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Merge

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This commit is contained in:
Igor Babaev
2011-01-15 12:42:32 -08:00
parent 92f2392eb5 84a0c9b2a2
commit e32efc013a
18 changed files with 485 additions and 47 deletions
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88
sql/sql_select.cc
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@ -1036,7 +1036,7 @@ JOIN::optimize()
}
/*
Permorm the the optimization on fields evaluation mentioned above
Perform the optimization on fields evaluation mentioned above
for all on expressions.
*/
for (JOIN_TAB *tab= join_tab + const_tables; tab < join_tab + tables ; tab++)
@ -1048,8 +1048,38 @@ JOIN::optimize()
map2table);
(*tab->on_expr_ref)->update_used_tables();
}
}
/*
Perform the optimization on fields evaliation mentioned above
for all used ref items.
*/
for (JOIN_TAB *tab= join_tab + const_tables; tab < join_tab + tables; tab++)
{
for (uint i=0; i < tab->ref.key_parts; i++)
{
Item **ref_item_ptr= tab->ref.items+i;
Item *ref_item= *ref_item_ptr;
COND_EQUAL *equals= tab->first_inner ? tab->first_inner->cond_equal :
cond_equal;
ref_item= substitute_for_best_equal_field(ref_item, equals, map2table);
ref_item->update_used_tables();
if (*ref_item_ptr != ref_item)
{
*ref_item_ptr= ref_item;
Item *item= ref_item->real_item();
if (item->type() == Item::FIELD_ITEM)
{
store_key_field *key_copy= (store_key_field *) tab->ref.key_copy[i];
key_copy->change_source_field((Item_field *) item);
}
}
}
}
if (conds && const_table_map != found_const_table_map &&
(select_options & SELECT_DESCRIBE))
{
@ -9508,10 +9538,14 @@ static COND *build_equal_items(THD *thd, COND *cond,
/**
Compare field items by table order in the execution plan.
If field1 and field2 belong to different tables then
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.
If field1 and field2 belong to the same table then the result
of comparison depends on whether the fields are parts of
the key that are used to access this table.
@param field1 first field item to compare
@param field2 second field item to compare
@ -9526,8 +9560,8 @@ static COND *build_equal_items(THD *thd, COND *cond,
*/
static int compare_fields_by_table_order(Item_field *field1,
Item_field *field2,
void *table_join_idx)
Item_field *field2,
void *table_join_idx)
{
int cmp= 0;
bool outer_ref= 0;
@ -9536,7 +9570,7 @@ static int compare_fields_by_table_order(Item_field *field1,
outer_ref= 1;
cmp= -1;
}
if (field2->used_tables() & OUTER_REF_TABLE_BIT)
if (field1->used_tables() & OUTER_REF_TABLE_BIT)
{
outer_ref= 1;
cmp++;
@ -9545,6 +9579,42 @@ static int compare_fields_by_table_order(Item_field *field1,
return cmp;
JOIN_TAB **idx= (JOIN_TAB **) table_join_idx;
cmp= idx[field2->field->table->tablenr]-idx[field1->field->table->tablenr];
if (!cmp)
{
JOIN_TAB *tab= idx[field1->field->table->tablenr];
uint keyno= MAX_KEY;
if (tab->ref.key_parts)
keyno= tab->ref.key;
else if (tab->select && tab->select->quick)
keyno = tab->select->quick->index;
if (keyno != MAX_KEY)
{
if (field2->field->part_of_key.is_set(keyno))
cmp= -1;
if (field1->field->part_of_key.is_set(keyno))
cmp++;
if (!cmp)
{
KEY *key_info= tab->table->key_info + keyno;
for (uint i= 0; i < key_info->key_parts; i++)
{
Field *fld= key_info->key_part[i].field;
if (fld->eq(field2->field))
{
cmp= -1;
break;
}
if (fld->eq(field1->field))
{
cmp= 1;
break;
}
}
}
}
else
cmp= field2->field->field_index-field1->field->field_index;
}
return cmp < 0 ? -1 : (cmp ? 1 : 0);
}
@ -9833,8 +9903,14 @@ static COND* substitute_for_best_equal_field(COND *cond,
cond= eliminate_item_equal(0, cond_equal, item_equal);
return cond ? cond : org_cond;
}
else
cond->transform(&Item::replace_equal_field, 0);
else if (cond_equal)
{
List_iterator_fast<Item_equal> it(cond_equal->current_level);
while((item_equal= it++))
{
cond= cond->transform(&Item::replace_equal_field, (uchar *) item_equal);
}
}
return cond;
}