database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00
Code Activity

Optimisation if simple IN subselect with primary index

Browse Source 
(SCRUM) (part of WL#818)


mysql-test/r/subselect.result:
  test of new optimisation
mysql-test/t/subselect.test:
  test of new optimisation
sql/item_subselect.cc:
  new engine for simple IN with primary index
sql/item_subselect.h:
  new engine for simple IN with primary index
sql/sql_lex.h:
  fixed typo
sql/sql_select.cc:
  engine changing
  report_error can't be static, because it used in new engine
sql/sql_select.h:
  new JT_ type (just for information in EXPLAIN statement)
  report_error can't be static, because it used in new engine
This commit is contained in:
unknown
2003-07-07 18:40:19 +03:00
parent 2cd6d8ec6b
commit 923dba86b1
7 changed files with 177 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
sql/item_subselect.h
View File

@ -48,7 +48,12 @@ protected:
bool have_to_be_excluded;
public:
/* changed engine indicator */
bool engine_changed;
enum trans_res {OK, REDUCE, ERROR};
enum subs_type {UNKNOWN_SUBS, SINGLEROW_SUBS,
EXISTS_SUBS, IN_SUBS, ALLANY_SUBS};
Item_subselect();
Item_subselect(Item_subselect *item)
@ -59,9 +64,12 @@ public:
max_columns= item->max_columns;
engine= item->engine;
engine_owner= 0;
engine_changed= item->engine_changed;
name= item->name;
}
virtual subs_type substype() { return UNKNOWN_SUBS; }
/*
We need this method, because some compilers do not allow 'this'
pointer in constructor initialization list, but we need pass pointer
@ -95,6 +103,12 @@ public:
else
str->append("-subselect-");
}
bool change_engine(subselect_engine *eng)
{
engine= eng;
engine_changed= 1;
return eng == 0;
}
friend class select_subselect;
friend class Item_in_optimizer;
@ -116,6 +130,9 @@ public:
max_length= item->max_length;
decimals= item->decimals;
}
subs_type substype() { return SINGLEROW_SUBS; }
void reset();
trans_res select_transformer(JOIN *join);
void store(uint i, Item* item);
@ -152,6 +169,7 @@ public:
}
Item_exists_subselect(): Item_subselect() {}
subs_type substype() { return EXISTS_SUBS; }
void reset()
{
value= 0;
@ -165,6 +183,7 @@ public:
void fix_length_and_dec();
friend class select_exists_subselect;
friend class subselect_simplein_engine;
};
/* IN subselect */
@ -185,6 +204,8 @@ public:
Item_in_subselect(THD *thd, Item * left_expr, st_select_lex *select_lex);
Item_in_subselect(Item_in_subselect *item);
Item_in_subselect(): Item_exists_subselect(), abort_on_null(0) {}
subs_type substype() { return IN_SUBS; }
void reset()
{
value= 0;
@ -218,6 +239,7 @@ public:
Item_allany_subselect(THD *thd, Item * left_expr, compare_func_creator f,
st_select_lex *select_lex);
Item_allany_subselect(Item_allany_subselect *item);
subs_type substype() { return ALLANY_SUBS; }
trans_res select_transformer(JOIN *join);
};
@ -288,3 +310,24 @@ public:
bool uncacheable();
void exclude();
};
struct st_join_table;
class subselect_simplein_engine: public subselect_engine
{
st_join_table *tab;
Item *cond;
public:
subselect_simplein_engine(THD *thd, st_join_table *tab_arg,
Item_subselect *subs, Item *where)
:subselect_engine(thd, subs, 0), tab(tab_arg), cond(where)
{}
int prepare();
void fix_length_and_dec(Item_cache** row);
int exec();
uint cols() { return 1; }
bool dependent() { return 1; }
bool uncacheable() { return 1; }
void exclude();
};