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Fix ORDER BY ... DESC optimization

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This commit is contained in:
monty@hundin.mysql.fi
2001-06-29 04:04:29 +03:00
parent 545e596ef7
commit f0dc189227
7 changed files with 377 additions and 106 deletions
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152
mysql-test/r/order_by.result
View File

@ -112,58 +112,118 @@ member_id nickname voornaam
1
2
table type possible_keys key key_len ref rows Extra
t1 index NULL a 20 NULL 10 Using index
a b c
1 NULL NULL
1 NULL b
1 1 NULL
1 1 b
1 1 b
2 0 a
2 0 b
2 1 a
2 1 b
2 1 c
table type possible_keys key key_len ref rows Extra
t1 index NULL a 20 NULL 10 Using index
a b c
2 1 c
2 1 b
2 1 a
2 0 b
2 0 a
1 1 b
1 1 b
1 1 NULL
1 NULL b
1 NULL NULL
table type possible_keys key key_len ref rows Extra
t1 range a a 20 NULL 2 where used; Using index
a b c
1 NULL b
table type possible_keys key key_len ref rows Extra
t1 range a a 4 NULL 10 where used; Using index
a b c
2 3 c
2 2 b
2 2 a
2 1 b
2 1 a
1 3 b
1 1 b
1 1 b
1 1 NULL
1 NULL b
1 NULL NULL
table type possible_keys key key_len ref rows Extra
t1 ref a a 4 const 5 where used; Using index; Using filesort
a b c
1 3 b
1 1 NULL
1 1 b
1 1 b
1 NULL NULL
1 NULL b
table type possible_keys key key_len ref rows Extra
t1 ref a a 9 const,const 2 where used; Using index; Using filesort
a b c
1 NULL NULL
1 NULL b
table type possible_keys key key_len ref rows Extra
t1 range a a 9 NULL 8 where used; Using index; Using filesort
table type possible_keys key key_len ref rows Extra
t1 range a a 9 NULL 5 where used; Using index
table type possible_keys key key_len ref rows Extra
t1 ref a a 9 const,const 1 where used; Using index; Using filesort
table type possible_keys key key_len ref rows Extra
t1 range a a 9 NULL 6 where used; Using index
table type possible_keys key key_len ref rows Extra
t1 range a a 9 NULL 5 where used; Using index
table type possible_keys key key_len ref rows Extra
t1 range a a 9 NULL 2 where used; Using index; Using filesort
table type possible_keys key key_len ref rows Extra
t1 index NULL a 18 NULL 11 Using index
a b c
1 0
1 0 b
1 1
1 1 b
1 1 b
1 3 b
2 1 a
2 1 b
2 2 a
2 2 b
2 3 c
table type possible_keys key key_len ref rows Extra
t1 index NULL a 18 NULL 11 Using index
a b c
2 3 c
2 2 b
2 2 a
2 1 b
2 1 a
1 3 b
1 1 b
1 1 b
1 1
1 0 b
1 0
table type possible_keys key key_len ref rows Extra
t1 range a a 18 NULL 3 where used; Using index
a b c
1 1 b
1 1 b
table type possible_keys key key_len ref rows Extra
t1 range a a 4 NULL 6 where used; Using index
a b c
1 1 b
1 1 b
1 1
1 0 b
1 0
count(*)
9
a b c
2 3 c
2 2 b
2 2 a
2 1 b
2 1 a
1 3 b
1 1 b
1 1 b
1 1
table type possible_keys key key_len ref rows Extra
t1 range a a 8 NULL 10 where used; Using index
a b c
2 1 b
2 1 a
1 1 b
1 1 b
1 1
1 0 b
1 0
table type possible_keys key key_len ref rows Extra
t1 range a a 4 NULL 5 where used; Using index
a b c
1 3 b
1 1 b
1 1 b
1 1 NULL
table type possible_keys key key_len ref rows Extra
t1 range a a 9 NULL 7 where used; Using index
a b c
2 1 c
2 1 b
2 1 a
2 0 b
2 0 a
1 1 b
1 1 b
1 1 NULL
table type possible_keys key key_len ref rows Extra
t1 range a a 4 NULL 4 where used; Using index
a b c
1 1 b
1 1 b
1 1 NULL
1 NULL b
1 NULL NULL
1 1
1 0 b
1 0

