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

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mysql-test/r/subselect.result:
  results of new optimisation
mysql-test/t/subselect.test:
  results of new optimisation
sql/item_cmpfunc.h:
  function type
sql/item_func.h:
  function type
sql/item_subselect.cc:
  new optimisation for ref_or_null
sql/item_subselect.h:
  new optimisation for ref_or_null
sql/sql_select.cc:
  new optimisation for ref_or_null
sql/sql_select.h:
  item_subselect.cc need safe_index_read
This commit is contained in:
unknown
2003-07-17 19:39:31 +03:00
parent 04c6e88c0e
commit ed8be699fe
8 changed files with 90 additions and 32 deletions
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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;