+0x19c964a)

Thread T5 created by T0 here:
#0 0x7f2d1ffebbba in pthread_create (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x23bba)
#1 0x11b4e2b in spawn_thread_v1 /data/src/10.0/storage/perfschema/pfs.cc:1911

SUMMARY: AddressSanitizer: heap-use-after-free /data/src/10.0/sql/item_subselect.cc:4242 subselect_engine::calc_const_tables(List<TABLE_LIST>&)
Shadow bytes around the buggy address:
0x0c4280004de0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x0c4280004df0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x0c4280004e00: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x0c4280004e10: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x0c4280004e20: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
=>0x0c4280004e30: fd fd fd fd fd fd fd fd fd fd fd[fd]fd fd fd fd
0x0c4280004e40: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x0c4280004e50: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x0c4280004e60: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x0c4280004e70: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x0c4280004e80: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Heap right redzone: fb
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack partial redzone: f4
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Contiguous container OOB:fc
ASan internal: fe
==25219==ABORTING

Elena Stepanova added a comment - 2018-01-19 16:16 Still reproducible on 10.0, but not on 10.1/10.2. 10.0 4b8cd4536a2c ASAN ==25219==ERROR: AddressSanitizer: heap-use-after-free on address 0x6210000671dd at pc 0xd3eb47 bp 0x7f2d15797c60 sp 0x7f2d15797c58 READ of size 1 at 0x6210000671dd thread T5 #0 0xd3eb46 in subselect_engine::calc_const_tables(List<TABLE_LIST>&) /data/src/10.0/sql/item_subselect.cc:4242 #1 0xd3ec22 in subselect_single_select_engine::upper_select_const_tables() /data/src/10.0/sql/item_subselect.cc:4251 #2 0xd2009a in Item_subselect::update_used_tables() /data/src/10.0/sql/item_subselect.cc:902 #3 0xc71a4d in Item_func::update_used_tables() /data/src/10.0/sql/item_func.cc:446 #4 0x7dad09 in JOIN::exec_inner() /data/src/10.0/sql/sql_select.cc:2937 #5 0x7dd343 in JOIN::exec() /data/src/10.0/sql/sql_select.cc:2379 #6 0x7d24a6 in 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*) /data/src/10.0/sql/sql_select.cc:3318 #7 0x7d2ad6 in handle_select(THD*, LEX*, select_result*, unsigned long) /data/src/10.0/sql/sql_select.cc:373 #8 0x6b566c in execute_sqlcom_select /data/src/10.0/sql/sql_parse.cc:5293 #9 0x6ccea8 in mysql_execute_command(THD*) /data/src/10.0/sql/sql_parse.cc:2553 #10 0x6e19f7 in mysql_parse(THD*, char*, unsigned int, Parser_state*) /data/src/10.0/sql/sql_parse.cc:6569 #11 0x6e5616 in dispatch_command(enum_server_command, THD*, char*, unsigned int) /data/src/10.0/sql/sql_parse.cc:1296 #12 0x6e9f0f in do_command(THD*) /data/src/10.0/sql/sql_parse.cc:999 #13 0x975c3b in do_handle_one_connection(THD*) /data/src/10.0/sql/sql_connect.cc:1377 #14 0x975ea2 in handle_one_connection /data/src/10.0/sql/sql_connect.cc:1292 #15 0x11a95d4 in pfs_spawn_thread /data/src/10.0/storage/perfschema/pfs.cc:1861 #16 0x7f2d1fdb2493 in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x7493) #17 0x7f2d1e16b93e in __clone (/lib/x86_64-linux-gnu/libc.so.6+0xe893e) 0x6210000671dd is located 2269 bytes inside of 4772-byte region [0x621000066900,0x621000067ba4) freed by thread T5 here: #0 0x7f2d2001c527 in __interceptor_free (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x54527) #1 0x18e68b3 in free_memory /data/src/10.0/mysys/safemalloc.c:276 previously allocated by thread T5 here: #0 0x7f2d2001c73f in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x5473f) #1 0x18e6986 in sf_malloc /data/src/10.0/mysys/safemalloc.c:115 #2 0x19c964a (/data/bld/10.0-asan/bin/mysqld+0x19c964a) Thread T5 created by T0 here: #0 0x7f2d1ffebbba in pthread_create (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x23bba) #1 0x11b4e2b in spawn_thread_v1 /data/src/10.0/storage/perfschema/pfs.cc:1911 SUMMARY: AddressSanitizer: heap-use-after-free /data/src/10.0/sql/item_subselect.cc:4242 subselect_engine::calc_const_tables(List<TABLE_LIST>&) Shadow bytes around the buggy address: 0x0c4280004de0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c4280004df0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c4280004e00: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c4280004e10: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c4280004e20: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd =>0x0c4280004e30: fd fd fd fd fd fd fd fd fd fd fd[fd]fd fd fd fd 0x0c4280004e40: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c4280004e50: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c4280004e60: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c4280004e70: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd 0x0c4280004e80: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Heap right redzone: fb Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack partial redzone: f4 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Contiguous container OOB:fc ASan internal: fe ==25219==ABORTING

Varun Gupta (Inactive) added a comment - 2018-03-12 06:50

explain extended

SELECT a FROM t1

WHERE 9 IN ( SELECT MIN( a ) FROM t1 )

