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Fix for BUG#13455: Make "ref" optimizer able to make this inference:

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"t.key BETWEEN c1 AND c2" and c1 = c2 -> can access table t using "t.key = c1".
This commit is contained in:
sergefp@mysql.com
2005-09-30 01:34:19 +04:00
parent acdc193a45
commit 71d8990f8e
6 changed files with 88 additions and 20 deletions
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8
mysql-test/r/heap.result
View File

@@ -379,10 +379,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL v NULL NULL NULL 271 Using where
explain select count(*) from t1 where v between 'a' and 'a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL v NULL NULL NULL 271 Using where
1 SIMPLE t1 ref v v 13 const 10 Using where
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL v NULL NULL NULL 271 Using where
1 SIMPLE t1 ref v v 13 const 10 Using where
alter table t1 add unique(v);
ERROR 23000: Duplicate entry '{ ' for key 1
select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a' order by length(concat('*',v,'*',c,'*',t,'*'));
@@ -602,10 +602,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 13 NULL # Using where
explain select count(*) from t1 where v between 'a' and 'a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 13 NULL # Using where
1 SIMPLE t1 ref v v 13 const # Using where
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 13 NULL # Using where
1 SIMPLE t1 ref v v 13 const # Using where
alter table t1 add unique(v);
ERROR 23000: Duplicate entry '{ ' for key 1
select concat('*',v,'*',c,'*',t,'*') as qq from t1 where v='a' order by length(concat('*',v,'*',c,'*',t,'*'));

12
mysql-test/r/innodb.result
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@@ -1997,10 +1997,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 13 NULL # Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 13 NULL # Using where; Using index
1 SIMPLE t1 ref v v 13 const # Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 13 NULL # Using where; Using index
1 SIMPLE t1 ref v v 13 const # Using where; Using index
alter table t1 add unique(v);
ERROR 23000: Duplicate entry '{ ' for key 1
alter table t1 add key(v);
@@ -2188,10 +2188,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 303 NULL # Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 303 NULL # Using where; Using index
1 SIMPLE t1 ref v v 303 const # Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 303 NULL # Using where; Using index
1 SIMPLE t1 ref v v 303 const # Using where; Using index
explain select * from t1 where v='a';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref v v 303 const # Using where
@@ -2268,10 +2268,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 33 NULL # Using where
explain select count(*) from t1 where v between 'a' and 'a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 33 NULL # Using where
1 SIMPLE t1 ref v v 33 const # Using where
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 33 NULL # Using where
1 SIMPLE t1 ref v v 33 const # Using where
explain select * from t1 where v='a';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref v v 33 const # Using where

12
mysql-test/r/myisam.result
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@@ -802,10 +802,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 13 NULL # Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 13 NULL # Using where; Using index
1 SIMPLE t1 ref v v 13 const # Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 13 NULL # Using where; Using index
1 SIMPLE t1 ref v v 13 const # Using where; Using index
alter table t1 add unique(v);
ERROR 23000: Duplicate entry '{ ' for key 1
alter table t1 add key(v);
@@ -993,10 +993,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 303 NULL # Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 303 NULL # Using where; Using index
1 SIMPLE t1 ref v v 303 const # Using where; Using index
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 303 NULL # Using where; Using index
1 SIMPLE t1 ref v v 303 const # Using where; Using index
explain select * from t1 where v='a';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref v v 303 const # Using where
@@ -1073,10 +1073,10 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 33 NULL # Using where
explain select count(*) from t1 where v between 'a' and 'a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 33 NULL # Using where
1 SIMPLE t1 ref v v 33 const # Using where
explain select count(*) from t1 where v between 'a' and 'a ' and v between 'a ' and 'b\n';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range v v 33 NULL # Using where
1 SIMPLE t1 ref v v 33 const # Using where
explain select * from t1 where v='a';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref v v 33 const # Using where

