Commit 3915c3d9 authored by unknown's avatar unknown
Browse files

Bug #21159: Optimizer: wrong result after AND with different data types 

Disable const propagation for Item_hex_string.
This must be done because Item_hex_string->val_int() is not
the same as (Item_hex_string->val_str() in BINARY column)->val_int().
We cannot simply disable the replacement in a particular context (
e.g. <bin_col> = <int_col> AND <bin_col> = <hex_string>) since
Items don't know the context they are in and there are functions like 
IF (<hex_string>, 'yes', 'no').
Note that this will disable some valid cases as well 
(e.g. : <bin_col> = <hex_string> AND <bin_col2> = <bin_col>) but 
there's no way to distinguish the valid cases without having the
Item's parent say something like : Item->set_context(Item::STRING_RESULT)
and have all the Items that contain other Items do that consistently.


mysql-test/r/compare.result:
  Bug #21159: Optimizer: wrong result after AND with different data types
   - test case
mysql-test/t/compare.test:
  Bug #21159: Optimizer: wrong result after AND with different data types
   - test case
sql/sql_select.cc:
  Bug #21159: Optimizer: wrong result after AND with different data types
   - disable const propagation for Item_hex_string.
parent 1cf65f31

mysql-test/r/compare.result

+7 −0
Original line number Diff line number Diff line
@@ -42,3 +42,10 @@ CHAR(31) = '' '' = CHAR(31) 
SELECT CHAR(30) = '', '' = CHAR(30);

CHAR(30) = ''	'' = CHAR(30)

0	0

create table t1 (a tinyint(1),b binary(1));

insert into t1 values (0x01,0x01);

select * from t1 where a=b;

a	b

select * from t1 where a=b and b=0x01;

a	b

drop table if exists t1;

mysql-test/t/compare.test

+9 −0
Original line number Diff line number Diff line
@@ -37,3 +37,12 @@ SELECT CHAR(31) = '', '' = CHAR(31); 
SELECT CHAR(30) = '', '' = CHAR(30);



# End of 4.1 tests



#

#Bug #21159: Optimizer: wrong result after AND with different data types

#

create table t1 (a tinyint(1),b binary(1));

insert into t1 values (0x01,0x01);

select * from t1 where a=b;

select * from t1 where a=b and b=0x01;

drop table if exists t1;

sql/sql_select.cc

+16 −1
Original line number Diff line number Diff line
@@ -6498,8 +6498,23 @@ static bool check_equality(Item *item, COND_EQUAL *cond_equal) 
        field_item= (Item_field*) right_item;

        const_item= left_item;

      }

      /* 

        Disable const propagation for Item_hex_string.

        This must be done because Item_hex_string->val_int() is not

        the same as (Item_hex_string->val_str() in BINARY column)->val_int().

        We cannot simply disable the replacement in a particular context (

        e.g. <bin_col> = <int_col> AND <bin_col> = <hex_string>) since

        Items don't know the context they are in and there are functions like 

        IF (<hex_string>, 'yes', 'no').

        Note that this will disable some valid cases as well 

        (e.g. : <bin_col> = <hex_string> AND <bin_col2> = <bin_col>) but 

        there's no way to distinguish the valid cases without having the

        Item's parent say something like : Item->set_context(Item::STRING_RESULT)

        and have all the Items that contain other Items do that consistently.

      */

      if (const_item &&

          field_item->result_type() == const_item->result_type())

          field_item->result_type() == const_item->result_type() &&

          const_item->type() != Item::VARBIN_ITEM)

      {

        bool copyfl;