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Optimisation if simple IN subselect with primary index

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(SCRUM) (part of WL#818)
This commit is contained in:
bell@sanja.is.com.ua
2003-07-07 18:40:19 +03:00
parent 7ad5331768
commit 6348e63f62
7 changed files with 177 additions and 10 deletions
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43
sql/sql_select.cc
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@ -32,7 +32,7 @@
const char *join_type_str[]={ "UNKNOWN","system","const","eq_ref","ref",
"MAYBE_REF","ALL","range","index","fulltext",
"ref_or_null"
"ref_or_null","simple_in"
};
static void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array);
@ -723,6 +723,45 @@ JOIN::optimize()
(select_lex->ftfunc_list->elements ?
SELECT_NO_JOIN_CACHE : 0));
/*
is this simple IN subquery?
*/
if (!group_list && !order && !having &&
unit->item && unit->item->substype() == Item_subselect::IN_SUBS &&
tables == 1 && join_tab[0].type == JT_EQ_REF &&
conds &&
!unit->first_select()->next_select())
{
Item *where= 0;
bool ok= 0;
if (conds->type() == Item::FUNC_ITEM &&
((class 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)
{
ok= 1;
join_tab->info= "Using index";
}
else if (conds->type() == Item::COND_ITEM &&
((class Item_func *)this->conds)->functype() ==
Item_func::COND_AND_FUNC)
{
ok= 1;
where= conds;
join_tab->info= "Using index; Using where";
}
if (ok)
{
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)));
}
}
/*
Need to tell Innobase that to play it safe, it should fetch all
columns of the tables: this is because MySQL may build row
@ -5337,7 +5376,7 @@ flush_cached_records(JOIN *join,JOIN_TAB *join_tab,bool skipp_last)
/* Help function when we get some an error from the table handler */
static int report_error(TABLE *table, int error)
int report_error(TABLE *table, int error)
{
if (error == HA_ERR_END_OF_FILE || error == HA_ERR_KEY_NOT_FOUND)
{