25
mysql-test/r/range.result
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@@ -1,4 +1,4 @@
drop table if exists t1, t2;
drop table if exists t1, t2, t3;
CREATE TABLE t1 (
event_date date DEFAULT '0000-00-00' NOT NULL,
type int(11) DEFAULT '0' NOT NULL,
@@ -787,3 +787,26 @@ id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 range PRIMARY PRIMARY 8 NULL # Using where; Using index
drop view v1;
drop table t1;
create table t3 (a int);
insert into t3 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (a varchar(10), filler char(200), key(a)) charset=binary;
insert into t1 values ('a','');
insert into t1 values ('a ','');
insert into t1 values ('a ', '');
insert into t1 select concat('a', 1000 + A.a + 10 * (B.a + 10 * C.a)), ''
from t3 A, t3 B, t3 C;
create table t2 (a varchar(10), filler char(200), key(a));
insert into t2 select * from t1;
explain select * from t1 where a between 'a' and 'a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 13 NULL # Using where
explain select * from t1 where a = 'a' or a='a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 13 NULL # Using where
explain select * from t2 where a between 'a' and 'a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref a a 13 const # Using where
explain select * from t2 where a = 'a' or a='a ';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref a a 13 const # Using where
drop table t1,t2,t3;

28
mysql-test/t/range.test
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@@ -3,7 +3,7 @@
#
--disable_warnings
drop table if exists t1, t2;
drop table if exists t1, t2, t3;
--enable_warnings
CREATE TABLE t1 (
@@ -600,3 +600,29 @@ explain select * from v1 where a between 3 and 4 and b between 1 and 2;
drop view v1;
drop table t1;
# BUG#13455:
create table t3 (a int);
insert into t3 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (a varchar(10), filler char(200), key(a)) charset=binary;
insert into t1 values ('a','');
insert into t1 values ('a ','');
insert into t1 values ('a ', '');
insert into t1 select concat('a', 1000 + A.a + 10 * (B.a + 10 * C.a)), ''
from t3 A, t3 B, t3 C;
create table t2 (a varchar(10), filler char(200), key(a));
insert into t2 select * from t1;
--replace_column 9 #
explain select * from t1 where a between 'a' and 'a ';
--replace_column 9 #
explain select * from t1 where a = 'a' or a='a ';
--replace_column 9 #
explain select * from t2 where a between 'a' and 'a ';
--replace_column 9 #
explain select * from t2 where a = 'a' or a='a ';
drop table t1,t2,t3;

21
sql/sql_select.cc
View File

@@ -2409,6 +2409,7 @@ add_key_field(KEY_FIELD **key_fields,uint and_level, Item_func *cond,
!field->table->maybe_null || field->null_ptr)
return; // Not a key. Skip it
exists_optimize= KEY_OPTIMIZE_EXISTS;
DBUG_ASSERT(num_values == 1);
}
else
{
@@ -2460,7 +2461,26 @@ add_key_field(KEY_FIELD **key_fields,uint and_level, Item_func *cond,
eq_func is NEVER true when num_values > 1
*/
if (!eq_func)
{
/*
Additional optimization: if we're processing
"t.key BETWEEN c1 AND c1" then proceed as if we were processing
"t.key = c1".
TODO: This is a very limited fix. A more generic fix is possible.
There are 2 options:
A) Make equality propagation code be able to handle BETWEEN
(including cases like t1.key BETWEEN t2.key AND t3.key)
B) Make range optimizer to infer additional "t.key = c" equalities
and use them in equality propagation process (see details in
OptimizerKBAndTodo)
*/
if ((cond->functype() == Item_func::BETWEEN) &&
value[0]->eq(value[1], field->binary()))
eq_func= TRUE;
else
return;
}
if (field->result_type() == STRING_RESULT)
{
if ((*value)->result_type() != STRING_RESULT)
@@ -2487,7 +2507,6 @@ add_key_field(KEY_FIELD **key_fields,uint and_level, Item_func *cond,
}
}
}
DBUG_ASSERT(num_values == 1);
/*
For the moment eq_func is always true. This slot is reserved for future
extensions where we want to remembers other things than just eq comparisons