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Commit 71f6ab7a authored by igor@rurik.mysql.com's avatar igor@rurik.mysql.com
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Merge for Item_equal.

parents 80d2d8d6 0dcc255b
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Showing with 1658 additions and 138 deletions
.bzrignore
View file @ 71f6ab7a
......@@ -508,6 +508,7 @@ mysql-test/install_test_db
mysql-test/mysql-test-run
mysql-test/ndb/ndbcluster
mysql-test/r/*.reject
mysql-test/r/index_merge_load.result
mysql-test/r/rpl000001.eval
mysql-test/r/rpl000002.eval
mysql-test/r/rpl000014.eval
......@@ -518,6 +519,7 @@ mysql-test/r/slave-running.eval
mysql-test/r/slave-stopped.eval
mysql-test/share/mysql
mysql-test/std_data/*.pem
mysql-test/t/index_merge.load
mysql-test/var/*
mysql.kdevprj
mysql.proj
......
mysql-test/r/func_group.result
View file @ 71f6ab7a
......@@ -476,7 +476,7 @@ CHI Los Angeles
explain
select max(a3) from t1 where a2 is null and a2 = 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
select max(a3) from t1 where a2 is null and a2 = 2;
max(a3)
NULL
......
mysql-test/r/func_test.result
View file @ 71f6ab7a
......@@ -77,7 +77,7 @@ select * from t1 where 1 xor 1;
a
explain extended select * from t1 where 1 xor 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
Warnings:
Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` where (1 xor 1)
select - a from t1;
......
mysql-test/r/index_merge.result
View file @ 71f6ab7a
......@@ -76,13 +76,13 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL i1,i2 NULL NULL NULL 1024 Using where
explain select * from t0 where key2 = 45 or key1 is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 range i1,i2 i2 4 NULL 1 Using where
1 SIMPLE t0 ref i2 i2 4 const 1
explain select * from t0 where key2=10 or key3=3 or key4 <=> null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 index_merge i2,i3,i4 i2,i3 4,4 NULL 2 Using union(i2,i3); Using where
explain select * from t0 where key2=10 or key3=3 or key4 is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 index_merge i2,i3,i4 i2,i3 4,4 NULL 2 Using union(i2,i3); Using where
1 SIMPLE t0 index_merge i2,i3 i2,i3 4,4 NULL 2 Using where
explain select key1 from t0 where (key1 <=> null) or (key2 < 5) or
(key3=10) or (key4 <=> null);
id select_type table type possible_keys key key_len ref rows Extra
......
mysql-test/r/odbc.result
View file @ 71f6ab7a
......@@ -12,5 +12,5 @@ select * from t1 where a is null;
a b
explain select * from t1 where b is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
drop table t1;
mysql-test/r/range.result
View file @ 71f6ab7a
......@@ -220,24 +220,22 @@ insert into t1 (x) values (1),(2),(3),(4),(5),(6),(7),(8),(9);
update t1 set y=x;
explain select * from t1, t1 t2 where t1.y = 2 and t2.x between 7 and t1.y+0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
1 SIMPLE t2 range x x 5 NULL 4 Using where
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
explain select * from t1, t1 t2 where t1.y = 2 and t2.x >= 7 and t2.x <= t1.y+0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
1 SIMPLE t2 range x x 5 NULL 4 Using where
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
explain select * from t1, t1 t2 where t1.y = 2 and t2.x between t1.y-1 and t1.y+1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
1 SIMPLE t2 ALL x NULL NULL NULL 9 Range checked for each record (index map: 0x1)
1 SIMPLE t2 range x x 5 NULL 3 Using where
explain select * from t1, t1 t2 where t1.y = 2 and t2.x >= t1.y-1 and t2.x <= t1.y+1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
1 SIMPLE t2 ALL x NULL NULL NULL 9 Range checked for each record (index map: 0x1)
1 SIMPLE t2 range x x 5 NULL 3 Using where
explain select * from t1, t1 t2 where t1.y = 2 and t2.x between 0 and t1.y;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
1 SIMPLE t2 ALL x NULL NULL NULL 9 Using where
1 SIMPLE t2 range x x 5 NULL 2 Using where
explain select * from t1, t1 t2 where t1.y = 2 and t2.x >= 0 and t2.x <= t1.y;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref y y 5 const 1 Using where
......@@ -415,14 +413,26 @@ count(*)
select count(*) from t2;
count(*)
1026
analyze table t1,t2;
Table Op Msg_type Msg_text
test.t1 analyze status OK
test.t2 analyze status Table is already up to date
explain select * from t1, t2 where t1.uid=t2.uid AND t1.uid > 0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range uid_index uid_index 4 NULL 128 Using where
1 SIMPLE t2 ref uid_index uid_index 4 test.t1.uid 38
explain select * from t1, t2 where t1.uid=t2.uid AND t2.uid > 0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range uid_index uid_index 4 NULL 128 Using where
1 SIMPLE t2 ref uid_index uid_index 4 test.t1.uid 38
explain select * from t1, t2 where t1.uid=t2.uid AND t1.uid != 0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range uid_index uid_index 4 NULL 129 Using where
1 SIMPLE t2 ref uid_index uid_index 4 test.t1.uid 38
explain select * from t1, t2 where t1.uid=t2.uid AND t2.uid != 0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range uid_index uid_index 4 NULL 129 Using where
1 SIMPLE t2 ref uid_index uid_index 4 test.t1.uid 38
select * from t1, t2 where t1.uid=t2.uid AND t1.uid > 0;
id name uid id name uid
1001 A 1 1001 A 1
......
mysql-test/r/select.result
View file @ 71f6ab7a
......@@ -1375,7 +1375,7 @@ id select_type table type possible_keys key key_len ref rows Extra
explain select t2.companynr,companyname from t4 left join t2 using (companynr) where t2.companynr > 0 and t4.companynr > 0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 1199 Using where
1 SIMPLE t4 eq_ref PRIMARY PRIMARY 1 test.t2.companynr 1 Using where
1 SIMPLE t4 eq_ref PRIMARY PRIMARY 1 test.t2.companynr 1
explain select t2.companynr,companyname from t4 left join t2 using (companynr) where t2.companynr > 0 or t2.companynr is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
......
mysql-test/t/range.test
View file @ 71f6ab7a
......@@ -378,8 +378,12 @@ insert into t2(id, uid, name) select id, uid, name from t1;
select count(*) from t1;
select count(*) from t2;
analyze table t1,t2;
explain select * from t1, t2 where t1.uid=t2.uid AND t1.uid > 0;
explain select * from t1, t2 where t1.uid=t2.uid AND t2.uid > 0;
explain select * from t1, t2 where t1.uid=t2.uid AND t1.uid != 0;
explain select * from t1, t2 where t1.uid=t2.uid AND t2.uid != 0;
select * from t1, t2 where t1.uid=t2.uid AND t1.uid > 0;
select * from t1, t2 where t1.uid=t2.uid AND t1.uid != 0;
......
sql/item.cc
View file @ 71f6ab7a
......@@ -408,6 +408,7 @@ bool DTCollation::aggregate(DTCollation &dt, bool superset_conversion)
Item_field::Item_field(Field *f)
:Item_ident(NullS, f->table_name, f->field_name),
item_equal(0),
have_privileges(0), any_privileges(0)
{
set_field(f);
......@@ -418,6 +419,7 @@ Item_field::Item_field(Field *f)
Item_field::Item_field(THD *thd, Field *f)
:Item_ident(NullS, thd->strdup(f->table_name),
thd->strdup(f->field_name)),
item_equal(0),
have_privileges(0), any_privileges(0)
{
set_field(f);
......@@ -434,6 +436,7 @@ Item_field::Item_field(THD *thd, Item_field *item)
any_privileges(item->any_privileges)
{
collation.set(DERIVATION_IMPLICIT);
item_equal= item->item_equal;
}
void Item_field::set_field(Field *field_par)
......@@ -1582,7 +1585,29 @@ void Item_field::cleanup()
I.e. we can drop 'field'.
*/
field= result_field= 0;
DBUG_VOID_RETURN;
}
/*
Find a field among specified multiple equalities
SYNOPSIS
find_item_equal()
cond_equal reference to list of multiple equalities where
the field (this object) is to be looked for
DESCRIPTION
The function first searches the field among multiple equalities
of the current level (in the cond_equal->current_level list).
If it fails, it continues searching in upper levels accessed
through a pointer cond_equal->upper_levels.
The search terminates as soon as a multiple equality containing
the field is found.
