database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00
Code Activity

Indexes can be used for optimization if the operation

Browse Source 
collation is the same with the index collation.
This commit is contained in:
unknown
2004-02-02 17:50:14 +04:00
parent c91c1470c8
commit 65534b77a1
6 changed files with 153 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
sql/sql_select.cc
View File

@ -2131,7 +2131,7 @@ merge_key_fields(KEY_FIELD *start,KEY_FIELD *new_fields,KEY_FIELD *end,
*/
static void
add_key_field(KEY_FIELD **key_fields,uint and_level,
add_key_field(KEY_FIELD **key_fields,uint and_level, COND *cond,
Field *field,bool eq_func,Item **value, uint num_values,
table_map usable_tables)
{
@ -2198,6 +2198,17 @@ add_key_field(KEY_FIELD **key_fields,uint and_level,
(*value)->result_type() != STRING_RESULT &&
field->cmp_type() != (*value)->result_type())
return;
/*
We can't use indexes if the effective collation
of the operation differ from the field collation.
*/
if (field->result_type() == STRING_RESULT &&
(*value)->result_type() == STRING_RESULT &&
field->cmp_type() == STRING_RESULT &&
((Field_str*)field)->charset() != cond->compare_collation())
return;
}
}
DBUG_ASSERT(num_values == 1);
@ -2261,7 +2272,7 @@ add_key_fields(JOIN_TAB *stat,KEY_FIELD **key_fields,uint *and_level,
// BETWEEN or IN
if (cond_func->key_item()->real_item()->type() == Item::FIELD_ITEM &&
!(cond_func->used_tables() & OUTER_REF_TABLE_BIT))
add_key_field(key_fields,*and_level,
add_key_field(key_fields,*and_level,cond_func,
((Item_field*) (cond_func->key_item()->real_item()))->
field, 0,
cond_func->arguments()+1, cond_func->argument_count()-1,
@ -2275,7 +2286,7 @@ add_key_fields(JOIN_TAB *stat,KEY_FIELD **key_fields,uint *and_level,
if (cond_func->arguments()[0]->real_item()->type() == Item::FIELD_ITEM &&
!(cond_func->arguments()[0]->used_tables() & OUTER_REF_TABLE_BIT))
{
add_key_field(key_fields,*and_level,
add_key_field(key_fields,*and_level,cond_func,
((Item_field*) (cond_func->arguments()[0])->real_item())
->field,
equal_func,
@ -2285,7 +2296,7 @@ add_key_fields(JOIN_TAB *stat,KEY_FIELD **key_fields,uint *and_level,
cond_func->functype() != Item_func::LIKE_FUNC &&
!(cond_func->arguments()[1]->used_tables() & OUTER_REF_TABLE_BIT))
{
add_key_field(key_fields,*and_level,
add_key_field(key_fields,*and_level,cond_func,
((Item_field*) (cond_func->arguments()[1])->real_item())
->field,
equal_func,
@ -2301,7 +2312,7 @@ add_key_fields(JOIN_TAB *stat,KEY_FIELD **key_fields,uint *and_level,
Item *tmp=new Item_null;
if (!tmp) // Should never be true
return;
add_key_field(key_fields,*and_level,
add_key_field(key_fields,*and_level,cond_func,
((Item_field*) (cond_func->arguments()[0])->real_item())
->field,
cond_func->functype() == Item_func::ISNULL_FUNC,