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Optimisation if simple IN subselect with primary index

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(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
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82
sql/item_subselect.cc
View File

@ -36,7 +36,7 @@ inline Item * and_items(Item* cond, Item *item)
Item_subselect::Item_subselect():
Item_result_field(), engine_owner(1), value_assigned(0), substitution(0),
have_to_be_excluded(0)
have_to_be_excluded(0), engine_changed(0)
{
reset();
/*
@ -117,16 +117,22 @@ bool Item_subselect::fix_fields(THD *thd_param, TABLE_LIST *tables, Item **ref)
bool Item_subselect::exec()
{
int res;
MEM_ROOT *old_root= my_pthread_getspecific_ptr(MEM_ROOT*, THR_MALLOC);
if (&thd->mem_root != old_root)
{
my_pthread_setspecific_ptr(THR_MALLOC, &thd->mem_root);
int res= engine->exec();
res= engine->exec();
my_pthread_setspecific_ptr(THR_MALLOC, old_root);
return (res);
}
else
return engine->exec();
res= engine->exec();
if (engine_changed)
{
engine_changed= 0;
return exec();
}
return (res);
}
Item::Type Item_subselect::type() const
@ -795,6 +801,13 @@ int subselect_union_engine::prepare()
return unit->prepare(thd, result, 0);
}
int subselect_simplein_engine::prepare()
{
//this never should be called
DBUG_ASSERT(0);
return 1;
}
static Item_result set_row(SELECT_LEX *select_lex, Item * item,
Item_cache **row, bool *maybe_null)
{
@ -873,6 +886,12 @@ void subselect_union_engine::fix_length_and_dec(Item_cache **row)
}
}
void subselect_simplein_engine::fix_length_and_dec(Item_cache **row)
{
//this never should be called
DBUG_ASSERT(0);
}
int subselect_single_select_engine::exec()
{
DBUG_ENTER("subselect_single_select_engine::exec");
@ -889,6 +908,10 @@ int subselect_single_select_engine::exec()
join->thd->lex.current_select= save_select;
DBUG_RETURN(join->error?join->error:1);
}
if (item->engine_changed)
{
DBUG_RETURN(1);
}
}
if ((select_lex->dependent || select_lex->uncacheable) && executed)
{
@ -922,6 +945,51 @@ int subselect_union_engine::exec()
return res;
}
int subselect_simplein_engine::exec()
{
DBUG_ENTER("subselect_simplein_engine::exec");
int error;
TABLE *table= tab->table;
if ((tab->ref.key_err= (*tab->ref.key_copy)->copy()))
{
table->status= STATUS_NOT_FOUND;
error= -1;
}
else
{
error= table->file->index_read(table->record[0],
tab->ref.key_buff,
tab->ref.key_length,HA_READ_KEY_EXACT);
if (error && error != HA_ERR_KEY_NOT_FOUND)
error= report_error(table, error);
else
{
error= 0;
table->null_row= 0;
if (table->status)
((Item_in_subselect *) item)->value= 0;
else
((Item_in_subselect *) item)->value= (!cond || cond->val_int()?1:0);
}
}
{
int tmp= 0;
if ((tmp= table->file->extra(HA_EXTRA_NO_CACHE)))
{
DBUG_PRINT("error", ("extra(HA_EXTRA_NO_CACHE) failed"));
error= 1;
}
if ((tmp= table->file->index_end()))
{
DBUG_PRINT("error", ("index_end() failed"));
error= 1;
}
if (error == 1)
table->file->print_error(tmp, MYF(0));
}
DBUG_RETURN(error != 0)
}
uint subselect_single_select_engine::cols()
{
return select_lex->item_list.elements;
@ -961,3 +1029,9 @@ void subselect_union_engine::exclude()
{
unit->exclude_level();
}
void subselect_simplein_engine::exclude()
{
//this never should be called
DBUG_ASSERT(0);
}