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new optimisation for ref_null (SCRUM) (WL#818)

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This commit is contained in:
bell@sanja.is.com.ua 2003-07-17 19:39:31 +03:00
parent d9b108c12f
commit 7e34954b5e
8 changed files with 90 additions and 32 deletions
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15
mysql-test/r/subselect.result
View File

@ -828,8 +828,21 @@ a t1.a in (select t2.a from t2)
explain SELECT t1.a, t1.a in (select t2.a from t2) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 index NULL PRIMARY 4 NULL 4 Using index
2 DEPENDENT SUBQUERY t2 index_in a a 5 const 2 Using where; Using index
CREATE TABLE t3 (a int(11) default '0');
INSERT INTO t3 VALUES (1),(2),(3);
SELECT t1.a, t1.a in (select t2.a from t2,t3 where t3.a=t2.a) FROM t1;
a t1.a in (select t2.a from t2,t3 where t3.a=t2.a)
1 1
2 1
3 1
4 0
explain SELECT t1.a, t1.a in (select t2.a from t2,t3 where t3.a=t2.a) FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 index NULL PRIMARY 4 NULL 4 Using index
2 DEPENDENT SUBQUERY t2 ref_or_null a a 5 const 2 Using where; Using index
drop table t1,t2;
2 DEPENDENT SUBQUERY t3 ALL NULL NULL NULL NULL 3 Using where
drop table t1,t2,t3;
create table t1 (a float);
select 10.5 IN (SELECT * from t1 LIMIT 1);
ERROR 42000: This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'

6
mysql-test/t/subselect.test
View File

@ -469,7 +469,11 @@ INSERT INTO t1 VALUES (1),(2),(3),(4);
INSERT INTO t2 VALUES (1),(2),(3);
SELECT t1.a, t1.a in (select t2.a from t2) FROM t1;
explain SELECT t1.a, t1.a in (select t2.a from t2) FROM t1;
drop table t1,t2;
CREATE TABLE t3 (a int(11) default '0');
INSERT INTO t3 VALUES (1),(2),(3);
SELECT t1.a, t1.a in (select t2.a from t2,t3 where t3.a=t2.a) FROM t1;
explain SELECT t1.a, t1.a in (select t2.a from t2,t3 where t3.a=t2.a) FROM t1;
drop table t1,t2,t3;
#LIMIT is not supported now
create table t1 (a float);

1
sql/item_cmpfunc.h
View File

@ -669,6 +669,7 @@ public:
Item_is_not_null_test(Item_in_subselect* ow, Item *a)
:Item_func_isnull(a), owner(ow)
{}
enum Functype functype() const { return ISNOTNULLTEST_FUNC; }
longlong val_int();
const char *func_name() const { return "is_not_null_test"; }
void update_used_tables();

2
sql/item_func.h
View File

@ -41,7 +41,7 @@ public:
GE_FUNC,GT_FUNC,FT_FUNC,
LIKE_FUNC,NOTLIKE_FUNC,ISNULL_FUNC,ISNOTNULL_FUNC,
COND_AND_FUNC, COND_OR_FUNC, COND_XOR_FUNC, BETWEEN, IN_FUNC,
INTERVAL_FUNC,
INTERVAL_FUNC, ISNOTNULLTEST_FUNC,
SP_EQUALS_FUNC, SP_DISJOINT_FUNC,SP_INTERSECTS_FUNC,
SP_TOUCHES_FUNC,SP_CROSSES_FUNC,SP_WITHIN_FUNC,
SP_CONTAINS_FUNC,SP_OVERLAPS_FUNC,

22
sql/item_subselect.cc
View File

@ -999,8 +999,15 @@ int subselect_indexin_engine::exec()
DBUG_ENTER("subselect_indexin_engine::exec");
int error;
TABLE *table= tab->table;
((Item_in_subselect *) item)->value= 0;
if ((tab->ref.key_err= (*tab->ref.key_copy)->copy()))
if (check_null)
{
*tab->null_ref_key= 0;
((Item_in_subselect *) item)->was_null= 0;
}
if ((*tab->ref.key_copy) && (tab->ref.key_err= (*tab->ref.key_copy)->copy()))
{
table->status= STATUS_NOT_FOUND;
error= -1;
@ -1022,12 +1029,21 @@ int subselect_indexin_engine::exec()
{
if (!cond || cond->val_int())
{
((Item_in_subselect *) item)->value= 1;
if (check_null && *tab->null_ref_key)
((Item_in_subselect *) item)->was_null= 1;
else
((Item_in_subselect *) item)->value= 1;
goto finish;
}
}
else
goto finish;
{
if (!check_null || *tab->null_ref_key)
goto finish;
*tab->null_ref_key= 1;
if (safe_index_read(tab))
goto finish;
}
error= table->file->index_next_same(table->record[0],
tab->ref.key_buff,
tab->ref.key_length);