RETURN VALUES
First Item_equal containing the field, if success
0, otherwise
*/
}
void Item::init_make_field(Send_field *tmp_field,
......
sql/item.h
View file @ 71f6ab7a
......@@ -90,6 +90,7 @@ public:
};
typedef bool (Item::*Item_processor)(byte *arg);
typedef Item* (Item::*Item_transformer) (byte *arg);
class Item {
Item(const Item &); /* Prevent use of these */
......@@ -261,8 +262,15 @@ public:
return (this->*processor)(arg);
}
virtual Item* transform(Item_transformer transformer, byte *arg)
{
return (this->*transformer)(arg);
}
virtual bool remove_dependence_processor(byte * arg) { return 0; }
virtual bool remove_fixed(byte * arg) { fixed= 0; return 0; }
virtual Item *equal_fields_propagator(byte * arg) { return this; }
virtual bool replace_equal_field_processor(byte * arg) { return 0; }
virtual Item *this_item() { return this; } /* For SPs mostly. */
virtual Item *this_const_item() const { return const_cast<Item*>(this); } /* For SPs mostly. */
......@@ -440,6 +448,8 @@ public:
bool any_privileges, bool allocate_view_names);
};
class Item_equal;
class COND_EQUAL;
class Item_field :public Item_ident
{
......@@ -458,7 +468,8 @@ public:
Item_field(const char *db_par,const char *table_name_par,
const char *field_name_par)
:Item_ident(db_par,table_name_par,field_name_par),
field(0), result_field(0), have_privileges(0), any_privileges(0)
field(0), result_field(0), item_equal(0),}
have_privileges(0), any_privileges(0)
{ collation.set(DERIVATION_IMPLICIT); }
// Constructor need to process subselect with temporary tables (see Item)
Item_field(THD *thd, Item_field *item);
......@@ -498,6 +509,9 @@ public:
bool is_null() { return field->is_null(); }
Item *get_tmp_table_item(THD *thd);
void cleanup();
Item_equal *find_item_equal(COND_EQUAL *cond_equal);
Item *equal_fields_propagator(byte *arg);
bool replace_equal_field_processor(byte *arg);
inline uint32 max_disp_length() { return field->max_length(); }
Item_field *filed_for_view_update() { return this; }
friend class Item_default_value;
......@@ -1173,6 +1187,19 @@ public:
return arg->walk(processor, args) ||
(this->*processor)(args);
}
/*
This method like the walk method traverses the item tree, but
at the same time it can replace some nodes in the tree
*/
Item *transform(Item_transformer transformer, byte *args)
{
Item *new_item= arg->transform(transformer, args);
if (!new_item)
return 0;
arg= new_item;
return (this->*transformer)(args);
}
};
class Item_insert_value : public Item_field
......
sql/item_cmpfunc.cc
View file @ 71f6ab7a
......@@ -256,7 +256,7 @@ void Item_bool_func2::fix_length_and_dec()
}
}
}
if (args[1]->type() == FIELD_ITEM)
if (args[1]->type() == FIELD_ITEM /* && !args[1]->const_item() */)
{
Field *field=((Item_field*) args[1])->field;
if (field->store_for_compare())
......@@ -2008,6 +2008,44 @@ bool Item_cond::walk(Item_processor processor, byte *arg)
return Item_func::walk(processor, arg);
}
/*
Transform an Item_cond object with a transformer callback function
SYNOPSIS
transform()
transformer the transformer callback function to be applied to the nodes
of the tree of the object
arg parameter to be passed to the transformer
DESCRIPTION
The function recursively applies the transform method with the
same transformer to each member item of the codition list.
If the call of the method for a member item returns a new item
the old item is substituted for a new one.
After this the transform method is applied to the root node
of the Item_cond object.
RETURN VALUES
Item returned as the result of transformation of the root node
*/
Item *Item_cond::transform(Item_transformer transformer, byte *arg)
{
List_iterator<Item> li(list);
Item *item;
while ((item= li++))
{
Item *new_item= item->transform(transformer, arg);
if (!new_item)
return 0;
if (new_item != item)
li.replace(new_item);
}
return Item_func::transform(transformer, arg);
}
void Item_cond::split_sum_func(Item **ref_pointer_array, List<Item> &fields)
{
List_iterator<Item> li(list);
......@@ -2854,3 +2892,289 @@ Item *Item_bool_rowready_func2::negated_item()
DBUG_ASSERT(0);
return 0;
}
Item_equal::Item_equal(Item_field *f1, Item_field *f2)
: Item_bool_func(), const_item(0), eval_item(0), cond_false(0)
{
const_item_cache= 0;
fields.push_back(f1);
fields.push_back(f2);
}
Item_equal::Item_equal(Item *c, Item_field *f)
: Item_bool_func(), eval_item(0), cond_false(0)
{
const_item_cache= 0;
fields.push_back(f);
const_item= c;
}
Item_equal::Item_equal(Item_equal *item_equal)
: Item_bool_func(), eval_item(0), cond_false(0)
{
const_item_cache= 0;
List_iterator_fast<Item_field> li(item_equal->fields);
Item_field *item;
while ((item= li++))
{
fields.push_back(item);
}
const_item= item_equal->const_item;
cond_false= item_equal->cond_false;
}
void Item_equal::add(Item *c)
{
if (cond_false)
return;
if (!const_item)
{
const_item= c;
return;
}
Item_func_eq *func= new Item_func_eq(c, const_item);
func->set_cmp_func();
cond_false = !(func->val_int());
}
void Item_equal::add(Item_field *f)
{
fields.push_back(f);
}
uint Item_equal::members()
{
uint count= 0;
List_iterator_fast<Item_field> li(fields);
Item_field *item;
while ((item= li++))
count++;
return count;
}
/*
Check whether a field is referred in the multiple equality
SYNOPSIS
contains()
field field whose occurence is to be checked
DESCRIPTION
The function checks whether field is occured in the Item_equal object
RETURN VALUES
1 if nultiple equality contains a reference to field
0 otherwise
*/
bool Item_equal::contains(Field *field)
{
List_iterator_fast<Item_field> it(fields);
Item_field *item;
while ((item= it++))
{
if (field->eq(item->field))
return 1;
}
return 0;
}
/*
Join members of another Item_equal object
SYNOPSIS
merge()
item multiple equality whose members are to be joined
DESCRIPTION
The function actually merges two multiple equalitis.
After this operation the Item_equal object additionally contains
the field items of another item of the type Item_equal.
If the optional constant items are not equal the cond_false flag is
set to 1.
RETURN VALUES
none
*/
void Item_equal::merge(Item_equal *item)
{
fields.concat(&item->fields);
Item *c= item->const_item;
if (c)
{
/*
The flag cond_false will be set to 1 after this, if
the multiple equality already contains a constant and its
value is not equal to the value of c.
*/
add(const_item);
}
cond_false|= item->cond_false;
}
/*
Order field items in multiple equality according to a sorting criteria
SYNOPSIS
sort()
cmp function to compare field item
arg context extra parameter for the cmp function
DESCRIPTION
The function perform ordering of the field items in the Item_equal
object according to the criteria determined by the cmp callback parameter.
If cmp(item_field1,item_field2,arg)<0 than item_field1 must be
placed after item_fiel2.
IMPLEMENTATION
The function sorts field items by the exchange sort algorithm.
The list of field items is looked through and whenever two neighboring
members follow in a wrong order they are swapped. This is performed
again and again until we get all members in a right order.
RETURN VALUES
None
*/
void Item_equal::sort(Item_field_cmpfunc cmp, void *arg)
{
bool swap;
List_iterator<Item_field> it(fields);
do
{
Item_field *item1= it++;
Item_field **ref1= it.ref();
Item_field *item2;
swap= FALSE;
while ((item2= it++))
{
Item_field **ref2= it.ref();
if (cmp(item1, item2, arg) < 0)
{
Item_field *item= *ref1;
*ref1= *ref2;
*ref2= item;
swap= TRUE;
}
else
{
item1= item2;
ref1= ref2;
}
}
it.rewind();
} while (swap);
}
bool Item_equal::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
{
List_iterator_fast<Item_field> li(fields);
Item *item;
not_null_tables_cache= used_tables_cache= 0;
const_item_cache= 0;
while ((item=li++))
{
table_map tmp_table_map;
used_tables_cache|= item->used_tables();
tmp_table_map= item->not_null_tables();
not_null_tables_cache|= tmp_table_map;
if (item->maybe_null)
maybe_null=1;
}
fix_length_and_dec();
fixed= 1;
return 0;
}
void Item_equal::update_used_tables()
{
List_iterator_fast<Item_field> li(fields);
Item *item;
not_null_tables_cache= used_tables_cache= 0;
if ((const_item_cache= cond_false))
return;
while ((item=li++))
{
item->update_used_tables();
used_tables_cache|= item->used_tables();
const_item_cache&= item->const_item();
}
}
longlong Item_equal::val_int()
{
if (cond_false)
return 0;
List_iterator_fast<Item_field> it(fields);
Item *item= const_item ? const_item : it++;
if ((null_value= item->null_value))
return 0;
eval_item->store_value(item);
while ((item= it++))
{
if ((null_value= item->null_value) || eval_item->cmp(item))
return 0;
}
return 1;
}
void Item_equal::fix_length_and_dec()
{
Item *item= const_item ? const_item : get_first();
eval_item= cmp_item::get_comparator(item);
if (item->result_type() == STRING_RESULT)
eval_item->cmp_charset= cmp_collation.collation;
}
bool Item_equal::walk(Item_processor processor, byte *arg)
{
List_iterator_fast<Item_field> it(fields);
Item *item;
while ((item= it++))
if (item->walk(processor, arg))
return 1;
return Item_func::walk(processor, arg);
}
Item *Item_equal::transform(Item_transformer transformer, byte *arg)
{
List_iterator<Item_field> it(fields);
Item *item;
while ((item= it++))
{
Item *new_item= item->transform(transformer, arg);
if (!new_item)
return 0;
if (new_item != item)
it.replace((Item_field *) new_item);
}
return Item_func::transform(transformer, arg);
}
void Item_equal::print(String *str)
{
str->append(func_name());
str->append('(');
List_iterator_fast<Item_field> it(fields);
Item *item;
if (const_item)
const_item->print(str);
else
{
item= it++;
item->print(str);
}
while ((item= it++))
{
str->append(',');
str->append(' ');
item->print(str);
}
str->append(')');
}
sql/item_cmpfunc.h
View file @ 71f6ab7a
......@@ -20,6 +20,9 @@
#ifdef __GNUC__
#pragma interface /* gcc class implementation */
#endif
#ifdef __GNUC__
template class List_iterator_fast<Item_field>;
#endif
extern Item_result item_cmp_type(Item_result a,Item_result b);
class Item_bool_func2;
......@@ -27,6 +30,8 @@ class Arg_comparator;
typedef int (Arg_comparator::*arg_cmp_func)();
typedef int (*Item_field_cmpfunc)(Item_field *f1, Item_field *f2, void *arg);
class Arg_comparator: public Sql_alloc
{
Item **a, **b;
......@@ -957,6 +962,7 @@ public:
Item_cond(List<Item> &nlist)
:Item_bool_func(), list(nlist), abort_on_null(0) {}
bool add(Item *item) { return list.push_back(item); }
void add_at_head(List<Item> *nlist) { list.prepand(nlist); }
bool fix_fields(THD *, struct st_table_list *, Item **ref);
enum Type type() const { return COND_ITEM; }
......@@ -969,13 +975,151 @@ public:
void top_level_item() { abort_on_null=1; }
void copy_andor_arguments(THD *thd, Item_cond *item);
bool walk(Item_processor processor, byte *arg);
Item *transform(Item_transformer transformer, byte *arg);
void neg_arguments(THD *thd);
};
/*
The class Item_equal is used to represent conjuctions of equality
predicates of the form field1 = field2, and field=const in where
conditions and on expressions.
