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

opt_range.cc, range.result, range.test:

Browse Source 
Bug #6045: Binary Comparison regression in MySQL 4.1
  Binary searches didn't use a case insensitive index, now they do.
This commit is contained in:
bar@mysql.com
2004-11-03 15:22:33 +04:00
parent 4650f0acab
commit 45451568bf
3 changed files with 42 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
mysql-test/r/range.result
View File

@ -561,3 +561,19 @@ select count(*) from t1 where x = 18446744073709551601;
count(*)
1
drop table t1;
set names latin1;
create table t1 (a char(10), b text, key (a)) character set latin1;
INSERT INTO t1 (a) VALUES
('111'),('222'),('222'),('222'),('222'),('444'),('aaa'),('AAA'),('bbb');
explain select * from t1 where a='aaa';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref a a 11 const 2 Using where
explain select * from t1 where a=binary 'aaa';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 11 NULL 2 Using where
explain select * from t1 where a='aaa' collate latin1_bin;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 11 NULL 2 Using where
explain select * from t1 where a='aaa' collate latin1_german1_ci;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL a NULL NULL NULL 9 Using where

14
mysql-test/t/range.test
View File

@ -431,3 +431,17 @@ select count(*) from t1 where x = 18446744073709551601;
drop table t1;
#
# Bug #6045: Binary Comparison regression in MySQL 4.1
# Binary searches didn't use a case insensitive index.
#
set names latin1;
create table t1 (a char(10), b text, key (a)) character set latin1;
INSERT INTO t1 (a) VALUES
('111'),('222'),('222'),('222'),('222'),('444'),('aaa'),('AAA'),('bbb');
# all these three can be optimized
explain select * from t1 where a='aaa';
explain select * from t1 where a=binary 'aaa';
explain select * from t1 where a='aaa' collate latin1_bin;
# this one cannot:
explain select * from t1 where a='aaa' collate latin1_german1_ci;

15
sql/opt_range.cc
View File

@ -1013,13 +1013,22 @@ get_mm_leaf(PARAM *param, COND *conf_func, Field *field, KEY_PART *key_part,
}
/*
We can't use an index when comparing strings of
different collations
1. Usually we can't use an index if the column collation
differ from the operation collation.
2. However, we can reuse a case insensitive index for
the binary searches:
WHERE latin1_swedish_ci_column = 'a' COLLATE lati1_bin;
WHERE latin1_swedish_ci_colimn = BINARY 'a '
*/
if (field->result_type() == STRING_RESULT &&
value->result_type() == STRING_RESULT &&
key_part->image_type == Field::itRAW &&
((Field_str*)field)->charset() != conf_func->compare_collation())
((Field_str*)field)->charset() != conf_func->compare_collation() &&
!(conf_func->compare_collation()->state & MY_CS_BINSORT))
DBUG_RETURN(0);
if (type == Item_func::LIKE_FUNC)