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avoid null check on fields where NULL is impossible

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(BUG#2393)


mysql-test/r/subselect.result:
  BUG#2393 test suite
  test ref replaced ref_of_null joining
mysql-test/t/subselect.test:
  BUG#2393 test suite
  test ref replaced ref_of_null joining
sql/item_subselect.cc:
  avoid null check on fields where NULL is impossible
sql/sql_select.cc:
  convert JT_REF_OR_NULL to JT_REF in case of impossible NULL and protect buffer of rewriting through join_tab->null_ref_key
This commit is contained in:
unknown
2004-02-02 02:23:53 +02:00
parent 150c99dffe
commit ecfaa75221
4 changed files with 81 additions and 5 deletions
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56
mysql-test/r/subselect.result
View File

@ -1625,3 +1625,59 @@ PIPPO
1
NULL
DROP TABLE t1, t2;
create table t1 (id int not null, text varchar(20) not null default '', primary key (id));
insert into t1 (id, text) values (1, 'text1'), (2, 'text2'), (3, 'text3'), (4, 'text4'), (5, 'text5'), (6, 'text6'), (7, 'text7'), (8, 'text8'), (9, 'text9'), (10, 'text10'), (11, 'text11'), (12, 'text12');
select * from t1 where id not in (select id from t1 where id < 8);
id text
8 text8
9 text9
10 text10
11 text11
12 text12
select * from t1 as tt where not exists (select id from t1 where id < 8 and (id = tt.id or id is null) having id is not null);
id text
8 text8
9 text9
10 text10
11 text11
12 text12
explain extended select * from t1 where id not in (select id from t1 where id < 8);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 12 Using where
2 DEPENDENT SUBQUERY t1 unique_subquery PRIMARY PRIMARY 4 func 1 Using index; Using where
Warnings:
Note 1003 select high_priority test.t1.id AS `id`,test.t1.text AS `text` from test.t1 where not(<in_optimizer>(test.t1.id,<exists>(<primary_index_lookup>(<cache>(test.t1.id) in t1 on PRIMARY where (test.t1.id < 8)))))
explain extended select * from t1 as tt where not exists (select id from t1 where id < 8 and (id = tt.id or id is null) having id is not null);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY tt ALL NULL NULL NULL NULL 12 Using where
2 DEPENDENT SUBQUERY t1 eq_ref PRIMARY PRIMARY 4 test.tt.id 7 Using where; Using index
Warnings:
Note 1275 Field or reference 'tt.id' of SELECT #2 was resolved in SELECT #1
Note 1003 select high_priority test.tt.id AS `id`,test.tt.text AS `text` from test.t1 tt where not(exists(select test.t1.id AS `id` from test.t1 where ((test.t1.id < 8) and ((test.t1.id = test.tt.id) or isnull(test.t1.id))) having (test.t1.id is not null) limit 1))
insert into t1 (id, text) values (1000, 'text1000'), (1001, 'text1001');
create table t2 (id int not null, text varchar(20) not null default '', primary key (id));
insert into t2 (id, text) values (1, 'text1'), (2, 'text2'), (3, 'text3'), (4, 'text4'), (5, 'text5'), (6, 'text6'), (7, 'text7'), (8, 'text8'), (9, 'text9'), (10, 'text10'), (11, 'text1'), (12, 'text2'), (13, 'text3'), (14, 'text4'), (15, 'text5'), (16, 'text6'), (17, 'text7'), (18, 'text8'), (19, 'text9'), (20, 'text10'),(21, 'text1'), (22, 'text2'), (23, 'text3'), (24, 'text4'), (25, 'text5'), (26, 'text6'), (27, 'text7'), (28, 'text8'), (29, 'text9'), (30, 'text10'), (31, 'text1'), (32, 'text2'), (33, 'text3'), (34, 'text4'), (35, 'text5'), (36, 'text6'), (37, 'text7'), (38, 'text8'), (39, 'text9'), (40, 'text10'), (41, 'text1'), (42, 'text2'), (43, 'text3'), (44, 'text4'), (45, 'text5'), (46, 'text6'), (47, 'text7'), (48, 'text8'), (49, 'text9'), (50, 'text10');
select * from t1 a left join t2 b on (a.id=b.id or b.id is null) join t1 c on (if(isnull(b.id), 1000, b.id)=c.id);
id text id text id text
1 text1 1 text1 1 text1
2 text2 2 text2 2 text2
3 text3 3 text3 3 text3
4 text4 4 text4 4 text4
5 text5 5 text5 5 text5
6 text6 6 text6 6 text6
7 text7 7 text7 7 text7
8 text8 8 text8 8 text8
9 text9 9 text9 9 text9
10 text10 10 text10 10 text10
11 text11 11 text1 11 text11
12 text12 12 text2 12 text12
1000 text1000 NULL NULL 1000 text1000
1001 text1001 NULL NULL 1000 text1000
explain extended select * from t1 a left join t2 b on (a.id=b.id or b.id is null) join t1 c on (if(isnull(b.id), 1000, b.id)=c.id);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE a ALL NULL NULL NULL NULL 14
1 SIMPLE b eq_ref PRIMARY PRIMARY 4 test.a.id 2
1 SIMPLE c eq_ref PRIMARY PRIMARY 4 func 1 Using where
Warnings:
Note 1003 select high_priority test.a.id AS `id`,test.a.text AS `text`,test.b.id AS `id`,test.b.text AS `text`,test.c.id AS `id`,test.c.text AS `text` from test.t1 a left join test.t2 b on(((test.a.id = test.b.id) or isnull(test.b.id))) join test.t1 c where (if(isnull(test.b.id),1000,test.b.id) = test.c.id)
drop table t1,t2;