All equality predicates of the form field1=field2 contained in a
conjuction are substituted for a sequence of items of this class.
An item of this class Item_equal(f1,f2,...fk) respresents a
multiple equality f1=f2=...=fk.
If a conjuction contains predicates f1=f2 and f2=f3, a new item of
this class is created Item_equal(f1,f2,f3) representing the multiple
equality f1=f2=f3 that substitutes the above equality predicates in
the conjuction.
A conjuction of the predicates f2=f1 and f3=f1 and f3=f2 will be
substituted for the item representing the same multiple equality
f1=f2=f3.
An item Item_equal(f1,f2) can appear instead of a conjuction of
f2=f1 and f1=f2, or instead of just the predicate f1=f2.
An item of the class Item_equal inherites equalities from outer
conjunctive levels.
Suppose we have a where condition of the following form:
WHERE f1=f2 AND f3=f4 AND f3=f5 AND ... AND (...OR (f1=f3 AND ...)).
In this case:
f1=f2 will be substituted for Item_equal(f1,f2);
f3=f4 and f3=f5 will be substituted for Item_equal(f3,f4,f5);
f1=f3 will be substituted for Item_equal(f1,f2,f3,f4,f5);
An object of the class Item_equal can contain an optional constant
item c. Thenit represents a multiple equality of the form
c=f1=...=fk.
Objects of the class Item_equal are used for the following:
1. An object Item_equal(t1.f1,...,tk.fk) allows us to consider any
pair of tables ti and tj as joined by an equi-condition.
Thus it provide us with additional access paths from table to table.
2. An object Item_equal(t1.f1,...,tk.fk) is applied to deduce new
SARGable predicates:
f1=...=fk AND P(fi) => f1=...=fk AND P(fi) AND P(fj).
It also can give us additional index scans and can allow us to
improve selectivity estimates.
3. An object Item_equal(t1.f1,...,tk.fk) is used to optimize the
selected execution plan for the query: if table ti is accessed
before the table tj then in any predicate P in the where condition
the occurence of tj.fj is substituted for ti.fi. This can allow
an evaluation of the predicate at an earlier step.
When feature 1 is supported they say that join transitive closure
is employed.
When feature 2 is supported they say that search argument transitive
closure is employed.
Both features are usually supported by preprocessing original query and
adding additional predicates.
We do not just add predicates, we rather dynamically replace some
predicates that can not be used to access tables in the investigated
plan for those, obtained by substitution of some fields for equal fields,
that can be used.
*/
class Item_equal: public Item_bool_func
{
List<Item_field> fields; /* list of equal field items */
Item *const_item; /* optional constant item equal to fields items */
cmp_item *eval_item;
bool cond_false;
DTCollation cmp_collation;
public:
inline Item_equal()
: Item_bool_func(), const_item(0), eval_item(0), cond_false(0)
{ const_item_cache=0 ;}
Item_equal(Item_field *f1, Item_field *f2);
Item_equal(Item *c, Item_field *f);
Item_equal(Item_equal *item_equal);
inline Item* get_const() { return const_item; }
void add(Item *c);
void add(Item_field *f);
uint members();
bool contains(Field *field);
Item_field* get_first() { return fields.head(); }
void merge(Item_equal *item);
enum Functype functype() const { return MULT_EQUAL_FUNC; }
longlong val_int();
const char *func_name() const { return "multiple equal"; }
optimize_type select_optimize() const { return OPTIMIZE_EQUAL; }
void sort(Item_field_cmpfunc cmp, void *arg);
friend class Item_equal_iterator;
void fix_length_and_dec();
bool fix_fields(THD *thd, TABLE_LIST *tables, Item **ref);
void update_used_tables();
bool walk(Item_processor processor, byte *arg);
Item *transform(Item_transformer transformer, byte *arg);
void print(String *str);
CHARSET_INFO *compare_collation()
{ return fields.head()->collation.collation; }
};
class COND_EQUAL
{
public:
uint max_members; /* max number of members the current level
list and all lower level lists */
COND_EQUAL *upper_levels; /* multiple equalities of upper and levels */
List<Item_equal> current_level; /* list of multiple equalities of
the current and level */
COND_EQUAL()
{
max_members= 0;
upper_levels= 0;
}
};
class Item_equal_iterator :List_iterator_fast<Item_field>
{
public:
inline Item_equal_iterator(Item_equal &item_equal)
:List_iterator_fast<Item_field> (item_equal.fields)
{}
inline Item_field* operator++(int)
{
Item_field *item= (*(List_iterator_fast<Item_field> *) this)++;
return item;
}
inline void rewind(void)
{
List_iterator_fast<Item_field>::rewind();
}
};
class Item_cond_and :public Item_cond
{
public:
COND_EQUAL cond_equal; /* contains list of Item_equal objects for
the current and level and reference
to multiple equalities of upper and levels */
Item_cond_and() :Item_cond() {}
Item_cond_and(Item *i1,Item *i2) :Item_cond(i1,i2) {}
Item_cond_and(THD *thd, Item_cond_and *item) :Item_cond(thd, item) {}
......
sql/item_func.cc
View file @ 71f6ab7a
......@@ -260,6 +260,45 @@ bool Item_func::walk (Item_processor processor, byte *argument)
return (this->*processor)(argument);
}
/*
Transform an Item_func object with a transformer callback function
SYNOPSIS
transform()
transformer the transformer callback function to be applied to the nodes
of the tree of the object
argument parameter to be passed to the transformer
DESCRIPTION
The function recursively applies the transform method with the
same transformer to each argument the function.
If the call of the method for a member item returns a new item
the old item is substituted for a new one.
After this the transform method is applied to the root node
of the Item_func object.
RETURN VALUES
Item returned as the result of transformation of the root node
*/
Item *Item_func::transform(Item_transformer transformer, byte *argument)
{
if (arg_count)
{
Item **arg,**arg_end;
for (arg= args, arg_end= args+arg_count; arg != arg_end; arg++)
{
Item *new_item= (*arg)->transform(transformer, argument);
if (!new_item)
return 0;
*arg= new_item;
}
}
return (this->*transformer)(argument);
}
void Item_func::split_sum_func(Item **ref_pointer_array, List<Item> &fields)
{
Item **arg, **arg_end;
......
sql/item_func.h
View file @ 71f6ab7a
......@@ -40,7 +40,8 @@ public:
enum Functype { UNKNOWN_FUNC,EQ_FUNC,EQUAL_FUNC,NE_FUNC,LT_FUNC,LE_FUNC,
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,
COND_AND_FUNC, COND_OR_FUNC, COND_XOR_FUNC,
BETWEEN, IN_FUNC, MULT_EQUAL_FUNC,
INTERVAL_FUNC, ISNOTNULLTEST_FUNC,
SP_EQUALS_FUNC, SP_DISJOINT_FUNC,SP_INTERSECTS_FUNC,
SP_TOUCHES_FUNC,SP_CROSSES_FUNC,SP_WITHIN_FUNC,
......@@ -50,7 +51,8 @@ public:
NOT_FUNC, NOT_ALL_FUNC,
NOW_FUNC, TRIG_COND_FUNC,
GUSERVAR_FUNC};
enum optimize_type { OPTIMIZE_NONE,OPTIMIZE_KEY,OPTIMIZE_OP, OPTIMIZE_NULL };
enum optimize_type { OPTIMIZE_NONE,OPTIMIZE_KEY,OPTIMIZE_OP, OPTIMIZE_NULL,
OPTIMIZE_EQUAL };
enum Type type() const { return FUNC_ITEM; }
virtual enum Functype functype() const { return UNKNOWN_FUNC; }
Item_func(void):
......@@ -150,6 +152,7 @@ public:
bool allow_superset_comversion= FALSE);
bool walk(Item_processor processor, byte *arg);
Item *transform(Item_transformer transformer, byte *arg);
};
......
