mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-01-18 21:12:26 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

Merge rkalimullin@work.mysql.com:/home/bk/mysql-4.1

Browse source 
into mysql.r18.ru:/usr/home/ram/work/mysql-4.1
This commit is contained in:
unknown 2003-01-06 13:13:57 +04:00
commit 60cf17cb36
3 changed files with 139 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

34
mysql-test/r/order_by.result
View file

@ -506,3 +506,37 @@ SELECT titre,t1.numeropost,auteur,icone,nbrep,'0',date,vue,ouvert,lastauteur,des
titre numeropost auteur icone nbrep 0 date vue ouvert lastauteur dest
test 1 joce 0 0 0 0000-00-00 00:00:00 0 1 bug
drop table t1,t2;
CREATE TABLE t1 (
FieldKey varchar(36) NOT NULL default '',
LongVal bigint(20) default NULL,
StringVal mediumtext,
KEY FieldKey (FieldKey),
KEY LongField (FieldKey,LongVal),
KEY StringField (FieldKey,StringVal(32))
);
INSERT INTO t1 VALUES ('0',3,'0'),('1',2,'1'),('1',1,'3'), ('1',0,'2');
EXPLAIN SELECT * FROM t1 WHERE FieldKey = '1' ORDER BY LongVal;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref FieldKey,LongField,StringField LongField 36 const 2 Using where
SELECT * FROM t1 WHERE FieldKey = '1' ORDER BY LongVal;
FieldKey LongVal StringVal
1 0 2
1 1 3
1 2 1
EXPLAIN SELECT * FROM t1 WHERE FieldKey > '0' ORDER BY LongVal;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range FieldKey,LongField,StringField FieldKey 36 NULL 3 Using where; Using filesort
SELECT * FROM t1 WHERE FieldKey > '0' ORDER BY LongVal;
FieldKey LongVal StringVal
1 0 2
1 1 3
1 2 1
EXPLAIN SELECT * FROM t1 WHERE FieldKey > '0' ORDER BY FieldKey, LongVal;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range FieldKey,LongField,StringField LongField 36 NULL 3 Using where
SELECT * FROM t1 WHERE FieldKey > '0' ORDER BY FieldKey, LongVal;
FieldKey LongVal StringVal
1 0 2
1 1 3
1 2 1
DROP TABLE t1;

21
mysql-test/t/order_by.test
View file

@ -330,3 +330,24 @@ INSERT INTO t2 (numeropost,pseudo) VALUES (1,'joce'),(1,'bug');
SELECT titre,t1.numeropost,auteur,icone,nbrep,0,date,vue,ouvert,lastauteur,dest FROM t2 LEFT JOIN t1 USING(numeropost) WHERE t2.pseudo='joce' ORDER BY date DESC LIMIT 0,30;
SELECT titre,t1.numeropost,auteur,icone,nbrep,'0',date,vue,ouvert,lastauteur,dest FROM t2 LEFT JOIN t1 USING(numeropost) WHERE t2.pseudo='joce' ORDER BY date DESC LIMIT 0,30;
drop table t1,t2;
#
# Test of test_if_subkey() function
#
CREATE TABLE t1 (
FieldKey varchar(36) NOT NULL default '',
LongVal bigint(20) default NULL,
StringVal mediumtext,
KEY FieldKey (FieldKey),
KEY LongField (FieldKey,LongVal),
KEY StringField (FieldKey,StringVal(32))
);
INSERT INTO t1 VALUES ('0',3,'0'),('1',2,'1'),('1',1,'3'), ('1',0,'2');
EXPLAIN SELECT * FROM t1 WHERE FieldKey = '1' ORDER BY LongVal;
SELECT * FROM t1 WHERE FieldKey = '1' ORDER BY LongVal;
EXPLAIN SELECT * FROM t1 WHERE FieldKey > '0' ORDER BY LongVal;
SELECT * FROM t1 WHERE FieldKey > '0' ORDER BY LongVal;
EXPLAIN SELECT * FROM t1 WHERE FieldKey > '0' ORDER BY FieldKey, LongVal;
SELECT * FROM t1 WHERE FieldKey > '0' ORDER BY FieldKey, LongVal;
DROP TABLE t1;

84
sql/sql_select.cc
View file

@ -5933,6 +5933,69 @@ static uint find_shortest_key(TABLE *table, key_map usable_keys)
return best;
}
/*
SYNOPSIS
is_subkey()
key_part - first key parts
ref_key_part - second key parts
ref_key_part_end - last+1 part of the second key
DESCRIPTION
Test if a second key is the subkey of the first one.
NOTE
Second key MUST be shorter than the first one.
RETURN
1 - is the subkey
0 - otherwise
*/
inline bool
is_subkey(KEY_PART_INFO *key_part, KEY_PART_INFO *ref_key_part,
KEY_PART_INFO *ref_key_part_end)
{
for (; ref_key_part < ref_key_part_end; key_part++, ref_key_part++)
if (!key_part->field->eq(ref_key_part->field))
return 0;
return 1;
}
/*
SYNOPSIS
test_if_subkey()
ref - number of key, used for WHERE clause
usable_keys - keys for testing
DESCRIPTION
Test if we can use one of the 'usable_keys' instead of 'ref' key.
RETURN
MAX_KEY - if we can't use other key
the number of found key - otherwise
*/
static uint
test_if_subkey(ORDER *order, TABLE *table, uint ref, key_map usable_keys)
{
uint nr;
uint min_length= (uint) ~0;
uint best= MAX_KEY;
uint not_used;
KEY_PART_INFO *ref_key_part= table->key_info[ref].key_part;
uint ref_key_parts= table->key_info[ref].key_parts;
KEY_PART_INFO *ref_key_part_end= ref_key_part + ref_key_parts;
for (nr= 0; usable_keys; usable_keys>>= 1, nr++)
{
if ((usable_keys & 1) &&
table->key_info[nr].key_length < min_length &&
table->key_info[nr].key_parts >= ref_key_parts &&
is_subkey(table->key_info[nr].key_part, ref_key_part,
ref_key_part_end) &&
test_if_order_by_key(order, table, nr, &not_used))
{
min_length= table->key_info[nr].key_length;
best= nr;
}
}
return best;
}
/*
Test if we can skip the ORDER BY by using an index.
@ -5980,6 +6043,27 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
*/
int order_direction;
uint used_key_parts;
if (!(usable_keys & ((key_map) 1 << ref_key)))
{
/*
We come here when ref_key is not among usable_keys
*/
uint a;
if ((a= test_if_subkey(order, table, ref_key, usable_keys)) < MAX_KEY)
{
if (tab->ref.key >= 0)
{
tab->ref.key= a;
table->file->index_init(a);
}
else
{
select->quick->index= a;
select->quick->init();
}
ref_key= a;
}
}
/* Check if we get the rows in requested sorted order by using the key */
if ((usable_keys & ((key_map) 1 << ref_key)) &&
(order_direction = test_if_order_by_key(order,table,ref_key,