16
mysql-test/t/subselect.test
View File

@ -1075,3 +1075,19 @@ s.id_cns = cns.id ORDER BY s.anno_dep DESC LIMIT 1) AS PIPPO FROM
t2 AS cns;
DROP TABLE t1, t2;
#
# ref_or_null replacing with ref
#
create table t1 (id int not null, text varchar(20) not null default '', primary key (id));
insert into t1 (id, text) values (1, 'text1'), (2, 'text2'), (3, 'text3'), (4, 'text4'), (5, 'text5'), (6, 'text6'), (7, 'text7'), (8, 'text8'), (9, 'text9'), (10, 'text10'), (11, 'text11'), (12, 'text12');
select * from t1 where id not in (select id from t1 where id < 8);
select * from t1 as tt where not exists (select id from t1 where id < 8 and (id = tt.id or id is null) having id is not null);
explain extended select * from t1 where id not in (select id from t1 where id < 8);
explain extended select * from t1 as tt where not exists (select id from t1 where id < 8 and (id = tt.id or id is null) having id is not null);
insert into t1 (id, text) values (1000, 'text1000'), (1001, 'text1001');
create table t2 (id int not null, text varchar(20) not null default '', primary key (id));
insert into t2 (id, text) values (1, 'text1'), (2, 'text2'), (3, 'text3'), (4, 'text4'), (5, 'text5'), (6, 'text6'), (7, 'text7'), (8, 'text8'), (9, 'text9'), (10, 'text10'), (11, 'text1'), (12, 'text2'), (13, 'text3'), (14, 'text4'), (15, 'text5'), (16, 'text6'), (17, 'text7'), (18, 'text8'), (19, 'text9'), (20, 'text10'),(21, 'text1'), (22, 'text2'), (23, 'text3'), (24, 'text4'), (25, 'text5'), (26, 'text6'), (27, 'text7'), (28, 'text8'), (29, 'text9'), (30, 'text10'), (31, 'text1'), (32, 'text2'), (33, 'text3'), (34, 'text4'), (35, 'text5'), (36, 'text6'), (37, 'text7'), (38, 'text8'), (39, 'text9'), (40, 'text10'), (41, 'text1'), (42, 'text2'), (43, 'text3'), (44, 'text4'), (45, 'text5'), (46, 'text6'), (47, 'text7'), (48, 'text8'), (49, 'text9'), (50, 'text10');
select * from t1 a left join t2 b on (a.id=b.id or b.id is null) join t1 c on (if(isnull(b.id), 1000, b.id)=c.id);
explain extended select * from t1 a left join t2 b on (a.id=b.id or b.id is null) join t1 c on (if(isnull(b.id), 1000, b.id)=c.id);
drop table t1,t2;