sql/item_row.cc
View file @ 71f6ab7a
......@@ -145,6 +145,18 @@ bool Item_row::walk(Item_processor processor, byte *arg)
return (this->*processor)(arg);
}
Item *Item_row::transform(Item_transformer transformer, byte *arg)
{
for (uint i= 0; i < arg_count; i++)
{
Item *new_item= items[i]->transform(transformer, arg);
if (!new_item)
return 0;
items[i]= new_item;
}
return (this->*transformer)(arg);
}
void Item_row::bring_value()
{
for (uint i= 0; i < arg_count; i++)
......
sql/item_row.h
View file @ 71f6ab7a
......@@ -65,6 +65,7 @@ public:
void print(String *str);
bool walk(Item_processor processor, byte *arg);
Item *transform(Item_transformer transformer, byte *arg);
uint cols() { return arg_count; }
Item* el(uint i) { return items[i]; }
......
sql/item_strfunc.h
View file @ 71f6ab7a
......@@ -428,6 +428,14 @@ public:
return item->walk(processor, arg) ||
Item_str_func::walk(processor, arg);
}
Item *transform(Item_transformer transformer, byte *arg)
{
Item *new_item= item->transform(transformer, arg);
if (!new_item)
return 0;
item= new_item;
return Item_str_func::transform(transformer, arg);
}
void print(String *str);
};
......
sql/opt_range.cc
View file @ 71f6ab7a
......@@ -3148,12 +3148,98 @@ QUICK_SELECT_I *TRP_ROR_UNION::make_quick(PARAM *param,
DBUG_RETURN(quick_roru);
}
/****************************************************************************/
/*
Build a SEL_TREE for a simple predicate
SYNOPSIS
get_func_mm_tree()
param PARAM from SQL_SELECT::test_quick_select
cond_func item for the predicate
field field in the predicate
value constant in the predicate
cmp_type compare type for the field
RETURN
Pointer to thre built tree
*/
static SEL_TREE *get_func_mm_tree(PARAM *param, Item_func *cond_func,
Field *field, Item *value,
Item_result cmp_type)
{
SEL_TREE *tree= 0;
DBUG_ENTER("get_func_mm_tree");
switch (cond_func->functype()) {
case Item_func::NE_FUNC:
tree= get_mm_parts(param, cond_func, field, Item_func::LT_FUNC,
value, cmp_type);
if (tree)
{
tree= tree_or(param, tree, get_mm_parts(param, cond_func, field,
Item_func::GT_FUNC,
value, cmp_type));
}
break;
case Item_func::BETWEEN:
tree= get_mm_parts(param, cond_func, field, Item_func::GE_FUNC,
cond_func->arguments()[1],cmp_type);
if (tree)
{
tree= tree_and(param, tree, get_mm_parts(param, cond_func, field,
Item_func::LE_FUNC,
cond_func->arguments()[2],
cmp_type));
}
break;
case Item_func::IN_FUNC:
{
Item_func_in *func=(Item_func_in*) cond_func;
tree= get_mm_parts(param, cond_func, field, Item_func::EQ_FUNC,
func->arguments()[1], cmp_type);
if (tree)
{
Item **arg, **end;
for (arg= func->arguments()+2, end= arg+func->argument_count()-2;
arg < end ; arg++)
{
tree= tree_or(param, tree, get_mm_parts(param, cond_func, field,
Item_func::EQ_FUNC,
*arg,
cmp_type));
}
}
break;
}
default:
{
/*
Here the function for the following predicates are processed:
<, <=, =, >=, >, LIKE, IS NULL, IS NOT NULL.
If the predicate is of the form (value op field) it is handled
as the equivalent predicate (field rev_op value), e.g.
2 <= a is handled as a >= 2.
*/
Item_func::Functype func_type=
(value != cond_func->arguments()[0]) ? cond_func->functype() :
((Item_bool_func2*) cond_func)->rev_functype();
tree= get_mm_parts(param, cond_func, field, func_type, value, cmp_type);
}
}
DBUG_RETURN(tree);
}
/* make a select tree of all keys in condition */
static SEL_TREE *get_mm_tree(PARAM *param,COND *cond)
{
SEL_TREE *tree=0;
SEL_TREE *ftree= 0;
Item_field *field_item= 0;
Item *value;
DBUG_ENTER("get_mm_tree");
if (cond->type() == Item::COND_ITEM)
......@@ -3201,9 +3287,12 @@ static SEL_TREE *get_mm_tree(PARAM *param,COND *cond)
DBUG_RETURN(new SEL_TREE(SEL_TREE::IMPOSSIBLE));
}
table_map ref_tables=cond->used_tables();
table_map ref_tables= 0;
table_map param_comp= ~(param->prev_tables | param->read_tables |
param->current_table);
if (cond->type() != Item::FUNC_ITEM)
{ // Should be a field
ref_tables= cond->used_tables();
if ((ref_tables & param->current_table) ||
(ref_tables & ~(param->prev_tables | param->read_tables)))
DBUG_RETURN(0);
......@@ -3214,80 +3303,42 @@ static SEL_TREE *get_mm_tree(PARAM *param,COND *cond)
if (cond_func->select_optimize() == Item_func::OPTIMIZE_NONE)
DBUG_RETURN(0); // Can't be calculated
param->cond= cond;
if (cond_func->functype() == Item_func::BETWEEN)
{
if (cond_func->arguments()[0]->type() == Item::FIELD_ITEM)
switch (cond_func->functype()) {
case Item_func::BETWEEN:
if (cond_func->arguments()[0]->type() != Item::FIELD_ITEM)
DBUG_RETURN(0);
field_item= (Item_field*) (cond_func->arguments()[0]);
value= NULL;
break;
case Item_func::IN_FUNC:
{
Field *field=((Item_field*) (cond_func->arguments()[0]))->field;
Item_result cmp_type=field->cmp_type();
DBUG_RETURN(tree_and(param,
get_mm_parts(param, cond_func, field,
Item_func::GE_FUNC,
cond_func->arguments()[1], cmp_type),
get_mm_parts(param, cond_func, field,
Item_func::LE_FUNC,
cond_func->arguments()[2], cmp_type)));
}
Item_func_in *func=(Item_func_in*) cond_func;
if (func->key_item()->type() != Item::FIELD_ITEM)
DBUG_RETURN(0);
field_item= (Item_field*) (func->key_item());
value= NULL;
break;
}
if (cond_func->functype() == Item_func::IN_FUNC)
{ // COND OR
Item_func_in *func=(Item_func_in*) cond_func;
if (func->key_item()->type() == Item::FIELD_ITEM)
case Item_func::MULT_EQUAL_FUNC:
{
Field *field=((Item_field*) (func->key_item()))->field;
Item_result cmp_type=field->cmp_type();
tree= get_mm_parts(param,cond_func,field,Item_func::EQ_FUNC,
func->arguments()[1],cmp_type);
if (!tree)
DBUG_RETURN(tree); // Not key field
for (uint i=2 ; i < func->argument_count(); i++)
Item_equal *item_equal= (Item_equal *) cond;
if (!(value= item_equal->get_const()))
DBUG_RETURN(0);
Item_equal_iterator it(*item_equal);
ref_tables= value->used_tables();
while ((field_item= it++))
{
SEL_TREE *new_tree=get_mm_parts(param,cond_func,field,
Item_func::EQ_FUNC,
func->arguments()[i],cmp_type);
tree=tree_or(param,tree,new_tree);
}
DBUG_RETURN(tree);
Field *field= field_item->field;
Item_result cmp_type= field->cmp_type();
if (!((ref_tables | field->table->map) & param_comp))
{
tree= get_mm_parts(param, cond, field, Item_func::EQ_FUNC,
value,cmp_type);
ftree= !ftree ? tree : tree_and(param, ftree, tree);
}
DBUG_RETURN(0); // Can't optimize this IN
}
if (ref_tables & ~(param->prev_tables | param->read_tables |
param->current_table))
DBUG_RETURN(0); // Can't be calculated yet
if (!(ref_tables & param->current_table))
DBUG_RETURN(new SEL_TREE(SEL_TREE::MAYBE)); // This may be FALSE or TRUE
/* check field op const */
/* btw, ft_func's arguments()[0] isn't FIELD_ITEM. SerG*/
if (cond_func->arguments()[0]->type() == Item::FIELD_ITEM)
{
tree= get_mm_parts(param, cond_func,
((Item_field*) (cond_func->arguments()[0]))->field,
cond_func->functype(),
cond_func->arg_count > 1 ? cond_func->arguments()[1] :
0,
((Item_field*) (cond_func->arguments()[0]))->field->
cmp_type());
}
/* check const op field */
if (!tree &&
cond_func->have_rev_func() &&
cond_func->arguments()[1]->type() == Item::FIELD_ITEM)
{
DBUG_RETURN(get_mm_parts(param, cond_func,
((Item_field*)
(cond_func->arguments()[1]))->field,
((Item_bool_func2*) cond_func)->rev_functype(),
cond_func->arguments()[0],
((Item_field*)
(cond_func->arguments()[1]))->field->cmp_type()
));
}
DBUG_RETURN(tree);
DBUG_RETURN(ftree);
}
......@@ -3296,17 +3347,10 @@ get_mm_parts(PARAM *param, COND *cond_func, Field *field,
Item_func::Functype type,
Item *value, Item_result cmp_type)
{
bool ne_func= FALSE;
DBUG_ENTER("get_mm_parts");
if (field->table != param->table)
DBUG_RETURN(0);
if (type == Item_func::NE_FUNC)
{
ne_func= TRUE;
type= Item_func::LT_FUNC;
}
KEY_PART *key_part = param->key_parts;
KEY_PART *end = param->key_parts_end;
SEL_TREE *tree=0;
......@@ -3344,15 +3388,6 @@ get_mm_parts(PARAM *param, COND *cond_func, Field *field,
}
}
if (ne_func)
{
SEL_TREE *tree2= get_mm_parts(param, cond_func,
field, Item_func::GT_FUNC,
value, cmp_type);
if (tree2)
tree= tree_or(param,tree,tree2);
}
DBUG_RETURN(tree);
}
......
