database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-29 05:21:33 +03:00
Code Activity

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

Browse Source 
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.
This commit is contained in:
gkodinov/kgeorge@macbook.gmz
2006-08-15 10:13:17 +03:00
parent 83896aa8f6
commit c606c63f0e
3 changed files with 32 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
sql/sql_select.cc
View File

@ -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;