HAVING a <> ( SELECT COUNT(*) FROM t2 )

ORDER BY a;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	PRIMARY	<subquery2>	const	distinct_key	distinct_key	4	const	1	100.00	Using temporary; Using filesort

1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (flat, BNL join)

3	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away

2	MATERIALIZED	t1	ALL	NULL	NULL	NULL	NULL	2	100.00

Warnings:

Note	1003	select `test`.`t1`.`a` AS `a` from  <materialize> (select min(`test`.`t1`.`a`) from `test`.`t1`) join `test`.`t1` where (`<subquery2>`.`MIN( a )` = 9) having (`test`.`t1`.`a` <> (select count(0) from `test`.`t2`)) order by `test`.`t1`.`a`

Varun Gupta (Inactive) added a comment - 2018-03-12 06:50 explain extended SELECT a FROM t1 WHERE 9 IN ( SELECT MIN( a ) FROM t1 ) HAVING a <> ( SELECT COUNT(*) FROM t2 ) ORDER BY a; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY <subquery2> const distinct_key distinct_key 4 const 1 100.00 Using temporary; Using filesort 1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00 Using join buffer (flat, BNL join) 3 SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL Select tables optimized away 2 MATERIALIZED t1 ALL NULL NULL NULL NULL 2 100.00 Warnings: Note 1003 select `test`.`t1`.`a` AS `a` from <materialize> (select min(`test`.`t1`.`a`) from `test`.`t1`) join `test`.`t1` where (`<subquery2>`.`MIN( a )` = 9) having (`test`.`t1`.`a` <> (select count(0) from `test`.`t2`)) order by `test`.`t1`.`a`

Varun Gupta (Inactive) added a comment - 2018-03-13 11:00

In the function JOIN::exec_inner , I see

/*

      curr_join->join_free() will call JOIN::cleanup(full=TRUE). It will not

      be safe to call update_used_tables() after that.

*/

    if (curr_join->tmp_having)

        curr_join->tmp_having->update_used_tables();

But later in this function we have

            table_map used_tables= (curr_join->const_table_map |

                                    curr_table->table->map);

            curr_join->tmp_having->update_used_tables();

So this is where we kind of start accessing tables(temporary table) which were freed with the call to JOIN::join_free()

Varun Gupta (Inactive) added a comment - 2018-03-13 11:00 In the function JOIN::exec_inner , I see /* curr_join->join_free() will call JOIN::cleanup(full=TRUE). It will not be safe to call update_used_tables() after that. */ if (curr_join->tmp_having) curr_join->tmp_having->update_used_tables(); But later in this function we have table_map used_tables= (curr_join->const_table_map | curr_table->table->map); curr_join->tmp_having->update_used_tables(); So this is where we kind of start accessing tables(temporary table) which were freed with the call to JOIN::join_free()

Sergei Petrunia added a comment - 2018-03-15 21:23

The patch is here: http://lists.askmonty.org/pipermail/commits/2018-March/012084.html (it has an incorrect comment, it says ~~MDEV-6731~~ instead)

Sergei Petrunia added a comment - 2018-03-15 21:23 The patch is here: http://lists.askmonty.org/pipermail/commits/2018-March/012084.html (it has an incorrect comment, it says MDEV-6731 instead)

Sergei Petrunia added a comment - 2018-03-16 13:03

Looking at the patch...

table_map subselect_engine::calc_const_tables(List<TABLE_LIST> &list)

  table_map map= 0;

  List_iterator<TABLE_LIST> ti(list);

  TABLE_LIST *table;

  //for (; table; table= table->next_leaf)

  while ((table= ti++))

    TABLE *tbl= table->table;

    if (tbl && tbl->const_table)   //(*)

      map|= tbl->map;

and this is invoked from

table_map subselect_single_select_engine::upper_select_const_tables()

For JTBM materialization nests, we have tbl==NULL and skip them in the computation.

There is no much point in computing a bitmap of const_tables in the upper select after JOIN::cleanup has been called for the upper select.

OTOH, this is what 10.1 does, and it seems to be harmless.

Sergei Petrunia added a comment - 2018-03-16 13:03 Looking at the patch... table_map subselect_engine::calc_const_tables(List<TABLE_LIST> &list) { table_map map= 0; List_iterator<TABLE_LIST> ti(list); TABLE_LIST *table; //for (; table; table= table->next_leaf) while ((table= ti++)) { TABLE *tbl= table->table; if (tbl && tbl->const_table) //(*) map|= tbl->map; and this is invoked from table_map subselect_single_select_engine::upper_select_const_tables() For JTBM materialization nests, we have tbl==NULL and skip them in the computation. There is no much point in computing a bitmap of const_tables in the upper select after JOIN::cleanup has been called for the upper select. OTOH, this is what 10.1 does, and it seems to be harmless.

Sergei Petrunia added a comment - 2018-03-16 13:03

So, let's have 10.0 do what 10.1 does, here.

Sergei Petrunia added a comment - 2018-03-16 13:03 So, let's have 10.0 do what 10.1 does, here.

People

Assignee:: Varun Gupta (Inactive)

Reporter:: Elena Stepanova

Votes:: 1 Vote for this issue

Watchers:: 5 Start watching this issue

Dates

Created:: 2014-09-12 13:59

Updated:: 2018-11-05 10:26

Resolved:: 2018-03-17 05:23

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