sql/opt_sum.cc
View file @ 71f6ab7a
......@@ -341,6 +341,18 @@ static bool simple_pred(Item_func *func_item, Item **args, bool *inv_order)
Item *item;
*inv_order= 0;
switch (func_item->argument_count()) {
case 0:
/* MULT_EQUAL_FUNC */
{
Item_equal *item_equal= (Item_equal *) func_item;
Item_equal_iterator it(*item_equal);
args[0]= it++;
if (it++)
return 0;
if (!(args[1]= item_equal->get_const()))
return 0;
}
break;
case 1:
/* field IS NULL */
item= func_item->arguments()[0];
......@@ -481,6 +493,9 @@ static bool matching_cond(bool max_fl, TABLE_REF *ref, KEY *keyinfo,
case Item_func::BETWEEN:
between= 1;
break;
case Item_func::MULT_EQUAL_FUNC:
eq_type= 1;
break;
default:
return 0; // Can't optimize function
}
......
sql/sql_list.h
View file @ 71f6ab7a
......@@ -127,10 +127,12 @@ public:
void remove(list_node **prev)
{
list_node *node=(*prev)->next;
delete *prev;
*prev=node;
if (!--elements)
last= &first;
else if (last == &(*prev)->next)
last= prev;
delete *prev;
*prev=node;
}
inline void *pop(void)
{
......@@ -142,11 +144,38 @@ public:
return tmp->info;
}
inline void concat(base_list *list)
{
if (!list->is_empty())
{
*last= list->first;
last= list->last;
elements+= list->elements;
}
}
inline void disjoin(base_list *list)
{
list_node **prev= &first;
list_node *node= first;
list_node *list_first= list->first;
elements=0;
while (node && node != list_first)
{
prev= &node->next;
node= node->next;
elements++;
}
*prev= *last;
last= prev;
}
inline void prepand(base_list *list)
{
if (!list->is_empty())
{
*list->last= first;
first= list->first;
elements+= list->elements;
}
}
inline list_node* last_node() { return *last; }
inline list_node* first_node() { return first;}
inline void *head() { return first->info; }
......@@ -257,6 +286,9 @@ public:
inline T* head() {return (T*) base_list::head(); }
inline T** head_ref() {return (T**) base_list::head_ref(); }
inline T* pop() {return (T*) base_list::pop(); }
inline void concat(List<T> *list) { base_list::concat(list); }
inline void disjoin(List<T> *list) { base_list::disjoin(list); }
inline void prepand(List<T> *list) { base_list::prepand(list); }
void delete_elements(void)
{
list_node *element,*next;
......@@ -267,7 +299,6 @@ public:
}
empty();
}
inline void concat(List<T> *list) { base_list::concat(list); }
};
......@@ -278,6 +309,8 @@ public:
inline T* operator++(int) { return (T*) base_list_iterator::next(); }
inline T *replace(T *a) { return (T*) base_list_iterator::replace(a); }
inline T *replace(List<T> &a) { return (T*) base_list_iterator::replace(a); }
inline void rewind(void) { base_list_iterator::rewind(); }
inline void remove() { base_list_iterator::remove(); }
inline void after(T *a) { base_list_iterator::after(a); }
inline T** ref(void) { return (T**) base_list_iterator::ref(); }
};
......
sql/sql_select.cc
View file @ 71f6ab7a
......@@ -43,6 +43,7 @@ static bool make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
static bool update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,
JOIN_TAB *join_tab,
uint tables, COND *conds,
COND_EQUAL *cond_equal,
table_map table_map, SELECT_LEX *select_lex);
static int sort_keyuse(KEYUSE *a,KEYUSE *b);
static void set_position(JOIN *join,uint index,JOIN_TAB *table,KEYUSE *key);
......@@ -90,6 +91,11 @@ static int return_zero_rows(JOIN *join, select_result *res,TABLE_LIST *tables,
uint select_options, const char *info,
Item *having, Procedure *proc,
SELECT_LEX_UNIT *unit);
static COND *build_all_equal_items(COND *cond,
COND_EQUAL *inherited);
static COND* substitute_for_best_equal_field(COND *cond,
COND_EQUAL *cond_equal,
void *table_join_idx);
static COND *simplify_joins(JOIN *join, List<TABLE_LIST> *join_list,
COND *conds, bool top);
static COND *optimize_cond(JOIN *join, COND *conds,
......@@ -525,6 +531,52 @@ JOIN::optimize()
}
#endif
/* Eliminate NOT operators */
conds= eliminate_not_funcs(conds);
DBUG_EXECUTE("where", print_where(conds, "after negation elimination"););
{
TABLE_LIST *tables;
for (tables= tables_list; tables; tables= tables->next)
{
if (tables->on_expr)
tables->on_expr= eliminate_not_funcs(tables->on_expr);
}
}
/*
Build all multiple equality predicates and eliminate equality
predicates that can be inferred from these multiple equalities.
For each reference of a field included into a multiple equality
that occurs in a function set a pointer to the multiple equality
predicate. Substitute a constant instead of this field if the
multiple equality contains a constant.
*/
if (conds)
{
conds= build_all_equal_items(conds, NULL);
conds->update_used_tables();
if (conds->type() == Item::COND_ITEM &&
((Item_cond*) conds)->functype() == Item_func::COND_AND_FUNC)
cond_equal= &((Item_cond_and*) conds)->cond_equal;
else if (conds->type() == Item::FUNC_ITEM &&
((Item_cond*) conds)->functype() == Item_func::MULT_EQUAL_FUNC)
{
cond_equal= new COND_EQUAL;
cond_equal->current_level.push_back((Item_equal *) conds);
}
}
{
TABLE_LIST *tables;
for (tables= tables_list; tables; tables= tables->next)
{
if (tables->on_expr)
{
tables->on_expr= build_all_equal_items(tables->on_expr, cond_equal);
tables->on_expr->update_used_tables();
}
}
}
conds= optimize_cond(this, conds,&cond_value);
if (thd->net.report_error)
{
......@@ -617,7 +669,31 @@ JOIN::optimize()
if (const_tables && !thd->locked_tables &&
!(select_options & SELECT_NO_UNLOCK))
mysql_unlock_some_tables(thd, table, const_tables);
/*
Among the equal fields belonging to the same multiple equality
choose the one that is to be retrieved first and substitute
all references to these in where condition for a reference for
the selected field.
*/
if (conds)
{
conds= substitute_for_best_equal_field(conds, cond_equal, map2table);
conds->update_used_tables();
}
{
TABLE_LIST *tables;
for (tables= tables_list; tables; tables= tables->next)
{
if (tables->on_expr)
{
tables->on_expr= substitute_for_best_equal_field(tables->on_expr,
cond_equal,
map2table);
tables->on_expr->update_used_tables();
map2table[tables->table->tablenr]->on_expr= tables->on_expr;
}
}
}
if (!conds && outer_join)
{
/* Handle the case where we have an OUTER JOIN without a WHERE */
......@@ -2150,7 +2226,8 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
if (conds || outer_join)
if (update_ref_and_keys(join->thd, keyuse_array, stat, join->tables,
conds, ~outer_join, join->select_lex))
conds, join->cond_equal,
~outer_join, join->select_lex))
DBUG_RETURN(1);
/* Read tables with 0 or 1 rows (system tables) */
......@@ -2482,6 +2559,7 @@ merge_key_fields(KEY_FIELD *start,KEY_FIELD *new_fields,KEY_FIELD *end,
add_key_field()
key_fields Pointer to add key, if usable
and_level And level, to be stored in KEY_FIELD
cond Condition predicate
field Field used in comparision
eq_func True if we used =, <=> or IS NULL
value Value used for comparison with field
......@@ -2497,8 +2575,8 @@ merge_key_fields(KEY_FIELD *start,KEY_FIELD *new_fields,KEY_FIELD *end,
*/
static void
add_key_field(KEY_FIELD **key_fields,uint and_level, COND *cond,
Field *field,bool eq_func,Item **value, uint num_values,
add_key_field(KEY_FIELD **key_fields, uint and_level, COND *cond,
Field *field, bool eq_func, Item **value, uint num_values,
table_map usable_tables)
{
uint exists_optimize= 0;
......@@ -2603,6 +2681,57 @@ add_key_field(KEY_FIELD **key_fields,uint and_level, COND *cond,
}
/*
Add possible keys to array of possible keys originated from a simple predicate
SYNPOSIS
add_key_equal_fields()
key_fields Pointer to add key, if usable
and_level And level, to be stored in KEY_FIELD
cond Condition predicate
field Field used in comparision
eq_func True if we used =, <=> or IS NULL
value Value used for comparison with field
Is NULL for BETWEEN and IN
usable_tables Tables which can be used for key optimization
NOTES
If field items f1 and f2 belong to the same multiple equality and
a key is added for f1, the the same key is added for f2.