43
mysql-test/t/order_by.test
View File

@ -168,8 +168,8 @@ drop table t1,t2,t3;
#bug reported by Wouter de Jong
drop table if exists members;
CREATE TABLE members (
drop table if exists t1;
CREATE TABLE t1 (
member_id int(11) NOT NULL auto_increment,
inschrijf_datum varchar(20) NOT NULL default '',
lastchange_datum varchar(20) NOT NULL default '',
@ -200,24 +200,51 @@ CREATE TABLE members (
PRIMARY KEY (member_id)
) TYPE=MyISAM PACK_KEYS=1;
insert into members (member_id) values (1),(2),(3);
select member_id, nickname, voornaam FROM members
insert into t1 (member_id) values (1),(2),(3);
select member_id, nickname, voornaam FROM t1
ORDER by lastchange_datum DESC LIMIT 2;
drop table members;
drop table t1;
#
# Test optimization of ORDER BY DESC
#
create table t1 (a int not null, b int, c varchar(10), key (a, b, c));
insert into t1 values (1, NULL, NULL), (1, NULL, 'b'), (1, 1, NULL), (1, 1, 'b'), (1, 1, 'b'), (2, 0, 'a'), (2, 0, 'b'), (2, 1, 'a'), (2, 1, 'b'), (2, 1, 'c');
insert into t1 values (1, NULL, NULL), (1, NULL, 'b'), (1, 1, NULL), (1, 1, 'b'), (1, 1, 'b'), (2, 1, 'a'), (2, 1, 'b'), (2, 2, 'a'), (2, 2, 'b'), (2, 3, 'c'),(1,3,'b');
explain select * from t1 where (a = 1 and b is null and c = 'b') or (a > 2) order by a desc;
select * from t1 where (a = 1 and b is null and c = 'b') or (a > 2) order by a desc;
explain select * from t1 where a >= 1 and a < 3 order by a desc;
select * from t1 where a >= 1 and a < 3 order by a desc;
explain select * from t1 where a = 1 order by a desc, b desc;
select * from t1 where a = 1 order by a desc, b desc;
explain select * from t1 where a = 1 and b is null order by a desc, b desc;
select * from t1 where a = 1 and b is null order by a desc, b desc;
explain select * from t1 where a >= 1 and a < 3 and b >0 order by a desc,b desc;
explain select * from t1 where a = 2 and b >0 order by a desc,b desc;
explain select * from t1 where a = 2 and b is null order by a desc,b desc;
explain select * from t1 where a = 2 and (b is null or b > 0) order by a
desc,b desc;
explain select * from t1 where a = 2 and b > 0 order by a desc,b desc;
explain select * from t1 where a = 2 and b < 2 order by a desc,b desc;
#
# Test things when we don't have NULL keys
#
alter table t1 modify b int not null, modify c varchar(10) not null;
explain select * from t1 order by a, b, c;
select * from t1 order by a, b, c;
explain select * from t1 order by a desc, b desc, c desc;
select * from t1 order by a desc, b desc, c desc;
# test multiple ranges, NO_MAX_RANGE and EQ_RANGE
explain select * from t1 where (a = 1 and b is null and c = 'b') or (a > 2) order by a desc;
explain select * from t1 where (a = 1 and b = 1 and c = 'b') or (a > 2) order by a desc;
select * from t1 where (a = 1 and b = 1 and c = 'b') or (a > 2) order by a desc;
# test NEAR_MAX, NO_MIN_RANGE
explain select * from t1 where a < 2 and b <= 1 order by a desc, b desc;
select * from t1 where a < 2 and b <= 1 order by a desc, b desc;
select count(*) from t1 where a < 5 and b > 0;
select * from t1 where a < 5 and b > 0 order by a desc,b desc;
# test HA_READ_AFTER_KEY (at the end of the file), NEAR_MIN
explain select * from t1 where a between 1 and 3 and b <= 1 order by a desc, b desc;
select * from t1 where a between 1 and 3 and b <= 1 order by a desc, b desc;
@ -226,4 +253,4 @@ explain select * from t1 where a between 0 and 1 order by a desc, b desc;
select * from t1 where a between 0 and 1 order by a desc, b desc;
drop table t1;
/* vim:set ft=sql sw=2 noet: */