Commit 6de27791 authored by unknown's avatar unknown
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Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized 

away.

During optimization stage the WHERE conditions can be changed or even
be removed at all if they know for sure to be true of false. Thus they aren't
showed in the EXPLAIN EXTENDED which prints conditions after optimization.

Now if all elements of an Item_cond were removed this Item_cond is substituted
for an Item_int with the int value of the Item_cond.
If there were conditions that were totally optimized away then values of the
saved cond_value and having_value will be printed instead.


mysql-test/t/explain.test:
  Added a test case for the bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized away.
mysql-test/r/subselect.result:
  Corrected test case result after fix for bug#22331.
mysql-test/r/func_test.result:
  Corrected test case result after fix for bug#22331.
mysql-test/r/explain.result:
  Added a test case for the bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized away.
sql/sql_select.cc:
  Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized
  away.
  Now if all elements of an Item_cond were removed this Item_cond is substituted
  for an Item_int with the int value of the Item_cond.
  If there were conditions that were totally optimized away then values of the
  saved cond_value and having_value will be printed instead.
sql/sql_lex.h:
  Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized
  away.
  The cond_value and the having_value variables are
  added to the SELECT_LEX class.
sql/sql_lex.cc:
  Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized
  away.
  The initialization of the cond_value and the having_value variables.
sql/sql_select.h:
  Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were optimized
  away.
  Now having_value is also stored in the JOIN class.
parent e656c582

mysql-test/r/explain.result

+29 −0
Original line number Diff line number Diff line
@@ -57,3 +57,32 @@ select 3 into @v1; 
explain select 3 into @v1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used

create table t1(f1 int, f2 int);

insert into t1 values (1,1);

create view v1 as select * from t1 where f1=1;

explain extended select * from v1 where f2=1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	system	NULL	NULL	NULL	NULL	1	

Warnings:

Note	1003	select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` where 1

explain extended select * from t1 where 0;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE

Warnings:

Note	1003	select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` where 0

explain extended select * from t1 where 1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	system	NULL	NULL	NULL	NULL	1	

Warnings:

Note	1003	select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` where 1

explain extended select * from t1 having 0;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible HAVING

Warnings:

Note	1003	select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` having 0

explain extended select * from t1 having 1;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t1	system	NULL	NULL	NULL	NULL	1	

Warnings:

Note	1003	select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` having 1

drop table t1;

mysql-test/r/func_test.result

+1 −1
Original line number Diff line number Diff line
@@ -79,7 +79,7 @@ explain extended select * from t1 where 1 xor 1; 
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE

Warnings:

Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1`

Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where 0

select - a from t1;

- a

-1

mysql-test/r/subselect.result

+8 −8
Original line number Diff line number Diff line
@@ -421,7 +421,7 @@ id select_type table type possible_keys key key_len ref rows Extra 
3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used

NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	

Warnings:

Note	1003	select 1 AS `1` from `test`.`t1`

Note	1003	select 1 AS `1` from `test`.`t1` where 1

drop table t1;

CREATE TABLE `t1` (

`numeropost` mediumint(8) unsigned NOT NULL auto_increment,
@@ -1180,7 +1180,7 @@ id select_type table type possible_keys key key_len ref rows Extra 
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used

2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE

Warnings:

Note	1003	select <in_optimizer>(0,<exists>(select 1 AS `Not_used` from `test`.`t1` `a`)) AS `0 IN (SELECT 1 FROM t1 a)`

Note	1003	select <in_optimizer>(0,<exists>(select 1 AS `Not_used` from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`

INSERT INTO t1 (pseudo) VALUES ('test1');

SELECT 0 IN (SELECT 1 FROM t1 a);

0 IN (SELECT 1 FROM t1 a)
@@ -1190,7 +1190,7 @@ id select_type table type possible_keys key key_len ref rows Extra 
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used

2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE

Warnings:

Note	1003	select <in_optimizer>(0,<exists>(select 1 AS `Not_used` from `test`.`t1` `a`)) AS `0 IN (SELECT 1 FROM t1 a)`

Note	1003	select <in_optimizer>(0,<exists>(select 1 AS `Not_used` from `test`.`t1` `a` where 0)) AS `0 IN (SELECT 1 FROM t1 a)`

drop table t1;

CREATE TABLE `t1` (

`i` int(11) NOT NULL default '0',
@@ -1532,7 +1532,7 @@ id select_type table type possible_keys key key_len ref rows Extra 
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE

2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	const row not found

Warnings:

Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3`

Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0

select * from t3 where NULL >= any (select b from t2 group by 1);

a

explain extended select * from t3 where NULL >= any (select b from t2 group by 1);
@@ -1540,7 +1540,7 @@ id select_type table type possible_keys key key_len ref rows Extra 
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE

2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	const row not found

Warnings:

Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3`

Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0

select * from t3 where NULL >= some (select b from t2);

a

explain extended select * from t3 where NULL >= some (select b from t2);
@@ -1548,7 +1548,7 @@ id select_type table type possible_keys key key_len ref rows Extra 
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE

2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	const row not found

Warnings:

Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3`

Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0

select * from t3 where NULL >= some (select b from t2 group by 1);

a

explain extended select * from t3 where NULL >= some (select b from t2 group by 1);
@@ -1556,7 +1556,7 @@ id select_type table type possible_keys key key_len ref rows Extra 
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE

2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	const row not found

Warnings:

Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3`

Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where 0

insert into t2 values (2,2), (2,1), (3,3), (3,1);

select * from t3 where a > all (select max(b) from t2 group by a);

a
@@ -1618,7 +1618,7 @@ id select_type table type possible_keys key key_len ref rows Extra 
3	UNION	t1	system	NULL	NULL	NULL	NULL	1	

NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	

Warnings:

Note	1003	select `test`.`t1`.`s1` AS `s1` from `test`.`t1`

Note	1003	select `test`.`t1`.`s1` AS `s1` from `test`.`t1` where 1

drop table t1;

CREATE TABLE t1 (number char(11) NOT NULL default '') ENGINE=MyISAM CHARSET=latin1;

INSERT INTO t1 VALUES ('69294728265'),('18621828126'),('89356874041'),('95895001874');

mysql-test/t/explain.test

+14 −0
Original line number Diff line number Diff line
@@ -51,4 +51,18 @@ set names latin1; 
select 3 into @v1;

explain select 3 into @v1;



#

# Bug#22331: Wrong WHERE in EXPLAIN EXTENDED when all expressions were

#            optimized away.

#

create table t1(f1 int, f2 int);

insert into t1 values (1,1);

create view v1 as select * from t1 where f1=1;

explain extended select * from v1 where f2=1;

explain extended select * from t1 where 0;

explain extended select * from t1 where 1;

explain extended select * from t1 having 0;

explain extended select * from t1 having 1;

drop table t1;



# End of 5.0 tests.

sql/sql_lex.cc

+1 −0
Original line number Diff line number Diff line
@@ -1192,6 +1192,7 @@ void st_select_lex::init_select() 
  is_correlated= 0;

  cur_pos_in_select_list= UNDEF_POS;

  non_agg_fields.empty();

  cond_value= having_value= Item::COND_UNDEF;

}



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