RETURN
*key_fields is incremented if we stored a key in the array
*/
static void
add_key_equal_fields(KEY_FIELD **key_fields, uint and_level,
COND *cond, Item_field *field_item,
bool eq_func, Item **val,
uint num_values, table_map usable_tables)
{
Field *field= field_item->field;
add_key_field(key_fields, and_level, cond, field,
eq_func, val, num_values, usable_tables);
Item_equal *item_equal= field_item->item_equal;
if (item_equal)
{
/*
Add to the set of possible key values every substitution of
the field for an equal field included into item_equal
*/
Item_equal_iterator it(*item_equal);
Item_field *item;
while ((item= it++))
{
if (!field->eq(item->field))
{
add_key_field(key_fields, and_level, cond, item->field,
eq_func, val, num_values, usable_tables);
}
}
}
}
static void
add_key_fields(JOIN_TAB *stat,KEY_FIELD **key_fields,uint *and_level,
COND *cond, table_map usable_tables)
......@@ -2663,9 +2792,8 @@ add_key_fields(JOIN_TAB *stat,KEY_FIELD **key_fields,uint *and_level,
if (cond_func->arguments()[0]->real_item()->type() == Item::FIELD_ITEM &&
!(cond_func->arguments()[0]->used_tables() & OUTER_REF_TABLE_BIT))
{
add_key_field(key_fields,*and_level,cond_func,
((Item_field*) (cond_func->arguments()[0])->real_item())
->field,
add_key_equal_fields(key_fields, *and_level, cond_func,
(Item_field*) (cond_func->arguments()[0])->real_item(),
equal_func,
cond_func->arguments()+1, 1, usable_tables);
}
......@@ -2673,9 +2801,8 @@ add_key_fields(JOIN_TAB *stat,KEY_FIELD **key_fields,uint *and_level,
cond_func->functype() != Item_func::LIKE_FUNC &&
!(cond_func->arguments()[1]->used_tables() & OUTER_REF_TABLE_BIT))
{
add_key_field(key_fields,*and_level,cond_func,
((Item_field*) (cond_func->arguments()[1])->real_item())
->field,
add_key_equal_fields(key_fields, *and_level, cond_func,
(Item_field*) (cond_func->arguments()[1])->real_item(),
equal_func,
cond_func->arguments(),1,usable_tables);
}
......@@ -2689,15 +2816,55 @@ add_key_fields(JOIN_TAB *stat,KEY_FIELD **key_fields,uint *and_level,
Item *tmp=new Item_null;
if (unlikely(!tmp)) // Should never be true
return;
add_key_field(key_fields,*and_level,cond_func,
((Item_field*) (cond_func->arguments()[0])->real_item())
->field,
add_key_equal_fields(key_fields, *and_level, cond_func,
(Item_field*) (cond_func->arguments()[0])->real_item(),
cond_func->functype() == Item_func::ISNULL_FUNC,
&tmp, 1, usable_tables);
}
break;
case Item_func::OPTIMIZE_EQUAL:
Item_equal *item_equal= (Item_equal *) cond;
Item *const_item= item_equal->get_const();
Item_equal_iterator it(*item_equal);
Item_field *item;
if (const_item)
{
/*
For each field field1 from item_equal consider the equality
field1=const_item as a condition allowing an index access of the table
with field1 by the keys value of field1.
*/
while ((item= it++))
{
add_key_field(key_fields, *and_level, cond, item->field,
TRUE, &const_item, 1, usable_tables);
}
}
else
{
/*
Consider all pairs of different fields included into item_equal.
For each of them (field1, field1) consider the equality
field1=field2 as a condition allowing an index access of the table
with field1 by the keys value of field2.
*/
Item_equal_iterator fi(*item_equal);
while ((item= fi++))
{
Field *field= item->field;
while ((item= it++))
{
if (!field->eq(item->field))
{
add_key_field(key_fields, *and_level, cond, field,
TRUE, (Item **) &item, 1, usable_tables);
}
}
it.rewind();
}
}
break;
}
return;
}
/*
......@@ -2840,15 +3007,19 @@ sort_keyuse(KEYUSE *a,KEYUSE *b)
static bool
update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
uint tables, COND *cond, table_map normal_tables,
SELECT_LEX *select_lex)
uint tables, COND *cond, COND_EQUAL *cond_equal,
table_map normal_tables, SELECT_LEX *select_lex)
{
uint and_level,i,found_eq_constant;
KEY_FIELD *key_fields, *end, *field;
uint m= 1;
if (cond_equal && cond_equal->max_members)
m= cond_equal->max_members;
if (!(key_fields=(KEY_FIELD*)
thd->alloc(sizeof(key_fields[0])*
(thd->lex->current_select->cond_count+1)*2)))
(thd->lex->current_select->cond_count+1)*2*m)))
return TRUE; /* purecov: inspected */
and_level= 0;
field= end= key_fields;
......@@ -4953,7 +5124,7 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
}
COND *tmp=make_cond_for_table(cond,used_tables,current_map);
if (!tmp && tab->quick)
if (!tmp && tab->quick && tab->type == JT_ALL)
{ // Outer join
if (tab->type != JT_ALL)
{
......@@ -5757,6 +5928,668 @@ template class List<Item_func_match>;
template class List_iterator<Item_func_match>;
#endif
/*
Find the multiple equality predicate containing a field
SYNOPSIS
find_item_equal()
cond_equal multiple equalities to search in
field field to look for
inherited_fl :out set up to TRUE iff multiple equality is found
on upper levels (not on current level of cond_equal)
DESCRIPTION
The function retrieves the multiple equalities accessed through
the con_equal structure from current level and up looking for
an equality containing field. It stops retrieval as soon as the equality
is found and set up inherited_fl to TRUE if it's found on upper levels.
RETURN
Item_equal for the found multiple equality predicate if a success;
NULL - otherwise.
*/
Item_equal *find_item_equal(COND_EQUAL *cond_equal, Field *field,
bool *inherited_fl)
{
Item_equal *item= 0;
bool in_upper_level= FALSE;
while (cond_equal)
{
List_iterator_fast<Item_equal> li(cond_equal->current_level);
while ((item= li++))
{
if (item->contains(field))
goto finish;
}
in_upper_level= TRUE;
cond_equal= cond_equal->upper_levels;
}
in_upper_level= FALSE;
finish:
*inherited_fl= in_upper_level;
return item;
}
/*
Check whether an item is a simple equality predicate and if so
create/find a multiple equality for this predicate
SYNOPSIS
check_equality()
item item to check
cond_equal multiple equalities that must hold together with the predicate
DESCRIPTION
This function first checks whether an item is a simple equality i.e.
the one that equates a field with another field or a constant
(item=constant_item or item=field_item).
If this is the case the function looks a for a multiple equality
in the lists referenced directly or indirectly by cond_equal inferring
the given simple equality. If it doesn't find any, it builds a multiple
equality that covers the predicate, i.e. the predicate can be inferred
from it.
The built multiple equality could be obtained in such a way:
create a binary multiple equality equivalent to the predicate, then
merge it, if possible, with one of old multiple equalities.
This guarantees that the set of multiple equalities covering equality
predicates will
be minimal.
EXAMPLE
For the where condition
WHERE a=b AND b=c AND
(b=2 OR f=e)
the check_equality will be called for the following equality
predicates a=b, b=c, b=2 and f=e.
For a=b it will be called with *cond_equal=(0,[]) and will transform
*cond_equal into (0,[Item_equal(a,b)]).
For b=c it will be called with *cond_equal=(0,[Item_equal(a,b)])
and will transform *cond_equal into CE=(0,[Item_equal(a,b,c)]).
For b=2 it will be called with *cond_equal=(ptr(CE),[])
and will transform *cond_equal into (ptr(CE,[Item_equal(2,a,b,c)]).
For f=e it will be called with *cond_equal=(ptr(CE), [])
and will transform *cond_equal into (ptr(CE,[Item_equal(f,e)]).
NOTES
Now only fields that have the same type defintions (verified by
the Field::eq_def method) are placed to the same multiple equalities.
Because of this some equality predicates are not eliminated and
can be used in the constant propagation procedure.
We could weeken the equlity test as soon as at least one of the
equal fields is to be equal to a constant. It would require a
more complicated implementation: we would have to store, in
general case, its own constant for each fields from the multiple
equality. But at the same time it would allow us to get rid
of constant propagation completely: it would be done by the call
to build_all_equal_items.
IMPLEMENTATION
The implementation does not follow exactly the above rules to
build a new multiple equality for the equality predicate.
If it processes the equality of the form field1=field2, it
looks for multiple equalities me1 containig field1 and me2 containing
field2. If only one of them is found the fuction expands it with
the lacking field. If multiple equalities for both fields are
found they are merged. If both searches fail a new multiple equality
containing just field1 and field2 is added to the existing
multiple equalities.
If the function processes the predicate of the form field1=const,
it looks for a multiple equality containing field1. If found, the
function checks the constant of the multiple equality. If the value
is unknown, it is setup to const. Otherwise the value is compared with
const and the evaluation of the equality predicate is performed.