8
sql/item_subselect.h
View File

@ -228,6 +228,7 @@ public:
friend class Item_asterisk_remover;
friend class Item_ref_null_helper;
friend class Item_is_not_null_test;
friend class subselect_indexin_engine;
};
/* ALL/ANY/SOME subselect */
@ -337,10 +338,13 @@ public:
class subselect_indexin_engine: public subselect_simplein_engine
{
bool check_null;
public:
subselect_indexin_engine(THD *thd, st_join_table *tab_arg,
Item_subselect *subs, Item *where)
:subselect_simplein_engine(thd, tab_arg, subs, where)
Item_subselect *subs, Item *where,
bool chk_null)
:subselect_simplein_engine(thd, tab_arg, subs, where),
check_null(chk_null)
{}
int exec();
};

67
sql/sql_select.cc
View File

@ -456,7 +456,7 @@ err:
bool JOIN::test_in_subselect(Item **where)
{
if (conds->type() == Item::FUNC_ITEM &&
((class Item_func *)this->conds)->functype() == Item_func::EQ_FUNC &&
((Item_func *)this->conds)->functype() == Item_func::EQ_FUNC &&
((Item_func *)conds)->arguments()[0]->type() == Item::REF_ITEM &&
((Item_func *)conds)->arguments()[1]->type() == Item::FIELD_ITEM)
{
@ -763,38 +763,57 @@ JOIN::optimize()
/*
is this simple IN subquery?
*/
if (!group_list && !order && !having &&
if (!group_list && !order &&
unit->item && unit->item->substype() == Item_subselect::IN_SUBS &&
tables == 1 && conds &&
!unit->first_select()->next_select())
{
Item *where= 0;
if (join_tab[0].type == JT_EQ_REF)
if (!having)
{
if (test_in_subselect(&where))
Item *where= 0;
if (join_tab[0].type == JT_EQ_REF)
{
join_tab[0].type= JT_SIMPLE_IN;
error= 0;
DBUG_RETURN(unit->item->
change_engine(new subselect_simplein_engine(thd, join_tab,
unit->item,
where)));
if (test_in_subselect(&where))
{
join_tab[0].type= JT_SIMPLE_IN;
error= 0;
DBUG_RETURN(unit->item->
change_engine(new subselect_simplein_engine(thd,
join_tab,
unit->item,
where)));
}
}
}
else if (join_tab[0].type == JT_REF)
else if (join_tab[0].type == JT_REF)
{
if (test_in_subselect(&where))
{
join_tab[0].type= JT_INDEX_IN;
error= 0;
DBUG_RETURN(unit->item->
change_engine(new subselect_indexin_engine(thd,
join_tab,
unit->item,
where,
0)));
}
}
} else if (join_tab[0].type == JT_REF_OR_NULL &&
having->type() == Item::FUNC_ITEM &&
((Item_func *) having)->functype() ==
Item_func::ISNOTNULLTEST_FUNC)
{
if (test_in_subselect(&where))
{
join_tab[0].type= JT_INDEX_IN;
error= 0;
DBUG_RETURN(unit->item->
change_engine(new subselect_indexin_engine(thd, join_tab,
unit->item,
where)));
}
join_tab[0].type= JT_INDEX_IN;
error= 0;
DBUG_RETURN(unit->item->
change_engine(new subselect_indexin_engine(thd,
join_tab,
unit->item,
conds,
1)));
}
}
/*
Need to tell Innobase that to play it safe, it should fetch all
columns of the tables: this is because MySQL may build row
@ -5445,7 +5464,7 @@ int report_error(TABLE *table, int error)
}
static int safe_index_read(JOIN_TAB *tab)
int safe_index_read(JOIN_TAB *tab)
{
int error;
TABLE *table= tab->table;

1
sql/sql_select.h
View File

@ -411,3 +411,4 @@ bool cp_buffer_from_ref(TABLE_REF *ref);
bool error_if_full_join(JOIN *join);
void relink_tables(SELECT_LEX *select_lex);
int report_error(TABLE *table, int error);
int safe_index_read(JOIN_TAB *tab);