When expanding/merging equality predicates from the upper levels
the function first copies them for the current level. It looks
acceptable, as this happens rarely. The implementation without
copying would be much more complicated.
RETURN
TRUE - if the predicate is a simple equality predicate
FALSE - otherwise
*/
static bool check_equality(Item *item, COND_EQUAL *cond_equal)
{
if (item->type() == Item::FUNC_ITEM &&
((Item_func*) item)->functype() == Item_func::EQ_FUNC)
{
Item *left_item= ((Item_func*) item)->arguments()[0];
Item *right_item= ((Item_func*) item)->arguments()[1];
if (left_item->type() == Item::FIELD_ITEM &&
right_item->type() == Item::FIELD_ITEM)
{
/* The predicate the form field1=field2 is processed */
Field *left_field= ((Item_field*) left_item)->field;
Field *right_field= ((Item_field*) right_item)->field;
if (!left_field->eq_def(right_field))
return FALSE;
if (left_field->eq(right_field)) /* f = f */
return TRUE;
/* Search for multiple equalities containing field1 and/or field2 */
bool left_copyfl, right_copyfl;
Item_equal *left_item_equal=
find_item_equal(cond_equal, left_field, &left_copyfl);
Item_equal *right_item_equal=
find_item_equal(cond_equal, right_field, &right_copyfl);
if (left_item_equal && left_item_equal == right_item_equal)
{
/*
The equality predicate is inference of one of the existing
multiple equalities, i.e the condition is already covered
by upper level equalities
*/
return TRUE;
}
/* Copy the found multiple equalities at the current level if needed */
if (left_copyfl)
{
/* left_item_equal of an upper level contains left_item */
left_item_equal= new Item_equal(left_item_equal);
cond_equal->current_level.push_back(left_item_equal);
}
if (right_copyfl)
{
/* right_item_equal of an upper level contains right_item */
right_item_equal= new Item_equal(right_item_equal);
cond_equal->current_level.push_back(right_item_equal);
}
if (left_item_equal)
{
/* left item was found in the current or one of the upper levels */
if (! right_item_equal)
left_item_equal->add((Item_field *) right_item);
else
{
/* Merge two multiple equalities forming a new one */
left_item_equal->merge(right_item_equal);
/* Remove the merged multiple equality from the list */
List_iterator<Item_equal> li(cond_equal->current_level);
while ((li++) != right_item_equal);
li.remove();
}
}
else
{
/* left item was not found neither the current nor in upper levels */
if (right_item_equal)
right_item_equal->add((Item_field *) left_item);
else
{
/* None of the fields was found in multiple equalities */
Item_equal *item= new Item_equal((Item_field *) left_item,
(Item_field *) right_item);
cond_equal->current_level.push_back(item);
}
}
return TRUE;
}
{
/* The predicate of the form field=const/const=field is processed */
Item *const_item= 0;
Item_field *field_item= 0;
if (left_item->type() == Item::FIELD_ITEM &&
right_item->const_item())
{
field_item= (Item_field*) left_item;
const_item= right_item;
}
else if (right_item->type() == Item::FIELD_ITEM &&
left_item->const_item())
{
field_item= (Item_field*) right_item;
const_item= left_item;
}
if (const_item &&
field_item->result_type() == const_item->result_type())
{
bool copyfl;
if (field_item->result_type() == STRING_RESULT &&
((Field_str *) field_item)->charset() !=
((Item_cond *) item)->compare_collation())
return FALSE;
Item_equal *item_equal = find_item_equal(cond_equal,
field_item->field, &copyfl);
if (copyfl)
{
item_equal= new Item_equal(item_equal);
cond_equal->current_level.push_back(item_equal);
}
if (item_equal)
{
/*
The flag cond_false will be set to 1 after this, if item_equal
already contains a constant and its value is not equal to
the value of const_item.
*/
item_equal->add(const_item);
}
else
{
item_equal= new Item_equal(const_item, field_item);
cond_equal->current_level.push_back(item_equal);
}
return TRUE;
}
}
}
return FALSE;
}
/*
Replace all equality predicates in a condition by multiple equality items
SYNOPSIS
build_all_equal_items()
cond condition(expression) where to make replacement
inherited path to all inherited multiple equality items
DESCRIPTION
At each 'and' level the function detects items for equality predicates
and replaced them by a set of multiple equality items of class Item_equal,
taking into account inherited equalities from upper levels.
If an equality predicate is used not in a conjunction it's just
replaced by a multiple equality predicate.
For each 'and' level the function set a pointer to the inherited
multiple equalities in the cond_equal field of the associated
object of the type Item_cond_and.
The function also traverses the cond tree and and for each field reference
sets a pointer to the multiple equality item containing the field, if there
is any. If this multiple equality equates fields to a constant the
function replace the field reference by the constant.
The function also determines the maximum number of members in
equality lists of each Item_cond_and object assigning it to
cond_equal->max_members of this object and updating accordingly
the upper levels COND_EQUAL structures.
NOTES
Multiple equality predicate =(f1,..fn) is equivalent to the conjuction of
f1=f2, .., fn-1=fn. It substitutes any inference from these
equality predicates that is equivalent to the conjunction.
Thus, =(a1,a2,a3) can substitute for ((a1=a3) AND (a2=a3) AND (a2=a1)) as
it is equivalent to ((a1=a2) AND (a2=a3)).
The function always makes a substitution of all equality predicates occured
in a conjuction for a minimal set of multiple equality predicates.
This set can be considered as a canonical representation of the
sub-conjunction of the equality predicates.
E.g. (t1.a=t2.b AND t2.b>5 AND t1.a=t3.c) is replaced by
(=(t1.a,t2.b,t3.c) AND t2.b>5), not by
(=(t1.a,t2.b) AND =(t1.a,t3.c) AND t2.b>5);
while (t1.a=t2.b AND t2.b>5 AND t3.c=t4.d) is replaced by
(=(t1.a,t2.b) AND =(t3.c=t4.d) AND t2.b>5),
but if additionally =(t4.d,t2.b) is inherited, it
will be replaced by (=(t1.a,t2.b,t3.c,t4.d) AND t2.b>5)
IMPLEMENTATION
The function performs the substitution in a recursive descent by
the condtion tree, passing to the next AND level a chain of multiple
equality predicates which have been built at the upper levels.
The Item_equal items built at the level are attached to other
non-equality conjucts as a sublist. The pointer to the inherited
multiple equalities is saved in the and condition object (Item_cond_and).
This chain allows us for any field reference occurence easyly to find a
multiple equality that must be held for this occurence.
For each AND level we do the following:
- scan it for all equality predicate (=) items
- join them into disjoint Item_equal() groups
- process the included OR conditions recursively to do the same for
lower AND levels.
We need to do things in this order as lower AND levels need to know about
all possible Item_equal objects in upper levels.
RETURN
pointer to the transformed condition
*/
static COND *build_all_equal_items(COND *cond,
COND_EQUAL *inherited)
{
Item_equal *item_equal;
uint members;
COND_EQUAL cond_equal;
cond_equal.upper_levels= inherited;
if (cond->type() == Item::COND_ITEM)
{
bool and_level= ((Item_cond*) cond)->functype() ==
Item_func::COND_AND_FUNC;
List<Item> *args= ((Item_cond*) cond)->argument_list();
List_iterator<Item> li(*args);
Item *item;
if (and_level)
{
/*
Retrieve all conjucts of this level detecting the equality
that are subject to substitution by multiple equality items and
removing each such predicate from the conjunction after having
found/created a multiple equality whose inference the predicate is.
*/
while ((item= li++))
{
if (check_equality(item, &cond_equal))
li.remove();
}
List_iterator_fast<Item_equal> it(cond_equal.current_level);
while ((item_equal= it++))
{
item_equal->fix_length_and_dec();
item_equal->update_used_tables();
members= item_equal->members();
if (cond_equal.max_members < members)
cond_equal.max_members= members;
}
members= cond_equal.max_members;
if (inherited && inherited->max_members < members)
{
do
{
inherited->max_members= members;
inherited= inherited->upper_levels;
}
while (inherited);
}
((Item_cond_and*)cond)->cond_equal= cond_equal;
inherited= &(((Item_cond_and*)cond)->cond_equal);
}
/*
Make replacement of equality predicates for lower levels
of the condition expression.
*/
li.rewind();
while((item= li++))
{
Item *new_item;
if ((new_item = build_all_equal_items(item, inherited))!= item)
{
/* This replacement happens only for standalone equalities */
li.replace(new_item);
}
}
if (and_level)
args->concat((List<Item> *)&cond_equal.current_level);
}
else if (cond->type() == Item::FUNC_ITEM)
{
/*
If an equality predicate forms the whole and level,
we call it standalone equality and it's processed here.
E.g. in the following where condition
WHERE a=5 AND (b=5 or a=c)
(b=5) and (a=c) are standalone equalities.
In general we can't leave alone standalone eqalities:
for WHERE a=b AND c=d AND (b=c OR d=5)
b=c is replaced by =(a,b,c,d).
*/
if (check_equality(cond, &cond_equal) &&
(item_equal= cond_equal.current_level.pop()))
{
item_equal->fix_length_and_dec();
item_equal->update_used_tables();
return item_equal;
}
/*
For each field reference in cond, not from equalitym predicates,
set a pointer to the multiple equality if belongs to (if there is any)
*/
cond= cond->transform(&Item::equal_fields_propagator,
(byte *) inherited);
cond->update_used_tables();
}
return cond;
}
/*
Compare field items by table order in the execution plan
SYNOPSIS
compare_fields_by_table_order()
field1 first field item to compare
field2 second field item to compare
table_join_idx index to tables determining table order
DESCRIPTION
field1 considered as better than field2 if the table containing
field1 is accessed earlier than the table containing field2.
The function finds out what of two fields is better according
this criteria.
RETURN
1, if field1 is better than field2
-1, if field2 is better than field1
0, otherwise
*/
static int compare_fields_by_table_order(Item_field *field1,
Item_field *field2,
void *table_join_idx)
{
int cmp= 0;
bool outer_ref= 0;
if (field2->used_tables() & OUTER_REF_TABLE_BIT)
{
outer_ref= 1;
cmp= -1;
}
if (field2->used_tables() & OUTER_REF_TABLE_BIT)
{
outer_ref= 1;
cmp++;
}
if (outer_ref)
return cmp;
JOIN_TAB **idx= (JOIN_TAB **) table_join_idx;
cmp= idx[field2->field->table->tablenr]-idx[field1->field->table->tablenr];
return cmp < 0 ? -1 : (cmp ? 1 : 0);
}
/*
Generate minimal set of simple equalities equivalent to a multiple equality
SYNOPSIS
eliminate_item_equal()
cond condition to add the generated equality to
upper_levels structure to access multiple equality of upper levels
item_equal multiple equality to generate simple equality from
DESCRIPTION
The function retrieves the fields of the multiple equality item
item_equal and for each field f:
- if item_equal contains const it generates the equality f=const_item;
- otherwise, if f is not the first field, generates the equality
f=item_equal->get_first().
All generated equality are added to the cond conjunction.
NOTES
Before generating an equality function checks that it has not
been generated for multiple equalies of the upper levels.
E.g. for the following where condition
WHERE a=5 AND ((a=b AND b=c) OR c>4)
the upper level AND condition will contain =(5,a),
while the lower level AND condition will contain =(5,a,b,c).
When splitting =(5,a,b,c) into a separate equality predicates
we should omit 5=a, as we have it already in the upper level.
The following where condition gives us a more complicated case:
WHERE t1.a=t2.b AND t3.c=t4.d AND (t2.b=t3.c OR t4.e>5 ...) AND ...
Given the tables are accessed in the order t1->t2->t3->t4 for
the selected query execution plan the lower level multiple
equality =(t1.a,t2.b,t3.c,t4.d) formally should be converted to
t1.a=t2.b AND t1.a=t3.c AND t1.a=t4.d. But t1.a=t2.a will be
generated for the upper level. Also t3.c=t4.d will be generated there.
So only t1.a=t3.c should be left in the lower level.
If cond is equal to 0, then not more then one equality is generated
and a pointer to it is returned as the result of the function.
RETURN
The condition with generated simple equalities or
a pointer to the simple generated equality, if success.
0, otherwise.
*/
static Item *eliminate_item_equal(COND *cond, COND_EQUAL *upper_levels,
Item_equal *item_equal)
{
List<Item> eq_list;
Item_func_eq *eq_item= 0;
Item *item_const= item_equal->get_const();
Item_equal_iterator it(*item_equal);
Item *head;
if (item_const)
head= item_const;
else
{
head= item_equal->get_first();
it++;
}
Item_field *item_field;
while ((item_field= it++))
{
Item_equal *upper= item_field->find_item_equal(upper_levels);
Item_field *item= item_field;
if (upper)
{
if (item_const && upper->get_const())
item= 0;
else
{
Item_equal_iterator li(*item_equal);
while ((item= li++) != item_field)
{
if (item->find_item_equal(upper_levels) == upper)
break;
}
}
}
if (item == item_field)
{
if (eq_item)
eq_list.push_back(eq_item);
eq_item= new Item_func_eq(item_field, head);
if (!eq_item)
return 0;
eq_item->set_cmp_func();
}
}
if (!cond && !eq_list.head())
return eq_item;
eq_list.push_back(eq_item);
if (!cond)
cond= new Item_cond_and(eq_list);
else
((Item_cond *) cond)->add_at_head(&eq_list);
return cond;
}
/*
Substitute every field reference in a condition by the best equal field
and eliminate all multiplle equality predicates
SYNOPSIS
substitute_for_best_equal_field()
cond condition to process
cond_equal multiple equalities to take into consideration
table_join_idx index to tables determining field preference
DESCRIPTION
The function retrieves the cond condition and for each encountered
multiple equality predicate it sorts the field references in it
according to the order of tables specified by the table_join_idx
parameter. Then it eliminates the multiple equality predicate it
replacing it by the conjunction of simple equality predicates
equating every field from the multiple equality to the first
field in it, or to the constant, if there is any.
After this the function retrieves all other conjuncted
predicates substitute every field reference by the field reference
to the first equal field or equal constant if there are any.
NOTES
At the first glance full sort of fields in multiple equality
seems to be an overkill. Yet it's not the case due to possible
new fields in multiple equality item of lower levels. We want
the order in them to comply with the order of upper levels.
RETURN
The transformed condition
*/
static COND* substitute_for_best_equal_field(COND *cond,
COND_EQUAL *cond_equal,
void *table_join_idx)
{
Item_equal *item_equal;
if (cond->type() == Item::COND_ITEM)
{
List<Item> *cond_list= ((Item_cond*) cond)->argument_list();
bool and_level= ((Item_cond*) cond)->functype() ==
Item_func::COND_AND_FUNC;
if (and_level)
{
cond_equal= &((Item_cond_and *) cond)->cond_equal;
cond_list->disjoin((List<Item> *) &cond_equal->current_level);
List_iterator_fast<Item_equal> it(cond_equal->current_level);
while ((item_equal= it++))
{
item_equal->sort(&compare_fields_by_table_order, table_join_idx);
}
}
List_iterator<Item> li(*cond_list);
Item *item;
while ((item= li++))
{
Item *new_item =substitute_for_best_equal_field(item, cond_equal,
table_join_idx);
if (new_item != item)
li.replace(new_item);
}
if (and_level)
{
List_iterator_fast<Item_equal> it(cond_equal->current_level);
while ((item_equal= it++))
{
eliminate_item_equal(cond, cond_equal->upper_levels, item_equal);
}
}
}
else if (cond->type() == Item::FUNC_ITEM &&
((Item_cond*) cond)->functype() == Item_func::MULT_EQUAL_FUNC)
{
item_equal= (Item_equal *) cond;
item_equal->sort(&compare_fields_by_table_order, table_join_idx);
if (cond_equal && cond_equal->current_level.head() == item_equal)
cond_equal= 0;
return eliminate_item_equal(0, cond_equal, item_equal);
}
else
cond->walk(&Item::replace_equal_field_processor, 0);
return cond;
}
/*
change field = field to field = const for each found field = const in the
and_level
......@@ -6165,14 +6998,12 @@ simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top)
}
}
DBUG_RETURN(conds);
}
static COND *
optimize_cond(JOIN *join, COND *conds, Item::cond_result *cond_value)
{
THD *thd= join->thd;
SELECT_LEX *select= thd->lex->current_select;
SELECT_LEX *select= thd->lex->current_select;}
DBUG_ENTER("optimize_cond");
if (select->first_cond_optimization)
......@@ -6216,7 +7047,6 @@ optimize_cond(JOIN *join, COND *conds, Item::cond_result *cond_value)
DBUG_EXECUTE("where",print_where(conds,"after const change"););
conds= remove_eq_conds(thd, conds, cond_value) ;
DBUG_EXECUTE("info",print_where(conds,"after remove"););
}
DBUG_RETURN(conds);
}
......@@ -6340,6 +7170,11 @@ remove_eq_conds(THD *thd, COND *cond, Item::cond_result *cond_value)
}
}
}
if (cond->const_item())
{
*cond_value= eval_const_cond(cond) ? Item::COND_TRUE : Item::COND_FALSE;
return (COND*) 0;
}
}
else if (cond->const_item())
{
......@@ -9843,6 +10678,7 @@ join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count)
}
if (!(cache->field=(CACHE_FIELD*)
sql_alloc(sizeof(CACHE_FIELD)*(cache->fields+table_count*2)+(blobs+1)*
sizeof(CACHE_FIELD*))))
{
my_free((gptr) cache->buff,MYF(0)); /* purecov: inspected */
......
sql/sql_select.h
View file @ 71f6ab7a
......@@ -222,6 +222,7 @@ class JOIN :public Sql_alloc
Item *conds_history; // store WHERE for explain
TABLE_LIST *tables_list; //hold 'tables' parameter of mysql_select
List<TABLE_LIST> *join_list; // list of joined tables in reverse order
COND_EQUAL *cond_equal;
SQL_SELECT *select; //created in optimisation phase
JOIN_TAB *return_tab; //used only for outer joins
Item **ref_pointer_array; //used pointer reference for this select
......@@ -284,6 +285,7 @@ class JOIN :public Sql_alloc
ref_pointer_array_size= 0;
zero_result_cause= 0;
optimized= 0;
cond_equal= 0;
fields_list= fields_arg;
bzero((char*) &keyuse,sizeof(keyuse));
......
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